Describe the investigation of a suspected otogenic complication.

When to Suspect and What to Order

• The investigation OF A suspected otogenic complication IS A sequence, and the order matters more than the list
• The clinical triggers — in a patient with acute or chronic ear disease: pain in a chronically discharging ear; fever with rigors; persistent or severe headache; vomiting, drowsiness or altered behaviour; vertigo or a positive fistula sign; facial weakness; diplopia; neck stiffness; seizures or focal neurological signs; and failure to improve on adequate treatment
• Bedside assessment first, and it is free — conscious level; temperature chart (looking for the swinging pattern); fundoscopy for papilloedema; all cranial nerves; meningism; cerebellar signs; nominal aphasia; and the neck along the jugular vein
• Blood — full blood count (leucocytosis, and anaemia suggesting a prolonged septic course); ESR and CRP; blood glucose; and blood cultures, taken during a rigor where sinus thrombosis is suspected
• Microbiology — ear swab, and pus from the mastoid at surgery, sent for aerobic, anaerobic and fungal culture, and for acid-fast bacilli and GeneXpert where tuberculosis is possible

Rules, Pitfalls and Interpretation

• The rules that matter most:
• 1. Image before lumbar puncture, always, where there is any suspicion of a space-occupying lesion or raised pressure — because coning kills
• 2. Lumbar puncture is contraindicated in brain abscess and subdural empyema; it is essential in meningitis and diagnostic in otitic hydrocephalus — but in all three cases only after a scan
• 3. A normal temporal bone CT does not exclude AN intracranial complication.
• 4. Absence OF fever does not exclude A brain abscess; the temperature is frequently normal in the manifest stage
• 5. Antibiotics mask everything — partial treatment removes the rigors, the meningism and the swelling while the disease advances. A patient who is simply not improving deserves imaging, not another antibiotic
• 6. Finding one complication does not end the search. They frequently coexist — cerebellar abscess with lateral sinus thrombosis, otitic hydrocephalus with sinus thrombosis, meningitis with labyrinthitis, and extradural abscess with almost anything
• 7. DO not let the scan delay treatment — antibiotics are started before the imaging in a septic or deteriorating patient
• Specific investigations for specific questions:
• Audiometry and tuning fork tests in all cases, to document the hearing before any intervention and for medicolegal record
• Fistula test for a labyrinthine fistula, remembering the false negative of a dead labyrinth
• Caloric testing to assess residual labyrinthine function