A Plea to Reconsider the Diagnosis

An eight-month-old unvaccinated boy presented to an emergency department (ED) with fever, neck pain, and lethargy. Examination of the cerebrospinal fluid (CSF) demonstrated hazy fluid with a white blood cell count of 3,906 cells/uL (90% polymorphonuclear cells, 6% lymphocytes, and 4% monocytes), 0 red blood cells/uL, protein of 40 mg/dL, and glucose of 56 mg/dL. No organisms were seen on Gram stain. Ceftriaxone and vancomycin were administered. CSF, blood, and urine cultures remained sterile; arbovirus serology was nonreactive, and polymerase chain reactions (PCRs) for enterovirus, Herpes simplex virus (HSV), Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenza were negative. His irritability improved, but his fevers continued. The antibiotics were stopped after 10 days of empiric treatment, and his fever resolved within 36 hours of cessation of antibiotics. He was diagnosed with aseptic meningitis and possible drug fever, attributed to either ceftriaxone or vancomycin.

There are many possibilities to consider in an unimmunized child with signs and symptoms of meningitis. The vaccine-preventable infections are ruled out in the setting of negative cultures and PCRs. While the most common etiology of aseptic meningitis is secondary to viral infections, the considerations of drug fever and aseptic meningitis deserve more attention. A thorough medication history should be taken as nonsteroidal anti-inflammatory drugs (NSAIDs) are relatively commonly linked to aseptic meningitis. Evaluation should focus on family history, medications, and exposures.

There was no family history of meningitis nor known exposures to mosquitos or ticks. The patient did not have a history of atypical or severe infections. He had one episode of acute otitis media that resolved without antibiotics. He had a history of delayed speech and was more irritable than his siblings.
Sixteen months later, at two years of age, he presented to his primary care physician in Wisconsin for evaluation of one day of fever and fussiness without rhinorrhea or cough. Examination showed enlarged tonsils without exudate or pharyngeal erythema. His tympanic membranes were normal, and the lung fields were clear. Two of his older siblings and his father had been diagnosed with streptococcal pharyngitis and were receiving antibiotic treatment. A rapid streptococcal antigen test was positive, and amoxicillin started.

Group A streptococcal (GAS) pharyngitis is an acute infection of the oropharynx or nasopharynx caused by Streptococcus pyogenes and is most common in school-aged children. GAS pharyngitis is less common at age two years unless there is definite exposure. The most frequent presentations in this age group (<3 years of age) include protracted nasal symptoms (congestion and rhinorrhea) and cough instead of a well-localized episode of pharyngitis.

The amoxicillin was continued for four days without improvement in fever or fussiness. His oral intake decreased, and he developed nonbilious, nonbloody emesis without diarrhea. He followed up with his pediatrician for the presumed streptococcal pharyngitis. Because of the previous concern for drug fever related to his ceftriaxone exposure, the amoxicillin was discontinued. Supportive care was recommended.

While viral infections remain the most likely etiology, noninfectious etiologies, such as vasculitis, should be considered. Kawasaki disease should be considered in any child with prolonged fever. Kawasaki disease can also cause aseptic meningitis that could provide an explanation for his original episode at eight months of age; nevertheless, it is rare for Kawasaki disease to recur.

Over the next three days, his temperature was as high as 38.8°C (101.8°F), he became more irritable, and his vomiting worsened; his family believed he had a headache. He was again seen by his pediatrician, now with eight days of fever. On examination, his oropharynx was mildly erythematous with palatal petechiae and 2+ tonsillar enlargement; shotty anterior cervical lymphadenopathy was present. Concern for incompletely treated streptococcal pharyngitis prompted prescription of azithromycin for five days.

This information does not change the differential diagnosis significantly. Azithromycin is as effective as beta lactams for the treatment of GAS pharyngitis if the GAS is susceptible to macrolides. Macrolide resistance rates vary between communities and have been as high as 15% in Wisconsin; knowledge of local resistance patterns is important.¹

Despite the azithromycin, his symptoms worsened, and he became lethargic. The family believed the symptoms were similar to those during his previous episode of meningitis. They presented to an ED where he was febrile to 39.4°C (102.9°F) with a heart rate of 159 beats per minute and blood pressure of 113/84 mm Hg. His head circumference was 50.5 cm (97th percentile) compared with his weight of 10.8 kg (23.81 lbs; 22nd percentile). He was listless when undisturbed and irritable during the examination; his neck was supple and strong, and reflexes were normal. The remainder of his examination, including joints and skin, was normal. His white blood cell count was 18.6 K/uL, hemoglobin 11.8 g/dL, and platelets 401 K/uL. A chest radiograph was normal.

The patient is presenting on the 10th day of fever—a long time for any patient to remain febrile. Although most typically due to infectious etiologies, rheumatologic and oncologic diseases must be considered. It is important to characterize the pattern of fevers during the past 10 days and whether the patient has had similar febrile illnesses in the past. In this case, his past medical history substantially alters the differential diagnosis. The positive rapid strep test and history of recent strep pharyngitis are of uncertain importance, and the patient’s nonresponsiveness to antibiotics should raise concern for a second disease process (other than streptococcal infection) causing the fever. His unimmunized status changes the pretest probability of serious conditions such as bacterial meningitis caused by S. pneumoniae. A lumbar puncture should be performed, including an opening pressure; if the CSF again shows pleocytosis, but no infectious etiology is identified, then imaging of the brain (magnetic resonance imaging [MRI] or magnetic resonance angiogram) should be performed to evaluate for anatomic abnormalities.

CSF examination revealed 9,327 white blood cells/uL (82% polymorphonuclear cells, 1% lymphocytes, and 17% monocytes), 114 red blood cells/uL, protein of 87 mg/dL, and glucose of 63 mg/dL. Gram stain revealed no organisms. Ceftriaxone, vancomycin, and acyclovir were started, and he was transferred to a children’s hospital.

This history must be viewed through two alternate lenses: that the two episodes of meningitis are related or that they are unrelated. The finding of a neutrophil predominance in the CSF in the setting of aseptic (or nonbacterial) meningitis is less common than a lymphocytic predominance. Most commonly, aseptic meningitis is due to viral infection and is typically associated with a lymphocyte predominance, although a moderate neutrophil predominance can be seen in patients with enterovirus meningitis. Neutrophil-predominant aseptic meningitis can also accompany genetic auto-inflammatory syndromes (eg, familial Mediterranean fever and cryopyrin-associated periodic syndrome). This finding can also be seen in other noninfectious conditions such as neurosarcoidosis, Behçet’s disease, Cogan syndrome, and other vasculitides. Drug-induced aseptic meningitis can also cause neutrophil predominance. Additionally, the apparent neutrophil predominance could be explained if the patient had lymphopenia associated with primary or acquired immunodeficiency; therefore, the peripheral leukocyte differential obtained at the same time as the CSF should be evaluated. However, immunodeficiency is less likely given the patient’s lack of history of recurrent infections.