" E x p e r t n e s s " f r o m S t r u c t u r e d T e x t . ? R~CONSIDEI~ A Diagnostic P r o m p t i n g P r a g r a m
Mark S. Turtle a'b, David D. Sherertz c, Marsden S. Btois a, Stuart Nelson d baS ection on Medical Information Science, A-16, Univ. Cal. S a n Francisco, San Francisco, C A 94143
C o m p u t e r Science Division -EECS, Univ. Cal. Berkeley, Berkeley, C A 947~0 C ( f o r m e r l y ) S e c t i o n on Medical I n f o r m a t i o n S c i e n c e , UCSF
C ( c u r r e n t l y ) T a n d e m C o m p u t e r s , Inc., 19333 Vallco Park~-ay, C u p e r t i n o , CA 9 5 0 1 4 "Dept. of Medicine, State Univ. of N e w York at Stony Brook, S t o n y Brook. N Y 11794
All~tract:
R E C O N S I D E R is a n i n t e r a c t i v e d i a g - n o s t i c p r o m p t i n g p r o g r a m w h i c h u s e s s i m p l e i n f o r m a t i o n r e t r i e v a l t e c h - n i q u e s t o p r o m p t a p h y s i c i a n r e g a r d - ing possible diagnoses, given a list of
positive patient findings. Its
k n o w l e d g e base consists of "struc- L u r e d text" d e f i n i t i o n s o f 3262 d i s e a s e s a n d a s y n o n y m d i c t i o n a r y P a t i e n t f i n d i n g s , a n d t h e i r s y n o n y m s , a r e m a t c h e d a g a i n s t i n v e r t e d f i l e s of t e r m s f r o m t h e d i s e a s e d e s c r i p t i o n s , t h e n u m b e r a n d s e l e c t i v i t y of t h e p a - t i e n t f i n d i n g s m a t c h i n g t e r m s i n a g i v e n d i s e a s e d e s c r i p t i o n d e t e r m i n e t h a t d i s e a s e ' s " s c o r e " , a n d t h e m a t c h e d d i s e a s e s a r e s o r t e d o n t h i s score to f o r m a preliminary differential diagnosis. Defimtions of diseases c a n b e referenced for view- ing b y n a m e , or b y their position in a differential While its first formal evaluation is not yet complete, the p e r f o r m a n c e of R E C O N S I D E R contin- u e s to e x c e e d the expectations of u s e r a n d d e s i g n e r a l i k e .
1. ] i o U ~ t l ~ ~ B ~ c l ~ r o ~ d
A review of the various m e a n s by which m e d i c a l k n o w l e d g e is represented in symbolic f o r m [ 6 , 7 ] led u s to f o r m u l a t e t h e [o[Iowing s p e e t r u n ~ :
H u m a n . Machine
Processible Processible
S p e c t r u m of
Medical Knowledge Representation Schemes
The two endpoints of the spectrum represent the limiting cases wherein
k n o w t e d g e is difficult, or i m p o s s i b l e , to process algorithmically, but transparent to medical personnel, e.g. free text; or easily processibte algorithmicatty, and dil~cuit to process by h u m a n s untrained in applied m a t h e m a t i c s or computer sci- ence. e.g. a m a t r i x of Bayesian p r o b a b i l i - t i e s , or a semantic network.
Those attending this conference will be familiar with work at both ends of the spectrum, if not in medicine, then in other knowledge domains. Most will c o n c e d e t h a t t h e g r e a t e s t " s u c c e s s e s " in t h e field of e x p e r t s y s t e m s h a s b e e n a c h i e v e d b y those working at or near the right-hand end of the spectrum; and that progress has been m o s t d i f f i c u l t t o a c h i e v e a t t h e L e f t - h a n d e n d of t h e s p e c t r u m . We c o n c l u d e d t h a t . for t h e s h o r t run at least, those successes at the right-hand e n d would prove to be self-limiting - knowledge that was not readily accessible to and modifiable by the medical c o m m u n i t y at large could not remain in the m a i n s t r e a m of medical practice. Similarly, w e saw no immediate prospects for a breakthrough in the algorithmic understanding of free text. though ~npressecL with accomplish- m e n t s in the area of natural language access to databases [9, I0].
The d i l e m m a these observations implied led us to formulate the following question:
s u r p r i s i n g l y , well d e t e r m i n e d m e a n i n g s for w o r d s , d i m i n i s h i n g t h e n e e d for s y n t a x to clarify o r d i s a m b i g u a t e m e a n i n 8.
Our s e a r c h for a n b o d y of knowledge on w h i c h to e x p l o r e c e r t a i n h y p o t h e s e s r e g a r d i n g s u c h a n o m i n a l - a t t r i b u t e m o d e l in m e d i c i n e led u s to r e g a r d a f a m i l i a r b u t little u s e d r e s o u r c e ill m e d i c i n e in a new light. A c o r p u s of c o m - p u t e r r e a d a b l e d i s e a s e d e f l m t i o n s was s e e n to be a c r u d e i n s t a n t i a t i o n of t h e model. In this c o r p u s e a c h d i s e a s e was g i v e n a n a m e (a nomi- nal). a n d defined by its ( u s u a l l y clinical) a t t r i - b u t e s - t h e original m o t i v a t i o n for the c o r p u s b e i n g t h e s t a n d a r d i z a t i o n of d i s e a s e n o m e n c l a - l u r e . The a t t r i b u t e s w e r e w r i t t e n in a tale- g r a p h i c , b u t o t h e r w i s e easily r e a d a b l e style, and o r g a n i z e d , for e a c h disease, in a relatively s t a b l e f o r m a t - a f o r m we have c h o s e n to call s t ~ c - t ~ d ttzt.
Superficially. the corpus had but one level of d e s c r i p t i o n , a t t r i b u t e s of d i s e a s e s . But e a c h d i s e a s e definition was divided, explicitly, i n t o " c o n t e x t s " (etiology. s y m p t o m s . . . lab. x-ray. ...). and each disease was place in one (or. at m o s t two) " b o d y systems" (whole body. skin ... u r o g e n i t a l . . . . ). T h e s e c o n t e x t s and s y s t e m s w e r e obviously s t r o n g , if i m p r e c i s e , d e t e r m i n e r s of c o n t e x t .
Early e x p e r i m e n t s [3.4] with t h i s corpus. t h e c o m p u t e r r e a d a b l e v e r s i o n of Cto-rtn2 Msd/- c,., I, t f o , ' , n u . ~ n ~
T ~ n ~ o ~
(C~IT), 4¢h
Edition
[II].
e x p l o r e d t h e s e l e c t i v e a n d a s s o c i a - tive p o w e r of t h e w o r d s it e m p l o y e d , and c o n f i r m e d o u r h y p o t h e s i s t h a t w o r d u s e in it was b o t h r e l a t i v e l y c o n s i s t e n t a n d s y s t e m a t i c . We s o o n realized t h a t the s h a r p e s t t e s t of the abil- ity of words to convey m e a n i n g in this context was to evaluate the corpus as a knowledge base for a "diagnoses p r o g r a m " which would accept a d e s c r i p t i o n of t h e patient in the f o r m of a list of words, such as 'pain. fever, jaundice .... '. The specific d i a g n o s t i c p r o b l e m we a d d r e s s e d was that of formulating a "differential diagnosis ''z [12. 15]. which included, as alluded to by Scad- ding [21, 5]. diseases that a physician might not othaT~ise think of. but. p e r h a p s , should think of. Important to our attempt to formulate a diagnostic prompting p r o g r a m was not only that the knowledge b a s e should be readily comprehensible, but, if the disease "prompts" were to be credible, the "reasoning" by which d i s e a s e s were r e t r i e v e d a n d r a n k e d had to be equally accessible - a consultative criterion n o t e d by Shortlfffe a n d c o - w o r k e r s [P~. 23].In addition, t h e availability of a knowledge b a s e contmning in e x c e s s of 3000 d i s e a s e d e s c r i p t i o n s has allowed us to s t u d y p h e n o m e n a that would be hard to reproduce in the context of m o s t "expert systems". ~ For example.
zA "dlfferentla/ d i a g n o s e " ts u.sua].ly a List of dJxcases
which r e p r e s e n t s the c u r r e n t L~'~:ing of a phymcian resard-
tr~ poamble ~ha~n~em for • 81ven p a u e n t , at a Iliven point m
the diagnor..lc process.
best know Cll~q~noms program, an expert sy~ern fm'merly named .~NTERbr~T - ,now eai~cd CADUCEUS, current-
a p p e n d e d to t h i s p a p e r is a t r a n s c r i p t of a n i n t e r a c t i o n with RECONSIDER r e g a r d i n g a c a s e of m e t h a n o l p o i s o n i n g s u p p l i e d by one of t h e a u t h o r s (SIN). None of t h e p a t i e n t findings a r e p a r t i c u l a r l y specific, b u t RECONSIDER p l a c e s t h e c o r r e c t d i a g n o s i s in Oth place, a n d d e t e r - m i n e s t h a t m o s t of t h e d i s e a s e s n e a r t h e t o p of t h e differential a r e "whole b o d y " d i s e a s e s , a g r o u p c o n t a i n i n g m o s t t o x i c i t y d i s e a s e s . If t h i s differential w e r e s e l e c t e d f r o m a m o n g a few h u n - d r e d d i s e a s e s , or e v e n f r o m a k n o w l e d g e b a s e of t o x i c i t y d i s e a s e s , t h e r e s u l t w o u l d he m o r e o p e n t o a v a r i e t y of l e s s f a v o r a b l e i n t e r p r e t a t i o n s . P u t differently, w h e n o n e is r e t r i e v i n g f r o m s u c h a l a r g e knowledile b a s e . o n e is m o r e t o l e r a n t a b o u t t h e a p p e a r a n c e of "false p o s i t i v e s " ( d i s e a s e s t h a t s h o u l d n ' t be t h e r e ) in the i n t e r e s t s of m i n i m i z i n g t h e n u m b e r of "false n e g a t i v e s " ( d i s e a s e s t h a t s h o u l d b e t h e r e , b u t a r e not).
Finally.
RECONSIDER
p r o v i d e s a test b e d for t h e e v a l u a t i o n of s o m e h y p o t h e s e s r e g a r d i n g t h e kind of p r o b l e m s e n c o u n t e r e d r e p r e s e n t i n g a n d utilizing k n o w l e d g e a b o u t t h e ' n a t u r a l ' , as o p p o s e d to 'artificial'. world. Briefly. RECON- SIDER b e n e f i t s f r o m t h e h i g h d e g r e e of s t r u c - t u r e o b s e r v a b l e in d i a g n o s t i c m e d i c i n e , in s p i t e of o u r i g n o r a n c e in m a n y a r e a s , a n d t h e o t h e r - wise g e n e r a l l y u n a p p r e c i a t e d s t a b i l i t y a n d specificity of m e d i c a l l a n g u a g e r e g a r d i n g this s t r u c t u r e .2. Zxtmtetattons?
N o n - m e d i c a l a u d i e n c e s s h o u l d be r e m i n d e d of differing e x p e c t a t i o n s r e g a r d i n g s u c h m e a n - ing r e p r e s e n t a t i o n e x p e r i m e n t s . As c o m p u t e r s c i e n t i s t s , two of u s (MST & DDS) "knew" t h a t m e a n i n g could n o t be r e p r e s e n t e d s a t i s f a c t o r i l y by w o r d s alone: w o r d s w e r e a m b i g u o u s , in g e n - eral. and, besides, syntax was a partner with semantics, and to separate the two was to g r o s s l y d i s t o r t t h e m e a n i n g of either. 4 We r e g a r d e d e a r l y e f f o r t s as p o t e n t i a l l y i n t e r e s t i n g from the point of view of statistical linquistics - h o w did words a n d contexts associate? However. the medically trained m e m b e r of t h e initial t e a m (MSB) p r e d i c t e d t h e successful perfor- m a n c e of
RECONSIDER
o n c e he saw the resultso f s o m e early word-counting experiments.
Later. SN, an internist with a b a c k g r o u n d in mathematics, anticipated the p e r f o r m a n c e lim- iting aspect of
RECONSIDER
without ever using the program! (He predicted that inadequacies in the knowledge base would be m o r e important than any s h o r t c o m i n g s in the algorithms by which descriptions of patients were "matched" w~th the descriptions of the diseases.)]y "understands" a few hundred dineaJee in the field of '--'Iter- aal medicine [19, 18. 20, 18, 14].
4A local example of failure m " ~ - t e x t l e a r ~ h l ~ " WaS recently bro~l~tt to our a t t e n t i o n [13]. [n a search of docu-
nnen~ in a daymblum collected for a m~ut regarding a large
-3. An E x a m p l e of ' S t r u c t u r e d Text'
C M I T was designed first for h u m a n users, as a r e f e r e n c e of s t a n d a r d d i s e a s e n a m e s (in b o o k f o r m it is about the size of the World Almanac), a n d second for c o m p u t e r applications. (The
R E C O N S I D E R - f o r m a t t e d CKIT d e f i n i t i o n of
.tet/~yl 0~co/wL, to~c~t~J appears in the appendix of t h i s p a p e r . ) The " s t r u c t u r e " i m p o s e d on C M I T definitions is Largely external to the language of those definitions.
First. t h e e n t i r e t e x t of C ~ T iS o r g a n i z e d in the a f o r e m e n t i o n e d n o T m ~ t ~ - c ~ t r ~ b ~ e f o r m . the disease n a m e s being the nominals and the d e s c r i p t i o n s consisting of t h e attributes of the disease, s
S e c o n d . each disease is a s s i g n e d to one. o r pos- sibly two, bod~j s ' t j s t s ~ s :
,~Aots bco~
skin
w t u s c ~ o s k e l e t a l
c m - d ~ a s c u / m " h.mn~c & l y m p h a t i c g ~s ~s'o ~ e s ~nu~ z u ~ g ~ i ~ a ~ e'n~ocr~ae n ~ o u s
¢pec~aZ sense ~ r g ~ t s
Third, each disease is described in p o ~ t s :
O ~ terms ( s y n o n y m s x, eponyrns) e ~ o t o ~
r~m~to,ns
c or~pt ic at~ons
p ~ A o f o ~ z ~
• i.~fe.Fff~.ce~ 6
Fourth. within each :DaFt, the descending h i e r a r - chy of se~.ences, ct~zuaes, and phrases (all i n f e r r a b l e f r o m punctuation) a r e used relatively c o n s i s t e n t l y t o d e n o t e a p p r o p r i a t e " c h u n k s " of m e a n i n g .
Thus, in this instance, s t r u c t u r e d tezt is tightly edited prose written in nominal-attribute form, employing external markers, a n d rela- tively c o n s i s t e n t p u n c t u a t i o n , style, a n d v o c a b u - Lary. Put differently. CMIT can be "structurally" p a r s e d w i t h o u t t h e n e e d t o / z t f e r a n y of t h e s e m a n t i c s f r o m t h e text. (Again. a p o r t i o n of this "parse" is what produces the "display" of the deflnLtaon of m e t h y l - l c o t w l , toz~c-iZy shown in the a p p e n d i x . )
~/t~ we are l e ~ n ~ . ~ m ore" eva~ua,Aon, the rm~n~s of dmeeses, even when they are descnp~ve r~aw.es (as CM[T zs deslff~ed to encotu-age), are not aJways sufficzent ,.o deter- re.he which d~ease ~ beLn 8 spoken o!. Without the descr~p- t~orm (attributes) phymcmr~ world he u.nabLe ~.0 resolve the problems created by different ~]'stems of disease nomencLa- tl~'e.
SAn u'tcpca-tan~ feat'~u'e of the compu~.er readable vernon of CMIT is that it contm.ns references, men, on of which is aot m~de in the printed vermont
4. T h e C u r r e n t I~CONSIDKR I m p l e m e n t a t i o n 4-. L T h e I n v e r t e d File
Using a b s t r a c t s y n t a x to r e p r e s e n t t h e s t r u c t u r e in t h e t e x t . C?41T was s c a n n e d a n d " p a r s e d ''~ to p r o d u c e a s e q u e n c e of ts~w.~, e a c h w i t h t h e following a t t r i b u t e s :
o r d i n a l p o s i t i o n of t e e m in p h r a s e o r d i n a l p o s i t i o n of p h r a s e in c l a u s e o r d i n a l p o s i t i o n of c l a u s e in s e n t e n c e o r d i n a l p o s i t i o n of s e n t e n c e in p a r t n a m e of p a r t
d i s e a s e
body s y s t e m ( s ) of d i s e a s e
Thus. a d i c t i o n a r y ( c o n t a i n i n g in e x c e s s of 20.000 s u c h t e r m s ) was f o r m e d a n d CM.IT "inverted", so that e a c h dictionary entry was fol- Lowed by pointers to every occurrence of that e n t r y in CMIT. I n c l u d e d with e v e r y p o i n t e r w e r e t h e s e v e n attributes associated with each o c c u r r e n c e of that t e r m . T h e r e a r e 333.211 t e r r a o c c u r r e n c e s in CMIT. for an a v e r a g e of a b o u t 102 t e r m s p e r d i s e a s e , o r 79 u n i q u e t e r m s p e r d i s e a s e , t h e d i f f e r e n c e being t e r m s t h a t a r e u s e d m o r e t h a n o n c e in a g i v e n deflnitior~ In p r i n c i p l e , t h i s " d i c t i o n a r y " c o u l d be u s e d to r e c o n s t r u c t CMIT, a s i t r~preswrtts, i n aZter,ta- t~ve for.7.at, e=actty tlw s a w ~ ~ n f o r m a t ~ r n !
This Large i n v e r t e d file allows e t ~ c i e n t searching for t e r m s in the text. T h e searches can be (I) constrained to a context (diseases of t h e skin). (2) c o n s t r a i n e d t o t e x t u a l p r o x i m i t y (adjacency. or m e m b e r s h i p within a clause), or (3) constrained to a definition p a r t ( s y m p t o m s only).
4.2~ S y n o n y m D i c t i o n a r y
A 15.388 t e r m " s y n o n y m " dictionary a. i n c l u d e s w o r d s n o t in CMIT w h i c h a r e s y n o n y m s of w o r d s u s e d in t h e CMIT definitions a n d w o r d s a l r e a d y in CMIT t h a t a r e s y n o n y m s of e a c h o t h e r (e.g. prur~tu,s a n d i t c A • g ) These a r e p a r t i - t i o n e d a_mongst 4.165 " s y n o n y m classes" ( t h e two o r m o r e w o r d s w i t h i n e a c h class a r e s y n o n y m s of each other). Search options allow searches with or without equiv~dencmg t h e synonyms, a n d with or without invoking hierarchical synonyms. The t e r m " s y n o n y m " is used generously, as the dictionary is actually f u n c t i o n i n g as a k i n d of s e m a n t i c n e t - c o n n e c t - ing words with strong c o n c e p t u a l Links. It s h o u l d a l s o be noted t h a t R E C O N S I D E R does not e m p l o y " s t e m m i n g " . All variants of a t e r m ( a n d s o m e p h r a s e s , e.g. a b d o m i n a l p e n n ). including. in s o m e c a s e s , mis-speLlings, a p p e a r wittun a sin- gle • 'synonym class". Though we h a v e n o t proven this, it is our opinion that this s y n o n y m diction- ary is what converts an interesting tool for r e s e a r c h into m e d i c a l term-use, into s o m e t h i n g vOnce age.u~ this par~e L~ .nOt identifylr~ "pa."~ of speech" Ln L~e conventional serme. Rat.her ".he ab~rac% t ~ (a BICF grammar akan to those deflnLng program,'vzJ~ languages) encodes the meaning of :he ex'.erna~ mcrke..-s and ptmctuatic~W conventions employed in C.MIT.
-that f u n c t i o n s not unlike an e x p e r t s y s t e m . 4.3. S e a r c h e s
S e a r c h e s for a s e t of t e r m s c a n r e q u i r e a m a t c h o n e v e r y t e r m . o r a m a t c h on one o r m o r e of t h e t e r m s in the set. In t h e l a t t e r case. m a t c h e s a r e s c o r e d in a m a n n e r r e m i n i s c e n t of t e c h n i q u e s u s e d for l i t e r a t u r e a n d infm-mation r e t r i e v e / by Salton. ~ p a r c k - J o n e s and o t h e r s . and in p a r t i c u l a r Doszkocs [8]. The scoring a/go- r i t h m is i l l u s t r a t e d in t h e n e x t s e c t i o n .
4. 4. T h e U s e r - I n t e r f a c e
R E C O N S I D E R is a n i n t e r a c t i v e user i n t e r -
face r u n n i n g on t o p of the i n v e r t e d file a n d t h e s e a r c h algorithms. It accepts terms, search
modifiers, a n d r e q u e s t s for one of t h e two m a t c h i n g a l g o r i t h m s , f o r m u l a t e s the a p p r o p r i - a t e query, s e a r c h e s the i n v e r t e d files, c o m p u t e s t h e s c o r e of t h e d i s e a s e s r e t r i e v e d (if r e q u e s t e d ) , c o n s t r u c t s a b o d y - s y s t e m h i s t o g r a m (if r e q u e s t e d ) , r a n k s t h e d i s e a s e s if a p p r o p r i a t e , a n d d i s p l a y s a n y d i s e a s e definitions s e l e c t e d for viewing or b r o w s i n g b y t h e u s e r .
5. P e r f o r m a n c e
S . L & C o m p a r t s e n w i t h two l Y ~ n c e t / e E x p e r t When applied Lo t h e p u b l i s h e d c a s e s diag- n o s e d b y I N T E R N I S T a n d PIP [R0.17,16],
RECONSIDER p r o d u c e d t h e c o r r e c t d i a g n o s i s ( o r d i a g n o s e s ) at. o r n e a r , t h e t o p of t h e d i s e a s e List p r o d u c e d b y e n t e r i n ~ the positive findings given Lo t h e s e p r o g r a m s [5]. (Again. CADUCEUS c o n s i d e r s 300 d i s e a s e s f r o m i n t e r n a l medicine, a n d PIP c o n s i d e r s 20 d i s e a s e s f e a t u r i n g e d e m a . ) While t h e s e c a s e s were o f t e n c o m p l e x , a l a r g e a m o u n t of clinical information was available for e a c h p a t i e n t .
5.2. D i a g n o s t i c P r ~ n p t i n ~ : An E x a m p l e We believe t h a t R E C O N S I D E R p e r f o r m s b e t t e r , a n d m u c h m o r e usefully, a t an e a r l i e r p o i n t in the d i a g n o s t i c process, at a t i m e p r i o r to a n y e x t e n s i v e p a t i e n t work-up, when t h e p h y s i c i a n ' s "cognitive s p a n " is widest [2].
F o r e x a m p l e , a p a t i e n t p r e s e n t s with findings a s n o t e d at t h e beginning of the a p p e n - dix. RECONSIDER b e g i n s b y p r o m p t i n g for t e r m s . T h e prefix ~s/is used b y the physician-
u s e r to i n d i c a t e t h a t t h e s u c c e e d i n g t e r m s a r e to be searched ~or in e i t h e r the s'y~npton~s, o r s~]rts p o r t i o n s of Lhe d i s e a s e d e s c r i p t i o n s . This g r o u p i n g , a union of the two vocabularies, was n e c e s s i t a t e d by the non-consistent usage of t e r m s in these c o n t e x t s . ~ The phrase oObdo~r~,,/
pmL't will m a t c h (given the R E C O N S I D E R o p t i o n s
setected to r u n this case) any c o - o c c u r r e n c e of
these two words (or its s y n o n y m s ) within a si~gie ctause. R E C O N S I D E R r e s p o n d s with the s y n o n y m s it knows for t h e t e r m s e n t e r e d , a n d
sThe ~ of terms withe CMIT did not follow t~e ~dioal do~rrm as to what was • ~m;~om, and what w,,, a ssgn.
t h e n u m b e r of d i s e a s e s c o n t a i n i n g one of mor'e o c c u r r e n c e s of e a c h of t h e t e r m s within t h e s s / c o n t e x t . The r e s p o n s e =bdo.tinaL pain[ 191+80] i n d i c a t e s t h a t t h e pah" a b d o m ~ n ~ p e n o c c u r s in 191 diseases a n d t h a t 80 a d d i t i o n a l diseases
h a v e b e e n r e t r i e v e d b y t h e s y n o n y m s for ~bdom- paL-t, n a m e l y ccL/c[3~], csL~ck~/~16], e n d pWut / n a b d o m 4 ~ 4 8 ] . The f a c t t h a t 3.5÷15+48
exceeds 80. and 191+35+18+48 exceeds
191+180, i n d i c a t e s t h a t some d i s e u e def i nit io ns c o n t a i n m o r e t h a n o n e t e r m f r o m t h i s s y n o n y m class.
The score (a m e a s u r e of selectivity) for a b d o m ~ n ~ p ~ n is
0.917 = 1 - ( 2 7 1 / 3 2 6 2 )
w h e r e 271 is t h e n u m b e r of " d i s e a s e o c c u r r e n c e s " of abdomma~ p ~ , a n d 3252 is the t o t a l n u r n b a r of d i s e a s e s in CMIT. A d i s e a s e ' s s c o r e is t h e s u m of t h e s c o r e s of t h e t e r m s its d e s c r i p t i o n m a t c h e d .
Most p h y s i c i a n s would p r o b a b l y c o n c l u d e t h a t t h e o b s e r v a t i o n t h a t t h e patienL s m o k e d was not r e l e v a n t to t h e p a t i e n t ' s illness, b u t the t e r m s m o ~ was e n t e r e d h e r e to s h o w its obvi- o u s effect on t h e d i s e a s e List (it b r i n g s n~.ott~ur, t o = / ¢ / ~ a n d ~ g ~ p e n d e . c e , ma=-/h~m~ n e a r e r to t h e top, p a r t l y b e c a u s e it is so "seLec- tive"). It is n o t c l e a r which ' p a r t ' of t h e d i s e a s e d e s c r i p t i o n s t h e t e r m ~ w l o ~ g will be f o u n d in. so its s e a r c h c o n t e x t is a l l / . a n d t h e s a m e deci- s i o n is m a d e with r e s p e c t to =e/dos.iv. An/on g a p ~ / d o s / 8 is n o t u s e d in C~]T, s o we e n t e r the m o r e g e n e r a / f o r m . I° E n t e r i n g swto~lk~g in t h e a ~ / c o n t e x t h a s t h e d i s a d v a n t a g e t h a t it b r i n g s in a r e f e r e n c e to s m o k y , w h i c h is u s e d as a n adjective.
The h i s t o g r a m d i s p l a y s t h e b o d y s y s t e m f r e q u e n c i e s for t h e d i s e a s e s n e a r t h e top of the d i s e a s e list ( t h e top 4~, was s e l e c t e d by t h e u s e r to include a b o u t t h e first " s c r e e n ' s w o r t h " of the d i s e a s e List - 8?9 d i s e a s e s c o n t a i n i n g one or m o r e of t h e t e r m s e n t e r e d , o r t h e i r s y n o n y m s ) .
A p h y s i c i a n - u s e r viewing t h e first s c r e e n - full of this ~st ( t h e p o r t i o n s h o w n in the a p p e n - dix) would n e x t f o r m u l a t e a s t r a t e g y for resolv- ing it, a s s u m i n g t h e d i a g n o s i s was still noL i m m e d i a t e l y a p p a r e n t . A m e t h o d i c a l a p p r o a c h
would n o t e first that no d i s e a s e m a t c h e d all five
entries (as n o disease has a score of 4.738).
Similarly, diseases #I, #2. a n d #3 would be r u l e d o u t by asking t h e p a t i e n t a p p r o p r i a t e questions.
(If the patient w e r e f r o m Matin County, h e r e in t h e B a y Area. we might f o c u s our initial aLLen-
Lion on #2, rn~.sh~'oont, toe'S.city, in response to recent n e w s reports of cases of tt t h e r e -
1°An a%ternpt on the par~ of the ,~er so enter witch g ~ ~ n a , whJJe !audable (it wou~d be very Selectee). wouid be greeted 5y a rr~essage 01at the :er.'n was not found m CMIT or
its synonym, dictionary - Ln QI~s case because CM,'T predates wide v~e o+ '+ this ~es~. At t~e point the phy~e~a.~user must use hi~ ~" her own knowled~[e of med~cme, to know ~hat ~he term ~'ldom Ls the bern. ~bst~tu~e under ~.hese c~r-
cum~anc~. Looked at differently, our eva~uaUon ~ee.'u= to con.~Lrm ~h~t, in genera], alor~ medical ~alowledge makes one a more effee~ve ~ECOH~ID~ user. ~f t.~e, we regard "~h~s
as a po~Uve featm-~ ~' RRCON.elDER.
" ~ o w l e d g e that is not available tu RECON- SIDER.) Disease #4, e c t o ~ p ~ , raises a m o r e i n t e r e s t i n g issue. R E C O N S I D E R does not have a m o d e l of g e n d e r ( o r of a n y t h i n g else), s o a disease that occurs d u r i n g p r e g n a n c y is not automatically ruled out w h e n the patient is m a l e . WhAle u n d e r s t a n d a b l y d i s t r a c t i n g at first. u s e r s a r e s o o n c o m f o r t a b l e i g n o r i n g s u c h i n c l u - s i o n s , e s p e c i a l l y s i n c e i t ' s e a s y to u n d e r s t a n d
RECONSIDER p u t the disease there. View- ing the C ~ ] T d e f i n i t i o n of d i s e a s e #5. nej#u-Lbi~,
s"It £ o ~
r e v e a l s t h a t it is u s u a l l y a c c o m p a n i e d b y a r i c h c o m p l e x of symptoms, so while it c a n n o t b e r u l e d o u t a t t h i s point, it b e c o m e s e x t r e m e l y u n l i k e l y . S i n c e t h e p a t i e n t is n o t a n a l c o h o l i c , the d e f i n i t i o n of d i s e a s e #6, rn.ethTjt ~l.cohoL,Lozic%tll.
s u g g e s t s t h e possibility of o c c u p a t i o n a l e x p o s u r e ( p e r h a p s p e r c u t a n e o u s o r r e s p k a t o r y ) . O n c e c o n s i d e r e d , a n a p p r o p r i - a t e t e s t w o u l d c o n f i r m t h e e x i s t e n c e of t h e t o x i c substance in t h e body.8. / k ~ l - U m r Experience
We h a v e not p e r m i t t e d R E C O N S I D E R to b e used '~iva" in a clinical context. In addition to the fact that evaluation of the p r o g r a m is not c o m p l e t e , t h e k n o w l e d g e b a s e is k n o w n to be o u t
of d a t e . N o n e t h e l e s s s i n c e we h a v e b e e n able to move RECONSIDER to t h e M I S - U C S F V A X 11/750 r u n n i n g UNIX~ ( B e r k e l e y 4.1) s t u d e n t s , p o s t - d o c t o r a l fellows a n d s o m e f a c u l t y h a v e b e e n a b l e to use the program. The initial reaction usually consists of the following three observations: (I) " W h y is that disease there?" (sometimes it's t h e r e Legitimately, a n d s o m e t i m e s not), (2) "How does such a d u m b p r o g r a m do so well?" (refer- ring to RECONSIDER's lack of evident reasoning power), a n d (3) "What I n e e d to b e a b l e to do now is ..." (1111 in your favorite interactive- knowledge-base user-feature).
W e t o l e r a t e the p r o b i e m alluded to by ques- tion (I) because it is m o r e important, at this stage of development, not to miss important diseases, and because it is easier for a physician-user to r e j e c t totally inappropriate diseases than it is for the p r o g r a m to do so. Question (2) alludes to the point r a i s e d by the title of this paper. R E C O N S I D E R can only be considered an " e x p e r t " (if at all) because its knowledge base is so Large (relative to what a p h y s i c i a n c a n k e e p r e a d i l y a v a i l a b l e in his or h e r
head), and because of its performance. It is
o b v i o u s l y n o t like a h u m a n " e x p e r t " un the w a y it a ~ ' ~ v e s at the d i s e a s e list. A n d question (3) we take to be a c o m p h m e n t that reveals, a m o n g other things, that occasionally the utility of R E C O N S I D E R is iu~uted not by the knowledge it eonteuns, but by the m e a n s w e currently have of accessing it through the narrow w i n d o w of a 23- line C R T terminal.
Question (1) d e s e r v e s f u r t h e r c o m m e n t . The author (MST) has o b s e r v e d considerable user-discomfort caused by C M I T hexing diseases f r o m several b o d y systems near the top of a eUN1X is a produc~ of Ben Telephone Laboratories, ~nc.
s o r t e d d i s e a s e list. A p p a r e n t l y , t h e c o g n i t i v e d i s s o n a n c e is u s u a l l y avoided by t h i n k i n g a b o u t d i s e a s e s by s y s t e m , an t h e discomfort can b e r e l i e v e d by r e s t r i c t i n g t h e s e a r c h ( a n d t h u s t h e s o r t e d list) to a single b o d y s y s t e m . T h e p r o b - l e m with t h e l a t t e r p r a c t i c e is t h a t t h e p r e l i m - inary results of our evaluation reveals that con- textless (0~/searches) are the m o s t e~Lcacious. on average. AS this is also the opposite of the behavior p r e d i c t e d by our model of c o n t e x t in a norruna/-attribute knowled4[e base. f u r t h e r study is s u g g e s t e d . In any case, i t m a y prove neces- sary to r e - d e s i g n t h e u s e r - i n t o r f a c e to a c c o m o - d a t e s o m e u s e r s ' n e e d to view d e s e a s e s by s y s - t e m , within a contextless search.
7. Evaluation
A formal evaluation of R E C O N S I D E R on i00 s e r i a l a d m i s s i o n s to a t e r t m r y c a r e m e d i c a l w a r d . is in p r o g r e s s ( a n d will b e r e p o r t e d e l s e - w h e r e ) , b u t t h e p r e l i m / n a r y r e s u l t s a r e b o t h
encouraging
a n d i n t e r e s t i n g . T h e y a r e e n c o u r a g i n g b e c a u s e t h e c o r r e c t d i a g n o s e s is i n c l u d e d so o f t e n in t h e f i r s t f r a m e o r two ( a n d u s u a l l y h i g h e r ) , a n d i n t e r e s t i n g b e c a u s e t h e d i f f e r e n c e b e t w e e n d i a g n o s t i c p r o g r a m s , a n d d i a g n o s t i c p ~ r n 4 ~ g p r o g r a m s is m a d e q u i t e c l e a r , The f o r m e r h a v e a v e r y s p e c i f i c goal. a n d it is e a s y to tell w h e t h e r it is r e a c h e d o r n o t . A p r o m p t i n g p r o g r a m is e v a l u a t e d against a d i f f e r e n t s t a n d a r d ; n o t w h e t h e r it is c o r r e c t b u t w h e t h e r it is h a l p f u i And j u d g i n g w h e t h e r s o m e - thing is helpful or not m a y be a subtle matter. If the correct diagnosis is included h ~ h on the List, the performance can be given a hiKh score. But if, instead, a listed disease closely r e l a t e d to the c o r r e c t one has the r e s u l t of d i r e c t i n g the physician's a t t e n t i o n to the c o r r e c t body sys- tem, a n d finally t h e c o r r e c t d i a g n o s i s , how is t h i s to be s c o r e d ?8. S u s p e c t e d [~mitat/ons: 8.1. The ]Qaowtedge
As h a s b e e n t h e e x p e r i e n c e with s i m i l a r
projects, c o m p u t e r processing subjects
" k n o w l e d g e " to a h a r s h a n d u n y i e l d i n g l ~ h t . We anticipate that a half a m a n - y e a r of "tuning" would significantly i m p r o v e R E C O N S I D E E s per- f o r m a n c e , b u t t h a t t h e next a n d m u c h m o r e s e r i o u s Limitation will b e t h e q u a l i t y , u n i f o r m i t y , c o m p l e t e n e s s , a n d t i m e l i n e s s of CMIT a n d t h e s y n o n y m dictionary. Given the opportunity to rewrite CMIT (and continue to do so on an on- g o i n g basis), or i n t r o d u c i n g A] t e c h n i q u e s to R E C O N S I D E R (we have r e c e i v e d m a n y sugges- tions), we would c h o o s e the f o r m e r .
8.2, Other l J r n i t ~ U o l ~
c o n t a i n i n g a c e r t a i n t e r m . o r t e r m s . E s p e c i a l l y t r i c k y would b e i n t e r a c t i o n s b e t w e e n t h e s e two u s e s of n e g a t i o n .
On a m o r e global level. CMITs h o m o g e n i z a - t i o n of d i s e a s e s c o n t r i b u t e s to c o n f u s i o n a n d l o s s of i n f o r m a t i o n . C o n g e s t i v e h e a r t f a i l u r e is l i s t e d a s a d i s e a s e u n d e r ~ r ( . fa~,ui'e, cov~ss- tt~e. a s a symptom u n d e r ~ a r t . AMoe~tm,~mye. ~ e - - e . a s a s i g n u n d e r H a r t , AV/m,-tT~pA V, /mm-t. f ~ t v 0 k g e ~ r t a n d ~ s t a ~ a ' ~ .
,fu.bv,dvuZar, a n d as a complication in, for exam-
pie. t r ~ p z n a s o ~ a ~ s , ~awm~c~m. And to illus- t r a t e t h e s t r e s s o n t h e p r o c e s s of a t t e m p t i n g t o f o r m a c l o s e d s e t of s y n o n y m s , t h e s y m p t o m s a n d s i g n s of c 0 n ~ e s ~ e ~ m ' ~ ~ s a r e d e s c r i b e d a t v a r i o u s p o i n t s as in cm-dio~.,~o- pa£A!@, but t h e p h r a s e conges~bue heart f ~ d o e s n o t o c c u r in t h a t d e s c r i p t i o n .
9. Futuure I m p { e m e n t a U ~ u m
Given a n o p p o r t u n i t y to r e - b r n p l e m e n t CMIT. we w o u l d r e t r e a t h-ore o u r o r i g i n a l n o t i o n t h a t it should not be modified (so as t o p r o v e that s t r u c t u r e d t e x t c o u l d b e u s e d , i n t a c t , as a k n o w l e d g e b a s e ) . R a t h e r we would m a i n t a I n t h e i n v e r t e d files d y n a m i c a l l y , in a r e l a t i o n a l d a t a - b a s e . s o as to f a c i l i t a t e m o d i f i c a t i o n s , a n d e x p e r i m e n t s with a l t e r n a t i v e k n o w l e d g e r e p r e s e n t a t i o n s a n d r e t r i e v a l t e c h n i q u e s . Specifically. we would i n v e s t i g a t e t h e d i f f i c u l t y of r e - w r i t I n g CM1T to i m p r o v e t h e q u a l i t y a n d t i m e l i n e s s of t h e i n f o r m a t i o n it c o n t a i n e d , t o u s e a m o r e s t a n d a r d m o d e l of d i s e a s e n o m e n c l a - t u r e [ 1]. to e v a l u a t e a l t e r n a t i v e w a y s of h a n d l i n g n e g a t i o n ( s u c h a s 2 m ~ u g ~ e - b s e n t ) . a n d t h e allow u s e r s t o specify n e c e s s / ~ (a term m.usf occur, or not occur, In a disease description for it to b e r e t r i e v e d ) .
RECONSIDER c u r r e n t l y requires s o m e 20 M B o{ disk space. A dynamically revisable ver- sion would require at least twice that. m a k i n g R E C O N S I D E R a little Like an orphan e l e p h a n t in already pressed medical computing environ- ments. A "production" version of R E C O N S I D E R might fit in 15 MB, leaving two alternatives for the future: running R E C O N S I D E R on the large address-space micro-based systems now avail.- able with large hard disks, or m a k i n g it available on a network. W e are toot~n~ into both possibili- t i e s .
10. C o n c l u m o n s
In t h e c o n t e x t of m e d i c a l d i a g n o s e s , a n d p e r h a p s in o t h e r a p p t i c a t i o n a r e a s . " s t r u c t u r e d t e x t " , a s d e f i n e d h e r e , h a s b e e n n e g l e c t e d as a m e a n s of representin 8 information in a form accessible to both h u m a n s and algorithms. If as Minsky has put it. "For a program, being s m a r t is knowing a tot.", then carefulty edited and con- structed natural language text, available in computer-readable form, m a y facilitate the pro- cess by which p r o g r a m s c o m e to "know a lot" and continue to " k n o w a tot" as the knowledge evolves o v e r t i m e .
We c o n c l u d e b y n o t i n g t h a t u l t i m a t e l y tile u s e f u l n e s s of d i a g n o s t i c a i d s s u c h a s RECON- SIDER. m u s t a w a i t t h e v e r d i c t of u s e r s . If t h e c o s t a n d b o t h e r of t h e i r u s e is l e s s t h a n t h e b e n e f i t t h e y a r e f o u n d t o provide, we c a n e x p e c t t h e m to m a k e t h e i r way Into clinical p r a c t i c e . U p u n t i l t h e p r e s e n t t h n e . n o d i a g n o s t i c s u p p o r t program seems to have accomplished t~s.
11. t~.knmeledgementa
F u t u r e r e p o r t s will i n c l u d e t h e p e r f o r m a n c e of t h e c a s e " e n t e r e r e " w h o h a v e l a b o r e d to c o m - p l e t e t h e t a s k of f o r m u l a t i n g d i f f e r e n t i a l s for 100 c a s e s . As s o m e o f t h e i r r e a c t i o n s a r e I n c l u d e d h e r e t h e y a r e a c k n o w l e d g e d below. T h o s e c a s e - e n t e r e r s who a r e n o t c o - a u t h o r s a r e M a r k P, r i b a u m , M.D.. P e t e r H a r r i s o n . M.D.. Hyo Kim. M.D.. P a u l i n e Yelez. m e d i c a l s t u d e n t . Ber- n a r d W i n k l m a n n , M.D.. Dale Y a m a s h i t a . M.D.
1P- l ~ . f e r e n c ~
I. . ICD. £ C M - T M I n £ ~ Clu.~cou~m~ o l ~seases, ~ h RmtL~r~ C o m ~ s s i o n on P r o f e s s i o n a l a n d H o s p i t a l Activities. G r e e n Road. A n n Arbor, M i c h i g a n (1970).
2. Blois. M. 5 . " C l h ~ c a l j u d g m e n t a n d c o m p u t - e r s , " N e w ~ , ~ . ,Tour. Mad. 340B pp. 192-197 (1980).
3. Blois. M. S.. D. D. S h e r e r t z . a n d M. 5. Turtle, " W o r d a n d O b j e c t In D i s e a s e D e s c r i p t i o n s . " P r e c . o f t~m 1 8 t a / s i n . Meattruj o f Assoc. f o r J u ~ . l ~ O ) . A s s o c . for C o m p u t a t i o n a l L i n g u i s t i c s , (1980).
4. BloL% M. 5 , D. D. S h e r e r t z . a n d Nu 5. T u t t l e . " T h e A l g o r i t h m i c P r o c e s s i n g of Medical T e x t Utilizing C o n t e x t , " ~ c . o f t h e 4 t h . ~ . Med~c,~ C ~ (W¢~lvLv~to~. D. C., No~err~er.
2~ao).
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Append/x:
A C a n e of MethAnol Poisoning
A 26 year old m a l e w a s a d m i t t e d to the m e d i c a l w a r d of the S U N Y S t o n y B r o o k hospital c o m p l a i n i n g of ab- dorninal pain, confusion, a n d vomit- i n g It w a s n o t e d that Lhe patient w a s a s m o k e r A lab test h a d revealed an- ion g a p acidosis.
Enter ten'm: ss/abdo~rml pain, confusion, v~ni t in~
Signs or Syrrptcrm: .~x~Ti. nat pain[191+O0]
(colic[35 i, cotickytZ6], pain in
abdu',=.[48]);
ccnfusiontBS+7] (confused[7]) ;
~m-~tirv, E4e~l]
(erms~s[2], byperm~sis[2],
r~r~m~sis[1], vm~tus[9]).
F n t e r t e n t s : a l l / s n a k i n g , a c i d o s i s
S i g n s or Synlptcrn~: _abd@~~l pa in[191+80]
(cotic[35J. colicky[m], pain in a ~ n [ 4 S ] ) :
con fus ion[SS+7] (confused[ 7]) ;
~ t i n g [ ~ + 1 ]
(~sis[2], ~o,p=-,,=s~[2].
hypereTisis[ I J. vani tusL9]).
all:
,r~kir~[Z~S]
(,m£c, ta].
s-mky[1]) .
acidos i s[37+1] (acids'l~a[ I ] ). Cu = m'zi: s
Cazputing scores for Signs or SMTpLcrs Leto's Finished abdo-n[r~ll pain, s e l e c t i v i t y = 0.917 Finished confusion, s e l e c t i v i t y = 0.972 F i n i s h e d v c m t t i n g , s e l e c t i v i t y = 0.570 C_xrrputing s c o r e s for a l l ternm
F i n i s h e d s ' m k i n g , s e l e c t i v i t y = 0.99] F i n i s h e d a c i d o s i s , s e l e c t i v i t y = 0.~39
S o r t i n g t o t a l e d d, sease s c o r e s . . . 4.738 - rmxuTu'n t o t a l score
679 d i s e a s e s in t h i s l i s t }-[isto~r:rn for the top 4~o of the [tsL
(27 diseases)
• • e , • e , + ) e+, • , I + • + o +
W n o ~ e 5 o d y • * " " * " " " " " " " " " ' " " " * ' " "
l h s c ' a o F ¢ e [ e = a ~ ' ' ' ' " ~ s p ; .-a'+ o.-y " "
Ca_"d : o v a s c u , a.- " * "=Wr= c--.wrp, hat : c °
[ ~ O g ~ ; t a . ' ' ° ° ° ' ' ' ' ° ° ° F-~Id oc .": ne "
N e ."~'otJs " ' ' "
S i g n s or Synlptcrns: ,~m::krrnnal pain[191+SO]: confuston(8,5+7] ; va.,m t ing{.'l.~"5+-I ]. a l l : ~--mkirg[Z3+a3]; a c i d o s i s [ 3 7 + l ]
4 . T 3 8 - n ' ~ x m n . m t o t a l s c o r e 679 dzseases m ~nzs !:st
l 3 , 7 5 0 n l c o r . l n e , : o x l c : t y O0 2 3 . 7 4 8 n%lsaro~% t o x l c : t y O0 3 2.833 dr.~ dependence, n'e.-i~ama O0 4 2.830 ec ia'rps ~ a 07
6 2.7"~ rmthyl alcohol, to~:czty O0 7 R.7~ food ;x)is~n~0 st m~hylococcal 8 2,776 ca=a, diabetic 08
9 2.7~9 tlmiliutt toxicity O0
10 2.7"J~ ars~nc, t ~ i c i t y O0
I I ~ . ~ r n g r a i z m s y r ~ r a m 00-09
12 2 . 7 ~ p ~ y r i a , acute int~mtt(mt
1 3 I , M I l ~ F e . h ~ i s withrretabolic,
.'~tr i t i ~ dis~den. O0
1 4 1 . 9 6 1 e . ~ b a n diomde, narcceis O~ 15 l.g61 ~ t i ~ ¢~4~lopat~y (~
16 I.~I cam, hepatic 06-09
17 I . ~ f ~ syr~'a~'m, adult,
18 I.~08 disrrhea, d~r~nc ~8
~@ ~ . ~ kidr, sy, c a l c u l ~ 07
00-08
8 2 . 7 ? 5 n e t h y t alcotx)t, t o x i c i t y 00
( s s ) a b d ~ n a i pain[0.917],
(as)
~t~ng[0.sv0],
{ a l ) a c i c t o s i s [ O . g { ~ J .
O0
( 8 ) methyl a l c ~ o L , toa:icity
A l t e r r m t e t e m ' i n o l o g y [ a t ] t o x i c i t y , r ~ t h y l a l c o h o l
wood a L c o h o l , toxicity;
methanoL, toxicity.
Etiology l e t ]
- I n h a l a t i o n o f vapor, i n g e s t i o n ,
p e r c u ~ absorption of
flmm'ebte liquid widely used
i n i n c ~ z try';
- effect of rmtabolization by body to
f o n m l d e h y d e a n d fon'ric a c i d , w i t h
d e p r e s s a n t a c t i o n o n e n s ;
- t i e , 200 p p r n o f air;
- internal l e t h a L close, 60-P.50 ml or 2-5 oz.
- OccxR~tiorml exposure: dry c l e a n i n g ,
organic synthesis;
-rfanufacture of antifreeze, dyes, explosives, fuel, leather, plastics.
- Acute poisoning from ir~estion, ir~;alation, or percutaneous absorption:
f a t i g u e :
- h e a d a c h e ;
- r ~ u ~ e a ;
~ > vcrra t ing;
- v i s i o n z q u a i r e d ;
- p h o t ~ i a ;
- d i z z i n e s s ;
~ > in exposure to h i g h concentration or ingestion of high dose.
rr~ni festat i o n s n ~ r e rmrked as sex'(~re
u p p e r abdtrr~nal co/icky patr~.
sweating, possibly b i i r ~ l n e s s .
- O'~ronie poisoning from i,~-~lation, percutaneous absorpt i on: vi s ion
~'zpaired initially, progressive: - fatigue:
- Y ~ u s e a .
S i g m [sgJ
- A c u t e p o i s o n i n g : w i t h i n g e s t i o n . o n s e t w i t h i n 8 - 4 8 h o u r s : - c y a n o s i s :
- c o l d , c l m m / s k i n ; o eu[Nnoria;
- r e s p i r a t i o n sb-.llovc,
- b l o o d p r e s s u r e low;,
~ > f e a t u r e s o f a c i d o s i s ;
- c r m d e p r e s s i o n ;
- c o n v u l s i o n s ;
- c a ' 1 " a .
- O n r o n i c p o i s o n i n g : ~zerratoid
d e m m t i t i s ;
- c o n j u n c t i v i t i s :
- t r a c b e i t i s ;
- b r o c c h i t i s :
- ~ . t t e a d y g a i t .
- C o u r s e : in s e v e r e a c u t e poisonir.~,
rmrtality rate 25-50 percent; - inrrilder fon'm, recovery w i L h i n
~ e k ~ t o r n m t h s ;
- v i s i o n , recal f u n c t i o n possibly
irrpai r e d pen~k,~mt ly~
- T r e a t n ~ n t : adrinistration of s o d i u m
b i c a r t x l ' m t e orally or sodiu-n i ~ c : , ~ ' e
i n t r a v e n c u e l y t o t acidosis:
- irrigation of eyes with ~ater: - washing conternirated areas of body
w i t h soap, w a t e r ;
- c(nbating shock with oxygen,
stkmlants;
- oral ~tninistration of whiskey or intravenous administration of ~'0 percent e t h a n o l possibly
i n h i b i t i n g o x i d a t i o n o f rreth~r,o'
to its toxic intemmdiates.
Laboratory [ l b ]
- M e t h y l a l c o h o l in e x p i r e d a i : ' , t'_"l~e,
blood;
- fore'de acid in u r i n e .
- 0phthalrrDscopy: i n a c u t e ~ . i ~ o n ! ~ g .
d i i a t a t i o n o f p u p i l s , ccn, r~':~ ! ~:. ,,f
v i m m l fields, h y p e r ~ ' ~ a o" o1,'. i," d!~l<
r e t i n a l ede'm.;
- b l i n d w h i l e d i s c s , a t t e n c : , ' e , : ' , ~ , - : : -
o f o p t i c atrophy.
P a t h o t c3:,. [ p c ]
- .Meningeal petechi~/;
- c e r e b r a [ ederm;
- necrosis of r e t i ~ l i neurc.:-.~;
- suh'rucose.l, s u b e p i c a r d i a ' s . . . . "
h~T~r r h a g e ;
- ~ a r e r ~ h } r m t o u s d e ~ e n ~ r a t . . ~" . : .
kich~ey.
R e f e r e n c e s [ r f ]
D r e i s b a c h 13 t,/:12
bIJnter 561 ff
Jot~nstone-mi 1 l e t t56./59
PLtmkett 2~30,,"5 .t
T h i e n e s - h a t e y 68