Infections Of Nervous System PDF

INFECTIONS OF NERVOUS SYSTEM DR. WONG JUN LEONG, MD, M.SC. SENIOR LECTURER FACULTY OF MEDICINE & HEALTH SCIENCES (FMHS) UNIVERSITI TUNKU ABDUL RAHMAN (UTAR) Email: [email protected] LinkedIn: my.linkedin.com/in/...

INFECTIONS OF NERVOUS SYSTEM DR. WONG JUN LEONG, MD, M.SC. SENIOR LECTURER FACULTY OF MEDICINE & HEALTH SCIENCES (FMHS) UNIVERSITI TUNKU ABDUL RAHMAN (UTAR) Email: [email protected] LinkedIn: my.linkedin.com/in/drjlwong  LEARNING OUTCOMES Students should be able to: List and describe common infections in the central and peripheral nervous systems List common pathogens causing these infections and associated disorders Discuss host characteristics and microbial virulence factors involved in nervous system disorders Central Nervous system (CNS) infections: Encephalitis, meningitis, myelitis Cimportant) meningoencephalitis meningoencephalomyelitis CNS (brain, Brain/epidural/subdural abscesses spinal cord) ↓ due to infection/necrosis on brain tissue - Peripheral nervous system Cervical, Thoracic, disorders: Lumbar, Neuritis, polyneuropathy Sacral nerves; Guillain-Barre syndrome Cauda equina  ROUTES OF INFECTION Haematogenous spread the most common Local extension from an infected site eg from sinusitis, otitis media, dental caries Direct implantation eg via skull/spinal fracture, surgical procedure, congenital neural tube defect Spread along peripheral nerves to the CNS eg herpes zoster, rabies  PATHOPHYSIOLOGY Inflammation of meninges causes Blood-CSF barrier disruption increase in subarachnoid space volume distortion of ventricles compression of periventricular white matter and brainstem structures Neuronal damage in meningitis involves bacterial components and/or toxins, cytotoxic products of immune competent cells such as neutrophils, and enzymes eg apoptosis-inducing factor(AIF) and caspases (cysteine-aspartic proteases) released from damaged parenchymal cells.  CLINICAL MANIFESTATIONS Fever Cerebellar ataxia Headache (increase intracranial pressure) Paraplegia, tetraplegia Stiff neck (typical sign of meningitis) Neuralgia Rash Paraesthesia Confusion Muscle weakness I features Sleepiness common clinical Flaccid paralysis of brain/NS disorder Seizures Spastic paralysis Photophobia  LATE COMPLICATIONS Cranial nerve palsies Inappropriate ADH (antidiuretic Papilloedema hormone) syndrome Hydrocephalus Learning difficulties Subdural effusion Neuropsychological deficits Recurrences Infarcts, stroke Paraspinal abscess Calcification Seizures, epilepsy Deafness/blindness * ** ETIOLOGY OF ACUTE PYOGENIC MENINGITIS common Group B Streptococcus Neonatal Listeria monocytogenes meningitis Gram-negative bacilli (E.coli, Klebsiella spp. etc.) Neisseria meningitidis Childhood meningitis Streptococcus pneumoniae Haemophilus influenzae S. Pneumoniae N. meningitidis Adult meningitis L. Monocytogenes (older adults and after trauma) Gram-negative bacilli S. Aureus P. aeruginosa, others  CHRONIC BACTERIAL MENINGITIS Chronic bacterial Mycobacterium tuberculosis meningitis Treponema pallidum * does not mean the bacterial cannot cause other  ASEPTIC MENINGITIS CSF shows pleocytosis, prominently lymphocytic Usually acute in onset Clinically nontoxic, mostly self-limiting HFM disease. ↑ Mostly viral (Coxsackie, Entero, Polio. Arbov, paramyxo, HSV, VZ, Spirochaetes eg Borrelia Treponema, Leptospira)  ASEPTIC MENINGITIS * not due to bacterial Signs of enteroviral infection: exanthemas pericarditis, myocarditis, conjunctivitis pleurodynia, Bornholm disease (pleurisy) herpangina, hand-foot-and-mouth disease Fungal infections (C. neoformans, C. gattii; Histoplasma capsulatum) Parasitic Infections (Toxoplasma gondii, Plasmodium spp, Naegleria fowleri, Taenia solium)  TYPICAL CSF FINDINGS (TO BE INTERPRETED IN LIGHT OF PATIENT FACTORS) * IMPORTANT - suspect what happen after collect the specimen can. Normal Bacterial Viral Fungal TB Appearance Clear Cloudy Clear Clear/Cloudy Clear/Cloudy Pressure Lying Down 100-180 mmH2O elevated +/- elevated elevated elevated 8-15 mmHg Sitting up 200-300 mmH2O 15-22 mmHg WBC 0-5/µl >100/µl