Neuroinfectious and Tropical Neurology
This domain mixes universal emergencies with infections common in Iraq and neighbouring regions, so learn both the CSF patterns and the geography.
Bacterial meningitis
CSF shows neutrophil predominance, glucose ratio below 0.4 and high protein. Start empirical ceftriaxone plus vancomycin, adding ampicillin for neonates and the elderly to cover Listeria. Give dexamethasone with or just before the first antibiotic dose when pneumococcal disease is suspected. Never delay antibiotics for lumbar puncture when the patient is unstable.
Tuberculous meningitis
Subacute presentation with basal meningeal enhancement, hydrocephalus and infarcts. CSF is lymphocytic with low glucose and very high protein; adenosine deaminase supports but does not confirm. Treat with a four-drug regimen plus adjunctive dexamethasone, which reduces mortality.
Viral and parasitic disease
Herpes simplex encephalitis causes fever, seizures and temporal lobe change; give intravenous aciclovir 10 mg/kg every eight hours for 14 to 21 days while awaiting CSF PCR. Cerebral malaria from Plasmodium falciparum shows ring forms and is treated with artesunate. Neurocysticercosis causes seizures with ring-enhancing lesions, sometimes showing a scolex; treat with albendazole plus steroids, and shunt if hydrocephalus. In HIV, multiple ring-enhancing lesions suggest toxoplasmosis, treated with pyrimethamine and sulfadiazine.
Worked example
A young man has fever, headache, neck stiffness and confusion. CSF shows 2000 neutrophils, glucose 20 mg/dL and protein 200 mg/dL. Begin ceftriaxone, vancomycin and dexamethasone immediately, look for otitis or sinusitis as a source, and do not wait for culture.
Traps
Partially treated meningitis shifts the CSF to a lymphocytic picture; lumbar puncture is unsafe with focal signs and raised intracranial pressure; missing HIV-related opportunistic infection.