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Meningitis. D efinition A etiology P athophysiology S igns and Symptoms I nvestigations C omplications A lternative Diagnosis M anagement P rognosis. Definition. - Inflammation of the meninges - Usually caused by an infection. Meninges : Three protective membranes
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Definition AetiologyPathophysiologySigns and SymptomsInvestigationsComplicationsAlternative Diagnosis Management Prognosis
Definition - Inflammation of the meninges - Usually caused by an infection Meninges: Three protective membranes enveloping the central nervous system • Approximately 3,200 cases per year in the UK • 1 in 10 mortality rate
The 3 Different Layers Arterial supply by the middle meningeal artery Innervated by the middle meningeal nerve All composed of fibrous tissue DURA: Very thick and durable layer - provides effective protection and cushioning, contains venous sinuses and has 4 major infoldings ARACHNOID: Thin layer of fibrous tissue - provides an impermeable barrier for the CSF in the subarachnoid space PIA: Very thin and delicate layer of fibrous tissue – pierced with fine holes through which BVs travel to supply the brain and spinal cord
Aetiology Viral Bacterial Fungal Parasitic (Aseptic) - Enterovirus- Herpes Simplex - Streptococcus Pneumoniae - Neisseria Meningitidis - Cryptococcus Neoformans - Schistosoma ! Contagious ! Spread via prolonged, close contact! Infected saliva/mucus spread ! Poor hygiene ! Higher in more populated areas
Pathophysiology Initially, an infective must colonise a local area Then the transmission to meninges can happen in 5 different ways • Via the bloodstream • Most common • Direct contact • Vertical transmission in the newborn • Trauma Less common • Iatrogenic
Signs and Symptoms 44% TRIAD +VE
Investigations History Examination Kernig’s Sign ? Non-blanching Rash Bloods Blood Culture CSF Analysis ! CSF Culture
Complications Sepsis SIRS Hypotension Thrombus Raised ICP Seizures Abnormal CN Function
Alternative Diagnosis Meningioma CNS Vasculitis Stroke/TIA Encephalitis Subarachnoid Haemorrhage SOL Subdural Empyema
Management !Bloods for culture ! Initiate broad-spectrum antibiotics immediately ! Bacterial meningitis until proven otherwise
Management Bacterial Viral - Supportive Therapy Only - 3rd Gen Cephalosporin IV B-lactamase + Ampicillin if immunocompromised
Prognosis If left untreated: - bacterial meningitis is almost always fatal - viral meningitis tends to resolve spontaneously and is rarely fatal Death rates: - paediatrics 15-30% - adults 10-20% 66% of all cases resolve with no association with any disabilities