| This is a medical emergency. | | | | with the age and immune status of the patient. |
| Meningitis is the inflammation of the meninges, the | | | | Children may present with fever, convulsions, refusal |
| coverings of the brain: dura, arachnoid, and pia. It | | | | of feeds, irritability, excessive cry and vomiting. |
| carries a high mortality rate despite medical advances. | | | | Adults may present with fever, headache, vomiting, |
| Meningitis may be caused by various agents including | | | | lethargy, confusion, and a stiff neck. |
| trauma, chemicals e.g released from tumours and | | | | The manifestations, however, may be subtle, |
| several infectious agents. However, bacterial | | | | especially in newborns, immunosuppressed patients, |
| meningitis represents the best known type of | | | | and the aged. In addition, patients who develop |
| meningitis and perhaps, the most dangerous. | | | | meningitis after head trauma or neurosurgical |
| Types | | | | procedure may have features that are difficult to |
| - Acute | | | | distinguish from the underlying pathology. As such, a |
| - Chronic | | | | high index of suspicion is needed in this category of |
| - Recurrent | | | | patients to make a early diagnosis. |
| - Post-traumatic | | | | Clinical examination may reveal neck stiffness |
| Terminologies | | | | retraction, positive Kernig's and Brudzinski signs and |
| - Recurrent bacterial meningitis: new episode of | | | | features of acute ill-health with deranged neuro-vital |
| bacterial meningitis occurring after a period without | | | | signs. |
| clinical or laboratory evidence of meningitis. | | | | Diagnosis |
| Recurrence is due to reinfection with the same or | | | | The definite diagnosis of bacterial meningitis is based |
| different bacterial species rather than to persistence | | | | on the findings of cerebrovascular fluid (CSF) |
| of the original infection. | | | | examination. The CSF is obtained from lumbar |
| - Recrudescence denotes the reappearance, during | | | | puncture. The usual picture is pleocytosis with cell |
| therapy, of findings of meningitis and a positive | | | | count over 1,000 cells per mm3 (with |
| cerebrospinal fluid culture after an initial clinical | | | | polymorphonuclear cells predominating), |
| response and sterilization of the cerebrospinal fluid. | | | | hypoglycorrhagia with glucose under 30 mg per dL |
| - Relapse: reappearance of bacterial meningitis within | | | | and elevated protein usually over 200 mg per dL. |
| 3 weeks after completion of the initial course of | | | | Gram staining and microscopy may reveal the |
| therapy. | | | | causative organism. |
| Both recrudescence and relapse are caused by the | | | | Differential Diagnosis |
| same organism isolated from the initial episode, and | | | | - Systemic Lupus Erythematosus and other |
| both represent persistence of the initial infection | | | | connective tissue diseases |
| rather than reinfection. | | | | - Drug-induced meningitis |
| Causative Organisms | | | | - Tumours |
| The causative organisms of acute bacterial meningitis | | | | - Epidermoid & Parasitic cysts |
| are clearly associated with the age of the patient. | | | | Treatment |
| The common organisms in each age group are as | | | | Antibiotics are the mainstay of treatment of bacterial |
| detailed below: | | | | meningitis. It is essential to use antibiotics which |
| Neonatal period: Escherichia coli, group B streptococci | | | | readily cross the blood brain barrier. The third |
| (S. agalactiae), and L. monocytogenes. | | | | generation cephalosporins are in wide use for the |
| Ages 2 months to 5 years: H. influenzae | | | | treatment of meningitis especially in adults. |
| Above 5 years: S. pneumoniae and N. meningitidis. | | | | Broad-spectrum agents are used initially, while specific |
| In addition to the age of the patient, another factor | | | | drugs are commenced as soon as results of CSF |
| that determines the causative pathogens is the | | | | analysis are available. |
| presence of immunosuppression. In | | | | The use of corticosteroids in the management of |
| immunosuppressed patients, the most frequent | | | | bacterial meningitis is controversial. While some |
| pathogens include L. monocytogenes (especially in | | | | studies have documented its benefits, especially |
| patients with cell-mediated immunity deficiency), S. | | | | reduction in hearing impairment, others have not |
| pneumoniae (in patients with humoral immunity | | | | found it so useful. If dexamethazone is to be used, it |
| deficiency), and P. aeruginosa, enteric gram-negative | | | | needs to be started before, or along with the first |
| bacilli, and S. aureus (in neutropenic patients). | | | | dose of antibiotics to reduce the patient's |
| Clinical Features | | | | inflammatory response. |
| The clinical features of acute bacterial meningitis vary | | | | |