Meningitis Flashcards
Definition
Inflammation of the membranes covering the brain & spinal cord.
Types: - Bacterial
- Aspetic e.g. viral → most common, fungal
- Tuberculous
Bacterial (Septic) meningitis
Causes more then 1m
Pneumococci
Staphylococci
Streptococci
Nisseria meningitides
Acute Bacterial Meningitis
.neonat
y E.coli
y Listeria monocytogenes
y Hemophilus influenza.
Transmission /Bacterial (Septic) meningitis
Droplet infection mostly (Blood borne in neonatal sepsis)
Clinical picture/Non specific
- High fever (may be hypothermia in neonates).
- Poor feeding
• Rose spots may appear on the trunk & extremities in meningeococcal septicemia.
. irritability, restlessness, depressed mental status
Features of increased intracranial pressure (ICP)
- Before fontanel closure p tense, bulging anterior fontanel
- After closure of fontanels:
Severe bursting headache (irritability)
Blur of vision
Projectile vomiting (in the morning, not preceded by nausea)
😱Cushing response (hypertension & bradycardia)
Features of meningeal irritation: (less sensitive in infants)
- Neck rigidity (stiffness) p limited neck flexion
- Opisthotonus p arched back
- Kernig’s sign p inability to extend the leg after the thigh is flexed to a right angle with the axis of the trunk.
- Brudzinski leg sign: Passive flexion of one hip p flexion of the other hip and knee
- Brudzinski neck sign: Passive flexion of the neck p flexion of the hip & knee.
Neurologic signs
• Stupor & drowsiness
• Convulsions ➡️ usually generalized
😓 Coma
Complications
1- Syndrome of inappropriate secretion of antidiuritic hormone (SIADH) p so, maintenance fluids must be at 2/3 normal to avoid brain edema.
2- Neurologic complications:
- Increased intracranial pressure (ICP) p May leads to cerebral or cerebellar herniation
- Subdural effusion
- Cranial nerve lesions (commonly oculomotor, 6 th & 8 th 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 of infection: endocarditis, arthritis , osteomyelitis
Investigations in the bacterial form
- CBC➡️⬆️PMNL
- Blood culture reveals the responsible bacteria in up to 80-90% of cases
- C-reactive protein, ESR, and procalcitonin have been used to differentiate bacterial (usually elevated) from viral causes of meningitis
- Lumbar puncture (LP) & CSF examinations
Lumbar puncture (LP) & CSF examinations/Value
-Diagnostic➡️organism,⬆️PMNL, ⬆️ protein,⬇️glucose, Turbid fluid
- Determine appropriate antibiotics by culture & sensitivity.
- Evaluate treatment: CSF become sterile within 24- 48 hours of appropriate antibiotics
Lumbar puncture (LP) & CSF examinations/Contraindications for an immediate LP
- Evidence of increased ICP (other than a bulging fontanel), such as 3rd or 6th cranial nerve palsy with a depressed level of consciousness, or hypertension and bradycardia with respiratory abnormalities
- Severe cardiopulmonary compromise requiring prompt resuscitative measures for shock
- Infection of the skin overlying the site of the LP
Lumbar puncture (LP) & CSF examinations -What to do if an LP is delayed?
- Initiate empirical antibiotic therapy
_ CT scanning for evidence of a brain abscess or increased ICP - LP may be performed after increased ICP has been treated
CSF in Viral meningitis
Clear,,⬆️protein,N. Glucose,⬆️ mononuclear cells predominate
In partially treated meningitis
: Culture and gram stain are usually negative
: But Pleocytosis with a predominance of neutrophils, elevated protein level, and a reduced CSF glucose usually persist for several days
Differential diagnosis
1- From other causes of meningitis
2- Meningism:
- Noninfectious meningeal irritation due to extra cranial lesions
- Causes: Upper lobe pneumonia, otitis media, shigellosis
- CSF is normal
3- Brain abscess
4- Encephalitis
Management
1- antibiotics
- Ceftriaxone 100mg/kg/d given twice daily, or cefoaxime 200mg/kg/d given 6hourly, plus vancomygin 60 mg/kg/ d given 6hourly.
- duration 2-3
2- supportive
😗-Dexamethasone if initiated just before or concurrently with the first dose of antibiotics, significantly diminishes the incidence of hearing loss and neurologic deficits resulting from H. inflenzae meningitis
😗-Measures to q ICp
- Mannitol 0.5 –1gm/kg iv
- Furosemide 1mg/kg iv
😗 Treatment of complications e.g. convulsions
- Immediate relief by diazepam or lorazepam
- Then phenytoin loading and maintenance
😗fluid , nutrition
Prevention
- Isolation of the case
- Vaccination against H.influenza, meningococci, pneumococci
- Chemoprophylaxis for contacts: e.g. rifampicin 10-20 mg/k/day
Aseptic meningitis definition
Meningitis with no micro organisms detected in CSF by gram stain or bacterial culture.
Aseptic meningitis, causes
- Mostly viral , Herpes simplex virus, Enteroviruses (Echo & coxachie) Mumps, Ebstein barr virus
- Protozoa ➡️ Malaria & Toxoplasma
- Non infectious ➡️ CNS leukemia p Intrathecal injection p Post vaccination.
Diagnosis aseptic
- CSF analysis
- Viral isolation
Treatment
- Supportive ± antiviral.
Encephalitis
Encephalitis presents as diffuse or focal neuropsychological dysfunction. Although it primarily involves the brain, it often involves the meninges as well (meningoencephalitis). From an epidemiologic and pathophysiologic perspective, encephalitis is distinct from meningitis, though on clinical evaluation both can be present, with signs and symptoms of meningeal inflammation.
Encephalitis causes
Encephalitis caused by varicella-zoster virus (VZV), Epstein-Barr virus (EBV), cytomegalovirus (CMV), measles virus, or mumps virus: Rash, lymphadenopathy, hepatosplenomegaly, and parotid enlargement