Encephalitis Brain Abscess Reat zaras MD Prof Infection

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) patients) (immunosuppressed

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.

HSV-1 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 • CSF analysis • Cranial imaging Nonspecific Main diagnostic methods

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

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

CSF Analysis • Cell count: 10 -2000 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 24 -48 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, X 400.

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 Chronic period • • • • Seizure Inappropriate ADH synd. Intracranial pressure inc. Resp. arrest Coma Death 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(<1, and >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 %

www. rochester. edu