Nervous System Pathology. Kristine Krafts, M.D.

Transcription

1 Nervous System Pathology Kristine Krafts, M.D.

2 CNS Outline Introduc1on Increased intracranial pressure Vascular and circulatory disorders Trauma Infec1ons Tumors Demyelina1ng diseases Degenera1ve diseases

3 Introduc1on CNS Outline

4 Gross anatomy of brain

5 Cells of the CNS Neurons transmit impulses Astrocytes part of blood brain barrier Oligodendrocytes produce myelin Microglia phagocytose intruders Ependymal cells line ventricles

6 Neurons

7 Astrocytes and oligodendrocytes

8 Microglial cells

9 Ependymal cells

10 Ependymal cells

11 Reac1ons of Cells to Injury Neurons: become red and degenerate Astrocytes: undergo hypertrophy, hyperplasia Microglia: proliferate Oligodendrocytes: don t react much Ependymal cells: don t react much

12 CNS Outline Introduc1on Increased intracranial pressure

13 Causes of Increased ICP Cerebral edema Generalized (diffuse insult, like hypoxia, toxin exposure, encephali1s, trauma) Focal (around focal lesions, like acute infarcts, contusions, penetra1ng injuries, mass lesions) Increased CSF volume (hydrocephalus) Expanding mass lesions

14 Hydrocephalus Defini1on: accumula1on of excessive CSF within the ventricular system Usually due to impaired flow and resorp1on of CSF (rarely due to overproduc1on of CSF) If occurs in infancy, head enlarges If axer infancy, ventricles expand, ICP increases

15 CSF circula1on

16 Hydrocephalus ex vacuo

17 Types of Hydrocephalus Noncommunica1ng: block is in ventricular system; only a por1on of the ventricular system is enlarged Communica1ng: block is in subarachnoid space; en1re ventricular system is enlarged Ex vacuo: ventricular system is dilated due to brain atrophy (with compensatory increase in CSF volume)

18 Feared Outcome: Hernia1on One part of brain gets pushed into another compartment Symptoms: Headache Vomi1ng Decreased level of consciousness Papilledema OXen fatal

19 Case: A Friday Night Football Problem A 17-year-old male was knocked unconscious while playing in a football game one Friday night A CT scan in the ER was normal During the following week, he appeared normal but was secretly suffering from headaches Played part of the game the following Friday before collapsing on the field

20 Case: A Friday Night Football Problem Rushed to ER again, where a CT scan showed a lex subdural hematoma with a midline brain shix On exam, lethargic but awake Decreased vision in part of visual field of right eye Limited ocular mo1lity Ptosis of lex eye

21 Ptosis of lex eye Impaired adduc1on of lex eye Somewhat limited eleva1on and depression of lex eye

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23 CNS Outline Introduc1on Increased intracranial pressure Vascular and circulatory disorders

24 Global Cerebral Ischemia Due to hypotension Outcome depends on severity of hypotension Mild: transient confusion Severe: persistent vegeta1ve state or brain death Watershed infarcts

25 Global ischemia

26 Anterior cerebral artery area Infarct at ACA/MCA watershed Middle cerebral artery area Posterior cerebral artery area Infarct at PCA/MCA watershed Watershed infarcts

27 Focal Cerebral Ischemia Due to obstruc1on of blood flow Hemorrhagic (red) infarcts due to emboli + reperfusion oxen arise from heart Ischemic (pale) infarcts due to thrombi oxen arise from atherosclero1c plaques Transient ischemic abacks (TIAs) are oxen harbingers

28 Thrombus Hemorrhagic (L) vs. ischemic (R) infarc1on

29 Recent hemorrhagic infarct

30 Old infarct

31 What if you think someone might have had a stroke?

32 CNS Outline Introduc1on Increased intracranial pressure Vascular and circulatory disorders Trauma

33 Skull Fractures Displaced if bone is depressed Falls while awake are usually occipital; falls with loss of consciousness are usually frontal. Basal skull fractures have unique symptoms: lower cranial nerves affected orbital or mastoid hematomas distant from impact site CSF draining from ear or nose

34 Raccoon eyes following basal skull fracture

35 Raccoon eyes following basal skull fracture

36 Raccoon eyes following basal skull fracture

37 Concussion Defini1on: Altered consciousness from head injury due to change in momentum of head (head hits rigid surface) Mechanism unknown Symptoms: amnesia, confusion), headache, visual disturbances, nausea, vomi1ng, dizziness Post-concussive neuropsychiatric syndromes exist (especially axer repe11ve injuries)

38 Direct Parenchymal Injury Contusion (bruising) Lacera1on (tearing of 1ssue) Blows can result in: Coup injury (contusion at point of contact) Contrecoup injury (contusion on opposite side)

39 Frontal and temporal contusions

40 Lacera1on (gunshot wound)

41 Coup vs. contrecoup injury

42 Diffuse Axonal Injury Injury of axons in deep white maber of brain Twis1ng/shearing of axons Can be caused by angular accelera1on alone Shaken baby syndrome Common cause of coma axer trauma

43 Axonal shearing

44 Trauma1c Vascular Injury Epidural hemorrhage Blood above dura Tear in middle meningeal artery Neurosurgical emergency Subdural hemorrhage Blood between dura and arachnoid Shearing of bridging veins Acute (hours) or chronic (months) Subarachnoid hemorrhage Blood in subarachnoid space Contusions, ruptured berry aneurysms Neurosurgical emergency

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47 Epidural hematoma

48 Subdural hematoma

49 Subarachnoid hemorrhage from ruptured berry aneurysm

50 Huge berry aneurysm near basilar artery

51 Common sites for berry aneurysms

52 Treatment of aneurysm with coils

53 CNS Outline Introduc1on Increased intracranial pressure Vascular and circulatory disorders Trauma Infec1ons

54 Meningi1s Inflamma1on of the meninges Symptoms: Fever, headache, s1ff neck. Bacterial meningi1s Newborns: E. coli, Strep agalac/ae Young adults: Neisseria meningi/dis Elderly: Strep pneumoniae Dangerous! High mortality if untreated. Viral meningi1s Much less serious

55 Bacterial meningi1s

56 Encephali1s Inflamma1on of the brain substance OXen caused by viruses Symptoms: seizures, confusion, delirium, coma reflex asymmetry, ocular palsies altered mood, memory, behavior

57 Abscess Focal infec1ous lesion Routes of infec1on: direct implanta1on, local extension, hematogenous spread Predisposing condi1ons: endocardi1s, congenital heart disease, chronic pulmonary infec1ons Causa1ve bacteria: Strep viridans, Staph aureus Symptoms: progressive focal deficits plus signs of increased ICP

58 Purulent bacterial abscess

59 Purulent bacterial abscess

60 Prion diseases Prion = abnormal form of a cellular protein called prion protein (PrP) Weird: prions are infec1ous and transmissible Diseases: Creutzfeldt-Jakob disease, kuru, scrapie, mad cow disease Causes spongiform change (intracellular vacuoles) in neurons and glia Symptoms: progressive demen1a

61 Creutzfeldt-Jakob disease

62 CNS Outline Introduc1on Increased intracranial pressure Vascular and circulatory disorders Trauma Infec1ons Tumors

63 Tumors in the Brain Primary brain tumors classified by cell of origin: glial cells neurons meningeal cells nerve sheath cells Metastases also occur but are a lible less common lung cancer breast cancer melanoma

64 Gliomas Arise from astrocytes, oligodendrocytes, ependymal cells OXen fatal (loca1on and infiltra1ve borders prevent complete excision) Glioblastoma (highest-grade astrocytoma) is most malignant

65 Glioblastoma mul1forme (high-grade astrocytoma)

66 Oligodendroglioma

67 Ependymoma

68 Medulloblastoma Tumor of primi1ve neurons Cerebellum Children Very radiosensi1ve!

69 Medulloblastoma

70 Medulloblastoma

71 Meningioma Encapsulated, benign tumor Surface of brain (no invasion) Symptoms caused by compression Cured by resec1on

72 Meningioma

73 Meningioma

74 Nerve Sheath Tumors Arise from cranial (esp. VIII) and spinal nerve roots, and peripheral nerves Derived from support cells of nerve Benign but may compress nerve Schwannoma ( acous1c neuroma if involving VIII), neurofibroma

75 Acous1c neuroma (schwannoma)

76 Schwannoma: Antoni A and B areas

77 Schwannoma: Verocay body

78 Neurofibromas

79 Neurofibromatosis

80 Neurofibromatosis

81 CNS Outline Introduc1on Increased intracranial pressure Vascular and circulatory disorders Trauma Infec1ons Tumors Demyelina1ng diseases

82 Mul1ple Sclerosis Most common demyelina1ng disorder E1ology unknown; related to autoimmunity Variety of motor and sensory symptoms Relapsing-remijng course Plaques (areas of demyelina1on) in brain, cord

83 Mul1ple sclerosis

84 Mul1ple sclerosis plaques around ventricles

85 Guillain-Barré Syndrome Acute peripheral neuropathy Progressive, ascending weakness Usually self-limited (but may involve respiratory muscles, requiring respiratory intensive care) Autoimmune aback on peripheral nerve resul1ng in demyelina1on and conduc1on block

86 CNS Outline Introduc1on Increased intracranial pressure Vascular and circulatory disorders Trauma Infec1ons Tumors Demyelina1ng diseases Degenera1ve diseases

87 Alzheimer Disease Most common cause of demen1a in the elderly Symptoms: Early on: forgelulness, memory disturbances Language deficits, loss of learned motor skills, altera1ons in mood/behavior, disorienta1on Finally, pa1ent becomes profoundly disabled, mute, immobile Gross: Cor1cal atrophy, neuronal loss Microscopic: neurofibrillary tangles, neuri1c plaques

88 Alzheimer disease: brain atrophy

89 Alzheimer disease: brain atrophy

90 Alzheimer disease: brain atrophy

91 Alzheimer disease: progression

92 Alzheimer disease: plaques and tangles

93 Alzheimer disease: plaques (L) and tangles (R)

94 Parkinson Disease Degenera1on of pigmented neurons (containing dopamine) in the substan1a nigra Cause unknown Early symptoms: tremor, rigidity, slow movement Later: cogni1ve problems, demen1a, dyskinesia Gross: atrophy of substan1a nigra Microscopic: Lewy bodies (inclusions in neurons)

95 Parkinson disease (R) : atrophy of substan1a nigra

96 Parkinson disease: Lewy body

97 Michael J. Fox and Muhammad Ali

98 Hun1ngton Disease Degenera1on of basal ganglia and cerebral cortex Early symptoms: lack of coordina1on, unsteady gait Later: chorea (involuntary writhing), psychiatric symptoms, demen1a Autosomal dominant muta1on Begins in 30s-40s; slow progression over years

99 Read this story about Katharine and her family: hbp://

100 Amyotrophic Lateral Sclerosis Degenera1on of neurons involved in motor control Rapidly progressive weakness, muscle atrophy, spas1city, dysphagia Early symptoms: muscle weakness in an arm or leg, twitching, slurred speech Death within 2-3 years due to respiratory compromise Sensory and cogni1ve func1on are unaffected

101 Steven Hawking

102 CNS Outline Introduc1on Increased intracranial pressure Vascular and circulatory disorders Trauma Infec1ons Tumors Demyelina1ng diseases Degenera1ve diseases