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A 19-year-old university student is brought to the emergency department in January with a 14-hour history of fever (39.4 degrees C), severe headache, neck stiffness and photophobia. On examination he is drowsy (GCS 13), has marked nuchal rigidity and a positive Kernig sign, and a rapidly evolving non-blanching petechial rash over the trunk, limbs and conjunctivae. BP 84/50, HR 128, RR 30, SpO2 95% on air, capillary refill 4 seconds. He lives in a hall of residence; his girlfriend and two flatmates are well.
Questions
a) What is the most likely diagnosis, and what two priorities must be addressed within the first hour? (2 marks)
Diagnosis: meningococcal septicaemia with meningitis (Neisseria meningitidis) — fever, meningeal signs, altered mentation AND a non-blanching petechial/purpuric rash with shock.
The two first-hour priorities are: (1) give empirical IV antibiotics IMMEDIATELY — IV ceftriaxone 2 g STAT, not delayed for any investigation; and (2) resuscitate septic shock (Surviving Sepsis hour-1 bundle: oxygen, IV access, blood cultures, lactate, balanced crystalloid 30 mL/kg, noradrenaline if fluid-refractory).
b) Outline your immediate investigations and the order in which they are performed relative to treatment. (3 marks)
- Blood cultures (two sets) and a throat swab — ideally before antibiotics, but never delay antibiotics for them.
- Lumbar puncture for opening pressure, cell count, protein, glucose (with a simultaneous blood glucose), Gram stain, culture and PCR — but defer until the patient is cardiovascularly stable; in this case (altered GCS, shock, petechial rash) start antibiotics first and consider LP/CT once stabilised.
- CT head before LP if any red flag (immunocompromise, new seizures, papilloedema, decreased GCS, focal neurology) — here, the decreased GCS is itself an indication to image before LP, but antibiotics come first regardless.
- Bloods: FBC, U&E (watch SIADH/hyponatraemia), LFT, coagulation, CRP, lactate, blood gas, glucose; HIV test.
- PCR of blood and CSF for N. meningitidis (valuable after antibiotics).
c) Give the expected CSF findings in bacterial meningitis, and contrast them with viral and tuberculous meningitis. (3 marks)
| Parameter | Bacterial | Viral | Tuberculous |
|---|---|---|---|
| Appearance | Cloudy/turbid | Clear | Fibrin cobweb coagulum |
| Opening pressure | Raised | Normal/mildly raised | Raised |
| Cells (type) | Neutrophils (100-5000) | Lymphocytes (10-500) | Lymphocytes (early PMNs) |
| Protein | Over 1 g/L (high) | Normal / mildly raised | Very high (1-5 g/L) |
| Glucose | Low (under 40 mg/dL or under 40% of serum) | Normal | Very low (under 20-40 mg/dL) |
| Other | Gram stain / culture positive | Enterovirus / HSV PCR | AFB stain, GeneXpert/Xpert Ultra, culture |
d) What public-health measures must be taken for this patient and his contacts? (2 marks)
- Droplet isolation of the index case until 24 hours of effective antibiotics.
- Statutory notification of suspected meningococcal disease to public health.
- Chemoprophylaxis of close (kissing/household) contacts within 24 hours: adult oral ciprofloxacin 500 mg single dose (alternatives rifampicin 600 mg BD x 2 days; ceftriaxone 250 mg IM in pregnancy).
- Vaccination of contacts if the strain is vaccine-preventable; the index case should have missing vaccines given before discharge.
- Audiology follow-up at 6-8 weeks (sensorineural hearing loss is the commonest complication).