Listerial Meningitis
โ ๏ธ Consider Listeria in any patient over 50, immunosuppressed, diabetic, alcoholic, or pregnant. In these cases, always add Ampicillin to standard meningitis therapy.
๐ About
- ๐ Must not be missed โ identify at-risk groups early.
- Caused by Listeria monocytogenes, an intracellular Gram-positive bacillus.
- Can cause meningitis and rhombencephalitis (brainstem infection).
๐งฌ Aetiology
- Gram-positive bacillus, transmitted via contaminated food (e.g., soft cheeses, deli meats, unpasteurised milk).
- Causes CNS infections: meningitis, brain abscess, and brainstem encephalitis.
โ ๏ธ Risk Groups
- Immunosuppressed patients (transplants, chemotherapy, HIV).
- Diabetes mellitus.
- Chronic alcohol misuse.
- Pregnant females ๐คฐ (risk of miscarriage, stillbirth, neonatal sepsis/meningitis).
- Neonates ๐ถ (via vertical transmission).
๐ฉบ Clinical Features
- Brainstem signs โ cranial nerve palsies, ataxia, dysarthria.
- Confusion, headache, reduced GCS.
- Pyrexia, meningism (nuchal rigidity, photophobia).
- Seizures possible.
๐ Investigations
- CT head ๐ฅ๏ธ โ exclude raised ICP, hydrocephalus, or mass lesions before LP.
- CSF (LP) ๐ โ low glucose, high protein, raised WCC, Gram-positive bacilli (not cocci โ correction).
- Blood cultures โ may grow Listeria.
- MRI brain โ brainstem lesions if rhombencephalitis suspected.
๐ Management
- Stabilise โ ABC, oxygen, IV fluids, HDU/ITU support as required.
- Empirical therapy for meningitis:
- Cefotaxime 2 g IV q6h OR Ceftriaxone 2 g IV q12h.
- PLUS Ampicillin 2 g IV q4h (to cover Listeria).
- Alternative if allergic: IV Co-trimoxazole (5 mg/kg daily in 2 doses).
- Add Dexamethasone in suspected bacterial meningitis unless contraindicated.
- Consider longer treatment course (โฅ3 weeks) for Listeria meningitis.
๐ References