DIFINITION Meningitis is defined as an inflammation of the meninges covering the brain and spinal cord .
CLASSIFICATION Bacterial or Pyogenic Meningitis : It is caused by a wide variety of pyogenic bacteria's like Haemophilus influenzae, Meningococcus, Pneumococcus, Streptococcus , etc. Haemophilus influenzae and Meningococcus together account for 70% of all cases of bacterial meningitis. Bacterial meningitis is almost always a complication of bacteremia occurring due to-pneumonia, empyema, osteomyelitis and endocarditis. It is rarely seen but is serious and can be life-threatening. Aseptic Meningitis : It is caused by virus, fungi or protozoa, It is relatively common and less serious. Its symptoms are similar to common flu. Tubercular meningitis : It is caused by mycobacterium tuberculosis.
Route of Entry Bloodstream Insect bite Otitis media Direct extension - Fracture of frontal or facial bones Cerebrospinal fluid Dural tear Poor sterile technique during procedure
Cont... Nose or mouth - Meningococcus meningitis In utero Contamination of amniotic fluid Rubella Vaginal infection
Causes of Meningitis Bacterial- Meningococcus, Pneumococcus etc. Viral- Influenza, Herpes simplex virus type2 (especially in infants), Varicella zoster, HIV Fungal- Aspergillus, Candida (yeasts) Parasitic/protozoal- Amoeba, Plasmodium Physical injury
Causes of Meningitis Cancer Certain drugs (mainly, NSAID’S) Head injury Cerebral abscess Middle ear infection
PREDISPOSING FACTORS The conditions that predispose to meningitis are: Children on immunosuppressive drugs. Patients with diabetes mellitus and malignancies Immunocompromised patients like babies of HIV positive mothers. Meningitis may follow trauma, invasive procedures, lumbar puncture and penetrating head wounds. Meningitis is common in infants and young children because their immune mechanism is immature
PATHOPHYSIOLOGY
SIGN AND SYMPTOMS Severe headache Irritability Restlessness Stiffness of neck Malaise Nausea/vomiting High grade fever Tachypnoea Seizures
SIGN AND SYMPTOMS Disorientation Tachycardia Coma Sleeplessness Phonophobia Photophobia Altered mental status(confusion)
DIAGNOSTIC EVALUATION Lumbar puncture shows elevated pressure. CSF examination shows that CSF is cloudy or milky. WBC count is raised, predominantly Neutrophil count. The protein level is high and glucose level is markedly decreased to below 30 mg CSF culture is positive, unless the cause is viral. Blood examination reveals leucocytosis. Blood culture may be positive. Computed tomography and MRI may reveal hydrocephalus
PHYSICAL EXAMINATION Kernig’s sign: with patient in supine position and hip flexed, passive straightening of the leg at knee causes active resistance and back pain. Brudzinski’s sign : with patient in supine position, on passive flexion of neck there is involuntary bending of hip and knees.
MEDICAL MANAGEMENT SPECIFIC TREATMENT Penicillin with third generation cephalosporins. Vancomycin with third generation Cephalosporin, if penicillin resistance is suspected. Cefotaxime/Ceftriaxone with Aminoglycosides DURATION OF ANTIBIOTIC THERAPY 7-14 days depending upon the type of organism 3weeks in case of gram negative bacteria
SYMPTOMATIC TREATMENT Seizure management : For controlling seizures, Phenobarbitone 10 mg is given intravenously. Dilantin can also be given in a dose of 7 mg/kg body weight. Diazepam 2.5 mg may be give reduce restlessness. Management of increased Intracranial pressure Mannitol-0.5 mg/kg body weight as 20% solution is administered. Frusemide 1 mg/kg body weight may be given. Fever and headache Aspirin or acetaminophen may be used to manage fever and headache.
SUPPORTIVE CARE IV fluids to maintain fluid-electrolyte balance. Monitoring of neurological status. Patients with septic shock require vasoactive drugs like epinephrine and dopamine
COMPLICATIONS Cerebral infarction Cranial nerve palsies including deafness and optic- neuritis Encephalitis Endocarditis Subdural effusion Hydrocephalus
COMPLICATIONS Hearing loss Memory difficulty Brain damage Gait problems Seizures Kidney failure Shock Death