Infection · Moderate
This case is fictional and exists for study. It describes no real patient.
24 years · female
A 24-year-old female university student is brought to the emergency department with a 12-hour history of severe generalized headache, high fever, photophobia, and nausea. Her housemate notes she became increasingly lethargic and confused over the past two hours. On physical examination, she appears acutely unwell. Neurological examination reveals marked nuchal rigidity and a positive Kernig's sign. Examination of her skin reveals several non-blanching petechial and purpuric lesions across her trunk and lower extremities. She has no focal neurological deficits, and fundoscopy demonstrates normal optic discs without papilloedema.
Vital signs
- HR
- 118 bpm
- BP
- 92/58 mmHg
- RR
- 24/min
- Temp
- 38.9 °C
- SpO₂
- 96%
Examination findings
- Marked nuchal rigidity
- Positive Kernig's sign
- Non-blanching petechial and purpuric rash on lower limbs and trunk
- GCS 13 (E3 V4 M6)
Investigations
| Haemoglobin | 13.2 g/dL | reference: 12.0-15.5 |
| White Blood Cell Count | 19.5 10^9/L | reference: 4.0-11.0 |
| Platelets | 110 10^9/L | reference: 150-400 |
| C-reactive Protein (CRP) | 210 mg/L | reference: 0-5 |
Question 1 of 3
Which of the following is the most appropriate next step in management?
In suspected bacterial meningitis (especially with signs of meningococcal septicaemia such as a non-blanching rash), empirical parenteral antibiotics (e.g., intravenous ceftriaxone) should be administered immediately without delay. Option D is incorrect because performing a lumbar puncture must not delay life-saving antibiotic therapy. Option B is incorrect because neuroimaging is not required prior to LP/antibiotics unless there are focal neurological signs, papilloedema, continuous seizures, or severe coma. Option A is incorrect because corticosteroids should never be given as monotherapy; dexamethasone is an adjunct to antibiotics, not a substitute.
Teaching point: Parenteral antibiotic administration must never be delayed for investigations when acute bacterial meningitis or meningococcal septicaemia is suspected.
Question 2 of 3
Lumbar puncture is performed after initial stabilization and administration of intravenous antibiotics. The cerebrospinal fluid (CSF) analysis reveals: opening pressure 28 cmH2O (10–20), WBC 1,400 cells/µL (92% neutrophils), protein 2.4 g/L (0.15–0.45), and CSF glucose 1.2 mmol/L with a blood glucose of 6.0 mmol/L (CSF:serum ratio 0.20). Which diagnosis is most strongly supported by these CSF results?
The CSF profile demonstrates markedly elevated opening pressure, severe neutrophilic pleocytosis (>1000 cells/µL, predominantly neutrophils), significantly elevated protein (>1.0 g/L), and a reduced CSF-to-serum glucose ratio (<0.4). This profile is classic for acute bacterial meningitis. Option B (viral meningitis) typically features lymphocytic predominance, normal glucose, and normal or slightly elevated protein. Option A (tuberculous meningitis) shows lymphocytic predominance and very high protein with low glucose, usually over a subacute course. Option D is incorrect as all parameters are significantly abnormal.
Teaching point: A CSF profile featuring high opening pressure, neutrophil-predominant pleocytosis, elevated protein, and low CSF:serum glucose ratio (<0.4) confirms bacterial meningitis.
Question 3 of 3
Blood and CSF cultures subsequently confirm Neisseria meningitidis infection. What is the most appropriate chemoprophylactic regimen for the patient's close household contacts?
Close contacts of individuals with invasive meningococcal disease (Neisseria meningitidis) require urgent chemoprophylaxis to eradicate nasopharyngeal carriage. A single dose of oral ciprofloxacin (or alternatively a 2-day course of oral rifampicin, or single-dose intramuscular ceftriaxone) is the recommended regimen. Option B is incorrect as amoxicillin is not effective for carriage eradication. Option D is incorrect because vaccination alone does not eliminate immediate carriage risk, though vaccination may be offered as an adjunct in specific outbreak settings. Option C is incorrect because high-risk close contacts require post-exposure prophylaxis regardless of symptoms.
Teaching point: A single oral dose of ciprofloxacin is recommended for chemoprophylaxis in close contacts of patients with confirmed meningococcal disease.
Key learning points
- Empirical parenteral antibiotics must be administered immediately when bacterial meningitis or meningococcal disease is suspected, without delaying for LP or imaging.
- Bacterial CSF profile shows polymorphonuclear (neutrophil) pleocytosis, low CSF glucose (<40% of blood glucose), and high CSF protein.
- Close household contacts of patients with meningococcal infection require urgent chemoprophylaxis with single-dose oral ciprofloxacin or rifampicin.
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