-IBIS-1.5.0-
tx
nervous system
meningitis
diagnoses
definition and etiology
definition:
Inflammation and infection of the brain or spinal cord.
etiology:
The cause may be bacterial (Neisseria meningitidis, Hemophilus influenzae, Streptococcus pneumoniae, Group A Streptococcus, E. coli, Pseudomonas, Staphylococcus) or viral (arbo/polio/echo/coxsackie viruses; herpes simplex/zoster).
Bacterial: There are 4.6-10 cases of bacterial meningitis/100,000 people a year. H. influenzae is usually the associated microorganism in children 2 months to 3 years old, while pneumococcal meningitis occurs mostly in the over-40 population.
Viral: Most cases of viral meningitis occur after a viral infection and are thought to have an immunologic mechanism.
signs and symptoms
signs and symptoms:
bacterial:
History recent URI or sore throat.
Fever, headache, stiff neck/back ((+) Kernig's and Brudzinski's), vomiting.
Changes in consciousness: irritability; confusion; lethargy; stupor; delirium; coma, in more serious disease.
25% of patients become severely ill within 24 hours.
Skin rash: with meningococcal infections.
In babies: Fever; vomiting; shrill/metallic/high-pitched cry; bulging fontanelle; seizures.
viral:
The disease appears in one of three ways:
Asymptomatic: No symptoms, fever or malaise though there would be a (+) CSF analysis.
Meningitis: Fever, headache, vomiting, malaise, stiff neck/back.
Encephalitis: Meningitis with cerebral symptoms (change in consciousness, seizures etc.)
lab findings:
analysis of CSF for cells, protein; culture and gram stain
CBC: increased WBC with shift to left
chemscreen for acid-base balance, rule out uremia
course and prognosis
In cases receiving early conventional treatment, antibiotics have reduced the fatality rate of bacterial meningitis to < 10%. However, if diagnosed late, or in neonates, the elderly or debilitated, bacterial meningitis is frequently fatal. In surviving children, 10% will experience neurologic deficits, especially hearing loss. The course of viral meningitis is usually more benign, and even patients that are extremely ill may recover fully.
differential diagnosis
Subacute meningitis.
Meningismus.
Lead encephalopathy.
Inebriation.
Delirium tremens.
Hepatic encephalopathy.
Behcet's syndrome.
footnotes