07. Meningitis

OTHER NAMES
viral meningitis; bacterial meningitis
DEFINITION
Meningitis is the inflammation of the protective membranes covering the central nervous system, known collectively as the meninges. Meningitis may develop in response to a number of causes, including infectious agents, physical injury, cancer, or certain drugs. While some forms of meningitis are mild and resolve on their own, meningitis is a potentially serious condition owing to the proximity of the inflammation to the brain and spinal cord.

CAUSES, INCIDENCE, AND RISK FACTORS
The most common causes of meningitis are bacterial infections that start in other parts of the body and spread to the brain or spinal cord via the bloodstream. Meningitis is also caused by viruses, chemical irritation, or tumors.
Types include:
- meningitis, cryptococcal
- syphilitic aseptic meningitis
- meningitis, H. influenza
- meningitis; meningococcal
- meningitis, pneumococcal
- meningitis, staphylococcal
- meningitis, tuberculous
- aseptic meningitis
- meningitis gram negative
Acute bacterial meningitis is very serious and should be treated immediately to prevent permanent damage. Bacterial strains that cause meningitis include Streptococcus, Haemophilus influenzae, Staphylococcus, and Meningococcus

Common viral meningitis is milder and occurs more often than bacterial meningitis. It usually develops in the winter and affects people under 30. Seventy percent of the infections occur in children under the age of 5. Other types of viral meningitis are rare, but more serious.
SYMPTOMS
- fever
- headache, severe
- nausea and vomiting
- stiff neck
- sensitivity to light (photophobia)
- mental status changes
Additional symptoms that may be associated with this disease:
- speech impairment
- neck pain
- muscle pain
- hallucinations
- facial paralysis
- eye lid drooping
- drowsiness
- consciousness, decreased
- chills
- breathing, rapid
- agitation
- positive Babinski’s reflex

 fontanelles - bulging
- opisthotonos
- poor feeding
- irritability
SIGNS AND TESTS
- lumbar puncture
- CSF smear
- culture of CSF (cerebral spinal fluid)
- skull X-ray, sinuses X-ray, and chest X-ray
- head CT scan looking for abscess or deep swelling
This disease may also alter the results of the following tests:
- CSF glucose
- CSF cell count
TREATMENT
Treatment Options      

Treatment Strategy

    When a patient presents acutely ill with the signs and symptoms of meningitis, the   following strategy may be warranted: (1) cultures should be taken immediately to identify   the offending organism, including from the blood and CSF; (2) broad-spectrum antibiotics   for presumed bacterial meningitis given immediately (within the hour) prior to return of   culture results.  Currently, there is no specific antiviral therapy available for infection with enteroviruses,   arboviruses, mumps virus, or lymphocytic choriomeningitis virus; treatment is supportive   only. HSV meningitis may be treated with acyclovir, but it is not clear that the natural   course of the disease is changed. HIV meningitis is not treated with antiretroviral agents   such as zidovudine, didanosine, or dicalcitrine unless the CD4 lymphocyte count is below   500/mm3. Intravenous gamma-globulin is sometimes used as adjunctive therapy for   enteroviral meningitis.         

Drug Therapies

    The length of treatment varies with the organism being treated, ranging from 7 days for a   meningococcal infection to 21 days for a Listeria infection.     _... For neonates with likely pathogens of S. agalactiae, E. coli, L. monocytogenes,   and K. pneumoniae-ampicillin plus third-generation cephalosporins (e.g.,   cefotaxime, ceftriaxone) or ampicillin plus an aminoglycoside such as gentamicin      _... For infants with above pathogens plus S. pneumoniae, H. influenzae, or   N. meningitidis-ampicillin (vancomycin substituted if PCN allergic) plus a third-  generation cephalosporin (e.g., cefotaxime, ceftriaxone)      _... For children and young adults with S. pneumoniae, N. meningitidis, or H.   influenzae-a third-generation cephalosporin plus vancomycin     _... For adults with S. pneumoniae or L. monocytogenes-ampicillin plus third-  generation cephalosporin (e.g., cefotaxime or ceftriaxone); third generation   cephalosporin plus vancomycin for penicillin-resistant strains (25%);   trimethoprim-sulfamethoxazole (TMP/SMX) and vancomycin for PCN allergy      _... For immunocompromised patients with S. pneumoniae, N. meningitidis, L.   monocytogenes, and P. aeruginosa-vancomycin plus ampicillin plus   ceftazidime; TMP/SMX for penicillin-allergic patients      _... For patients with recent head trauma or neurosurgery with likely gram-positive   and gram-negative organisms-vancomycin plus ceftazidime      _... Corticosteroid therapy (e.g., dexamethasone, 0.15 mg/kg every 6 hours for 4   days, 2 to 3 hours before antimicrobial therapy)-to reduce neurologic sequelae     _... For seizures-diazepam (5 to 10 mg in adults) and intravenous phenytoin    Dosages: ampicillin 2 g every 4 hours (children 50 mg/kg IV q 12 hours); cefotaxime 2.0   gm IV every 4 to 6 hours; ceftazidime 2 g IV every 8 hours (children 50 mg/kg IV q 12   hours); ceftriaxone 2 g every 12 hours (children 50 mg/kg IV QD); gentamicin 2 mg/kg IV   load, then 1.7 mg/kg every 8 hours; TMP/SMX 160 mg/800 mg every 6 hours;   vancomycin 1 g IV every 8 to 12 hours (children 15 mg/kg IV q 6 hours).         

Surgical Procedures

      _... Surgical closure of CSF fistulas to prevent recurrent meningitis     _... Surgical correction of CSF rhinorrhea         

Complementary and Alternative Therapies

    Bacterial meningitis has severe sequelae if not recognized and treated aggressively.  

Nutritional and herbal therapies should be used only in support of conventional treatment.   Homeopathic remedies may be useful for symptomatic relief and some herbal studies   suggest efficacious antimicrobial and immunomodulatory activities in the treatment of   certain kinds of meningitis. Garlic, for example, has demonstrated activity against   cryptococcal meningitis and appears to work synergistically with amphotericin B to treat   this condition.  To understand better how CAM therapies may be useful, some studies implicate reactive   oxygen species (ROS) and nitric oxide (NO) in the pathophysiologic changes seen in   early bacterial meningitis, particularly:     _... Increased intracranial pressure     _... Increased cerebral edema     _... Increased CSF WBC count   The theory is that antioxidants would help to attenuate this damage. However, results   from studies of two antioxidants-vitamin C and N-acetyl-L-cysteine-have been mixed   and fairly disappointing.          

Nutrition

    N-acetyl-L-cysteine (NAC)  N-acetyl-L-cysteine (NAC), an antioxidant, and S-methylisothiourea, an inhibitor of   inducible NO synthase (iNOS), have both been shown to limit early pathological events in   the course of bacterial meningitis. In view of these results, an animal study was   undertaken to evaluate the protective effects of NAC and S-methylisothiourea against   occurrences of advanced bacterial meningitis. Treatment with NAC significantly reduced   CSF white blood cell counts but did not modulate CSF bacterial titers. In addition,   although NAC did modulate early brain changes in the rats with meningitis, the   antioxidant did not affect later brain manifestations of the disease. It is difficult to know   what to conclude from this information except, perhaps, that NAC may confer some   antioxidant properties against ROS early in the disease process, but does not seem to   impact upon the disease process during advanced stages in animals (Koedel and Pfister   1997).   Vitamin C  Because vitamin C may be depleted in cases of infectious disease, it was hypothesized   that administering supplemental dosages of this vitamin might be beneficial for patients   with meningitis. However, in a controlled clinical trial of this antioxidant, 42 children and   infants hospitalized with acute meningeal disease (either bacterial or viral) were randomly   assigned to vitamin C or placebo. The experimental group received an IV infusion of   vitamin C, 100 mg/kg up to a maximum of 3,000 mg infused over 30 minutes, followed by   50 mg/kg every 8 hours for a total of 9 doses over 3 days. Treatment failed to show any   beneficial effect on the clinical course of either form of meningitis compared to placebo   (Destro and Sharma 1977).  Vitamin B12   In a study of neurochemical markers in patients with aseptic and tuberculous meningitis,   decreased levels of vitamin B12 and significantly increased levels of homocysteine were   found only in CSF of patients with tuberculous meningitis; no changes were noted in CSF   of aseptic meningitis patients (Qureshi et al. 1998). More research is needed to determine   whether measures to supplement vitamin B12 or decrease homocysteine can influence the   course of disease in patients with tuberculous meningitis.   Vitamin A  A study investigating meningococcal disease found that stores of vitamin A were depleted   in 41 children in sub-Saharan Africa; it is unknown whether vitamin A supplementation   would be beneficial for this condition.

EXPECTATIONS (PROGNOSIS)
Early diagnosis and treatment of bacterial meningitis is essential to prevent permanent neurological damage. Viral meningitis is usually not serious, and symptoms should disappear within 2 weeks with no residual complications.
COMPLICATIONS
- hearing loss
- brain damage
- loss of vision
- deafness

Courtesy:

Compiled and Shared By: Habib Anwar 

habib.anwar@hotmail.com