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C00002 00002 16-Apr-81 23:20:24-PST,14455000000000001
C00006 00003 April 16, 1981 10:46PM in <MYCIN>MYCIN.SAV10310 by SHORTLIFFE
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16-Apr-81 23:20:24-PST,14455;000000000001
Mail-from: ARPANET site SUMEX-AIM rcvd at 16-Apr-81 2319-PST
Date: 16 Apr 1981 2317-PST
From: Shortliffe@SUMEX-AIM
Subject: what MYCIN says
To: csd.lenat@SCORE
Doug,
Appended is a MYCIN run on Nicole's case. You'll note that the
program thinks that a viral syndrome is most likely and did not even
recommend therapy pending a repeat LP in 6-8 hours or so.
I asked a few additional questions at the end, though, to show
you why the treatment of ampicillin with chloramphenicol has been chosen.
The organism that one worries about most in a child Nicole's age is
hemophilus influenzae; I've listed the 3 applicable rules that show
why hemophilus is considered particularly likely. Ampicillin also covers
for the other common organisms, and it once was used routinely as a single
agent in situations such as this, but because about 3% of childhood
hemophilus is resistant to ampicillin, the second choice drug (chlorampheni-
col) is routinely given with the ampicillin until the sensitivities of the
organism are known. It's a conservative precaution but generally considered
reasonable in a potentially serious infection such as meningitis.
As for why the Stanford physicians started treatment but MYCIN
didn't, this reflects the fact that MYCIN knows nothing about infections
at other sites. The house staff were pushed to start antibiotics by the
high likelihood of urinary tract infection as much as by the rather mild
abnormalities in the CSF. I believe you said that the intern indicated that
in similar circumstances it might have been reasonable to wait and do a
repeat LP if there weren't reason to start antibiotics to cover for possible
infections at other sites.
I'm not sure you're interested in all this analysis, but I was
concerned that the MYCIN run might raise more questions than it answers
unless I also provide a little explanation.
Hope Nicole is markedly improved by the morning.
Regards,
Ted
----------------------------
April 16, 1981 10:46PM in <MYCIN>MYCIN.SAV;10310 by SHORTLIFFE
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16-Apr-81 22:46:12
--------PATIENT-1--------
1) Patient's name:
** Nicole L
2) Age:
** 4 MONTHS
3) Sex:
** F
4) Race:
** CAUC
=CAUCASIAN
5) Are there any cultures for Nicole L which may be related to the
present illness, and from which organisms have been grown successfully
in the microbiology laboratory?
** N
6) Are there any pending cultures for Nicole L?
** Y
--------CULTURE-1--------
7) From what site was the specimen for CULTURE-1 taken?
** CSF
8) Please give the date and time when the pending csf culture
(CULTURE-1) was obtained. (mo/da/yr time)
** 4/16/81 3PM
9) Was a smear examined at the time that the specimen for the pending
csf culture (CULTURE-1) was obtained?
** Y
10) Were any organisms seen on the smear of the specimen submitted as
the pending csf culture (CULTURE-1)?
** N
11) Are there any other pending cultures?
** N
12) Have there been negative (as opposed to pending) cultures obtained
from Nicole L which may be relevant to the present illness?
** N
13) Do you suspect Nicole L may have an infection at a site from which
you have not obtained culture specimens?
** N
14) Is Nicole L currently receiving therapy with any antimicrobial
agent?
** N
15) During the present illness, has Nicole L been treated with an
antimicrobial agent which is no longer being administered?
** N
[Considering organisms (other than those isolated from cultures) which might
be present...]
16) Has Nicole L recently had symptoms of persistent headache or other
abnormal neurologic symptoms (dizziness, lethargy, etc.)?
** Y
17) Has Nicole L recently had objective evidence of abnormal
neurologic signs (nuchal rigidity, coma, seizures, etc.) documented by
physician observation or examination?
** Y
The CSF cultures will be considered to be associated with MENINGITIS.
18) Please give the date on which clinical evidence (symptoms, signs, or
laboratory tests) of the meningitis first appeared.
** 4/15/81 6PM
19) Does Nicole L have an abnormal chest X-ray?
** UNK
20) Does Nicole L have one or more of the following risk factors for
tb: a) positive intermediate strength PPD, b) history of close contact
with a person with active tb, c) a household member with a past
history of active tb, d) apical scarring on chest xray, e) history of
granulomas on biopsy of liver, lymph node, or other organs.?
** N
21) Does Nicole L have any cutaneous lesions or rash on physical
examination?
** N
22) Does Nicole L have evidence of ocular nerve dysfunction?
** N
23) Is Nicole L a compromised host (e.g. alcoholic, sickle-cell-
disease, immunosuppressed)?
** N
24) For how many days has Nicole L had abnormal neurologic signs?
** 1
25) For how many days has Nicole L had neurologic symptoms?
** 1
26) Has Nicole L had recent evidence of tender or enlarged salivary
glands?
** N
27) Has Nicole L been exposed to any contagious disease recently (e.g.
meningococcal disease, mumps) ?
** UNK
28) What is the protein value (mg/100cc) in the CSF?
** 22
29) What is the total WBC count of the CSF?
** 18
30) What percent of the WBCs in the CSF were polys?
** 74
31) What is the glucose value (milligrams percent) in the CSF?
** 94
32) What is the simultaneous blood glucose?
** 79
33) Do you know the results of a recent CBC of Nicole L?
** Y
34) What was Nicole L's peripheral white count (in thousands)?
** 24.8
35) Has Nicole L had any injury or insult to, or defect in the central-
nervous-system (excluding neurosurgery)?
** N
36) Has Nicole L ever undergone any type of surgery?
** N
37) Does Nicole L live in a crowded environment?
** N
38) Is the meningitis a hospital-acquired infection?
** N
39) Is Nicole L's clinical history consistent with EPIGLOTTITIS?
** N
40) Is Nicole L's clinical history consistent with OTITIS-MEDIA?
** N
41) Is Nicole L a burn patient?
** N
I have found evidence (RULE564) that treatment should cover for Virus causing
meningitis.
42) Does Nicole L have focal neurological signs?
** N
[Determining which drugs are desirable for use against the Virus...]
My therapy recommendations will be designed to treat for organisms
that either are very likely or, although less likely, would have a
significant effect on therapy selection if they were present. It is
important to cover for the following probable infection(s) and
associated organism(s):
INFECTION-1 is MENINGITIS
+ ... VIRUS [from clinical evidence only] Supportive therapy.
Please repeat the LP in 8 - 24 hours for cultures (bacterial, fungal,
Tb, and viral), cells, and chemistries.
Please ask questions now. When you are finished and want to
begin a new consultation or sign off the terminal, enter the word
STOP.
Type HELP for the list of question options.
** HOW DO YOU TREAT FOR HEMOPHILUS INFLUENZAE CAUSING MENINGITIS?
For treatment of HEMOPHILUS-INFLUENZAE in MENINGITIS
The drugs of choice (ranked by relative efficacy, assuming sensitivity)
are:
1st choice:
AMPICILLIN
2nd choice:
CHLORAMPHENICOL
3rd choice:
CARBENICILLIN
TETRACYCLINE
ERYTHROMYCIN
CEPHALOTHIN
Duration of therapy: Treat for at least 5 afebrile days or for a minimum
of 10 days.
** HOW DO YOU DECIDE TO COVER FOR HEMOPHILUS INFLUENZAE?
The following rules conclude about:
the likelihood that Hemophilus-influenzae is one of the organisms (other
than those seen on cultures or smears) which might be causing the
infection
562, 554, 549, 548, 547, 546, 507, 341, 73
The parameters most frequently used in these rules are:
the infection which requires therapy
the diagnoses which are consistent with the patient's clinical history
the type of the infection
the stain of the organism
the morphology of the organism
whether the patient has a head injury defect
the age of the patient
whether a smear of the culture was examined
whether organisms were seen on the stain of the culture
Would you like a summary of ALL the parameters used by these rules? ** NO
Which of the rules do you wish to see?
** 554 507 341
RULE554
-------
[This rule applies to organisms, and is tried in order to find out about the
organisms (other than those seen on cultures or smears) which might be
causing the infection]
If: 1) The infection which requires therapy is meningitis,
2) The stain of the organism is not Gramneg,
3) The morphology of the organism is not rod,
4) The patient does not have a head injury defect, and
5) The age of the patient is known
Then: The organisms (other than those seen on cultures or smears) which
might be causing the infection is as follows:
If the age of the patient is:
a) less than 10 days then: e.coli (.4), klebsiella-pneumoniae (.3),
streptococcus-group-b (.4),
b) between 10 days and 1 month then: e.coli (.4), klebsiella-
pneumoniae (.3), streptococcus-group-b (.4),
c) between 1 month and 2 months then: e.coli (.3), streptococcus-
group-b (.4), listeria (.3);
**-->> d) between 2 months and 1 year then: diplococcus-pneumoniae (.3),
hemophilus-influenzae (.4), neisseria-meningitidis (.3),
e) between 1 year and 5 years then: diplococcus-pneumoniae (.3),
hemophilus-influenzae (.4), neisseria-meningitidis (.3),
f) between 5 years and 15 years then: diplococcus-pneumoniae (.4),
hemophilus-influenzae (.3), neisseria-meningitidis (.4),
g) between 15 years and 55 years then: diplococcus-pneumoniae (.4),
neisseria-meningitidis (.4),
h) greater or equal to 55 years then: staphylococcus-coag-pos (.3),
diplococcus-pneumoniae (.4),
Author: Yu
RULE507
-------
[This rule applies to pending cultures and suspected infections, and is tried
in order to find out about the organisms (other than those seen on
cultures or smears) which might be causing the infection]
If: 1) The infection which requires therapy is meningitis,
2) A: A smear of the culture was not examined, or
B: Organisms were not seen on the stain of the culture,
3) The type of the infection is bacterial,
4) The patient does not have a head injury defect, and
5) The age of the patient is known
Then: The organisms (other than those seen on cultures or smears) which
might be causing the infection is as follows:
If the age of the patient is:
a) less than 10 days then: e.coli (.75), klebsiella-pneumoniae (.5),
streptococcus-group-b (.75),
b) between 10 days and 1 month then: e.coli (.75), klebsiella-
pneumoniae (.5), streptococcus-group-b (.75),
c) between 1 month and 2 months then: e.coli (.75), streptococcus-
group-b (.75), listeria (.4);
**--> d) between 2 months and 1 year then: diplococcus-pneumoniae (.41),
streptococcus-group-b (.4), hemophilus-influenzae (.75),
neisseria-meningitidis (.4),
e) between 1 year and 5 years then: diplococcus-pneumoniae (.41),
hemophilus-influenzae (.75), neisseria-meningitidis (.4),
f) between 5 years and 15 years then: diplococcus-pneumoniae (.75),
hemophilus-influenzae (.73), neisseria-meningitidis (.74),
g) between 15 years and 55 years then: diplococcus-pneumoniae (.75),
neisseria-meningitidis (.74),
h) greater or equal to 55 years then: staphylococcus-coag-pos (.4),
streptococcus-species (.4), diplococcus-pneumoniae (.75),
Author: Yu
RULE341
-------
[This rule applies to suspected infections, and is tried in order to find out
about the organisms (other than those seen on cultures or smears) which
might be causing the infection]
If: 1) The infection which requires therapy is meningitis,
2) The age of the patient is known,
3) The type of the infection is bacterial, and
4) The patient does not have a head injury defect
Then: The organisms (other than those seen on cultures or smears) which
might be causing the infection is as follows:
If the age of the patient is:
a) less than 10 days then: e.coli (.75), klebsiella-pneumoniae (.5),
streptococcus-group-b (.75),
b) between 10 days and 1 month then: e.coli (.75), klebsiella-
pneumoniae (.5), streptococcus-group-b (.75),
c) between 1 month and 2 months then: e.coli (.75), streptococcus-
group-b (.75), listeria (.4);
**--> d) between 2 months and 1 year then: diplococcus-pneumoniae (.41),
streptococcus-group-b (.4), hemophilus-influenzae (.75),
neisseria-meningitidis (.4),
e) between 1 year and 5 years then: diplococcus-pneumoniae (.41),
hemophilus-influenzae (.75), neisseria-meningitidis (.4),
f) between 5 years and 15 years then: diplococcus-pneumoniae (.75),
hemophilus-influenzae (.73), neisseria-meningitidis (.74),
g) between 15 years and 55 years then: diplococcus-pneumoniae (.75),
neisseria-meningitidis (.74),
h) greater or equal to 55 years then: staphylococcus-coag-pos (.4),
streptococcus-species (.4), diplococcus-pneumoniae (.75),
Author: "Scott"
** STOP
Do you wish advice on another patient?
** NO
-------