CNS Infections Flashcards
What is meningitis?
An infection confined to the meninges.
What are the causes of meningitis?
Bacterial or viral. Outcomes are worse for bacterial. Viral is more common.
What are the primary causes of brain damage in meningitis?
Primary cause is inflammation, which leads to tissue and vascular injury, thrombosis, and small infarcts. Other complications include edema and increased intracranial pressure - which can lead to hypoxic ischemic encephalopathy.
What is the biggest risk factor for contracting bacterial meningitis?
Immunosuppression, because this leads to increased risk for oppportunistic infections.
What are cardinal acute symptoms of bacterial meningitis?
Sudden fever, severe headache (due to inflammation of the meningeal blood vessels), and stiff neck (nuchal rigidity)
What are cardinal gradual symptoms of bacterial meningitis?
Flu-like symptoms
How do you diagnosis bacterial and viral meningitis?
Lumbar puncture and blood work. Confirmed by presence of bacteria in the CSF. CT and MRI do NOT aid in dx of bacterial meningitis.
What is encephalitis?
Infection of brain tissue. Viral causes are the most common, although bacteria, fungi, and parasites can also be to blame. Most common viral causes are herpes simplex, Epstein-barr, arboviruses from ticks and mosquitoes (including west nile virus)
What are presenting symptoms of encephalitis?
Acute symptoms include severe headache with fever, AMS, disorientation, behavioral and speech change. Subacute symptoms may include seizures with speech disturbance.
How do you diagnose encephalitis?
Lumbar puncture and blood work. Neuroimaging can be used to assess for any brain swelling/cerebral edema, mass effect, etc.
What is the cognitive domain most commonly affected in meningitis and encephalitis?
Processing speed. Difficulty with memory (particularly anterograde) is common sequelae of herpes simplex viral encephalitis (25-75% of cases).
What is an example of a prion disease?
Creutzfeldt-Jacob disease. CJD is a transmissable spongiform encephalopathy. Brain tissue develop holes and looks like a sponge. It can be sporadic, hereditary, or caused by exposure (e.g., surgery). Usually rapidly progressive and fatal (4 - 15 months) - including rapidly progressive dementia, memory loss, personality change, hallucinations, speech changes, and ataxia.
What are other CNS infections?
HIV
Progressive multifocal leukoencephalopathy (PML) - caused by JC virus and found in ppl who are immunocompromised (transplant patients, HIV patients)
Cerebral toxoplasmosis (caused by parasite, exposure from contaminated meat, infected cat feces, or transmission from mom to child during pregnancy)
