Abdominal Distention, Abdominal Mass and Hernia Notes

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M8, W6 – Abdominal Distention, Mass and Hernia Dr Sarah Carlton


Abdominal Distention, Abdominal Mass and Hernia Notes


Embryology and Anatomy of the Groin Region

● Describe the embryological formation and anatomy of the groin region and

relate this to hernia formation.


Abdominal Swellings

● Compare and contrast pathophysiological causes of abdominal swelling and

outline investigations.

● Discuss the differential diagnosis investigation and management of patients

presenting with a left iliac fossa mass.

● Describe the pathophysiological causes of a swelling in the epigastrium

including liver masses/ enlargement



● Discuss the factors that need to be considered in decision making for

management of hernia including risks and economic costs



● Outlines the aetiology and pathogenesis of ascites. Describe complications

and management.


Intestinal Obstruction

● Describe the aetiology, presentation and management of intestinal



Abdominal infections


Liver Tumours

● Discuss arguments for and against population screening using gastric cancer

as an example.


M8, W6 – Abdominal Distention, Mass and Hernia Dr Sarah Carlton


Embryology and Anatomy of the Groin Region

Embryological Formation of the Groin Region

9. The gonads in foetal life are originally positioned on the posterior wall near the kidneys.

10. The gubernaculum attaches the gonads to the superficial perineal pouch which is the scrotum in males and the labia majora in females - this assists with the descent of the gonads.

11. In females, the ovaries cannot move past the uterus therefore the gubernaculum becomes stretched and passes through the inguinal canal as the round ligament (embryological remnant of the gubernaculum).

12. In males, the testes pass through the anterior abdominal wall and into the scrotal sac via the inguinal canal (therefore the gubernaculum is much shorter in males).

The Descent of the Testes

● The testes first pass through the deep inguinal ring (known as the internal inguinal ring) taking transversalis fascia with them.

● They then pass through the internal oblique and transversalis abdominis muscle. The cremaster muscle which is formed from the internal oblique helps to elevate the testicles when it is cold (for example). Cryptorchidism can occur here where there is absence of one or both testes from the scrotum.

● The testes then pass through the superficial inguinal ring (called the external inguinal ring in Figure 1), passing through the external oblique muscle and fascia.

● The spermatic cord contents pass through the inguinal canal and become the spermatic cord after it has picked up all of the 3 layers mentioned previously. Components of the spermatic cord include the

● Gonadal arteries

● Gonadal veins in the form of the pampiniform plexus ● Lymphatics

● Vas deferens (carries sperm to the prostate)


M8, W6 – Abdominal Distention, Mass and Hernia Dr Sarah Carlton


● The layers of the cord are external spermatic fascia (picked up from external oblique), cremasteric muscle (from internal oblique) and internal spermatic fascia (transversalis fascia).

● The inguinal canal: The inguinal canal is covered by peritoneum-the testes need to pass through this in order to pass through transversalis fascia (which contains the defect called the deep inguinal ring). An outpouching of peritoneum produces a covering called the processus vaginalis. This becomes the tunica vaginalis when it passes through the anterior abdominal wall and then closes off behind the testes to seal the hole-this is important as indirect hernias can form here (discussed later). Tunica vaginalis becomes a layer on the testes which can be divided into a parietal and a visceral layer- fluid can build up here and form a hydrocele.


M8, W6 – Abdominal Distention, Mass and Hernia Dr Sarah Carlton


Anatomy of the Groin in relation to Inguinal Hernias:

● There are two types of inguinal hernia: DIRECT and INDIRECT.

1. Direct Hernia (punch directly through the anterior abdominal wall): The conjoint tendon is the posterior border of the medial aspect of the inguinal canal. It sits behind the superficial inguinal ring and reinforces it. A conjoint tendon rupture can therefore punch straight through the abdominal wall (via the superficial inguinal ring) and is a medical emergency as this can cause bowel strangulation (muscles around the bowel contract to protect it). Injuries like this occur as a result of trauma or sudden strain. It is possible to tell that the hernia is direct as it will be medial to the inferior epigastric vessels.

2. Indirect hernia (takes an indirect route through the anterior abdominal wall via the inguinal canal- bowel and peritoneum herniate through the superficial and then deep inguinal rings via the inguinal canal): this tends to be a congenital problem caused by a failure of processus vaginalis to close properly behind the testes. Therefore bowel and peritoneum are able to herniate into the scrotal sac. This carries a much smaller risk of bowel strangulation than direct hernias but, as a rule, the larger the defect and extension into the scrotum, the higher the risk of

incarceration (bowel trapped outside the abdomen) and strangulation. Strangulation can cut off the blood supply to parts of the bowel and can result in necrosis.

o Indirect hernias can be denoted as being lateral to the inferior epigastric vessels.

● There are different types of indirect inguinal hernia which are associated with failure of the processus vaginalis to obliterate completely. Incomplete indirect inguinal hernias can be divided into bubonocele where the hernia is limited to the inguinal canal and funicular where the processus vaginalis has closed just above the epididymis. Complete indirect inguinal hernias (also known as scrotal) is where the hernia is present in the bottom of the scrotum.

Surgery for Hernias

● Risk factors for hernias: As previously discussed, indirect inguinal hernias are typically congenital lesions. However, there are a number of risk factors that predispose a patient for developing an indirect hernia (which have an additive effect on the congenital lesions). These risk factors also apply to direct hernias (caused by anything that puts strain on the lower abdomen or sudden trauma).

● The largest risk factor for developing a hernia is being male (men are 10 times more likely to develop one then women). Other risk factors which increase the pressure in the lower abdomen include positive family history, cystic fibrosis or conditions associated with chronic cough, chronic constipation and obesity and pregnancy (weakens and places stress on lower abdominal muscles). Also, previous history of hernias.


M8, W6 – Abdominal Distention, Mass and Hernia Dr Sarah Carlton



● It is usually good practice for the surgeon to go in and work out which type of hernia the patient has. Whilst indirect inguinal hernias can technically be left if they are small and risk of strangulation is low, most are repaired surgically. Direct hernias are a medical emergency and must be surgically repaired straight away. Surgical repair is known as herniorrhaphy which involves making a small incision over the hernia, pushing the bulging tissue back into place and removing the hernia sac. The muscles are then sewn together over the hernia orifice.

Layers of the Testes

● Tunica Vaginalis is the most superficial layer and is made up of parietal and visceral layers. ● Clinically, fluid can build up between these layers (known as a hydrocele).

● The cause of this is unknown and usually resolves spontaneously.

● Deep to this is tunica albigilia which is a thick, white capsule and is a remnant of processus vaginalis, rete testes is where the immature sperm drains and this then drains into the epididymis which has a head, body and tail.

● Sperm pass through the convoluted tubules and mature in the process. At the distal end of the epididymis is the ductus deferens which take the mature sperm up to the back of the prostate, through the spermatic cord and the inguinal canal and into the prostate.

● The testes are tethered inferiorly by a remnant of the gubernaculum. Superiorly the testis is suspended by the spermatic cord.


M8, W6 – Abdominal Distention, Mass and Hernia Dr Sarah Carlton


Abdominal Swellings

13. Abdominal distension occurs when substances accumulate in the abdomen causing outward expansion beyond normal girth of the stomach and waist. 14. People suffering from it often describe it as “feeling bloated”.

15. In broad terms abdominal distension can be caused by one of the five (six) Fs – flatus, fluid, foetus, fat or faeces (and fatal tumour).

16. Alternatively we can think of these as gaseous, fluid and solid causes of abdominal distension which encompasses a broader range of underlying pathologies.

17. On the whole, abdominal distension is typically caused by obstruction low in the GI tract

Causes of Abdominal Distension Summary

Gaseous and Liquid Causes Solid Causes Gastric Outlet Obstruction

Small Bowel Obstruction Intestinal Pseudo-Obstruction Ileus Hernia Organomegaly ● Liver ● Gall Bladder ● Spleen

The most common causes for abdominal swelling are:











M8, W6 – Abdominal Distention, Mass and Hernia Dr Sarah Carlton 7 Volvulus Cysts Ascites Lymphadenopathy AAA Tumour Crohn’s Disease Uterine Mass Pregnancy Obesity


M8, W6 – Abdominal Distention, Mass and Hernia Dr Sarah Carlton


Gaseous and Liquid causes



GOO is not a single disease entity but the pathophysiological consequence of any disease process that produces a mechanical impairment in gastric emptying. Generally causes of GOO can be categorised as either benign or malignant, which guides management. Major causes include:

Peptic ulcer disease (PUD) – ulcers within the pyloric sphincter and first portion of the duodenum can cause

outlet obstruction, either in the acute setting due to inflammation and oedema or, more commonly, due to chronic scarring and fibrosis. This means less gastric contents can move into the duodenum, collecting in the stomach and causing bloating and distension

Pyloric stenosis – constitutes the most important cause of GOO in the paediatric population, occurring in 1 per 750 births. By result of gradual hypertrophy of the circular smooth muscle of the pylorus, gastric contents are trapped in the stomach and thereby dilating it causing distension.

Pancreatic carcinoma is an important malignant cause of GOO, causing mechanical obstruction in 10-20% of patients suffering it – the mechanism is much the same as the two explained above. Other tumours to be aware of include gastric, ampullary, duodenal and metastatic carcinomas.


Again, the pathological consequence of impaired digestion along the alimentary canal, but in the small intestine this time. 60% of SBO cases in industrialised countries are caused by post-operative adhesions, with malignancy, Crohn’s disease and hernias being common causes too. SBO leads to proximal dilatation of the intestine due to accumulation of GI secretions and swallowed air. Bowel dilatation stimulates cell secretory activity, which results in more fluid accumulation and thus increased peristalsis above and below the obstruction. This leads to frequent loose stools and flatus, the latter causing abdominal swelling.


This syndrome is the clinical picture of mechanical small bowel obstruction in the absence of any evidence of such obstruction. It can be divided into acute and chronic forms. In acute colonic pseudo-obstruction (ACPO/Ogilvie syndrome) the colon may become massively dilated (causing abdominal distension), and the exact pathophysiology of this remains to be identified – however we do know that

Current theories suggest an imbalance in the autonomic nervous system

Common associations are trauma (particularly retroperitoneal), serious infection and cardiac disease

If not decompressed the patient risks perforation, peritonitis and death (40% of perforations).


M8, W6 – Abdominal Distention, Mass and Hernia Dr Sarah Carlton


ILEUS leus is hypomotility of the GI tract in the absence of mechanical bowel obstruction. Complex interactions between autonomic and central nervous systems, as well as local and regional substances, alter intestinal equilibrium and lead to disorganised electrical activity and paralysis of intestinal segments. The uncoordinated propulsive action of the GI tract that results causes accumulation of gas and fluids within the bowel, and so abdominal distension develops.

Most cases occur following intra-abdominal operations, in which inhibitory spinal reflex arcs are believed to be activated unintentionally – other causes include

● Sepsis

● Drugs e.g. opioids, anaesthesia, psychotropics etc.

Endocrine disorders such as diabetes, adrenal insufficiency and hypothyroidism.

VOLVULUS Volvulus is when a loop of bowel twists 180 degrees about its mesenteric axisIt most commonly affects the sigmoid colon but can affect the caecum, small

intestine, gall bladder and stomach too

● It’s rarely seen in the UK

● Risk factors include chronic constipation, adhesions and abnormally mobile loops of intestine

● Symptoms include sudden onset of colicky pain in the right iliac fossa and rapid abdominal distension

● Twisting of the bowel leads to obstruction and occludes vessels supplying the affected section, so potentially fatal gangrene and peritonitis can occur if volvulus isn’t treated.

CYSTSANDABSCESSES Intra-abdominal abscesses are localised collections of pus, containing a mixture of aerobic and anaerobic bacteria from the GI tract. They are confined to the peritoneal cavity by an

inflammatory barrier - normally the omentum, inflammatory adhesions or adjacent viscera. Pathophysiology:

Most common causes include perforation of viscera (particularly as a

complication of peptic ulcer disease), perforated appendicitis and diverticulitis, gangrenous cholecystitis and mesenteric ischaemia with bowel infarction

● Bacteria in peritoneal cavity stimulate an influx of acute inflammatory cells, causing hypoxia in the affected area and encouraging growth of anaerobes ● This impairs the bactericidal activity of granulocytes, resulting in a build-up of

cellular and bacterial debris in the affected region which expands the abscess cavity in response to osmotic forces

If untreated bacteraemia will develop and progress to generalised sepsis with shock.


M8, W6 – Abdominal Distention, Mass and Hernia Dr Sarah Carlton


ASCITES Covered further down


HERNIAS Occur in the abdomen when part of the bowel pushes through a weakness in the abdominal wall muscles, causing a visible or easily palpable bulge. The most common types are inguinal, femoral, umbilical and hiatal. They may also be caused by age, chronic coughing, and trauma.

Inguinal – usually occur due to a persistent processus vaginalis (an

embryonic developmental outpouching of the parietal peritoneum), leaving an empty peritoneal sac lying in the inguinal canal. May be direct (occurs because of degeneration and fatty changes in the aponeurosis of the transversalis fascia – most do not contain bowel) or indirect.

Umbilical - Most umbilical hernias are recognised shortly after birth, after the cord sloughs and the umbilicus heals. They are rarely symptomatic. The

umbilical ring continues to close over time and the umbilical fascia strengthens, resulting in spontaneous resolution of the defect in most children

Hiatal – occurs when part of the stomach protrudes up through the diaphragm into the chest. Common in patients over 50 years old, and almost always causes GORD.

HEPATOMEGALY Abnormal enlargement of the liver may cause abdominal swelling, particularly on the right side of the abdomen (right hypochondrium). However depending on the size of the liver, it may extend across the entire abdomen. Causes include infection (IM, hepatitis, malaria), granulomatous (TB, sarcoidosis), neoplasm, congestion (CHF),

haemochromatosis and amyloidosis amongst other rarer causes.


Typically, will cause swelling in the right hypochondrium. May be caused by cholecystitis due to gallstones, alcohol abuse, infections or even tumours that may cause bile build up. The

prevention of bile from leaving the gall bladder means it gets trapped and acts as irritant, causing cellular infiltration.

SPLENOMEGALY Abnormal enlargement of the spleen may cause abdominal swelling, particularly at the left hypochondrium. May be caused by infection, cirrhosis, blood diseases characterized by abnormal blood cells, problems with the lymph system, or other conditions. Other causes of an enlarged spleen include inflammatory diseases such as sarcoidosis, lupus, and rheumatoid arthritis.


M8, W6 – Abdominal Distention, Mass and Hernia Dr Sarah Carlton



This refers to swelling or disease of the lymph nodes behind the peritoneum. They are often dissected to treat testicular cancer. Swelling may be due to lymphoma or teratoma. This usually presents as an epigastric mass.


A localised permanent dilatation of the abdominal aorta. Most likely to cause an abdominal swelling in the epigastric or umbilical regions, and often may be palpable or pulsatile.

CARCINOMA Gastric – pernicious anaemia and Pylori are both risk factors. Abdominal mass

and pain tends to epigastric, however very vague in early disease. Gastric cancer can involve loss of the tumour suppression gene, p53.

Pancreatic – often presents as non-specific upper abdominal pain in the epigastric region or at the left hypochondrium.

Colon - The majority of colorectal cancers are adenocarcinomas derived from epithelial cells. About 71% of new colorectal cancers arise in the colon and 29% in the rectum. Occasionally presents with a mass, but often in advanced disease, typically in the left or right hypochondrium.

Hepatic - cancer arising from hepatocytes in predominantly cirrhotic liver. However, some patients may not have cirrhosis before developing hepatoma, especially patients with chronic hepatitis B virus. Swelling may be present in the right hypochondrium.

CROHN’SDISEASE Disease characterised by transmural inflammation of the GI tract. The transmural inflammation often leads to fibrosis causing intestinal obstruction. The inflammation can also result in sinus tracts that burrow through and penetrate the serosa, thus forming perforations and fistulae. It may cause abdominal swelling due to inflammation, scarring and bowel thickening, particularly in the left iliac fossa.


Uterine fibroids (leiomyomata) are benign tumours of the uterus primarily composed of smooth muscle and fibrous connective tissue. There is usually an irregular, firm central pelvic mass in the suprapubic area, very easily palpable.


M8, W6 – Abdominal Distention, Mass and Hernia Dr Sarah Carlton


Investigations for abdominal swelling ● FBC

o Raised white cell count in infection (hepatomegaly, splenomegaly) or malignancy o Anaemia with abnormal vaginal bleeding (fibroids) or due to malignancy


o Inflammatory markers, can show active inflammation in diseases such as crohn’s disease or infection

● U&Es

o renal dysfunction; hypokalaemia or uraemia may cause non-mechanical bowel obstruction

● LFTs

o May show liver failure or signs of liver disease

o Cholestatic hyperbilirubinaemia with carcinoma of the pancreas o Hypobilirubinaemia with ascites

● Urinalysis

o Haematuria in patients with kidney or bladder tumours ● Pregnancy test

● Sigmoidoscopy/colonoscopy

o To physically view any obvious cause of abdominal distension eg. stomach cancer, PUD

Radiological: ● X-ray

o Abdominal x-ray may show large bowel pathology, or obstruction. May see a

calcified mass due to fibroids or dermoid cysts of ovaries. Can also see faecal loading o CXR to exclude CHF

● Abdominal ultrasound

o Identifies ascites and can help differentiate pelvic from intraabdominal masses ● CT/MRI

o Useful to determine site and cause of bowel obstruction o Often used if pathology is not fully determined


M8, W6 – Abdominal Distention, Mass and Hernia Dr Sarah Carlton


Differential Diagnosis of a Left Iliac Fossa Mass

1. Faeces in a loaded sigmoid colon

o Indentable

o Should be diagnosed clinically through history and examination

o May want to perform Abdominal x-ray or colonoscopy to exclude sinister disease

2. Sigmoid/ Descending Colon cancer

o History: - haematochezia, weight loss, TATT o Investigation:

Samples taken during colonoscopy/ sigmoidoscopy

Imaging to rule out metastases – CT chest, abdo and pelvis 98% adenocarcinoma, others are lymphoma and SCC

o Treatments: Combination of surgery, radiotherapy, chemotherapy and targeted therapy

3. Sigmoid volvulus

o When the sigmoid colon twists on the sigmoid mesocolon

o The sigmoid mesocolon is a fold of peritoneum attaching the sigmoid colon to the pelvic wall – it is one of the four mesenteries in the abdominal cavity (figure 1) o Patients present with constipation, bloating, nausea and vomiting

o Investigations: - plain x-ray, barium enema and CT o Management:

▪ Urgent admission and treatment

▪ Surgical emergency if ‘Acute sigmoid volvulus’ due to risk of bowel ischaemia, perforation and peritonitis

▪ Decompression using sigmoidoscope

▪ Surgical resection of the section of colon if it recurs using the Paul-Mikulicz procedure. This is where both ends of the twisted section of bowel are brought to the anterior abdominal wall into a colostomy bag.


M8, W6 – Abdominal Distention, Mass and Hernia Dr Sarah Carlton


4. Diverticular disease

o Out pockets of colonic mucosa and submucosa through weaknesses in the muscular layers of the colon wall o Usually not inflamed, but named ‘diverticulitis’ if they

are following infection due to the accumulation of stool within the diverticula

o Systemic features with localised severe pain in the LIF should increase index of suspicion

o Typically occur in the sigmoid colon due to the high pressure from faeces

o Investigations:

Plain abdo x-ray may show signs of a thickened wall, ileus, constipation, small bowel obstruction or free air if perforated

Contrast CT – investigation of choice in cases of acute diverticulitis Colonoscopy (figure 2) – to visualise diverticula and exclude malignancy –

performed 4-6 weeks after an acute episode

Barium enema – only if colonoscopy is difficult e.g. patient has strictures/ tortous colon

MRI – provides good detail but expensive so rarely used

▪ CAUTION - Barium enema and colonoscopy are contra-indicated during an acute diverticulitis

o Management:

▪ Most are asymptomatic and do not require treatment ▪ Avoid colonic stimulants!

▪ High fibre diet is advised to avoid constipation

▪ In acute diverticulitis, the patient may require antibiotics, IV fluids and surgery if there is bleeding and perforation

o Complications are more common in people who use NSAIDs and aspirin! (It seems as if these little buggers irritate everything in the GI tract)

5. Ovarian tumour/ cyst

o Initially like IBS so should perform a pelvic examination and pelvic ultrasound with associated blood marker tests

6. Psoas abscess

o Rare abscess of the psoas muscle

o Due to the sheath’s origin in the lumbar vertebrae and intervertebral discs it is more prone to be infected by TB and Salmonella discitis


M8, W6 – Abdominal Distention, Mass and Hernia Dr Sarah Carlton


o MRI is investigation of choice

o Management: Drainage and antibiotics

7. Crohn’s disease

8. Iliac lymphadenopathy

o Could be enlarged due to infection or malignancy

o Examples: - pelvic infections, abdominal infections (from diverticulitis), cellulitis, cancer metastases, leukaemia, lymphoma

o Investigations – full workup of bloods to identify acute infection/ signs of malignancy, imaging to look for any evident masses

o Management – treat accordingly

9. Testicular tumours

10. Intra-abdominal sepsis and abscesses

11. Pelvic inflammatory disease

o Infection of the upper female genital tract including the uterus, fallopian tube and ovaries usually from sexually transmitted diseases

o Usually bilateral but always consider

o Investigations: Swabs are 65-90% accurate, inflammatory markers, endometrial biopsy, ultrasound, urinalysis and urine culture to rule out UTI

o Management:Should initiate antibiotic treatment if there is clinical suspicion even without test results due to the high risk of complications


M8, W6 – Abdominal Distention, Mass and Hernia Dr Sarah Carlton


Epigastric Masses

Anatomy of Epigastrium

● Includes Duodenum, Liver,

Stomach and Pancreas

Epigastric Hernia

● Men are most commonly affected and the mean age of diagnosis is between 20- 50 years.

● The primary risk factors are obesity and pregnancy (woman only!).

● It occurs due to protrusion of extra-peritoneal fat where the linea alba is pierced by a small blood vessel.

● The swelling enlarges and drags a pouch of peritoneum with it.

● Patients may be asymptomatic but symptoms may occur such as epigastric pain or deep burning pain radiating to the back

or lower abdomen. Abdominal bloating, vomiting and nausea may also occur.

● Diagnosis is made by any manoeuvre which increases intra-abdominal pressure and makes the mass bulge anteriorly, and a CT scan (particularly in obese patients).

● The only treatment is repair by surgery to avoid the high risk of strangulation.


● An enlarged liver can present as a mass in the epigastrium. Generally, it is palpable in Right Hypochondrium/Right Lumbar but can be felt in the epigastrium. There are multiple causes of hepatomegaly, and I have listed the more common ones in a table.

Infective Neoplastic Biliary Drugs Metabolic Congenital Vascular

Glandular Fever Hepatocellular Carcinoma Primary Biliary Cholangitis Alcohol Abuse

NAFLD Sickle Cell Anaemia Portal Hypertension Hepatitis Metastatic Tumours Primary Sclerosing Cholangitis Drug Induced Hepatitis

Hemochromatosis Cringler-Najjar Cardiomyopathy

Liver Abscess

Lymphoma/ Leukaemia

Wilson’s Disease Haemolytic - Anaemia’s i.e. Spherocytosis


M8, W6 – Abdominal Distention, Mass and Hernia Dr Sarah Carlton 17 Malaria Multiple Myeloma Amyloidosis TB Pancreas

● Pancreatic Pseudocyst: localised fluid collections that are rich in amylase and other pancreatic enzymes such as lipase and trypsin.

o 80% of pseudocyst are due to alcohol or gallstone disease, and can vary from 2-30cm. 1/3rd of pseudocust occur at the head of pancreas and 2/3rds appear in the tail.

o There are no specific set of symptoms however abdominal pain, particularly after pancreatitis can be suggestive.

o Abdominal CT Scans are diagnostic.

o Most pseudocyst resolve without interference but some may require drainage. ● Pancreatic Cancer: Epigastric mass is a late presentation. Will be non-mobile, smooth,

tender and not moving with respiration

Gastric Carcinoma

● Unfortunately, if patient presents late with epigastric mass, alongside other signs such as hepatomegaly, jaundice, ascites, Troisier’s sign, acanthosis nigricans suggests incurable disease.


● Other causes of epigastric masses include in Pyloric stenosis, Transverse Colon Cancer and dermatological pathologies such as Sebaceous Cysts and Lipomas. Haematological causes include lymphomas.




M8, W6 – Abdominal Distention, Mass and Hernia Dr Sarah Carlton


Types Common

● Inguinal (80% of all hernias are inguinal) o Direct o Indirect ● Femoral (5%) ● Umbilical (4%) ● Periumbilical ● Hiatus hernia ● Incisional hernia (10%) ● Epigastric hernias (1%) ● Diaphragmatic hernias Rare ● Obturator ● Spigelian ● Lumbar ● Spigelian hernias ● Muscle hernias Causes of hernias

● Increase in intra-abdominal pressure o Cough o Lifting o Straining o Obesity o Ascites Classification

● Reducible: can be put back into place

● Irreducible/obstructed/incarcerated: cannot usually be reduced manually because of adhesions forming in the hernia sac

● Strangulated: if part of the herniated contents becomes twisted or oedematous, causing serious complications - resulting in obstruction or necrosis

Natural Progression of Hernias How the Hernia Presents:

● In adults, the hernia usually starts after a specific event and gradually gets large o At first appearance: it is reducible when the patient reclines

o Manual reduction may be needed if large

o After time: the hernia enlarges and becomes harder to reduce, due to fibrous adhesions


M8, W6 – Abdominal Distention, Mass and Hernia Dr Sarah Carlton


o When it can no longer be reduced, it is irreducible or incarcerated. This can happen at any time, as can strangulation. This occurs when visceral contents of the hernia become twisted or entrapped by the narrow opening. This comprises the blood supply, causing swelling and eventually infarction. Strangulation usually leads to bowel obstruction


● Happens when the bowel twists or blood supply is impaired

● Clinical presentation: tense, tender, change in covering skin (redness), irreducible ● RF: more common in narrow necked hernias

● 40% of femoral hernias strangulate (due to the narrow neck) ● 2% of inguinal hernias

Management of Strangulation ● Diagnose

● Early surgery, they become dangerous after 6 hours

● May need bowel resection: depends upon viability of the bowel Investigations

● Mainly clinical diagnosis ● US: is unsure of the diagnosis

● CT and MRI are occasionally used if there is uncertainty

● Herniography: is an old investigation but is rarely used anymore

Hernia Management Overview

● Watch and wait: If asymptomatic and doesn’t interfere with the person’s life then make patient aware that if they get symptoms to come back to doctor

● Lifestyle changes: losing weight, elevating head of bed, avoid large meals, alcohol, acidic food

Indications for surgical repair

● Strangulation or bowel obstruction: surgery should be performed within 4-6hours from the onset of symptoms. Signs of strangulation include, skin changes (becoming red and

inflamed), peritonitis

● Incarcerated hernias without strangulation should be offered urgent surgical repair ● Working offshore: being unable to access treatment

● Symptomatic: in uncomplicated hernias, surgical repair is indicated in symptomatic hernias that are impacting someone’s life. Also if there is pain on exertion, inability

Surgical approach

● Aim is to excise the hernial sac and put in place tension free reinforcement of the posterior inguinal wall using mesh

● Open: used in complicated hernias. Open is preferred in femoral hernias as there is easier access


M8, W6 – Abdominal Distention, Mass and Hernia Dr Sarah Carlton


● Non mesh: if there is active infection

● Laparoscopic: do not do in a patient with history of abdominal surgery (as there is scarring and grafts are less likely to adhere), ascites, complicated hernias.

o There is less post op pain, less long term pain, no difference in recurrence o Two main:

▪ Totally extraperitoneal (TEP)

▪ Transabdominal peritoneal patch (TAPP) o Both use mesh and are considered tension free repairs o Prophylactic antibiotics also need to be given

Complications of surgery ● Pain ● Recurrence (2%) ● Infection ● Testes atrophy ● Urinary retention Hernias in Children

● Generally due to a congenital abnormality ● Most common hernias in children

o Umbilical o Inguinal ● Management

o Should have referral

o Usually watch and wait, most resolve as the child grows ● RF: prematurity, constipation

Different Types of Hernia

Inguinal hernias

● What is it? Protrusion through the internal inguinal hernia

● What do hernias contain? Always contain peritoneal sac and may contain viscera, small bowel, omentum

● Two types:

o Indirect: these come through the deep inguinal ring, and if large enough, out of the superficial inguinal ring. To reduce these, you have to go from medial to lateral. You will see this above and medial to the pubic tubercle – if it is large enough to have come out of the superficial ring. These account for 80% of inguinal hernias. They can strangulate – and usually at the deep inguinal ring as this is narrow

o Direct: these come into the inguinal canal through a defect in the posterior wall of the canal. These are easier to reduce – they should just pop straight back in - these account for 20% of inguinal hernias. They are generally easy to reduce and do not strangulate.

● Epidemiology:


M8, W6 – Abdominal Distention, Mass and Hernia Dr Sarah Carlton


● Presentation

o Swelling in groin that may appear with lifting, may have sudden pain

o Indirect hernias: more prone to cause pain in the scrotum and causing a dragging sensation

o An impulse (increase in swelling) may be palpable on coughing o May not see the hernia if its reduced

Femoral Hernias

● More common in women ● Higher risk of strangulation

o These go down the femoral canal (not the inguinal canal). They are usually found below and lateral to the inguinal ligament – this is the opposite of inguinal hernias. However, remember they can present above the inguinal ligament as well – but when they do, they will point along the femoral canal, and down the leg, as opposed to towards the groin (like inguinal ones do). Repair is recommended for these hernias.


● Repair femoral ring o Low approach o Inguinal approach o High approach ● Assessing the hernia

o Assess both standing and lying o Ask them to cough or strain

o Insert a finger through the scrotum into the external inguinal ring and palpate for a lump when coughing – cough impulse

o Sliding hernias are probable with large scrotal hernias DDX

● Femoral hernias ● Hydrocele

● Spermatic cord hydrocele ● Lymph node swelling ● Assess

● Saphena varix ● Varicocele Options

● Bassinis operation: conventional surgery

● Lichtenstein technique: widely used. A piece of open weave polypropylene mesh is used to repair and reinforce the abdominal wall. The standard repair now uses prostheses, usually polypropylene mesh

● There is increased risk of infection, IV antibiotics given 30mins before the procedure ● Children – management


M8, W6 – Abdominal Distention, Mass and Hernia Dr Sarah Carlton


Hiatus Hernia

● What is it? Protrusion of intra-abdominal contents through an enlarged oesophageal hiatus of the diaphragm.

● Most commonly contains a variable portion of the stomach; less commonly contains the transverse colon, omentum, small bowel, spleen

● Herniated contents usually contained within a sac of peritoneum ● Epidemiology

o Closely related to this incidence of GORD o Hiatal hernias, sliding type I is most common ● Aetiology

o Unsure ● Two main types

o Sliding

o Paraesophageal Classification

● Type I

o Sliding hiatal hernia

o Protrusion of the gastro-oesophageal junction followed by the body of the stomach through the oesophageal hiatus and above the diaphragm.

● Type II

o Pure para-oesophageal hernia or rolling hiatal hernia

o Herniation of the fundus or body of the stomach or both into the chest, with maintenance of the gastro-oesophageal junction below the diaphragm. ● Type III

o Mixed or combined para-oesophageal hernia

o Combination of types I and II. The fundus or body of the stomach or both have herniated into the chest; the gastro-oesophageal junction is also herniated into the chest, but r

o ests below the herniated stomach. ● Type IV

o Giant hiatal hernia

o Occurrence of any type of hiatal hernia along with herniation of one or more other organs, such as colon, small bowel, omentum, and spleen

o Secondary prevention Management

● Lifestyle changes: losing weight, elevating head of bed, avoid large meals, alcohol, acidic food

● Substances that inhibit the lower oesophageal sphincter to be avoided: nicotine, chocolate, peppermint, caffeine, fatty food, medications: CCB, nitrates, beta-blocker

● Findings on examination: Bowel sounds in chest


M8, W6 – Abdominal Distention, Mass and Hernia Dr Sarah Carlton


Uncommon: chest pain, dysphagia, odynophagia, haematemesis, SOB, oropharyngitis, wheezing, non-bilious vomiting, fever and chills, confusion ● RF

o Strong: obesity o Weak: previous GORD o Elevated intra-abdo pressure o Male gender

● Investigation

o CXR: do if person is symptomatic - retrocardiac air bubble or normal

o Upper GI series: do if moderate to severe symptoms - stomach is partially or completely intrathoracic

o OGD: do in moderate to severe symptoms, undergo endoscopy to check for the presence of oesophagitis or oesophageal dysplasia may see inflammation of the oesophagus and proximal migration of the gastro-oesophageal junction


● Angina ● GORD ● Pneumonia

● Gastric outlet obstruction

Umbilical Hernia

● What is it? Defect of the anterior abdominal wall fascia that occurs when the umbilical ring fails to close. The defect allows protrusion of a peritoneal sac that is covered by skin and may contain intra-abdominal contents, such as omentum or bowel

● Cause

o The umbilical cord is composed of the umbilical vein, paired umbilical arteries, vitelline duct, and the allantois.

o These structures traverse the abdominal wall through the umbilical ring, a defect in the dense fascia of the linea alba

o This ring normally closes by contracture after the cord is ligated and the umbilical vessels thrombose.

o When this ring fails to close, an umbilical hernia can protrude through the remaining fascial defect.

o The umbilical vein obliterates and becomes a fibrous cord known as the round ligament of the liver.

o This typically attaches to the inferior margin of the umbilical ring and provides strength to the umbilicus and protection from umbilical hernia.

o In approximately 25% of infants the round ligament attaches to the superior border of the umbilical ring.

o This leaves an attenuated umbilical floor, composed of only peritoneum and umbilical fascia (a thickening of the transversalis fascia), which allows the infant to develop an umbilical hernia.


● Most umbilical hernias are recognised shortly after birth, after the cord sloughs and the umbilicus heals.


M8, W6 – Abdominal Distention, Mass and Hernia Dr Sarah Carlton


● They are rarely symptomatic. The umbilical ring continues to close over time and the umbilical fascia strengthens, resulting in spontaneous resolution of the defect in most children.

● One study found that defects <1 cm in diameter have an 80% chance of spontaneous closure.

History and Examination

● Presence of risk factors: low birth weight ● Present since birth

● Bulge at umbilicus

● Change in size/tension during movement ● Skin changes

● Easily reducible hernia sac

● Well defined rim of fascia with central defect

Femoral Hernia

● The inguinal ligament, the posterior border is the pectineal ligament, the medial border is the lacunar ligament and the lateral border is the femoral vein

● Epidemiology

o More common in women o Rare in children

● Presentation

o Lump in groin, lateral and inferior to the pubic tubercle. A large hernia may bulge over the inguinal ligament and make DDX difficult

o Hernia often appears or swells on coughing or straining and reduces in size or disappears when relaxed or supine

o May be a cough impulse, may be able to reduce the hernia

Parastomal Hernia

● Very common around stomas ● Rarely strangulate

● Sometimes repair with mesh, but recurrence is high

Epigastric hernia

● Between the umbilicus and xiphersternum through the linea alba ● Other symptoms:

o May have dyspepsia ● Extra notes:

o They generally don’t contain much bowel

Incisional Hernia

● Causes: wound infection, obese, poor metabolic status of patient, post op cough, technical (suture material, bites), incision


M8, W6 – Abdominal Distention, Mass and Hernia Dr Sarah Carlton


o If asymptomatic and has a broad neck, then don’t treat o Otherwise repair: simple repair, mesh repair

o Open or laparoscopic


● Excess fluid in the peritoneal cavity

● Normally, there is about 50ml fluid is present ● Often presents as abdominal distension/weight gain


Mild (I): no clinical signs, detected only on imaging ● Moderate (II): abdomen is distended but not rigid

o +ve for shifting dullness o No fluid thrill

Severe (III): abdomen rigid, cannot be indented o +ve for shifting dullness

o +ve for fluid thrill


● Ascites are associated with any disease that may affect the peritoneum ● The most common causes of ascites are:

1. Liver disease (usually portal HTN) 2. Congestive heart failure

3. Malignancy

Causes According to Ascitic Fluid

Transudate Exudate


Congestive heart failure Hepatic venous occlusion

Alcoholic hepatitis Constrictive pericarditis


Nephrotic syndrome (increased protein)

Malignancy (liver, ovarian, mets) Pancreatitis Ruptured gallbladder/bowel Appendicitis Mesothelioma Tuberculosis SLE Haemoperitoneum Chylous* Acute pancreatitis Malignancy Trauma to abdomen Ruptured ectopic pregnancy


Thoracic duct obstruction (ie in malignancy) *White lymphatic fluid


M8, W6 – Abdominal Distention, Mass and Hernia Dr Sarah Carlton



Dullness in flanks - on percussion of the 9 quadrants

Shifting dullness (Figure 1) confirms presence of ascites (usually positive once 1-2l accumulated)

o Lay patient supine, allowing any fluid to settle (10-30s) o Percuss from the midline out to the flanks

o Note where resonance changes to dullness (ask patient if you can mark with a pen) o Ask patient to turn to their side and allow for fluid to settle

o Percuss again: if area that was previously dull is now resonant - positive for shifting dullness

Fluid thrill: positive if gross ascites (Figure 2)

o Place palm of left hand on left side of patient’s abdomen, and with your other hand flick the right side of their abdomen

o Ask the patient to position their hand upright in the midline and test again

o If thrill is still felt - indicates ascites

● Look for any signs indicating possible cause (ie cardiac/liver failure, malignancy etc)



● Procedure involving removal of fluid from the peritoneal cavity o Diagnostic: remove ~100ml for testing

● Performed in all new cases of ascites, and may be repeated if there is a sudden increase in fluid

● In analysing fluid, aiming to find out 2 things: 1. The underlying disease causing ascites:

Testing for shifting dullness in ascites


M8, W6 – Abdominal Distention, Mass and Hernia Dr Sarah Carlton


o Protein levels within the fluid are assessed to determine whether it is an exudate or transudate (this can then help direct the differential diagnoses) o Albumin levels within the fluid are measured

and compared to that within the blood to calculate a Serum: Ascitic Albumin Gradient (SAAG)

▪ If SAAG >11g/l - very likely portal HTN (97% sensitivity)

● A portion of the fluid is also sent for cytology, and reviewed for presence of malignant cells

2. Whether an infection is present

o The fluid is cultured to see if bacteria is

present, but this can take some time, so WCC is used as an indicator ▪ WCC increased in Spontaneous Bacterial Peritonitis (SBP) -

commonly seen in cirrhosis


● Useful in finding the underlying cause if not already indicated from history & examination o Ultrasound

o CT (chest, abdomen, pelvis) o Cardiac MRI/Echo

o Endoscopy


● In healthy liver cells, between the hepatocytes and the sinusoidal endothelial lining cells lies a space called Space of Disse which contains Ito cells

● Ito cells are normally round & regular, and filled with vitamin A

● When hepatocytes are damaged (by any mechanism), Ito cells proliferate, filling the space, and develops projections which express actin and myosin

o Leads to contraction, squeezing the sinusoid 🡪 increased resistance through the vessels

● In an attempt to counteract the increased resistance, capillaries dilate o Increased blood flow into gut

o Decreased blood flow out of gut

o 🡪 Decreased effective circulating volume: the volume of blood going through the heart

● The body responds to his as it would to shock

o Antidiuretic hormone (ADH/vasopressin) released from pituitary gland - retains water in the kidney

o RAAS activated - reabsorbs sodium & water in the kidneys

● So the overall effect is increased water and salt in an attempt to increase the circulating blood volume

o This then increases venous hydrostatic pressure, causing a gradient between the venules & capillaries

● Fluid leaves the capillaries and enters the peritoneal space

Serum: Ascitic Albumin Gradient (SAAG) = Serum albumin conc. (g/L) – Ascites albumin conc. (g/L)

A high gradient

(>11g/L) indicates the

ascites is due to


M8, W6 – Abdominal Distention, Mass and Hernia Dr Sarah Carlton


o In turn increases capillary pressure, which increases the gradient, which causes more fluid loss - vicious cycle

Known as the underfillling hypothesis of ascites formation

● When ascites develops, it is a sign of uncompensated cirrhosis - ~50% mortality in 2 years o At this point, patient should be considered for transplant


Reduce Sodium Intake

● Advise patient to control sodium intake to 90mmol/day (essentially the less salt they ingest, the less there is to reabsorb)

● May need dietician advice to prevent malnutrition states


● Increases excretion of salt and water ● Spironolactone

o Binds to receptors at aldosterone-dependent Na/K exchange site in the distal convoluted renal tubule 🡪 increased excretion of Na and water


o Inhibits water reabsorption by blocking sodium/potassium/chloride cotransporter in loop of Henle, causing osmotic change

o Managing therapeutic dose can be challenging - run risk of increasing the dose too much & causing renal injury, and patient may become ‘resistant’ to diuretic effect ● Main issue with diuretic use if risk of excreting too much water 🡪 reduced circulating volume

🡪 renal underperfusion

o If the risk of this is high, or the patient is contraindicated to diuretic use (ie. in existing renal disease), large volume paracentesis is the next best option


● Same procedure as peritoneal tap used for diagnosis, except a drain is left in the abdomen to remove fluid

● In end stage liver disease, patients may be entirely dependent on large volume paracentesis for symptomatic relief, and may be having it carried out on a monthly basis


● Bleeding (especially in liver disease) is a possibility, but this only becomes a problem when platelets drop below 40 x109/L

● Infection: drain must never be left in for more than 6 hours ● Post-paracentesis circulatory failure:

o As large volumes of fluid are lost, capillaries become more permeable in an attempt to compensate

o This drops the effective circulating volume further 🡪 renal perfusion o Used to be major cause of mortality in ascites

o Avoided by replenishing fluid by giving 20% human albumin serum (HAS) - 100ml HAS should be given for every 3l removed



M8, W6 – Abdominal Distention, Mass and Hernia Dr Sarah Carlton



Spontaneous Bacterial Peritonitis

● Infection within the ascitic fluid

● Mortality of ~25% - so early diagnosis is vital

o Microscopy carried out on ascitic fluid when patient presents o High neutrophil count (>250 / mm3) is diagnostic

o Sample can also be cultured - may help with antibiotic sensitivity but not always useful

● Mortality due to increased inflammatory mediators 🡪 arterial vasodilatation 🡪 more blood in capillaries, so more fluid lost 🡪 circulating volume decreases further 🡪 renal hypoperfusion 🡪hepatorenal syndrome

● Can be treated by giving: o IV antibiotics for 5 days o Fluid (HAS)

o Vasoconstrictors (Terlipressin)

● Should also be giving prophylactic antibiotics to prevent (Ciprofloxacin/Norfloxacin)


● Hernias - due to increased intra-abdominal pressure

● Severe ascites - diaphragm can’t move - breathing difficulties ● Hepatic hydrothorax - pleural effusion

● Hepatic encephalopathy (following TIPS) ● Post-paracentesis circulatory failure

Intestinal Obstruction

● Intestinal obstruction is the blockage of the intestine (small or large) leading to prevention of normal movement of digestive products

● It is most commonly due to a mechanical block of the bowel, although it can occur via paralytic ileus, in which there is failure of peristalsis

● The result of obstruction in an area of bowel is distention in the area preceding the obstruction

o In this area of distention bacteria can grow

● If part of the bowel becomes strangulated and the blood supply stopped, the bowel can become gangrenous and urgent treatment is required


● There are 4 main symptoms to look out for: ● Vomiting


M8, W6 – Abdominal Distention, Mass and Hernia Dr Sarah Carlton


o Upper bowel obstruction is more likely to present with vomiting compared to the lower bowel where it may not be present

o If the obstruction continues, fermentation of the intestinal contents before the obstruction can occur

o This can lead to fermentation of the contents, producing faeculent vomiting ▪ This is thicker, foul-smelling vomit

Small Bowel Large Bowel - Earlier Vomiting

- Less distention - Pain higher in the abdomen

- Less vomiting - Greater, widespread distention

- Pain is more constant

o Vomiting can occur even if the patient isn’t eating, due to saliva and gastrointestinal secretions

● Abdominal Colic

o This is pain in the abdomen, it usually occurs early after the obstruction o It can be absent if the obstruction is complete and long-standing ● Constipation

o Can be absolute constipation (no passing of faeces or flatus (wind)) especially in lower bowel obstruction

o In upper bowel obstruction they are more likely to still be able to go to the toilet ● Abdominal distention

o Distention of the abdomen can be seen on examination o It gets worse as the obstruction progresses

o There are also increased bowel sounds heard (“tinkling” sounds)

o Significant tenderness over the abdomen can indicate strangulation has occurred ● NB in Ileus there would be no pain and absent bowel sounds

Extent of Obstruction

● There are 3 types of obstruction: ● Simple

o The blood supply is not affected

o Obstruction in only one place in the bowel ● Closed Loop

o Obstruction occurs at two points in the bowel, forms a loop of bowel that becomes very distended


M8, W6 – Abdominal Distention, Mass and Hernia Dr Sarah Carlton


● Strangulated

o The abdominal pain will be very localised o The blood supply becomes compromised o It causes acute mesenteric ischaemia

▪ Acute severe abdominal pain disproportionate to other signs ▪ Rapid hypovolaemia leading to shock


Causes of Intestinal Obstruction Small Bowel Large Bowel Adhesions Hernias Crohn’s disease Intussusception Cancer Gallstone ileus Foreign body TB Colon cancer Volvulus Diverticulitis Ileus

Small Bowel Causes ● Adhesions

o Cause 80% of small bowel obstructions in adults

o This is when scar tissue forms between the bowel and the peritoneum or with other organs after abdominal surgery

o Can occur just hours after the surgery, although it can occur 20 or more years after the surgery

● Hernias

o The protrusion of viscera through the wall of the cavity in which it is contained o The most common is an inguinal hernia

o When a hernia becomes incarcerated it can lead to obstruction of the bowel ● Crohn’s disease


M8, W6 – Abdominal Distention, Mass and Hernia Dr Sarah Carlton


o This is a rarer cause of bowel obstruction

o Inflammation in Crohn’s can lead to strictures of the bowel

▪ Inflammation leads to scarring, which causes narrowing of parts of the bowel – the strictures, more likely in Crohn’s than UC as the inflammation is deeper

▪ The strictures can lead to bowel obstruction ● Intussusception (Figure 1)

o This is a very rare cause of bowel obstruction, but should always be considered in children

o This is “telescoping” of the bowel where on part of the bowel folds into another part o It most commonly occurs under the age of 1

o It is most commonly caused by infection, but can also be caused by Meckel’s diverticulum and Peutz-Jaegers syndrome

o They will often be crying and have their legs drawn into their stomach, treatment should be prompt to prevent necrosis

● Extrinsic cancer

o Rarer cause of bowel obstruction

o External cancers can lead to obstruction of the bowel, e.g. ovarian cancer o This can also cause large intestine obstruction

● Gallstone ileus

o This is a rarer cause of bowel obstruction

o A gallstone can erode through the gallbladder and into the duodenum and obstruct the bowel, but it has to be at least 2.5cm in diameter

o It most commonly obstructs the terminal ileum but can also obstruct the other parts of the small bowel

● Foreign body

o A rarer cause of small bowel obstruction, it can also cause obstruction of the oropharynx or the oesophagus

o These patients would have immediate surgery ● TB

o A very rare cause of bowel obstruction – most commonly occurs in the ileo-caecal region of the bowel

Large Bowel Causes ● Colon cancer

o Most common cause of large bowel obstruction o It is a very common cancer – the 3rd most

common, and the 2nd highest cause of cancer

deaths in the UK

o It is usually found in the elderly (there is 2 yearly screening for 60-75 year olds)

Figure SEQ Figure \* ARABIC 1 - Intussusception

Figure SEQ Figure \* ARABIC 2 - Sites of colon cancer


M8, W6 – Abdominal Distention, Mass and Hernia Dr Sarah Carlton


o It’s normally adenocarcinoma, most commonly found at the rectum or the sigmoid colon (Figure 2)

o Bowel obstruction is usually a complication of late-stage colon cancer ● Sigmoid volvulus

o This is a common cause of bowel obstruction in less developed countries but isn’t as common in developed countries like the UK

o Volvulus is the twisting of the bowel – it leads to rapid strangulated obstruction o It most commonly occurs following chronic constipation in the elderly

o Volvulus can also occur in the caecum and the stomach (very rare) ● Diverticulitis

o A diverticulum is an out-pouching of the mucosa of the gut lumen through the gut wall – when this becomes inflamed it is diverticulitis

o Chronic inflammation can lead to strictures forming (like in Crohn’s) o The strictures can then lead to bowel obstruction


● Ileus is when the bowel stops functioning and there is a loss of peristalsis ● Common causes include:

o Abdominal Surgery – postoperative ileus o Pancreatitis or peritonitis

o Spinal injury etc.


● When you suspect bowel obstruction you would immediately request blood tests, an abdominal and chest X-ray (to look for perforation), followed by a CT scan

● Radiology can be helpful to locate the problem, assess for complications (such as perforation or ischaemia) and to find the underlying cause ● Plain film X-rays are done first if bowel obstruction is suspected ● Abdominal X-ray (AXR)

o Can show distended bowel above the obstruction o May also show fluid levels in the bowel

o Even if it shows no sign of bowel obstruction it cannot be ruled out

o Small bowel obstruction (Figure 3)

▪ Dilated loops proximal to the obstruction, dilation > 2.5-3cm

▪ Valvulae conniventes can be seen – these are the mucosal folds of the small intestine most prominent in the jejunum

Small Bowel Obstruction


M8, W6 – Abdominal Distention, Mass and Hernia Dr Sarah Carlton


▪ Air fluid levels can be seen if it is an erect x-ray o Large bowel obstruction (Figure 4)

▪ Distention of the colon and can the distal colon can be collapsed

▪ Dilation of the colon > 6cm

▪ The dilation can follow up to the small bowel if the obstruction lasts long enough and there is incompetence of the ileocecal valve

▪ Sigmoid volvulus can produce an inverted U, “coffee bean” sign

● CT scans

o These are much more effective for bowel obstructions and are more commonly being used instead of AXRs

o They are very good for accurately locating the obstruction and identifying the cause, however they usually are only ordered if the x-rays are inconclusive


● “Drip and suck” and then treat the underlying cause

o Drip – resuscitation with IV fluids to correct fluid and electrolyte balance o Suck – Insert a nasogastric tube, but use it to suck out gastric contents to

decompress the bowel and let it rest ● Pain management with analgesia (e.g. morphine) ● Antiemetic to manage vomiting (e.g. Cyclizine)

● Small bowel obstructions are more likely to resolve spontaneously, however it may require surgery in some cases, such as when strangulation occurs

o It can require laparotomy (emergency open surgery – midline surgery) to remove the obstruction

● Large bowel obstruction can often lead to surgery as the main cause is colon cancer o They may require a colostomy (shortening of the colon)

● Sigmoid volvulus is usually treated by inserting a flexible sigmoidoscopy or rectal tube to open-up the twisted bowel

o If it recurs the patient may require sigmoid colostomy (shortening of the sigmoid colon)

Abdominal Infections


● The peritoneum consists of two layers, the parietal peritoneum on the outside and

visceral peritoneum.

● The peritoneal cavity is a closed sac lined by mesothelial cells, which produce

surfactant that acts as a lubricant within the peritoneal cavity.


M8, W6 – Abdominal Distention, Mass and Hernia Dr Sarah Carlton


● It is a potential space for pathogens and fluids to breed. In males, the peritoneal

cavity is closed, while in females the peritoneal cavity is opened via the cervix and

the vagina.

Intra-peritoneal organs – completely or almost

completely enclosed by the peritoneum

anteriorly and posteriorly

● Stomach ● Liver ● Gallbladder ● Transverse colon ● Jejunum ● Ileum ● Caecum

● Retro-peritoneal organs – can be subdivided into two groups:

Primary retroperitoneal – develop and remain

outside of the parietal peritoneum

Secondary retroperitoneal – initially intraperitoneal, eventually ending up as retroperitoneal ● Oesophagus ● Rectum ● Kidneys ● Ascending colon ● Descending colon ● Sigmoid colon Normal Flora


Number of



Common microbes





Lactobacilli, streptococci, yeasts

Numbers increase with age, achlorhydria

and drugs such as cimetidine can change

the concentration

Small bowel 10




As above plus clostridia,

enterobacteriaceae, enterococci

Increases distally

Antibiotics affect relative numbers

Large bowel 10




As above plus protozoa

(Chilomastix, Trichomonas), yeasts

Anaerobes outnumber facultative

organisms by 1000-10 000:1

Anaerobes within the large intestine are

the primary causative agents of


intra-M8, W6 – Abdominal Distention, Mass and Hernia Dr Sarah Carlton


abdominal abscesses and cause

problems within peritonitis

Usually stable however treatment with

antibiotics allow certain bacteria to

cause disease i.e. clostridium difficile


● This is inflammation of the peritoneum. It can be generalised or localised, and is often associated with rupture of an internal organ, e.g. as occurs in trauma.

● It usually represents a surgical emergency.

● There is almost always some localised peritonitis with inflammation of an underlying organ, e.g. with cholecystitis. The treatment in these cases is just treatment of the underlying condition.

● Generalised peritonitis is far more serious, and is a result of direct irritation of the peritoneum.

● In peritonitis, the peritoneum will produce inflammatory factors that will lead to intestinal dilatation and paralytic ileus

● On investigation, there will be an absence of bowel sounds.


● More common in men than women.

● In women they can occur from ruptures to the reproductive organs, such as an ectopic pregnancy, infected fallopian tube, or ovarian cyst.


● Sudden onset acute abdominal pain that is exacerbated by any movement, e.g. coughing. ● Often the pain may begin generalised but then become localised. This is because at first is

may be the visceral nerve fibres that are activated (which are poorly localising) and then later the parietal nerve fibres are activated.


M8, W6 – Abdominal Distention, Mass and Hernia Dr Sarah Carlton


● Shock and fever ● Washboard rigidity ● Fever

● Pulse >100 (sinus tachycardia) – the rhythm will still be normal ● Severe abdominal pain ● Nausea and vomiting ● Abdominal swelling

● Dullness may occur after 2-4 hours.


Infected peritonitis

● Perforation of part of the GI tract, or, in women, of the

reproductive system – this could be due to ingestion of a sharp object, e.g. a fishbone! Or could be due to trauma, or an ulcer etc. In these cases you will most often find Gram negative bacteria and anaerobic bacteria in the peritoneum. A common example is E. coli. ● Disruption of the peritoneum – e.g. by surgery or trauma. This can result in bacteria in the peritoneum from the external environment. In this case, the most common causing agent is Staphylococcus aureus.

● Spontaneous bacterial peritonitis (SBP) – this can occur in children and in those with ascites (i.e. in severe liver disease). It is treated differently to other types of peritonitis; usually only requiring antibiotic treatment.

● Systemic infections – e.g. such as TB can very rarely result in peritonitis. Non-Infected Peritonitis

● Leakage of sterile bodily fluids into the peritoneum – e.g. such as blood, bile urine etc. It is very important to note that although these fluids are sterile at first, they will usually become infected once in the peritoneal cavity, causing full blown peritonitis within 24-48 hours. ● Auto-immune disease – such as Lupus can cause peritonitis.


● Loss of fluids / disturbance of electrolyte balance – hypovolaemia may result and this could bring about shock or even renal failure.

● Difficulty breathing – due to pressure of fluid on diaphragm. ● Peritoneal abscess

● Any delay in treatment can produce a worse toxaemia and septicaemia.

● Abscess – These are relatively common after surgery and should be suspected if the





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