LECTURE MENINGITISProf. Abbas Hayat

Acute, Chronic, Bacterial, Viral, Fungal, Parasitic, Diagnosis and Treatment.

NAME OF DISEASE:Purulent meningitis Bacterial meningitis   • OVERVIEW:The disease usually begins as an infection by normal body flora, of:

• The ear (otitis media) - Haemophilus influenzae

• The lung (lobar pneumonia) - Streptococcus pneumoniae

• The upper respiratory tract (rhinopharyngitis) - Neisseria meningitidis, Haemophilus, influenzae, Streptococcus, Group B

• The skin and subcutaneous tissue (furunculosis) S. aureus

• The bone (osteomyelitis) - S. aureus

• The intestine - E. coli

This localized infection develops into a Bacteremia with a metastatic infection in the leptomeninges.

This is exceedingly rapid in acute bacterial meningitis and death may occur in hours.

Males are affected twice as often as females.

All ages Diabetics, alcoholics, elderly, debilitated, diseased (untreated):

• Listeria monocytogenes

• Streptococcus pneumoniae

• Treponema pallidum

ETIOLOGICAL AGENT: Neonates (0-2 weeks)

Infants (2 weeks to 3 months)

Children (3 months - 6years)

Normal adults (6 years to 21)

E.coli  

Strept. Group B

Staph. aureus   Listeria monocytogene Strept, Group A

Strept, Group B

Listeria monocytogenes

Escherichia coli

H. influenzae N. meningitidis

Strept. Pneumoniae

Staph. aureus M. tuberculosis

N.meningitidis

Strept.pneumoniae

PATHOLOGY:

The mechanism of pathology may be either:

• 1. Endotoxemic shock

• 2. Disseminated intravascular coagulation

CLINICAL SYMPTOMS: 1- Infectious manifestations:

- Chills - Headache - Fever - Myalgia - Malaise

2- Increased intracranial pressure, manifested as- Headache - lethargy - Vomiting --Papilledema- Unilateral or bilateral 6th nerve palsy,

  3- Meningeal irritation

(noted by elicitation of Brudzinski's and/or Kernig's sign) .- Stiff neck- Spasms of the Gracilis, Sartorius and/or Biceps

Femoris muscle - Nuchal rigidity.

4. Hemorrhage:- Petechia - Purpura- Ecchymosis.

5. Eye affects:

- Photophobia- Venous congestion of ocular fundi- Unequal pupils, Pupil dilation- Sluggish reaction to light.

6. Mental state:- Drowsiness - Coma- Delirium - Stupor

– The infant with meningitis has signs of infection but commonly is `simply fretful

and refuses food’. • Vomiting occurs early in the disease

and is often repeated,………. dehydration that may prevent the full

fontanelle as associated with increased intracranial pressure.

• Fever may be absent and there may be hypothermia.

• As the disease progresses, apnea episodes, twitching, seizures (up to

30% of cases), opisthotonos, and

coma and death result.

• Skin rashes occur with meningococcemia, with or without meningitis.

• From the 1st to the 3rd day, at least one-third of patients with meningococcal meningitis

develop petechiae, most prominently in areas subjected to pressure; for example, Axillary

folds and the belt line.

• Purplish ecchymoses and maculopapular nodules up to 2 cm in diameter may also be present, tending to appear first on the trunk

and later on the extensor surfaces of the thighs

and forearms.

The CSF should be examined in every patient in whom the clinical findings are consistent with even the possibility of meningitis, no matter how minimal the manifestations are.

Examine the CSF for:1. Pressure  2. Appearance: clear or turbid 3. Wet Mount 4. Gram Stain for bacteria.5. Geimsa stain for Presence of neutrophils or lymphocytes or R.B.C.s.

Examination of the cerebrospinal fluid (CSF)

6- Cell count:Normal 0-5 cells /mm3 Markedly increased in bacterial tuberculous and viral accordingly

7- Glucose measurement:Normal 60 % of blood glucose, decreases in bacterial meningitis.

8- Concentration of proteinNormal 40-60 mg/dl ++++ in bacterial +++in tuberculous ++ in viral.

9- Look for Bacterial antigens in C.S.Fby specific Antibodies.

10- Culture.

LAB. FINDINGS IN CSFCasualOrg.

Appearance

Cells/mm3

Microbiology

Protein Glucose

Normal Clear colorless

0-5 lympho Sterile 20-40mg/dl

40-60 mg/dl

Bacterial meningitis

Turbid 500-20,000 mainly polymorphs,few lymphos

Bacteria

Markedlyincreased ++++

Reduced or absent

Viral (aseptic meningitis)

Slightly turbid

10-500 mainly lympho

RarelyIsolatedSerology

NormalorSlightlyraised+

Normal or slightly raised+

Tuberculous meningitis

SlightlyTurbidSpiderWebcoagulam

10-500 mainly lympho, polys in early stages

AFB.medium.

ModeratelyRaised++

Usually reduced

DIFFERENTIAL DIAGNOSIS: • Bacterial Meningitis:

Polymorphonuclear cells outnumber monocytesPapilledema occurs late in disease when it occurs, acute onset.High lactate, Low glucose of CSF.

• Tubercular Meningitis:Insidious onsetSlight changes in CSF chemistryPositive tuberculin testlow chloride.

• Fungal Meningitis:Insidious onset, history of lung infection, yeast cells in CSF, slight changes in CSF chemistry.

• Syphilitic Meningitis:Insidious onset, slight change in CSF chemistry, positive RPR test.

• Parasitic MeningitisAcute onset, slight change in CSF chemistry, presence of IgM in CSF .(Trypanosoma cruzi infection = Chagas' disease, sleeping sickness).

(Acanthamoeba or Naegalaria species) Entry via contaminated water or in children swimming in contaminated water. 90% mortality, presense of vegetative forms of amoeba on direct examination of C.S.F.

• Viral Meningitis:Acute onset, slight change in CSF chemistry. Monocytes outnumber PMN's.

• Subarachnoid hemorrhage:Red blood cells in CSF.

• MeningiomaX-ray for tumor presence.

• MeningismusHistory of non-CNS viral disease ( a non-infective state resembling meningitis).

• Brain AbscessPMN's may outnumber monocytes, papilledema occurs early in disease, acute or insidious onset. Sterile CSF.

• TetanusTrismus, clean mentation.

THERAPY: • General:

The risk of death during early phases of acute bacterial meningitis relates to problems other than the infection.

• A combination of fever, dehydration secondary to vomiting, and decreased food and fluid intake & subsequent alkalosis predisposes patients, especially children, to seizures.

• Respiratory arrest or airway obstruction follows; if significant CNS or myocardial hypoxia occurs, fatal cardiac arrhythmias or brainstem damage may result.

• Procedures commonly employed include: 1. Correction of fluid and electrolyte deficits.

2. Provision for adequate oxygenation.

3. Monitoring of cardiovascular function (Give a cardiac-active glycoside if necessary).

4. Monitoring intracranial pressure - administer urea or mannitol to reduce cerebral edema.

Administration of antibiotics – Empiric regimen • Neonate (up to 1 month old) -    

Ampicillin + Cefotoxime or Ampicillin + Gentamycin

• Neonate (1-3 months old)-Ampicillin + Dexamethazone or

Ampicillin + Dexamethazone + Cefotoxime

• Other (3 months - 50 years old)Cefotoxime + Vancomycin

• (Over 50 years old or alcoholic)-     Ampicillin + Cefotoxime

CHRONIC MENINGITIS

• Tubercular meningitis• Cryptococcosis• Fungal meningitis• Syphilitic meningitis• Amoebic meningitis

TREATMENT: of Fungal Meningitis.

1. Amphotericin B injected I.V. and into the subarachnoid space.

2. Fluconazole 3. Ketoconazole 4. Itraconazole 5. Flucytosine (5-fluorocytosine)-

penetrates into all body fluids, including CSF. Less toxic but higher doses required.

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