A 77-year-old man is brought to the emergency department after several
days of illness that began with fever, nausea, emesis, and headache. Muscle
weakness and associated myalgia developed; the weakness became so severe
that the patient needed help to get out of bed and walk to the bathroom.
The day before he came to the hospital, he slept much of the time and was
difficult to arouse.
For several years, the patient has had mild diabetes, which is well controlled
by glyburide, 10 mg/d. Last year, congestive heart failure was diagnosed;
the ejection fraction at that time was 40%. Nonetheless, the patient, who
is retired, has been active and able to care for himself. He recently returned
from a 2-week Labor Day vacation on Long Island, NY.
The patient is lethargic. Temperature is 39oC (102.2oF); heart rate,
110 beats per minute; and blood pressure, 105/75 mm Hg. Heart, lungs, and
abdomen are normal, and neck is supple. There is no pallor or icterus of the
mucosae. Although the patient is able to move all extremities, his muscles
are diffusely weak. There are no localized neurologic findings; however, he is
somnolent and difficult to arouse.
White blood cell count is 12,000/μL with a normal differential. Serum
sodium level is 131 mEq/L, and glucose level is 278 mg/dL. Lumbar puncture
shows the cerebrospinal fluid (CSF) to have a protein level of 400 mg/dL, a
normal glucose level, and a pleocytosis of 980 white blood cells/μL with 88%
Which of the following is not true about the most likely diagnosis in
A. Advanced age (greater than 70 years) is the risk factor most likely to be
predictive of death.
B. This patient will benefit from plasmapheresis for 7 days.
C. There is roughly a 50% probability that this patient will have long-term
morbidity as a result of this illness.
D. The most efficient method of diagnosis is detection of IgM antibody in
the patient's serum or CSF.
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