Meningitis.

Dr; Abdulrahman Al shaikh

definition

Inflammatory disease of leptomeninges, the tissue surrounding the brain and spinal cord.

The meninges consist of three parts : the pia, arachnoid ; and dura maters.

It involves the arachnoid mater and the cerebrospinal fluid in the subarachnoid space as well as in the cerebral ventricles.

Types

Acute either pyogenic or viral. Chronic due to tuberculosis or fungal.

Pyogenic meningitis.

:

ETIOLOGICAL AGENT

"Normal" Adults (6-21 yrs)     Neisseria meningitidis     Streptococcus pneumoniae Children (3 months - 6 years)     Haemophilus influenzae     Neisseria meningitidis     Streptococcus pneumoniae     Staphylococcus aureus     Mycobacterium tuberculosis Infants (½ - 3 months)     Streptococcus, Group B     Listeria monocytogenes     Escherichia coli

Neonates     Escherichia coli     Streptococcus, Group B     Staphylococcus aureus     Listeria monocytogenes     Streptococcus, Group A Diabetics, alcoholics, elderly, debilitated, diseased (untreated)     Listeria monocytogenes     Streptococcus pneumoniae     Treponema pallidum

Clinical feature.

Fever and headache in majority. Headache severe and generalized. Most have fever but small percentage have

hypothermia. CNS symptoms: photophobia, and cloudy

sensorium. Changes in mentation and level of consciousness, seizures, and focal neurological signs tend to appear later in the course of the disease.

Nuchal rigidity. The patients might not complain of neck

stiffness but easy to find it by passive or active flexion of the neck will usually result in inability to touch the chin to the chest.

Brudzinski sign refers to spontaneous flexion of the hips during attempted passive flexion of the neck.

The kernig signs refers to the inability to allow full extension of the knee when the hip is flexed 90 degree.

Other finding.

Skin manifestation in form of petechiae and palpable purpura.( N. meningitides ).

If sequelae of infection in other part of the body, there may the feature of that infection. ( sinusitis and otitis).

Laboratory features.

Increased WBC. Low platelets if there is intravascular

coagulation. Electrolytes abnormalities mainly low

sodium. ( SIADH ). Blood culture at least one half have

positive before antibiotics.

CSF.

Can be diagnostic should be done in all only if there is contraindication.

Can distinguish viral from bacterial. Gram stain should be done if suspected

bacterial.

Complication.

Cerebrovascular involvement. Cerebral odema. Hydrocephalus. Septic shock. Disseminated intravascular coagulation. Acute respiratory distress syndrome.

Treatment.

Empiric ceftriaxone has a potent activity for causative organism except Listeria .

Ampicilin should be added if Listeria infection possible.

Dexamethazone reduced the complication.

H- influenza.

Ceftriaxone 2 gm twice a day. Cefotaxime 2gm 6 hourly. Rifampicin 6oo mg daily for 4 days to

clear the colonization. Should be treated 5 – 7 days.

Neisseria meningitis.

Penicillin, but there resistant cases. Third generation cephalosporin. Treatment for 5 days at least. Rifampicin if penicillin used in treatment. Rifampicin or ciprobay for contact.

             months of age.

PREVENTION:

Neisseria meningitidis - each dose of the multivalent vaccine provides A, C, Y and W-135 capsular polysaccharides. Effective in children over 3 months of age.       Streptococcus pneumoniae - each dose of the multivalent vaccine provides 23 types of capsular         polysaccharide covering the majority of strains causing meningitis. Recommended for children         over 2 years of age.

Haemophilus influenzae – each dose of the monovalent vaccine provides the capsular polysaccride from serotype b. organisms. Recommended for children over 18 months of age.

Viral meningitis

     Mumps virus       Polio virus       Coxsackie B virus        Echovirus       Arboviruses        Human Herpesvirus 1 (Herpes simplex 1 virus)         Lymphocytic choriomeningitis viruses-Arenavirus          Encephalomyocarditis viruses       Louping ill virus          Pseudolymphocytic meningitis virus           Hepatitis viruses           Adenovirus            Rhinovirus            Coxsackie A virus

ETIOLOGICAL AGENTS:

NAMES OF DISEASE:         Fungal meningitis                                           Cryptococcosis

                                 Torulosis                                               Tubercular meningitis

                                              Amoebic meningitis                                               Syphilitic meningitis

CHRONIC MENINGITIS

     Cryptococcus neoformans (Serotypes A,B,C,D)      Treponema pallidum                                             ) All slow      Mycobacterium tuberculosis                                 ) growers in       Naegleria fowleri                                                  ) the CNS       Human immunodeficiency virus                           )       Coccidioides immitis                                            )  

ETIOLOGICAL AGENTS:

Fungal meningitis-predisposing factors.   1.     Glucosteroid therapy     2.     Malignancy (particularly of the lymphoreticular system)     3.     Collagen - vascular disease.     4.     Sarcoidosis - a disorder involving many organs where

there is formation of epithelioid cell             tubercles.

    5.     Diabetes mellitus     6.     Pregnancy     7.     Alcoholism     8.     Genetic impairment of host defense mechanisms - 50%. T-

cell diseases (Di George Syndrome, Nezelof's syndrome)     9.     AIDS

Clinical feature: fungal. 1.     Headache - frontal, temporal or retro-orbital. Most

common feature and it becomes progressively more frequent and severe.

 2.     Mental aberrations (from simple irritability to psychosis)

 3.     Motor abnormalities (altered reflexes to paralyses)  4.     Cranial nerve dysfunctions (aphasia, visual

disturbances, hearing loss)  5.     Cerebellar signs (dyssynergia, dysmetria,

dysrhythmia, intentional tremor, slurring of speech)  6.     Evidence of increased intracranial pressure  7.     Fever in about 1/3 of patients

CSF: in fungal 1.     Increased CSF pressure  2.     Protein is elevated  3.     Leukocytosis (40-400/mm3 - mostly

mononuclear cells)  4.     Glucose is decreased (45% of blood

glucose)  5.     C. neoformans present in India ink

preparations  6.     Serological tests for cryptococcal antigen

TREATMENT:

1.     Amphotericin B injected I.V. and into the subarachnoid space. NOTE: This is poorly  absorbed into CSF. Treat for 6 weeks. Toxic.

2.     Flucytosine (5-fluorocytosine)-penetrates into all body fluids, including CSF. Less toxic but higher doses required.

3.     Miconazole-an imidazole derivative     4.     Amphotericin B methyl ester    

Tuberculous meningitis.

Clinical feature. Diagnosis. Treatment.

Clinical feature: TB.

Atypical presentations : Rapid progressive as pyogenic or slow dementia.

Stage 1: lucid with no focal neurological signs. Stage 11 are confused or focal signs such as

hemiparesis or cranial nerve palsies. Stage 111 advanced illness with delirium , stupor,

coma and dense hemiplegia.

Diagnosis.

High degree of suspicion. CSF – high protein, low sugar and a

mononuclear pleocytosis. Early in the illness the cellular reaction is

atypical with low cell or polymorphonuclear leukocyte.

AFB smear in 37%. Polymerase chain reaction = 70%. CT Scan of the brain with contrast or MRI.

Treatment. INH, Rifampicin and pyrazinamid for 2 months then

discontinue PYZ. In endemic areas where resistance to INH is high the

streptomycin or ethambutol added. The duration for 12 months but if PYZ not tolerated the

duration extended to 18 months and in case multiple drugs resistance for 18-24 months.

Steroid improve morbidity and mortality, prednisone 60 mg to be tapered over 4 weeks.

Surgery in case of hydrocephalus or increase intracranial pressure.( deterioration in conscious level and stupor).