CNS infection Dr V P C Rajakaruna MBBSCOLOMBO

CNS infection Dr. V. P. C. Rajakaruna MBBS(COLOMBO)

Content • Types of infections • Causative agents • Symptoms and signs

Infections – Terminology • • Meningitis Encephalitis Myelitis Meningoencephalitis Meningomyelitis Encephalomyelitis Meningo-encephalomyelitis Brain abscess

Meningitis

Meningitis • Purulent meningitis - polymorphonuclear cell - WBC > 1000 celss/mm 3 - pyogenic bacteria • Lymphocytic meningitis • Eosinophillic meningitis - eosinophil > 5% - parasite • Carcinomatous meningitis

Pathogenic organism • • • Virus Bacteria Mycobacterium Fungus – Cryptococcus neoformans Parasite – Angiostrongylus cantonensis, Gnathostomiasis, Cysticercosis Actinomycosis Protozoa Rickettsia Spirochete Mycoplasma

Pathogenesis • Hematogenous spreading • Parameningeal structures – sinusitis, mastoiditis, otitis media, dental carries • Direct infection to the subarachnoid space – fracture base of skull, dermal sinus tract, ruptured meningoceal abscess • Direct infection – surgery, lumbar puncture • Cranial nerve and peripheral nerve – rabies encephalitis, herpes simplex encephalitis

Symptoms and signs • Fever, Headache, Nausea and vomitting • Period - acute period: within 1 week bacteria, virus, amoeba, parasite, systemic infection - subacute period: 1 - 4 weeks tuberculosis, fungus, parasite, spirochete, systemic infection - chronic period: > 4 weeks

Chronic meningitis Infectious causes M. Tuberculosis Cryptococus neoformans Cysticercosis Angiostrongylus cantonensis Treponema pallidum Nocardia asteroides Actinomycosis Acanthamoeba

Noninfectious causes Neoplasm SLE Vasculitis Behcet’s disease lymphocytic meningitis Sjogren’s syndrome

Symptoms

Symptoms (children(

Kernig’s sign

Brudzinski’s sign

Symptoms • • • Alteration of consciousness Seizure Localizing signs: hemiparesis, paraplegia Cranial nerve palsy Autonomic hyperactivity

Investigations

Lumbar puncture

Lumbar puncture

CSF analysis • The characteristics of normal CSF - open pressure: 50 -200 mm. CSF - clear color - cells: RBC WBC- lymphocyte < 5 cells - protein 20 -45 mg/dl - CSF sugar/ Serum sugar > 50% - fresh smear, Gram stain, India ink, AFB, modified AFB - culture

CSF analysis for differential diagnosis (acute onset)

Pathogen Virus Bacteria Open pressure Normal Appearance Clear Normal, increased Turbid WBC + (+) Lymphocyte + +++ PMN ++ Normal Decreased Special lab Gram stain, culture, CIE, latex agglutination Protein CSF sugar/ Serum sugar Others

CSF analysis for differential diagnosis (acute onset)

Pathogens Parasite Protozoa (Naegleria) Systemic infection Open pressure Normal, increased Normal Appearance Angio: coconut juice Gnatho: xanthochrome Turbid Clear WBC ++ eosinophil +++ PMN + Protein ++ ++ + CSF sugar/ Serum sugar Normal Decreased Normal Others - Fresh smear, culture - Lymphocyte

CSF analysis for differential diagnosis (subacute onset)

Pathogen Tuberculosis Cryptococcosis Open pressure Normal, increased Appearance Straw color Xanthochrome Clear WBC ++ Lymphocyte Protein +++(+) ++ CSF sugar/ Serum sugar Decreased Others AFB, culture, cobweb, PCR India ink, culture, Crypto Ag

Viral Encephalitis

HSV encephalitis • In adult most caused by HSV-1 • Primary infection in oropharyngeal or intranasal mucosa • Latent ganglionic infection • Reactivation leads to encephalitis • Headache, fever, alteration of consciousness

VZV encephalitis • After varicella develop, VZV remain within the ganglia • Reactivation, spread to spinal cord & brain

Japanese encephalitis • Flavivirus, Culex- borne, Southeast Asia /China • Symptoms: headache and alteration of consciousness • Clinical signs (post encephalitis): tremor, dystonia, rigidity, mask-like face • Mortality rate 30% • Vaccine available – inactivated virus, age should be more than one year to get the vaccine

Rabies encephalitis • Rhabdovirus family, transmission through dog bites • Encephalitic form involve cerebrum, brainstem • Late state involve basal ganglia and thalamus coma • Paralytic form involve medulla, spinal cord

CMV encephalitis • Opportunistic infection in organ transplant, HIV • Brainstem encephalitis, cranial nerve palsy, associated retinitis visual pathway