1. INFECTIONS 4 routes which infectious agents can enter the CNS a) hematogenous spread i) most common - usually via arterial route - can enter retrogradely (veins) b) direct implantation i) most o ften is traumatic ii) iatrogenic (rare) via lumbar puncture iii) congenital (meningomyelocele) c) local extension (secondary to established infections) www.freelivedoctor.com

10. i) central liquefactive necrosis surrounded by fibrous cap - edema in surrounding area ii) common sites (in descending order) - frontal lobe - parietal lobe - cerebellum iii) present with progressive focal deficits - signs of  ICP www.freelivedoctor.com

14. d) CSF: i) moderate pleocytosis - PMN and MN ii) proteins markedly  iii) glucose slightly  or normal e) Subarachnoid space  fibrous exudate i) most often at base of brain ii) often obliterating the cisterns iii) encasing cranial nerves f) development of a single intraparenchymal mass  tuberculoma i) may cause significant mass effect www.freelivedoctor.com

16. - meningovascular neurosyphilis is chronic meningitis involving base of the brain, spinal leptomeninges and cerebral convexities. Obliterative endarteritis (Heubner arteritis) - paretic neurosyphilis caused by invasion of the brain by T. pallidum. Progressive loss of mental and physical functions with mood alterations - Tabes dorsalis is a result of damage by the spirochete to the sensory nerves in dorsal roots, causing locomotor ataxia and sense of position, loss of pain sensation, www.freelivedoctor.com

18. ii) and sometimes spinal cord involvement (encephalomyelitis) b) most characteristic features i) perivascular and ii) parenchymal mononuclear cell infiltration c) intrauterine viral infections may cause congenital malformations i) rubella d) slowly progressive degenerative disease may occur many years after viral illness i) postencephalitic parkinsonism - post WW 1 www.freelivedoctor.com

20. c) Clinical: i) generalized neurologic deficits - seizures - confusion - delirium - stupor and coma ii) CSF usually colorless - slightly  pressure - initially a neutrophilic pleocytosis, which rapidly - converts to lymphocytes - proteins are  - glucose is normal www.freelivedoctor.com

26. c) Clinical: i) virus enters the CNS in ascending fashion - along PNS around wound site - incubation 1-3 months - as infection advances, patients exhibit extraordinary excitability where slightest touch is painful. Violent motor responses  seizures ii) contraction of pharyngeal muscles on swallowing  foaming at the mouth  aversion to swallowing, even water (hydrophobia) www.freelivedoctor.com

29. ii) similar to subacute combined degeneration (Vit B 12 deficiency) iii) Vit B 12 is not changed in Vacuolar myelopathy iv) pathogenesis unknown 3. Myopathy and Peripheral Neuropathy a) inflammatory myopathy i) most often described disorder in patients with HIV - proximal weakness - pain -  serum CK www.freelivedoctor.com

30. b) most commonly reported syndromes i) acute and chronic inflammatory demyelinating polyneuropathy - segmental dymyelination - axonal degeneration 4. AIDS in children a) microcephaly with mental retardation b) motor development delay i) spasticity of limbs c) most frequent abnormality i) calcification of small and large vessels and parenchyma within basal ganglia www.freelivedoctor.com

35. b) vasculitis (thrombosis and infarcts) i) Mucor ii) Aspergillus c) parenchymal invasion i) granulomas or abscess ii) occur with most of the organisms iii) Candida and Cryptococcus are most common here iv) Candida  multiple micro abscesses www.freelivedoctor.com

37. iii) “ring” enhancing lesions - other pathologies also show these lesions. CNS lymphoma, TB and fungal infections iv) brain frequently shows multiple abscesses (necrotic lesions) - cortical areas near white-grey matter junction and deep grey nuclei - areas of necrosis v) may occur in the fetus (i.e., early during pregnancy) www.freelivedoctor.com