Gianani intro to neuropathology Flashcards
Approach to the patient with neurologic disease
- primary or secondary?
Most patients in hospital with a coma have a metabolic, toxic or infectious cause
Approach to the patient with neurologic disease- time course of disease
Vascular pathology: seconds to minutes
Abscesses: hours to days
Neoplasms: weeks to months
Degenerative disease: months (e.g. prion disease) to years (e.g. Huntington chorea) to decades (e.g. Alzheimer and Parkinson disease)
Multiple sclerosis: relapses and remissions over months to years
Mnemonic for toxic/metabolic causes of neurological diseases:
DEENO (drugs, endocrine, electrolytes, nutritional, organ failure)
localizing findings: cerebrum
decreased mental status seizures motor/ sensory abnormalities of the head visual field defects movement abnormalities (e.g. tremor, chorea)
localizing findings: brainstem
cranial nerve defects
“crossed” defect (i.e. head and limbs deffects on opposite sides)
localizing findings: spinal cord
back pain
specific body level/ sparing of the head
sphincter dysfunction
localizing findings: spinal roots
radiating limb pain
pattern of loss
areflexia
localizing findings: peripheral nerves
distal limb distribution
nerve distribution of abnormality
“stocking and glove” pattern
areflexia
localizing findings: neuromuscular junction
bilateral weakness increasing with exertion
proximal limb symptoms
sparing of sensation
localizing findings: muscle
bilateral weakness
sparing of sensation
Localization: Focal, multifocal or diffuse
Mass lesions (e.g. abscesses, bleeds, and neoplasms) typically have localized symptoms
Acute, diffuse, symmetrical symptoms are typically viral, metabolic or toxic in origin
localization: presence of pain
Only the meninges and vessels have pain fibers
Pathophysiologic pattern
Neuronal diseases
(i.e. gray matter) typically have cognitive loss, movement disorders or seizures
Pathophysiologic pattern: White matter
typically has “long tract” findings (i.e. motor, sensory, visual or cerebellar)
Pathophysiologic pattern: Progressive, symmetric loss is usually
metabolic or degenerative
Dementia
(loss of mental power) is a generic term, not a disease entity. Any pathology that causes significant brain damage, at any age, can cause dementia. The causes of dementia include:
- Stroke and ischemic encephalopathy (multi-infarct or vascular dementia)
- Hippocampal sclerosis
- Head trauma (subdural hematomas, diffuse axonal injury, chronic traumatic encephalopathy)
- Hydrocephalus
- CNS infections (HIV encephalitis, Creutzfeldt-Jakob disease)
- Metabolic CNS disorders (lysosomal storage and peroxisomal diseases)
- Demyelinative diseases (multiple sclerosis)
- Neurodegenerative diseases (Alzheimer’s disease, Parkinson’s disease, diffuse Lewy body dementia, Huntington’s disease, and other)
- Neuropsychiatric disorders
- Severe medical illness or organ failure
- The effects of medications
Three imaging modalities are commonly used in clinical practice:
CT scan, MRI scan, and angiography
CT scans are preferred in
Emergencies (fast)
Trauma (evaluation of skull fractures)
Stroke (sensitive for fresh hemorrhage)
CT scan
X-rays measure the density of a tissue.
Hypodense: Air is black (e.g. sinuses of skull), fat appears near black (e.g. subcutis of scalp) and water appears dark gray (e.g. CSF)
Isodense: white matter, with more fat from myelin, is darker than gray matter.
Hyperdense: ** bone is white, as is fresh blood. As fibrinolysis occurs, the clot becomes isodense with brain at 1 week, and hypodense by weeks 2-3 (the density of the clot can be used to date the time of the bleed).
