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Meningitis

Aetiology:

Meningitis means inflammation of the meninges. It may be caused by:

Bacteria
Viruses
Fungi
Malignant cells
Drugs and contrast media
Blood (following SAH)

Micro-organisms reach the meninges either via:

The bloodstream
Direct extension from the:

Ears
Nasopharynx
Cranial injury
Congenital meningeal defect

Clinical features:

The meningitic syndrome - a triad of:

Headache
Neck stiffness
Fever

In acute bacterial meningitis – developing within hours or minutes:

Intense malaise
Fever
Rigors
Severe headache
Photophobia
Vomiting
The patient often prefers to lie still. Neck stiffness and a positive Kernig’s sign appear within hours

In uncomplicated meningitis, consciousness is not impaired, although a patient with a high fever may be delirious

Complications:

Septicaemia
Venous sinus thrombus
Severe cerebral oedema
Hydrocephalus

Complications may be indicated by:

Progressive drowsiness
Lateralizing signs
Cranial nerve lesions

Differential diagnosis:

Migraine
SAH
Cerebral malaria

Clinical clues in meningitis:

Clinical feature Probable cause

Petechial rash Meningococcal infection

Skull fracture Pneumococcal infection

Ear disease “

Congenital CNS lesion “

Immunocompromised patient HIV opportunistic infection

Rash or pleurodynia Enterovirus infection

International travel Malaria

Management:

Condition is lethal. Even with optimal care, the mortality is still ~15%
Immediate parenteral antibiotic treatment should be given before any investigations
LP is usually contraindicated if the clinical diagnosis is meningococcal disease (because coning of the cerebellar tonsils may follow)
If there is any suspicion of an intracranial mass lesion. An immediate CT scan should be carried out
Immediate LP should be carried out (if deemed safe)
Blood should be taken for FBC, U&Es, LFTs, glucose and a culture

Antibiotics and acute bacterial meningitis:

Organism Antibiotic Alternative

Unknown pyogenic Cefotaxime Benzylpenicillin and chloramphenicol

Meningococcus Benzylpenicillin Cefotaxime

Pneumococcus Cefotaxime Penicillin

Haemophilus Cefotaxime Chloramphenicol


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	Meningitis Aetiology: Meningitis means inflammation of the meninges. It may be caused by: Bacteria Viruses Fungi Malignant cells Drugs and contrast media Blood (following SAH) Micro-organisms reach the meninges either via: The bloodstream Direct extension from the: Ears Nasopharynx Cranial injury Congenital meningeal defect Clinical features: The meningitic syndrome - a triad of: Headache Neck stiffness Fever In acute bacterial meningitis – developing within hours or minutes: Intense malaise Fever Rigors Severe headache Photophobia Vomiting The patient often prefers to lie still. Neck stiffness and a positive Kernig’s sign appear within hours In uncomplicated meningitis, consciousness is not impaired, although a patient with a high fever may be delirious Complications: Septicaemia Venous sinus thrombus Severe cerebral oedema Hydrocephalus Complications may be indicated by: Progressive drowsiness Lateralizing signs Cranial nerve lesions Differential diagnosis: Migraine SAH Cerebral malaria Clinical clues in meningitis: Clinical feature Probable cause Petechial rash Meningococcal infection Skull fracture Pneumococcal infection Ear disease “ Congenital CNS lesion “ Immunocompromised patient HIV opportunistic infection Rash or pleurodynia Enterovirus infection International travel Malaria Management: Condition is lethal. Even with optimal care, the mortality is still ~15% Immediate parenteral antibiotic treatment should be given before any investigations LP is usually contraindicated if the clinical diagnosis is meningococcal disease (because coning of the cerebellar tonsils may follow) If there is any suspicion of an intracranial mass lesion. An immediate CT scan should be carried out Immediate LP should be carried out (if deemed safe) Blood should be taken for FBC, U&Es, LFTs, glucose and a culture Antibiotics and acute bacterial meningitis: Organism Antibiotic Alternative Unknown pyogenic Cefotaxime Benzylpenicillin and chloramphenicol Meningococcus Benzylpenicillin Cefotaxime Pneumococcus Cefotaxime Penicillin Haemophilus Cefotaxime Chloramphenicol
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