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A 23-year-old university student is brought to the emergency department with a one-day history of fever, severe headache, and vomiting, and this morning became confused and drowsy. On examination: temperature 39.2 °C, pulse 122/min, blood pressure 96/58 mmHg, respiratory rate 24/min, GCS 13 (E3 V4 M6). She has marked neck stiffness, a positive Kernig sign, and a petechial rash on the trunk and lower limbs that does not blanch on pressure. Capillary refill is four seconds. There is no focal neurological deficit and no papilloedema.
Questions
a) What is the clinical diagnosis, and what is the immediate priority? (2 marks)
Diagnosis: acute community-acquired bacterial meningitis with meningococcal septicaemia. The combination of fever, headache, neck stiffness, and altered mental status (the classic tetrad), together with a non-blanching petechial rash and signs of sepsis (tachycardia, relative hypotension, prolonged capillary refill), is highly characteristic of meningococcal disease (Neisseria meningitidis). The immediate priority is the one-hour bundle: empiric intravenous antibiotics and dexamethasone within one hour of presentation, alongside resuscitation of her septic shock. Antibiotics must not be delayed for imaging or lumbar puncture — outcome is time-dependent.[1][2]
b) Outline the immediate resuscitation and empiric therapy, with drug doses. (3 marks)
- Airway, breathing, circulation: oxygen, two large-bore cannulae, intravenous fluid boluses (e.g. crystalloid 500 mL to 1 L) for shock, and an early vasopressor (noradrenaline) if shock is refractory; this patient meets sepsis criteria.
- Blood cultures (two sets) drawn before antibiotics, then empiric intravenous antibiotics immediately — for a community-acquired case in this age group: ceftriaxone 2 g IV twice daily plus vancomycin 15 to 20 mg/kg IV (the latter to cover penicillin-resistant pneumococcus). Ampicillin is added only when Listeria is in the differential (over 50, pregnant, or immunocompromised) — not required here.
- Dexamethasone 10 mg IV every six hours for four days, given before or with the first antibiotic dose, because antibiotic-induced bacterial lysis releases cell-wall components that intensify meningeal inflammation and cause cochlear damage.
- Lumbar puncture after stabilisation — there is no papilloedema, no focal deficit, and GCS above 8 with no new seizures, so she does not strictly require CT before LP; however, in practice, if LP cannot be achieved promptly, antibiotics come first.[2][3]
c) What CSF findings would support bacterial meningitis? (2 marks)
A bacterial CSF pattern: raised opening pressure (over 18 cmH₂O); a neutrophilic pleocytosis (typically hundreds to thousands of polymorphs per microlitre); glucose under 40 mg/dL or a CSF-to-blood glucose ratio under 0.4; protein over 1 g/L; a Gram stain showing gram-negative diplococci (intracellular, in meningococcal disease) — positive in 60 to 90 percent; and culture growing N. meningitidis (the gold standard). A meningococcal PCR on CSF or blood is useful if antibiotics were given before LP.[1]
d) List four complications she is at risk of, and the two preventive measures for close contacts. (2 marks)
Complications: (1) sensorineural hearing loss (the commonest long-term sequela, 10 to 30 percent — hence early audiology); (2) septic shock and disseminated intravascular coagulation with purpura fulminans, limb ischaemia, and Waterhouse-Friderichsen adrenal haemorrhage; (3) seizures and post-meningitis epilepsy; (4) stroke from vasculitis or venous sinus thrombosis; (5) hydrocephalus and cognitive impairment.
Prevention for close contacts — chemoprophylaxis within 24 hours of the index case: rifampicin 600 mg orally twice daily for two days, OR ciprofloxacin 500 mg orally as a single dose, OR ceftriaxone 250 mg intramuscularly as a single dose — given to household and kissing contacts, plus meningococcal vaccination (MenACWY, and MenB) per national schedule.[1]
e) Three days later a different patient — a 60-year-old with confusion and fever — is found to have a ring-enhancing temporal lobe lesion with restricted diffusion on MRI. How does this change the CSF decision and the empiric therapy? (1 mark)
This is a brain abscess (ring-enhancing with restricted diffusion on DWI distinguishes it from necrotic tumour). Lumbar puncture is contraindicated — the mass lesion risks cerebellar tonsillar or uncal herniation. Therapy shifts to ceftriaxone 2 g IV twice daily plus metronidazole 500 mg IV every eight hours, with stereotactic aspiration (both diagnostic — culture the pus — and therapeutic) by neurosurgery, and no role for dexamethasone unless there is severe mass effect. Antibiotics continue for four to six weeks intravenously.[2]
References5ShowHide
- [1]van de Beek D, Brouwer M, Hasbun R, et al. Community-acquired bacterial meningitis. Nature Reviews Disease Primers, 2016.PMID 27808261
- [2]Tunkel AR, Hartman BJ, Kaplan SL, et al. Practice guidelines for the management of bacterial meningitis. Clinical Infectious Diseases, 2004.PMID 15494903
- [3]de Gans J, van de Beek D. Dexamethasone in adults with bacterial meningitis. New England Journal of Medicine, 2002.PMID 12432041
- [4]Solomon T, Michael BD, Smith PE, et al. Management of suspected viral encephalitis in adults--Association of British Neurologists and British Infection Association National Guidelines. Journal of Infection, 2012.PMID 22120595
- [5]Wilkinson RJ, Rohlwink U, Misra UK, et al. Tuberculous meningitis. Nature Reviews Neurology, 2017.PMID 28884751