(a)This patient has Lyme disease, which is seen in the late spring and
early summer. Up to a week or so after a bite from an infected tick, patients
may develop a rash, erythema migrans (EM), at the site of the bite. The
lesion is characterized by a bright red border and central clearing and
quickly spreads outward. EM is the most characteristic clinical manifesta-
tion of Lyme disease, and is recognized in 90% or more of patients. Sero-
logic testing may be positive weeks after inoculation, but a biopsy of the
rash would neither be necessary nor informative. (b)If meningitis is sus-
pected, a LP is an appropriate aspect of the workup. In this case, however,
the patient has a clear history and characteristic rash for Lyme disease with-
out meningeal signs or focal neurological signs. A LP would not be war-
ranted.(d) Untreated Lyme disease may progress to a second stage,
involving neurologic and cardiac abnormalities, 4 weeks after the bite.
(e)Lyme disease is largely a clinical diagnosis based on history and physical
examination and serologic testing should be used discriminately to confirm
the diagnosis. Serum immunofluorescent antibody assays are usually nega-
tive until approximately 6 weeks, when immunoglobulin M (IgM) peaks
and indicates active disease. IgG antibodies are detected when the arthritis
presents and peak at 12 months. Syphilis can cause false-positive titers, but
the different clinical presentations should distinguish the diseases.
188.The answer is d.(Tintinalli, p 1513.)The patient has signs sugges-
tive of Erythema Multiforme (EM),an acute inflammatory skin disease
that ranges from a localized eruption (EM minor) to a severe multisystem
illness (EM major) with extensive vesiculobullous lesions and erosion of
the mucous membranes, known as Stevens-Johnson syndrome (SJS).
It affects all age groups with the highest incidence in males 20 to 40 years
of age. SJS has significant morbidity and a mortality rate of approximately
10%. Death is usually a result of infection and dehydration. As in this case,
patients with severe disease should be admitted. Therapy consists of IV
fluids, oral prednisone, analgesics, antihistamines, mouth rinses, and skin
care. While no causative factor can be found in 50% of cases, known trig-
gers include infection, especially Mycoplasmaand herpes simplex virus,
drugs, especially anticonvulsants and antibiotics, and malignancies.
(a, b, and c)Because of the high morbidity and mortality, patients
with EM, especially the more severe form, SJS, should be admitted to the
hospital. Outpatient therapy of EM minor with topical steroids is possible.
Patients with extensive disease, systemic toxicity, or mucous membrane
involvement require hospitalization, optimally in an ICU or a burn unit.
Fever Answers 205