Meningitis Acute bacterial meninigitis Definition Aetiology Meningitis is a clinical syndrome characterized ________ of the meninges, the three layers of membranes that enclose the brain and spinal cord. Can be ______ or ______. Meningitis is primarily involving the meninges Encephalitis is primarily involving the__________ The layers which enclose the brain and spinal cord are as following: _________ - A tough outer membrane _________ – A lacy, web like middle membrane _________ – A delicate, fibrous inner layer that contains many of the blood vessels that feed the brain and spinal cord. Aetiology Types of meningitis Bacterial Viral Fungal Parasites Drugs Bacterial, fungal and parasitic infections can cause chronic meningitis. The most common cause of a chronic bacterial infection is ___________ ____________ (TB!) Viral meningitis is more common and is usually more benign than bacterial meningitis Acute bacterial meninigitis Meningococcal meningitis Most common type of bacterial meningitis in children and young adults Caused by _________ _________ Often found in nasopharynx of otherwise healthy individuals. Thought that recent viral infections disrupt the epithelial surface and facilitate invasion by ________ __________. Causes the typical non-blanching rash. Pneumoncoccal meningitis Most common type of bacterial meningitis Caused by __________________. Present in 5-10% of healthy adults. Haemophilus Influenza meningitis Meningitis is the most serous acute manifestations of systemic infection with H influenza. In the past was a major cause of meningitis and the type __ strain accounted for the majority of these cases. However since the introduction of the _________ vaccine in the 1990 the overall incidence of H influenza meningitis has decreased by 35% _________accounts now for less than 9.4% of the H influenza cases Pathophysiology Most cases of meningitis are caused by an infectious agent that has colonized or established a localised infection elsewhere in the host. The pathogen can then gain access to the CNS by one of the following main pathways Most commonly, _________-> haematogenous seeding of the CNS A retrograde _________pathway via olfactory or peripheral nerves Direct _________spread (eg. Sinusitis, otitis media, trauma etc) Signs & symptoms Acute bacterial meningitis presents with a classical triad of _________ (+ altered mental state) Other symptoms of meningitis include Nausea and Vomiting Photophobia Sleepiness Confusion Irritability Delirium Coma Notably these symptoms will be similar for any cause that will cause inflammation of meninges. For example, _________ _________. Sepsis Meningococcal disease is the leading infectious cause of death in early childhood. It can present as bacterial meningitis (meningococcal meningitis) or as septicaemia . However it most commonly presents as both. The SIRS criteria is useful in diagnosis sepsis, two or more of the following with a source of infection indicates sepsis. Temperature _________ Heart Rate _________ Respiratory Rate _________ WBC __________________

Lumbar puncture Investigations Complications Management Indications _________(enceph/mening) _________ __________________ (sarcoid/MS) __________________ (GBS/CIDP) ___________________________ __________________ ____________________________________ Contraindications: S+S of ICP without negative imaging Focal neuro signs without negative imaging Local infection (skin, bone, pustular acne) Clotting disorders (INR>1.5 or platelets…) CONSENT: ‘Lumbar puncture with CSF sampling’  Aid further diagnosis and management RISKS = Pain Headache Bleeding Infection Failure of procedure Anesthetic Damage to surrounding structures (temp/perm) Elevated protein – very high (ie >2gl) Guillain-Barre Spinal block TB meningitis Fungal meningitis Malignant meningitis Elevated protein – high (>1g/L) Bacterial meningitis Viral encephalitis Cerebral abscess Neurosyphilis Subdural haematoma Low CSF glucose Mumps meningitis HSV encephalitis SAH (sometimes) Polymorphs Lymphocytes Viral encephalitis/meningitis Partially-treated meningitis Bechet syndrome, SLE, CNS vasculitis HIV-assoc Lymphoma, leukaemia Lyme disease Oligoclonal bands MS Neurosarcoidosis CNS lymphoma SLE Subacute sclerosing panencephalitis (rare, late comp of measles) Neurosyphillis Complications Immediate Increased intracranial pressure Coma Septic shock Seizures Delayed Decreased hearing, Cranial nerve dysfunction Multiple seizures Focal paralysis Subdural effusions Waterhouse-friderichsen syndrome (adrenal gland failure due to bleeding into the adrenal glands.) Management ABC! Treat causative organism Treat complications. Acute bacterial meningitis Initial “blind” treatment must be started immediately (IM benzylpenicillin) Guide with microbiological diagnosis If septic use the sepsis 6