A 40-year-old woman presented at the Accident and Emergency De partment with a 48-hour history of headache and neck stiffness. She had returned from a holiday in the
south of France just one week previously. On examination she had a temperature of 37.8°C (100.0°F). Her blood pressure measured 120/70 mmHg. There was no rash. Neurological examination was normal, with the exception of mild nuchal rigidity. Investigations are shown.
What is the diagnosist?
a. Herpes simplex encephalitis.
b. Listeria meningitis.
c. Viral meningitis.
d. Lyme disease.
e. Bacterial meningitis.
CT scan of brain Normal CSF analysis: Appearance – clear WCC 20 per mm3 (80% lymphocytes) Protein 0.48 g/l Glucose 2.3 mmol/l (simultaneous blood glucose 4.5 mmol/l) Gram stain No organism identified
The patient has a lymphocytic meningitis with a normal CSF protein and a very slight reduction in CSF glucose (Table). The differential diagnosis is between viral meningitis (and some cases of viral meningitis do cause a very slight reduction in glucose) or meningitis due to brucellosis, lyme disease, listeria monocytogenes, and partially treated bacterial meningitis. The patient has been to the south of France and one could infer that she may have indulged in soft cheeses and developed listerosis; however, listerosis usually affects immuno compromised
patients including neonates and pregnant women. The patient has none of the pointers for diagnoses other than viral meningitis.
Normal CSF values Opening pressure 60–150 mmH2O Protein content 0.2–0.4 g/l Glucose <2/3 blood glucose White cell count <5/mm3 Red cells 0 IgG 15% of total CSF protein