Meningitis Flashcards
Definition of meningitis
Meningitis
Definition: inflammation of the membranes covering the brain & spinal cord.
Types
— Bacterial
— Aseptic e.g. viral, fungal
— Tuberculous
Bacterial (septic) meningitis
The common cause is
— Neiseria meningitidis ( In children 1 month to 12 months )
— Streptococcus pneumonia and haemophilus influenza (type B)
Others include
— Group B Streptococcus.
— Haemophilus influenzae.
— Listeria monocytogenes.
— Escherichia coli.
Peak of H. influenza infection between 6-12 month–)> incidence declined by
vaccination
Transmission: - Droplet infection mostly
-Blood borne=> in neonatal sepsis
Clinical picture / Signs And Symptoms
- Non specific
-High fever (may be hypothermia in neonates).
- Poor feeding
- Rose spots may appear on the trunk & extremities in meningeococcal
septicemia. - Features of Increased Intracranial tension
* Before fontanel closure –)> tense, bulging anterior fontanel * After closure o f fontanels:
-Severe bursting headache (irritability)
- Blurr ofvision
- Projectile vomiting (in the morning, not preceded by nausea) -Cushing response (hypertension & bradycardia) - Features of meningeal Irritation: (less sensitive in infants)
*Neck rigidity (stiffhess)–)> limited neck flexion
*Opisthotonus–)> archedback
* Kernig’s sign –)> inability to extend the leg after the thigh is flexed to a right
angle with the axis ofthe trunk.
* Brodzinski leg sign: Passive flexion o f one hip ~ flexion o f the other hip
and knee
*Brodzinski neck sign: Passive flexion ofthe neck~ flexion ofthe hip & knee. - Neurologic signs
* Stupor & drowsiness.
* Convulsions –+ usually generalized *Coma
Clinical tvpes
1- Meningitic form –+ the classic presentation as before. 2- Fulminant meningitis.
- Abrupt fever.
- Severe headache and convulsions. - Rapidly progress to coma.
- Fatal within 48 hrs.
3- Septicemic form (usually complicating meningeococcal form) - Very bad general condition
-Shock
- Purpura & ecchymosis
- Meningitis develop within 1-2 days (or not at all) Complications
1- Syndrome ofinappropriate secretion ofantidiuritic hormone (SIADH) –+ so, maintenance fluids must be at 2/3 normal to avoid brain edema.
2- Neurologic complications:
- Increased intracranal pressure. –+ may leads to cerebral or cerebellar herniation - Subdural effusion
-Cranial nerve lesions (commonly oculomotor, 6th & 8th nerves).
- Hydrocephalus.
3- Peripheral circulatory complications
i- Waterhouse Friedrichson syndrome
-Septicemia
-Shock
- Extensive purpura
- Adrenal hemorrhage (acute adrenal failure).
ii- DIC: Gangrenous patches & extremities
4- Dissemination o f infection: endocarditis, arthritis , osteomyelitis Investigations
1- CBC –+ leucocytosis.
2- Blood culture –+ may detect the causative bacteria. 3- Lumbar puncture & CSF examinations:
- Diagnostic for infection
-Determine appropriate antibiotics by culture & sensitivity.
- Evaluate treatment : CSF become sterile within 24- 48 hours o f appropriate
antibiotics
- Avoided in: marked increase intracranial pressure , shock and with bleeding
disorder.
View table in page 365 of baby Nelson pediatrics book
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Differential diagnosis for bacteria 🦠 meningitidis
Differential diagnosis
1- From other causes of meningitis
2- Meningism :
-Non infectious meningeal irritation due to extracraniallesions -Causes: Upper lobe pneumonia, otitis media, shigellosis
- CSF is normal
3- Brain abscess
4- Encephalitis
Management of bacteria 🦠 Meningitidis
Management
A. Treatment
~365 ~
1- Antibiotic theraPY
* Parenteral antibiotics according to culture and sensitivity for 2- 4 weeks
* While waiting for culture results ;the following combination is recommended:
Ampiciilin 200 mglkg/d + 3rd generation cephalosporins 100- 200 mglkg/d
- In suspected organisms:
Meningococci— Penicillin G 400.000 unit/kg/d.
H.influenza — Ceftriaxone1OOmglkg/day
Pneumococci — -Vancomycin 60 mglkg /day+ 3rd generation cephalosporin
(cefotaxime 200mglkg/day or ceftriaxone) - Chloramphenicol 1OOmglkg/day
Pseudomonas — Ceftazidime
Listeria — Ampiciilin
2- Supportive therapy
2- Supportive therapy -9- Measures to .J, ICT:
- Hyperventilation to keep paco2 at 25 mmHg -Mannitol 0.5 -1gmlkg iv
- Furosemide 1mg!kg iv
-9- Corticosteriods Indications:
a- H. influenza meningitis:
-Value: Reduce inflammatory response caused by cell lysis -Use dexamethazone 0.15 mglkgldose every 6 hours for 2 days
b- Septic shock to improve general condition.
c- Adrenal failure
-9- Treatment ofconvulsions:
- Immediate relief by diazepam or lorazepam
- Then phenytoin loading and maintenance -9- Treatment ofcomplications
Prevention
Prognosis
B. Prevention:
- Isolation ofthe case
-Vaccination against H.influenza, meningococci, pneumococci. -Chemoprophylaxis for contacts: e.g. rifampicin 10-20 mg/k/day ::::>for 2-4 days.
Prognosis Depends on:
1- Age: the younger the age, the worse the prognosis.
2- Course: fulminant meningitis has worse prognosis.
3- Cause: - E.coli & staph –+t fatality & t long term sequalae.
- H.influenza & pneumococci –+ moderate prognosis.
- Meningococci –+ < 5% fatality & no residual disability.
(Aseptic meningitis
Meningitis with no micro organisms detected in CSF by gram stain .m: bacterial culture.
Causes
Mostly Viral:
–+Herpes simplex virus
–+ Enteroviruses (Echo & coxachie) –+Mumps
–+ Ebstein barr virus 🦠
Protozoa:
–+ Malaria
–+ Toxoplasma
Non infectious:
–+ CNS leukemia
–+ Intrathecal injection
–+ Post vaccination.
Diagnosis: - CSF analysis -Viral isolation
Treatment: - Supportive ± antiviral.
