Question

Patient with a history of chronic middle ear infection now presents with neurological manifestations, headache, and vomiting. CT Brain is shown (ring-enhancing lesion). What is the probable diagnosis?

• A. Extradural Abscess
• B. Cerebral Abscess
• C. Temporal lobe Abscess
• D. Meningitis

Hint:

Chronic middle ear infection spreads to the brain through the tegmen tympani, most commonly producing an abscess in an adjacent lobe.

Answer 1

The Correct Option is C

Step 1: Analyse the clinical history. The patient has a history of chronic middle ear infection (CSOM -- chronic suppurative otitis media). CSOM is the most common cause of brain abscess. The patient now presents with neurological manifestations, headache, and vomiting, suggesting intracranial spread of infection.

Step 2: Interpret the CT Brain finding. The CT Brain shows a ring-enhancing lesion (a hypodense centre with a ring of enhancement). This is the classic CT appearance of a brain abscess. The ring represents the abscess capsule with surrounding oedema.

Step 3: Determine the most likely location. In CSOM, the pathogen spreads from the middle ear to the brain through the tegmen tympani (the thin bony plate separating the middle ear from the middle cranial fossa). This route leads to a temporal lobe abscess. An alternative route through the sinodural angle leads to a cerebellar (posterior fossa) abscess.

Step 4: Differentiate from distractors.
- Extradural abscess: collection between dura and skull bone; CT shows a lenticular hypodense lesion -- not a ring-enhancing intracerebral lesion.
- Cerebral abscess: too non-specific; temporal lobe abscess is the specific answer given the CSOM origin.
- Meningitis: CT typically shows meningeal enhancement without a ring lesion; ring lesion distinguishes abscess from meningitis.

Conclusion: CSOM + ring-enhancing lesion on CT Brain = Temporal lobe abscess.