Meningitis - is an infection of the meninges, which includes arachnoid and pia mater, ventricular system, CSF and the subarachnoid space
Caused by different microorganisms - a systemic or blood stream infection or extension from an infected area, then the access route to the subarachnoid space.
Viral
Bacterial
Meningococcus (neisseria meningitides)
Causes include herpes simplex virus type two, varicella zoster virus. Also the viruses that cause measles and mumps.
Pathophsiology
The most common bacteria that causes meningitis live in the nasopharynx but a prior upper respiratory infection will be present before becomes blood-borne. The blood cells (neutrophils will then migrate into the subarachnoid space, producing an exudate which thickens the CSF and interferes with teh normal cerebral spinal fluid flow around the brain and the spinal cord.
Diagnosis
Nasopharngeal smear and antigen tests.
Cerebral spinal fluid culture s to confirm the cause - This is a distinguishing feature between viral and bacterial causes by doing a laboratory analysis of the leucocytes (white blood cells in teh CSF. In bacterial neutrophils will be more promidante where as lymphocytes are more prominate in the viral mengitis.
Clinical manifestations
Severe headache
Fever
Bacterial meningitis
Meningeal signs, infectious signs and neurological signs
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Fever, tachycardia, chills and petechial rash,
Neurological
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Throbbing headache, becoming severe
Photophobia
Nuchal rigidity (neck stiffness
Decrease in consciousness
Cranial nerve palsies
Seizures
Focal neurological which include weakness or paralysis on one side of the body
Meningococcal mengitis
Meningococcal meningitis
Petechial or purpuric rash covers the skin and mucous membranes
Intracranial pressure
Papilloedema develops
Delirium
Leading to unconsciousness
Viral meningitis
Generalised throbbing headache
Mild photophobia
Mild neck pain - stiffness
Fever and malaise viral meningitis.
Encephalitis
Is an acute febrile illness,
Viral origin
Causes an inflammation of the nervous tissue
Difference from meningitis, is an inflammatory of the meninges rather than the neural tissue
Treatment
Antibiotic therapy for bacterial causes
Could include rifampicin or ciprofloxacin
Using corticosteroids may be useful in minimising inflammation.
Comfort measures.