HYPERTENSIVE ENCEPHALOPATHY - Inova Presentations and...HYPERTENSIVE ENCEPHALOPATHY •Reversible...
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Transcript of HYPERTENSIVE ENCEPHALOPATHY - Inova Presentations and...HYPERTENSIVE ENCEPHALOPATHY •Reversible...
HYPERTENSIVE ENCEPHALOPATHY
• Reversible posterior leukoencephalopathy syndrome • Cause Renal disease Pheochromocytoma Disseminated vasculitis Eclampsia Acute toxemia Medications & illicit drugs (cocaine) Discontinuation of hypertensive medications • Disruption of BBB vasogenic edema • Vascular fibrinoid necrosis hemorrhages
Adams & Victor’s Principles of
Neurology, 9th edition, 2009
CHRONIC HYPERTENSION
• Atherosclerosis & microatheroma
Lacunar infarcts
• Arteriolarsclerosis
Subcortical ischemic vascular dementia
• Fibrinoid necrosis
Bleeding
• ?Microaneurysms (Charcot Bouchard aneurysms)
Bleeding
Ferrer I, et al: Vascular Diseases. In: Greenfield’s Neuropathology, 8th edition, 2008
Lacunar Infarct
• Less than 15 mm in diameter
• Occlusion of terminal arteries
• Arteriolarsclerosis
• Embolism
• Narrowing of ostium at site of origin
Trichrome
AMYLOID ANGIOPATHIES
• Sporadic or AD-associated
• Familial AD
• HCHWA-D
• HCHWA-I
• Meningovascular amyloidosis
• Familial amyloidosis, Finnish type
• Familial British dementia
• Familial Danish dementia
• Prion disease
• Amyloid beta
• Amyloid beta
• Amyloid beta
• Cystain C
• Transthyretin
• Gelsolin
• ABri
• ADan
• APrion protein
Ellison D, et al. Neuropathology, 3rd edition. 2013
Congo red
Beta amyloid Beta amyloid
CADASIL • Cerebral autosomal dominant artheriopathy with
subcortical infarcts and leukoencephalopathy
• Clinically associated with migraine, recurrent strokes, psychiatric symptoms & dementia
• Linked to mutations in the NOCHT 3 gene on chromosome 19
• Related to deposits of PAS positive granular material in the tunica media of arteries of the CNS, skin, skeletal muscle and peripheral nerve
• Demyelination of centrum semiovale
• Lacunar infarcts in white matter, basal ganglia, thalamus and brain stem
PAS
PAS
Courtesy Dr. D. Louis, Boston, MA
Brain Ischemia • Arterial cerebral blood flow is insufficient to
maintain cellular functions
• Normal CBF:
55 ml/100g/min – Moderate ischemia:
CBF 15-20ml/100g/min
Short duration <30 min
Reversible cell injury
– Severe ischemia:
CBF 10 ml/100g/min
Irreversible cell injury
• Regional ischemia:
Pancellular necrosis
Anemic infarct
Hemorrhagic infarct
Lacunar infarct
Microscopic infarct
Incomplete infarct
Global ischemia
Selective neuronal necrosis
Brain Ischemia
Brain Infarct Gross Findings
• Recent (acute) Infarct
8-38 hours Blurring of gray/white matter junction
Dusky gray discoloration of neural tissue
Tissue softening on palpation
2-4 days Edema
• Organizing (subacute) infarct 5-30 days
Liquefactive necrosis
• Organized (chronic) infarct >1 month
Cystic cavity
Modified from Ellison D, et al. Neuropathology, 3rd edition. 2013
Hemorrhagic Infarct
• Result from hemorrhagic transformation of ischemic lesion
• Mechanism
Reperfusion of ischemic territory
Episodes of hypertension
Partial occlusion of arterial lumen
• Pathologic features
Cortical petechial hemorrhages
Hematoma
BRAIN INFARCT MICROSCOPIC FINDINGS
• Recent (acute) infarct 1-4 days Neuronal eosinophilia Edema Acute inflammation • Organizing (subacute) infarct 5-30 days Necrosis Macrophages Neovascularization • Organized (chronic) infarct >1 month Gliosis at periphery of cavity Few macrophages Mineralized neurons Spheroids Preservation of cortical molecular layer Modified from Ellison D, et al. Neuropathology, 3rd edition. 2013
NISSL
GLOBAL ISCHEMIA • Terminology
Diffuse anoxic/hypoxic -ischemic encephalopathy
Anoxic/hypoxic brain injury
Respirator brain
Non-perfused brain
Liquefied brain
• Transient: If blood flow to the brain is restored. Associated with selective neuronal necrosis
• Permanent: If blood flow to the brain is not restored. Associated with total brain necrosis
TRANSIENT GLOBAL ISCHEMIA
Modifying factors
• Duration of ischemic episode
• Severity of ischemia
• Body temperature
Hypothermia is protective
• Blood glucose level
Hyperglycemia worsens outcome
GLOBAL BRAIN ISCHEMIA CAUSES
• Cardiac pathology • Cardiac arrest • Hypotension • Shock • Seizures including status epilepticus • Intoxications (drug abuse) • Increased intracranial pressure Traumatic brain injury Intracranial space occupying lesion
SELECTIVE VULNERABILITY
Refers to differential susceptibility of CNS regions to
a hypoxic-ischemic event
Hippocampus: CA1 field (Summer sector)
• Cerebral cortex: Neurons in laminae 3 & 5
• Cerebellum: Purkinje cells
• In premature and term infants, neuronal susceptibility differs from that in adults
GLOBAL ANOXIC-ISCHEMIC ENCEPHALOPATHY
Gross acute/ subacute changes • Generalized dusky discoloration, edema and softening • Patchy gray discoloration of cortex with blurring of white and gray matter junction • Watershed infarcts • Cortical laminar or pancortical necrosis • Bilateral hemorrhagic/ischemic necrosis of basal ganglia/thalamus • Liquefaction necrosis • Normal brain
24-year-old female Drug use Found unresponsive in bathroom Dx: Anoxic brain injury Survived 6 days
GLOBAL ANOXIC-ISCHEMIC BRAIN INJURY
Macroscopic chronic changes • Diffuse or focal brain atrophy • Watershed infarcts • Cystic, bilateral, and symmetric necrosis of basal ganglia/
thalamus • Hippocampal atrophy due to sclerosis • Granular cerebral cortical atrophy related to watershed infarct • Leukoencephalopathy • Normal brain
32-year-old male Schizophrenia Seizures Died in hospital
Otto Binswanger, M.D. (1852-1928) Sir Thomas Willis (1621-1675)
C. Miller Fisher, M. D. (1913-2012)