Test your medicine knowledge with the MKSAP challenge, in partnership with the American College of Physicians.

A 20-year-old female college student is evaluated in December because of a 12-hour history of fever, myalgia, headache, and a rash. Her only medication is an oral contraceptive agent.

On physical examination, the patient appears ill. Temperature is 38.8 °C (101.8 °F), blood pressure is 90/45 mm Hg, pulse rate is 112/min, and respiration rate is 24/min. A petechial rash most prominent on the lower extremities is present. Passive neck flexion causes discomfort.

Laboratory studies:

Leukocyte count	10,500/µL (10.5 × 109/L) with 80% polymorphonuclear cells (PMNs) and 20% band forms
Platelet count	105,000/µL (105 × 109/L)
Blood urea nitrogen	30 mg/dL (10.7 mmol/L)
Creatinine	2.5 mg/dL (221 µmol/L)
Bicarbonate	15 meq/L (15 mmol/L)

Lumbar puncture is performed. Opening pressure is 300 mm H₂O. Cerebrospinal fluid leukocyte count is 1250/µL (1250 × 10⁶/L) with 95% PMNs. Protein is 100 mg/dL (1000 mg/L). Gram stain shows numerous PMNs; no organisms are seen.

Which of the following is the most likely diagnosis?

A) Listeria monocytogenes meningitis
B) Neisseria meningitidis meningitis
C) Rocky Mountain spotted fever
D) Viral meningitis

MKSAP Answer and Critique

The correct answer is B) Neisseria meningitidis meningitis. This item is available to MKSAP 15 subscribers as item 54 in the Infectious Disease section. More information about MKSAP 15 is available online.

This patient’s illness is most consistent with meningococcal infection, which is characterized by the sudden onset of fever, myalgia, headache, and rash in a previously healthy patient. Early in its course, meningococcal disease may be indistinguishable from other common viral illnesses; however the rapidity with which the disease worsens (often over hours) and progresses to septic shock differentiates it from these other illnesses. A petechial rash is most common and may coalesce to form purpuric lesions.

The diagnosis is established based on clinical presentation and confirmed with blood and cerebrospinal fluid (CSF) cultures. It is likely that this student received meningococcal vaccine because it is recommended for all adolescents aged 11 to 18 years and frequently is administered before entrance to college. The current vaccines are immunogenic and effective at preventing disease due to serogroups A, C, Y, and W-135. Unfortunately, none of the current vaccines is effective against serogroup B, which is also a common cause of disease occurring in the United States.

Meningitis caused by Listeria monocytogenes is associated with extremes of age (neonates and persons age >50 years), alcoholism, malignancy, immunosuppression, diabetes mellitus, hepatic failure, renal failure, iron overload, collagen vascular disorders, and HIV infection. The clinical presentation of Listeria meningoencephalitis ranges from a mild illness with fever and mental status changes to a fulminant course with coma.

The classic presentation of Rocky Mountain spotted fever is a severe headache, fever, myalgia, and arthralgia. Thrombocytopenia and acute kidney injury can occur. A maculopapular rash develops 3 to 5 days later (hardly ever on the first day of illness, as in this patient). It begins on the wrists and ankles and may involve the palms and soles. Rocky Mountain spotted fever is transmitted by the American dog tick in the spring and early summer, which is inconsistent with the timing of this patient’s presentation.

Viral (aseptic) meningitis can present similarly to bacterial meningitis with the classic findings of fever, headache and stiff neck, and photophobia and may be associated with a maculopapular eruption. However, acute viral meningitis is rarely associated with the combination of findings indicating early organ dysfunction such as metabolic acidosis and acute kidney injury.

Key Point

• Meningococcal infection should be considered in the differential diagnosis of any previously healthy patient who presents with acute-onset fever, headache, and myalgia.

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