The Nervous System
1. Raised intracranial pressure
- Intracranial pressure may be raised due
to swelling of the brain (inflammatory processes such as encephalitis, brain
abscess, after brain infarction, brain trauma), expanding mass of tissue
(primary or metastatic brain tumour) or accumulating blood (intracerebral,
subarachnoid, epidural or subdural haemorrhage).
- The pain is caused by
distortion of or traction on nearby arteries, venous sinuses or meninges which
are pain sensitive structures.
- The pain is felt diffusely over the cranium
(not localised); and may be aggravated by activities which further increase
the intracranial pressure (e.g., coughing, bending and straining).
- Associated phenomena include vomiting, drowsiness, confusion, impairment of
consciousness level, bradycardia and hypertension, papilloedema (swelling of
the optic nerve papilla, seen on ophthalmoscopy), and finally come supervenes.
- This necessitates prompt investigation depending on suspected cause (e.g.,
CT, MRI, spinal tap) and treatment, for patient's life can be in danger.
- It may be due to viruses (e.g., echoviruses,
coxsackieviruses, mumps virus, herpes simplex virus, influenza viruses) or to
various bacteria (e.g., meningococcus, streptococcus, Haemophilus influenzae,
- The pain is diffuse with poor localisation,
progressive and throbbing.
- Neck stiffness ('meningism' = meningeal
irritation) can be elicited by passive neck flexion which is resisted as a
result of muscle spasm.
- Fever is variable depending on the cause, sometimes
is very high.
- Patients frequently complain of malaise, myalgia, anorexia,
nausea, vomiting, abdominal pain and diarrhoea.
- Prostration, convulsions
and even coma can occur in a severe case of bacterial meningitis, whereas
viral infection usually results in a benign and self-limiting illness.
- Analysis of cerebro-spinal fluid (CSF) sample withdrawn by a lumbar puncture
will show whether the disease is bacterial or viral in origin.
- No specific
treatment is necessary for viral meningitis, in contrast to bacterial
meningitis which requires aggressive antibiotic treatment depending on
Clinical features: < BACK TO TOP >
Diagnosis: < BACK TO TOP >
Management < BACK TO TOP >
Prognosis < BACK TO TOP >
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