MENINGITIS
What is Meningitis?
Meningitis is an inflammation of the covering of the brain or meninges.
INCIDENCE
It occurs most often in males than females, peak incidence is at 6-12 months of age and highest rate of morbidity is from birth to 4 years of age.
CAUSES
Causative organisms include bacteria, virus and fungi but the bacteria infection is the most common.
PREDISPOSING FACTORS
- Fracture of the skull
- Break in spinal cord surgery
- Upper respiratory tract infection
- Infection of the middle ear
TYPES
- Bacteria/ Pyogenic meningitis
- Viral meningitis
- Fungal meningitis
BACTERIA / PYOGENIC MENINGITIS
Is a medical emergency and treatment must be instituted immediately or death can occur. It is inflammation of the pea, arachnoid and interventing cerebrospinal fluid. The infections spread throughout the subarachnoid space around the brain and spinal cord usually involving the ventricles. It may also occur by spread from nearby foci such as the nasopharynx, middle ear and sinuses. The commonest organisms are Hemophilus influenza, streptococci, staphylococci and pneumococci. Other group of bacteria is tuberculos organism, these causes tuberculosis meningitis. The onset of the disease is gradual and recovery is prolonged.
VIRAL MENINGITIS
It is also called Aseptic meningitis because it is not associated with pus formation. It is normally mild, self limiting infection of a few days duration. It is the most common cause of meningitis and because it is self limiting requires nonspecific treatment. Usually a less serious infection than the bacterial variety. It does have rarely cause associated. Encephalitis which is a potentially dangerous illness. The commonest viruses are Herpes simplex, Herpes zosters, measles and mumps virus. Is usually less severed and may affect children. It involves the subarachnoid space and usually it resolve within 2 weeks.
FUNGAL
The common fungal meningitis is streptococcus and commonly affects immuno compromised people such as HIV/Aids patients.
PATHOPHYSIOLOGY
When the meningitis bacteria invades the area either directly as a result of a traumatic injury or indirectly when they are transported from other sites in the body to the cerebrospinal fluid. A variety of organism can invade the central nervous system and produce an inflammation of the meninges which affects it, cerebrospinal fluid and ventricles of the brain.A purulent exudates may spread over the base of the brain, spinal cord and membranes lining the ventricles which causes the neurologic systems. Cerebrospinal fluid leakage also occurs when there is potential communication between the oropharynx and the meninges which causes the pathogenesis to enter the meninges. Certain drugs and other chemicals if introduced into the subarachnoid space for investigation can also setup an inflammatory process leading to meningitis.
CLINICAL FEATURES
- Fever
- Neck pain (nuchal rigidity)
- Irritability
- Positive Kernig’s sign
- Lethargy
- Pallor
- Anorexia
- Bulging fontanelle
- Increased pulse rate
- Positive Brudziski’s sign
- Rigor
- Drowsiness
- Seizures
- Vomiting and nausea
- Photophobia
DIAGNOSTIC INVESTIGATIONS
- Lumbar puncture for cerebrospinal fluid for culture and sensitivity test, shows increase white blood cell count and pussy nature of the fluid
- Blood culture to identify causative organism
- Computed tomography scan to identify abscess, subdural effusion or hydrocephalus
- Chest –x-ray to reveal pneumonitis
- Nasopharyngeal to identify causative organism
- Urine culture to identify causative organism
MEDICAL MANAGEMENT
- Antibiotics such as chloramphenicol, penicillin, Amoxicillin are given to control infection
- Anticonvulsants e.g. Phenobarbital are given to control convulsion
- Mild sedatives like phenegan are given to relax them
- Analgesics like paracetamol and analgen are given for pain
- Supportive measures like tepid sponge are done to reduce body temperature.
COMPLICATIONS
- Paralysis
- Contractures
- Hydrocephalus
- Cardiac failure
- Bronchopneumonia
- Circulatory collapse
- Blindness
- Mental retardation
- Deafness
- Otitis media
- Speech disturbance
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