A 32-year-old woman presented with a 2-day history of fever and myalgia and a 6-hour history of headache, photophobia and neck stiffness.
Investigations:
white cell count 10.4 × 109/L (4.0–11.0)
random plasma glucose 5.2 mmol/L
cerebrospinal fluid:
opening pressure 180 mmH2O (120–250)
total protein 0.60 g/L (0.15–0.45)
glucose 3.5 mmol/L (3.3–4.4)
cell count 76/µL (≤5)
lymphocyte count 46/μL (≤3)
neutrophil count 30/μL (0)
What is the most likely causative organism?
Question 88 A: enterovirus
B: Listeria monocytogenes
C: Mycobacterium tuberculosis
D: Neisseria meningitidis
E: Streptococcus pneumoniae
Correct answer: A Explanation A: The cerebrospinal fluid (CSF) values are most in keeping with viral meningitis and enterovirus is the most probable cause. It is probably early viral meningitis given that neutrophils are seen in addition to lymphocytes.
B: She has no risk factors for listeria. The CSF in listeria shows high protein and low glucose and lymphocytosis.
C: The CSF in tuberculous meningitis shows very high protein and low glucose and lymphocytosis.
D and E: The CSF in Neisseria meningitides and Streptococcus pneumoniae shows high protein and low glucose (<50% plasma) and a very high neutrophil