Infections of the CNS Flashcards
What are the definitions of menigitis, encephalitis, myelitis and radiculitis?
Meningitis - inflammation of the meninges
Encephalitis - inflammation of brain parenchyma
Myelitis - Inflammation of the spinal cord
Radiculitis - inflammation of the nerve roots
What is the definition of acute meningitis?
Inflammation of the brains meninges with characteristic increase in the number of inflammatory cells in the CSF (pleocytosis)
What are the classic presenting symptoms of acute meningitis?
Fever
Headache
Photophobia
Stiff neck
With or without altered consciousness
Kernig’s sign (flexion of hip to 90 degrees elicits pain)
Brudzinski’s sign (flexion of neck causes patient to flex hips)
What sort of questions should be asked in a history suspecting acute meningitis?
Travel Risk factors for HIV Immunocompromised Exposure to sick animals Exposure to insects Ingestion of contaminated food
What will be the findings on examination of a patient with acute meningitis?
They may have:
- lymphadenopathy
- Rash
- Oral candida
- Iv injection sites
- Head injuries
What are the main causes of acute bacterial meningitis?
Streptococcus pneumoniae
neisseria meningitides
In children - haemophilus influenza type B
What is the initial investigation and management for acute meningitis?
Examination of CSF by LP Sent for gram staining Initiate antibacterial and anti viral therapies with steroids FBC, blood cultures, LFTs MRI/CT
What is the treatment of acute meningitis?
Third generation Cephlasporins (Ceftriaxone)
If penicillin resistant strep is found then give vancomycin
Steriods given shortly before antibiotics to improve outcome
How does step pneumoniae appear on microscopy?
Gram positive , lancet shaped diplococci (paired)
Often follows pneumonia or otits media
How does niseria meningitidis appear on microscopy?
Gram negative coccus that is kidney shaped
Causes rash and septicaemia
What is the treatment for tuberculous meningitis?
4 drug therapy for 2 month
steroids given 4 - 8 weeks then gently tapered
What are the most common viral meningitis?
Enteroviruses are the commonest
HSV 1 and 2
What is the treatment for fungal meningitis?
Amphotericin B
What are the most common causes of encephalitis? How does it present?
Viruses (HSV1) Severe headache Reduced consciousness Seizures Focal neuro signs
What is the acute management of Viral encephalitis?
Antivirals
Aciclovir - antiviral agent
