Encephalitis Brain Abscess Reşat Özaras, MD, Prof. Infection Dept.

A 37-year-old male Headache, stupor, tendency to sleep, fever, unaware to recognise the time and the place...

Acute Encephalitis The inflammation of the parenchyma of the brain especially that of the cerebral cortex

The inflammation of the CNS Encephalitis… the parenchyma...mostly due to viral infections Meningitis… the meninges... mostly due to bacterial infections

Symptoms Fever Headache Mental changes Confusion Hallucinations Personality changes Diplopia Fatigue Tremors Rash Loss of consciousness

Acute Encephalitis Mostly due to viral inf. –Herpes simplex virus (HSV) (the most common etiology of acute sporadic encephalitis) –Arboviruses – arthropod-borne virus (outbreaks in summer time…mosquitos and ticks) –Varicella zoster virus (VZV ) (immunosuppressed patients)

HSV-1 The most common etiology of acute sporadic encephalitis HSV-1 –acquired in childhood period, –re-activates after years

HSV-1 Primary infection; On the mucosa of oropharynx, mostly asymptomatic fever, pain, dysphagia 2-3 weeks Following primary infection, a latent infection in trigeminal ganglion

HSV-1 Inferior and medial temporal lobe Orbito-frontal lobe Limbic structures Inflammation necrotizing lesions Hemorrhagic necrosis in herpes encephalitis especially when remains untreated.

Widespread edema and subarachnoid hemorrhage areas in medial temporal and orbitofrontal regions HSV-1

Fever Unilateral or generalized headache Mental changes Focal seizures Focal neurological deficits Dysphasia Hemiparesis

VZV Primary infection… chickenpox Latent infection thereafter The commonest reactivation… herpes labialis Chickenpox, herpes labialis and zona may be complicated with encephalitis

Epstein Barr Virus Causes infectious mononucleosis May cause encephalitis Direct invasion of CNS or immune mechanisms Cortex, brain stem, basal ganglia, temporal lobe

CMV Encephalitis in both immunocompetent and immunosuppressed Risk is higher –immunosuppressed, –organ transplanted –HIV-infected patients Organ transplantation, highest risk… CMV (-) donor to CMV (+) recipient

HIV In 10-50% of AIDS patients, HIV infection in CNS Multinuclear giant cells in gray matter and central white matter are pathognomonic.

Rabies Lyssavirus Acute progresive fatal encephalitis. Transmitted with infected saliva of the animal Incubation period: 5 days-6 mo.(20-60 days) III, IV and IXth canial nerve palsies Prodromal period, neurological disease period, paralysis, coma, and death.

Mumps The commonest complication; inflammation in CNS A pleocytosis in CSF in half of the cases In 5-30%: headache, vomiting, neck stiffnes

Clinical Evaluation History PE Neck stiffness CBC Biochemistry Culture Imaging Serology CSF analysis

History Season Localisation Travel Occupational exposure Exposure to animals Immunization Immune status of the patient

Lab CBC Renal and hepatic tests Coagulation studies Plain chest X-ray Nonspecific CSF analysis Cranial imaging Main diagnostic methods

Cranial Imaging Sensitive for early period HSV encephalitis Edema in orbitofrontal and temporal regions MRI Less sensitive than MRI CT

Herpes simplex encepalitis CT(A) and MRI (B-F) temporal lobe involvement

CSF Analysis Cell count: cells/mm 3 Mostly <500 cell/mm 3 Lymphocyte predominance Erythrocytes (in 80% of the cases) Normal CSF findings in 10% Glucose (mg/dl): normal or low CSF glucose/serum glucose: normal (>0.6) or low Protein (mg/dl): >50 Gram staining: no microorganisms Culture: none

Microbiology HSV PCR: For the first hours, detecting HSV DNA by PCR in CSF: –specific (100%) and –sensitive (75-98%)

Herpes simplex encephalitis; Neurons including Cowdry A type intranuclear inclusion bodies. Hematoxylen-Eosin, X400.

Treatment If shock/hypotension exists, crystaloid infusion If unconscious, provide airway/breathing Seizure, lorazepam 0.1 mg/kg, IV

Treatment For encephalitis, give acyclovir

Treatment Acyclovir IV, 14 – 21 days –HSV encephalitis –VZV encephalitis

Some keys Atypical lymphocytes on peripheral smear… IMN High amylase … Mumps

Complications Acute period Seizure Inappropriate ADH synd. Intracranial pressure inc. Resp. arrest Coma Death Chronic period Chronic fatigue Depression Personality changes Gait disorders Memory disorders Speech disorders Visual problems Mental retardation Hemiplegia Seizure

Prognosis The virulence of the virus Patient’s; –previous health status –immune status (chemotherapy, transplantation, AIDS) –age ( 55 years) –any neurological symptoms

Prognosis Being in coma on prsentation: severe inflammation in the brain, poor prognosis Treated –Mortality… 20% –Morbidity… 40% Untreated –Mortality … 50-75% –Morbidity… 100%

Brain Abscess Focal collection in the brain parenchyma due to – Infection – Trauma – Surgery

Pathogenesis Hematogenous: multiple abscess – Chronic pulmonary inf. (lung abscess, empyema…) – Skin inf. – Pelvic inf. – Intraabdominal inf. – Bacterial endocarditis – Cyanotic congenital heart dis.

Direct transmission – Subacute or chronic otitis media, mastoiditis (inferior temporal lobe and cerebellum) – Frontal or ethmoid sinusitis (frontal lobes) – Dental infections (frontal lobes)

Early lesion (first 1-2 weeks): – The borders are not clearly defined, localised edema – Inflammation, no necrosis – “Cerebritis” After 2-3 weeks, necrosis A fibrous capsule

Etiology Aerobs+Anaerobs

Signs&Symptoms Headache Fever Neck stiffness Mental changes Nausea, vomiting

Warning LP is contraindicated!

Diagnosis Imaging – MRI – CT

Treatment Intervention Antibiotics – Ceftriaxone + metronidazole Mortality 0-30 %