Block 4

• Common bacteria that cause meningitis

  S. pneumonia and N. meningitis 
• Acute pyogenic meningitis Gross Morphology

  • Meningeal vessels - engorged
  • Purulent exudates on the surface of brain
• Acute pyogenic meningitis Microscopy

  • Neutrophilic in the subarachnoid space
  • Leukocytosis with neutrophilia
• Common virus that cause meningitis

  Enterovirus - echovirus, coxsackie and polio
• Clinical feature of hydrocephalus

  • Spasticity or hyperreflexia in limbs
  • Double vision
  • Blurred vision
• What is brain abscess?

  Lesions in the brain due to bacteria infection - usually Strep and Staph
• Brain abscess - Present as expanding intraparenchymal mass - area - infected and liquefactive necrosis
• Brain abscess Microscopic - Neutrophil in subarachnoid space around leptomeningeal blood vessels
• Subdural empyema - collection of pus between the dura and arachnoid
• Subdural empyema is due to?

  Bacteria or fungi infection of bone or air sinus spread to the subdural space
• Extradural abscess - collection of pus between the dura and bones skull or spine
• • Pott's puffy tumor - sinusitis that lead to osteomyelitis
• Chronic Bacterial meningoencephalitis caused by

  • TB
  • T. Pallidum 
  • Borrelia
• Who are susceptible to M. avium compared to Tb meningitis?

  • people with low immune response - AIDs
  • little granulomatous response
• TB meningitis morphology - Fibrous exudate at the base of the brain
• TB meningitis micrology - caseating granuloma at the base of the brain
• Neurosyphilis caused by t. pallidum
• Tertiary syphilis show Area of necrosis and langhans giant cells
• Neuroborreliosis - Lyme disease
• which meningitis cause facial nerve palsy?

  Neuroborreliosis
• What position is the pt suppose to be in during lumbar puncture?

  fetal (lateral decubitus) position flexing spine - lateral recumbent or sitting
• Site for Lumbar puncture - L 3/4 or L 4/5 - avoid damage to conus medullaris
• Why is the fetal position preferred in lumbar puncture?

  • accurate measurement of opening pressure
  • reduce risk of post-lumbar puncture headache
• Where should the needle be inserted for lumbar puncture?

  stylet in place and with the bevel in the sagittal plane
• What is the pathological opening pressure for lumbar puncture?

  greater than 250 mmmH20
• Mucor and aspergillus - Vasculitis with thrombosis and hemorrhagic infarcts
• Candida and crypto - Parenchymal invasion with granulomas or microabscesses
• Kid and mass compressing on brain or mass compressing on optic chiasm

  Pilocytic astrocytoma
• Pilocytic astrocytoma

  • No p53 loss
  • Occur in optic nerve or cerebellar
  • Children and young adults
  • Rosenthal fibers
• Pilocytic astrocytoma - Rosenthal fibers

  • Elongated
  • Eosinophilic
  • Proteinaceous
• Pilomyxoid astrocytoma

  • Young children - < 5 years
  • around the optic tract
  • Intercellular mucin
• Differences between pilomyxoid and pilocytic?

  pilomyxoid - lack eosinophilic granular bodies and Rosenthal fibers
• Pleomorphic xanthoastrocytoma (PXA)

  • Multinucleated cells with foamy cytoplasm
  • Pt present with epilepsy
  • Loss on ch 9
  • BRAF mutation
• Desmoplastic astrocytoma (DA)

  • Tumor of infant
  • dense collagen
  • fibroblast and glial cell - tangle in a ball
  • Adherent to dura 
• Gliomas stain?

  GFAP
• Chordoid Glioma of the third ventricle

  • Epithelioid cells arranged in cords and clusters - mucinous background
  • Location - within ventricle and attached to hypothalamic and suprasellar structure
  • Russell body and lymphocytic infiltrate
• • Pituicytoma (infundibular astrocytoma)

  • Spindle cell astrocytic tumor of adults
  • Origin - posterior pituitary or stalk
  • Interweaving elongated cell
  • S100
• Subependymal giant cell astrocytoma (SEGA) manifestation

  • Infantile spasms
  • Autism
  • Mental retardation
  • Epilepsy
  • Visual disturbance
• Subependymal giant cell astrocytoma (SEGA) 3 type of cells?

  • Spindle
  • Gemistocytic
  • Ganglion
• Subependymal giant cell astrocytoma (SEGA)

  • Location - wall of lateral ventricle and foramen of Monro
  • Affects - pts with tuberous sclerosis (TS)
  • Mutation - TSC1 or TSC2