Meningitis

Content

•       Meningitis

•       Etiopathogenesis

•       Clinical features

•       Diagnosis

Objective

At the end of the class the students will be
able to

•       Define  meningitis

•       Difference between pachymeningitis,
leptomeningitis

•       Discuss  the etiology, pathogenesis and clinical Acute
Pyogenic Meningitis, Chronic (Tuberculous and Cryptococcal) Meningitis,

Meningitis

It is inflammatory involvement of
the meninges.

•       Meningitis may involve the dura
called pachymeningitis,

•        leptomeninges (pia-arachnoid) termed leptomeningitis

•       Pachymeningitis: inflammation from chronic
suppurative otitis media or from fracture of the skull.

•       Extradural abscess may form by suppuration between the
bone and dura- penetrate the dura and form a subdural abscess.

Leptomeningitis, commonly called meningitis-
infection

•       Infectious meningitis is broadly
classified into 3 types:

1. acute
pyogenic,

2. acute
lymphocytic (viral, aseptic)

3. chronic
(bacterial or fungal)

Acute
Pyogenic Meningitis

•       Acute pyogenic or acute purulent
meningitis is acute infection of the pia-arachnoid and of the CSF enclosed in
the subarachnoid space.

ETIOPATHOGENESIS-Acute Pyogenic Meningitis

Causative
organisms vary with age of the patient

1. Escherichia coli

2. Haemophilus influenzae

3. Neisseria meningitidis

4. Streptococcus pneumoniae

•       routes of infection as follows:

1. Most
commonly by the blood stream.

2. From an
adjacent focus of infection.

3. By
iatrogenic infection such as introduction of microorganisms at operation or
during lumbar puncture.

Symptoms of Meningitis

CLINICAL FEATURES AND DIAGNOSIS of MENINGITIS

Acute
bacterial meningitis is a medical emergency.

•        The immediate clinical manifestations are
fever, severe headache, vomiting, drowsiness, stupor, coma, and occasionally,
convulsions

•       The diagnosis is confirmed by
examining CSF

1. Naked
eye appearance of cloudy or frankly purulent CSF.

2. Elevated
CSF pressure (above 180 mm water).

3.
Polymorphonuclear neutrophilic leucocytosis in CSF(between 10-10,000/μl).

4. Raised
CSF protein level (higher than 50 mg/dl).

5.
Decreased CSF sugar concentration (lower than 40 mg/dl)

6.
Bacteriologic examination by Gram’s stain

Acute Lymphocytic (Viral, Aseptic) Meningitis

•       Acute lymphocytic meningitis is a
viral or aseptic meningitis, especially common in children and young adults.

•       Etiologic agents are numerous
viruses such as enteroviruses, mumps, ECHO viruses, coxsackie virus,
Epstein-Barr virus, herpes simplex virus-2, arthropode-borne viruses and HIV

•       viral meningitis has a benign and
self-limiting clinical course of short duration and is invariably followed by
complete recovery

Chronic (Tuberculous and Cryptococcal) Meningitis

•       There are two principal types of
chronic meningitis—bacterial (tuberculous meningitis) and fungal (cryptococcal
meningitis)

•       Tuberculous meningitis occurs in children and adults
through haematogenous spread of infection from tuberculosis

•       Cryptococcal meningitis develops particularly in debilitated
or immunocompromised persons, usually as a result of haematogenous
dissemination from a pulmonary lesion

CLINICAL FEATURES AND DIAGNOSIS

•       Tuberculous meningitis manifests
clinically as headache, confusion, malaise and vomiting

Summary

•       Meningitis is inflammatory
involvement of the meninges

•       Acute pyogenic or acute purulent
meningitis is acute infection of the pia-arachnoid and of the CSF enclosed in
the subarachnoid space

•       Acute lymphocytic meningitis is a
viral or aseptic meningitis, especially common in children and young adults.

•       There are two principal types of
chronic meningitis—bacterial (tuberculous meningitis) and fungal (cryptococcal
meningitis)