A 24-year-old man presents to an emergency department complaining of a severe headache. The headache started 24h previously and has rapidly become more intense. He describes the headache as generalized in his head. He has vomited twice and appears to be developing drowsiness and confusion. He finds bright lights uncomfortable. There is no significant previous medical history or history of allergy. He smokes 10 cigarettes per day and drinks 24 units of alcohol per week. He is not taking any medication currently. He is a graduate student doing an MA in psychology. He lives with his female partner and they have two children aged 3 and 4 years.
Examination He looks flushed and unwell. His temperature is 39.2°C. He has stiffness on passive flexion of his neck. There is no rash. His sinuses are not tender and his eardrums appear normal. His pulse rate is 120/min and blood pressure 98/74mmHg. Examination of heart, chest and abdomen are normal. His conscious level is decreased but he is rousable to command and there are no focal neurological signs. His fundi are normal.
Normal Haemoglobin 13.9g/dL 13.7–17.7g/dL White cell count 17.4 109/L 3.9–10.6 109/L Platelets 322 109/L 150–440 109/L Sodium 131mmol/L 135–145mmol/L Potassium 3.9mmol/L 3.5–5.0mmol/L Urea 10.4mmol/L 2.5–6.7mmol/L Creatinine 176amol/L 70–120amol/L Glucose 5.4mmol/L 4.0–6.0mmol/L Blood cultures results awaited Chest X-ray: normal Electrocardiogram (ECG): sinus tachycardia Computed tomography (CT) of brain: normal Lumbar puncture turbid cerebrospinal fluid (CSF) Leucocytes 8000/mL 5/mL CSF protein 1.4g/L 0.4g/L CSF glucose 0.8mmol/L 70 per cent plasma glucose Gram stain: result awaited INVESTIGATIONS
Questions • What is the diagnosis? • What are the major differential diagnoses? • How would you manage this patient?
ANSWER
This patient has bacterial meningitis. He has presented with sudden onset of severe headache, vomiting, confusion, photophobia and neck stiffness. The presence of hypotension, leucocytosis and renal impairment suggest acute bacterial infection rather than viral meningitis. The most likely causative bacteria are Neisseria meningitidis, Haemophilus influenzae and Streptococcus pneumonia. In patients in this age group Streptococcus pneumonia or Neisseria meningitidis are the most likely organisms. Meningococcal meningitis (Neisseria meningitidis) is usually associated with a generalized vasculitic rash. The most severe headaches are experienced in meningitis, subarachnoid haemorrhage and classic migraine. Meningitis and subarachnoid haemorrhage present as single episodes of headaches. Meningitis usually presents over hours, whereas subarachnoid haemorrhage usually presents very suddenly. Fundoscopy in patients with subarachnoid haemorrhage may show subhyaloid haemorrhage. Meningeal irritation can be seen in many acute febrile conditions particularly in children. Local infections of the neck/spine may cause neck stiffness. Other causes of meningitis include viral, fungal, cryptococcal and tuberculous meningitis which can be distinguished by analysis of the CSF. When meningitis is suspected appropriate antibioic treatment should be started even before the diagnosis is confirmed. In the absence of a history of significant penicillin allergy the most common treatment would be intravenous ceftriaxone or cefotaxime. Patients with no papilloedema or lateralizing neurological signs that suggest a spaceoccupying lesion should be lumbar punctured immediately (even before a CT scan is obtained). If there are localized neurological signs it is essential to perform a CT scan first to avoid the dangers of coning which can occur when a lumbar puncture is performed in the presence of raised intracranial pressure. The combination of 1000 neutrophils/mL CSF, a CSF glucose 40 per cent of the simultaneous blood level and a CSF protein 1.4g/L is strongly suggestive of bacterial meningitis. The Gram stain and culture will give the definitive diagnosis. In this case, the Gram stain demonstrated Gram-positive cocci consistent with Streptococcus pneumonia infection. Intravenous antibiotics must be started immediately. The patient must be nursed in a manner appropriate for the decreased conscious level. Adequate analgesia with opiates should be given. The patient has mild hyponatraemia due to the syndrome of inappropriate antidiuretic hormone (ADH) secretion, and fluid losses should be treated with normal saline. Inotropes may be needed to treat hypotension. The two children aged 3 and 4 years must be considered. It is not clear from the history who is looking after them. They should be examined, and if meningococcal meningitis is suspected or the organism is uncertain they should be given prophylactic treatment with rifampicin and vaccinated against meningococcal meningitis.