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Pathology Nervous System


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What are neural tube defects
A group of disorders characterized by incomplete closure of the neural tube in early gestation which results in dorsal midline defects at birth
What structures can be involved with neural tube defects
Vertebrae, skull, brain, spinal cord, and meninges
Neural tube defects are associated with an increase in what in the maternal serum
What are 3 possible reasons for neural tube defects
Presence of pathologic state in utero at time of neural tube closure (metabolic, nutritive, toxic, or infective causes)
Faulty implantation of placenta
Genetic abnormalities
What is the most common neural tube defect
Spina bifida
What is the defect in spina bifida
Failure of posterior vertebral arches to close
What is spina bifida occulta
Same as spina bifida, but with no clinical abnormalities. Often there are only one or two vertebral arch defects
What physical finding can be the only clue to spina bifida occulta
Doral midline tuft of hair, overlying the site of defective vertebra
What malformation can be associated with lumbar spina bifida
Arnold-Chiari malformation
What is a meningocele
Herniation of meninges (arachnoid, dura) through a vertebral defect
What is meningomyelocele
Herniation of meninges and spinal cord through a vertebral defect
What is the most severe neural tube defect
Describe the clinical features of anencephaly
Diminished or absent fetal brain tissue, usually associated with absence of overlying skull. Cerebral hemispheres, diencephalon, and midbrain can also be absent
In anencephaly, what is exposed instead of fetal brain tissue
A mass of undifferentiated vascular tissue
What is hydrocephalus
Increased volume of cerebrospinal fluid within the cranial cavity
Name 4 types of hydrocephalus
Internal hydrocephalus
External hydrocephalus
Communicating hydrocephalus
Noncommunicating hydrocephalus
What is the difference between internal and external hydrocephalus
Internal: Increased CSF in the ventricles
External: Increased CSF in the subarachnoid space
What is the difference between communicating and noncommunicating hydrocephalus
Communicating: CSF can freely flow between ventricles and spinal subarachnoid space
Noncommunicating: The flow of CSF is obstructed between the ventricles and spinal subarachnoid space, causing proximal dilation of the ventricular system
What can often be seen in infants with hydrocephalus
Marked enlargement of the skull
Why does enlargement of the skull occur in infants with hydrocephalus
Cranial sutures are not closed yet
What are the causes of noncommunicating hydrocephalus
Anything can obstruct the CSF flow, including:
Congenital malformations
Choroid plexus papilloma (rare; produces excess CSF)
What is hydrocephalus ex vacuo
Apparent enlargement of ventricles because of decreased cerebral mass, not because of obstruction or increased CSF production
Name two diseases characterized by decreased cerebral mass
Ischemic brain atrophy
Alzheimer disease (advanced)
What is Arnold-Chiari malformation
Caudal (downward) displacement of medulla and cerebellum through foramen magnum into the cervical vertebral canal. It can be associated with lumbar spina bifida
What defect is commonly associated with Arnold-Chiari malformation
Thoracolumbar meningomyelocele
Name 2 consequences of Arnold-Chiari malformation
Pressure atrophy of displaced brain tissue
Hydrocephalus, resulting from obstruction of CSF outflow tract
What is fetal alcohol syndrome
A spectrum of characteristic dysmorphic features and developmental defects resulting from maternal alcohol intake during pregnancy
Name 6 features that can be found in fetal alcohol syndrome
Interuterine growth retardation and subsequent growth failure
Mental retardation
Micrognathia (small mandible)
Short palpebral fissures
Atrial septal defect
What is Bourneville disease
Aother name for tuberous sclerosis syndrome
What is the pathogenesis of the tuberous sclerosis syndrome
Disorder of migration and arrested maturation of neural ectoderm, resulting in hamartomas (tubers) of the brain, retina, and viscera
Name 4 features of tuberous sclerosis syndrome
Multiple tubers in the cerebral cortex and periventricular areas
Adenoma sebaceum of the skin (primarily facial)
Angiomyolipoma of the kidney
Rhabdomyoma of the heart
What is the pathology of the “tuber” in tuberous sclerosis
Proliferations of atypical multinucleated astrocytes, appearing macroscopically as small, white nodules
What is seen on the skin of a tuberous sclerosis patient under an ultraviolet Wood lamp
Discrete areas of hypopigmentation known as “ash-leaf spots”
What is the common clinical presentation of patients with tuberous sclerosis syndrome
Infantile seizures and mental retardation
What is agenesis of the corpus callosum
Complete or partial absence of the corpus callosum, wherein the only connection between the 2 cerebral hemispheres is at the brainstem. It is often asymptomatic
What is von Recklinghausen disease
An autosomal dominant disorder characterized by café au lait spots, multiple cutaneous neurofibromas, and Lisch nodules
What is another name for von Recklinhausen disease
What are café au lait spots
Small areas with irregular margins of increased pigmentation on the skin
What are Lisch nodules
Pigmented nodules of the iris, consisting of melanocytes
Name the 2 types of neurofibromatosis, and the characteristics associated with each
Peripheral (Type 1): Skin lesions, dermal and peripheral nerve tumors
Central (Type II): Bilateral schwannomas of the acoustic nerve, and associated meningiomas, gliomas, and neurofibromas
Name 4 hereditary degenerative disorders of the nervous system and identify their pattern of inheritance
Huntington disease (AD)
Wilson disease (AR)
Lipid storage diseases (eg Tay-Sachs disease and Niemann-Pick disease)
Friedrich ataxia (AR)
What is the most common disorder of the central nervous system
Cerebrovascular disease; third most common cause of death in the US
Name 2 major categories of cerebrovascular disease
Infarction (more common)
What are transient ischemic attacks
Episodes of focal neurologic defects caused by temporary lack of cerebral blood flow, with complete resolution of deficits
How long do transient ischemic attacks last
Normally, a few minutes, but they can last up to 24 hours
What are some common neurologic defects seen in transient ischemic attacks
Amaurosis fugax (temporary blindness), hemiplegia, and other cranial nerve defects
If transient ischemic attacks are present, there is increased risk for what
Increased risk of cerebral infarct (stroke)
What are 2 mechanisms of brain infarction
Occlusion of the arterial blood supply to the brain from thrombosis, or embolism
What is the most common cause of vascular thrombosis
Atherosclerotic plaques in blood vessels. They can rupture and initiate the coagulation cascade
Name the 3 most common sites of cerebral thrombosis
Bifurcation site of common carotid into internal carotid and external carotid arteries
Branching sites of circle of Willis, especially the middle cerebral artery
Vertebral and basilar arteries, especially bifurcation sites
What clinical findings can be seen with arterial obstruction of the middle cerebral artery
Findings depend on extent of collateral circulation, but may include:
Contralateral paralysis
Motor and sensory deficits
Name 5 causes of embolic occlusion
Cardiac mural thrombi
Valvular vegetations, seen in infective endocarditis
Tumor cells
Air bubbles
Fat droplets
What is the most common site of embolic occlusions
Middle cerebral artery
What are lacunae
Small healed infarcts that appear grossly as “pits” in brain matter
What are some clinical manifestations of lacunar strokes if the obstruction of vessels occurs in the internal capsule
Pure motor deficits
What are some clinical manifestations of lacunar strokes if the obstruction of vessels occurs in the thalamus
Pure sensory deficits
Where are the 2 types of hemorrhagic brain disease
Intracerebral hemorrhage (brain substance)
Subarachnoid hemorrhage (subarachnoid space)
What are 4 predisposing conditions that increase the risk of intracerebral hemorrhage
Hypertension (most common)
Coagulation disorders, including thrombocytopenia
Hemorrhage within primary or metastatic cerebral neoplasms
Leukemia, in which neoplastic cells obstruct small vessels
Where are the 4 most common sites of intracerebral hemorrhage
Frontal lobe
Basal ganglia
What develops in the brain as a result of chronic hypertension
Charcot-Bouchard aneurysms
Are Charcot-Bouchard aneurysms likely to rupture into brain parenchyma
What increases risk of Berry aneurysms rupturing
What type of aneurysm can rupture into the subarachnoid space
Berry aneurysms, commonly found in the circle of Willis
Name 3 other causes of subarachnoid hemorrhage
Arteriovenous malformation
Hemorrhagic diatheses
What is the most common cause of subarachnoid hemorrhage
What is the #1 cause of most head and spine injuries
Motor vehicle accidents
Name 4 types of injury to the brain in head trauma
Intracranial hemorrhage (epidural, subdural, subarachnoid)
What artery is injured in an epidural hemorrhage
Middle meningeal artery
How is the middle meningeal artery injured
Laceration from skull fracture
What is the clinical presentation of epidural hemorrhage
First, loss of consciousness immediately after the injury. Then, a lucid interval, followed by acute signs of increased intracranial pressure
What causes intracranial pressure in an epidural hematoma
Hematoma external to the dura mater presses inward, causing local brain compression
What is the treatment for epidural hemorrhage
Immediate surgical decompression to prevent subtentorial herniation
What vessels are injured in a subdural hematoma
Most commonly, the bridging veins from the cerebrum to venous sinuses in the dura mater
Name 2 causes of subdural hematoma
Blow to the head, commonly in the frontal or occipital regions; Birth injury
What is the clinical presentation of subdural hematoma
More insidious signs of decreasing mental status and enlargement of the hematoma can occur days to weeks after seemingly insignificant head injury
Does the enlargement in a subdural hematoma result from the bridging vein still hemorrhaging days to weeks after the injury
No; the enlarging hematoma is thought to result from osmotic properties of water movement into the collection of blood
Describe the course of a concussion
It is usually associated with loss of consciousness, characterized by temporary widespread brain paralysis without obvious organic pathology, usually associated with complete recovery
What is hypothesized to be the mechanism of injury of a concussion
Rotational or shearing strains on the brain
What is a contusion brain injury
Linked to a “bruise” on the brain, it results from torn capillaries from a blow to the calvarium
What are 2 types of contusions
Coup: Lesion is located directly beneath area of impact
Contrecoup: Lesion is opposite to the area of impact
What is the clinical presentation of a contusion
Loss of consciousness, possibly progressing to coma or death
What is the gross appearance of an acute contusion
Swollen edematous gyri
Petechial hemorrhages
What is the gross appearance of an old contusion injury
Sunken areas of brain, with small cysts
What is the microscopic appearance of an old contusion injury
What is the microscopic appearance of an acute contusion injury
Edematous cortex and subcortical white matter; fresh pericapillary hemorrhages
What are Duret hemorrhages
The petechiae seen in acute contusions
What is a cord crush injury
Compression and contusion of the spinal cord
What is the common mechanism of injury in a cord crush injury
Dislocation of vertebra, most commonly in lower cervical area, following forcible flexion as in a motor vehicle accident
What is herniated in a “slipped disk”
Nucleus pulposus, the center of the intervertebral disc, through a defect in the annulus fibrosis, causing pressure on nerve roots
What is the most common area for a slipped disk
Lumbrosacral: L4-5 or L5-S1 discs
What is the common clinical presentation of a slipped disk
Sciatica, or lower back pain after mild or moderate trauma
What is the most common bacterial infection of the CNS
Bacterial meningitis
In what population is bacterial meningitis most common
Name 6 causative microorganisms of bacterial meningitis
Neisseria meningitidis
Streptococcus pneumoniae
Haemophilus influenzae type b
Eschericia coli
Group B Streptococcus
Listeria monocytogenes
What organisms cause bacterial meningitis in newborns
Group B Strep and E. coli
What organisms cause bacterial meningitis in children
S. Pneumoniae and H. influenzae
What organisms cause bacterial meningitis in adolescents and adults
Meningococcus and pneumococcus
What organisms cause bacterial meningitis in the elderly
Listeria monocytogenes and pneumococcus
How do pathogens obtain access to the meninges
Direct invasion (from facial sinuses or middle ear); Hematogenous seeding
What are the 3 classic clinical signs of bacterial meningitis
Mental status changes
Nuchal rigidity (neck stiffness)
What are some other signs of clinical meningitis
Vomiting, headache, confusion, and seizures
What are the 3 findings in CSF diagnostic for bacterial meningitis
Increased protein
Decreased glucose (<2/3 serum glucose)
Many polymorphonuclear neutrophils (PMNs)
What will be noted about the opening pressure on lumbar puncture for a patient with bacterial meningitis
Increased pressure
What imaging test should be performed for bacterial meningitis if papilledema or focal neurologic signs are present
Head CT scan before lumbar puncture, to rule out increased intracranial pressure from hydrocephalus or mass lesion
What can occur if a mass lesion is present
Risk for brain herniation into spinal canal when pressure is released at the site of a lumbar puncture
What are the gross pathologic findings of bacterial meningitis in the subarachnoid space
Purulent exudate
What is the most common etiology of cerebral abscess
Secondary infection from primary sources elsewhere in the body
Name 5 common primary sources of cerebral abscess
Otitis media
Frontal sinusitis
Lung abscess, empyema, or other bronchopulmonary infection
Infective bacterial endocarditis
What are the clinical symptoms of cerebral abscesses
Increased ICP and source of primary infection
What are the CSF findings of cerebral abscesses
Increased opening pressure, slightly increased protein and lymphocytes, and no change in glucose
What organisms are seen in the CSF with brain abscesses
None are usually seen, unless rupture of abscess has occurred
What are the gross pathologic findings with brain abscesses
Cavitary lesion in the brain filled with thick exudate, walled off by edematous tissue
What can occur if infection spreads beyond abscess walls
What part of the nervous system is the most common site of tuberculous infection
How do mycobacteria gain access to the meninges
Miliary dissemination from another source elsewhere in the body
What are the clinical features of tuberculous infection of the meninges
Gradual onset of anorexia, weight loss, and night sweats. Patient may also have mood changes, periods of drowsiness and delirium, and intermittent lucid intervals
What are the CSF findings with meningeal tuberculosis
Increased lymphocytes
Significantly increased protein
Decreased glucose
Acid-fast bacilli in CSF
What are the gross pathologic findings in tubercular meningitis
Gray-white thin exudate in meninges, pooling in the basilar cisterns and sylvian fissure; Tubercles (round white nodules) at the periphery
What is the microscopic pathology in meningeal tuberculosis
Granulomas composed of lymphocytes and large mononuclear cells; Tubercle bacilli
What are common pathogens of fungal infection in the CNS
Cryptococcus neoformans; Coccidioides immitis; Aspergillus; Histoplasma
What predisposes an individual to fungal infection
Impaired immunity
What is toxoplasmosis
Parasitic infection in which the pathogen is Toxoplasma gondii
What is the source of toxoplasmosis in neonates
Transmission transplacentally from infected mother
What are some modes of toxoplasmosis infection
Ingestion of foods contaminated by animal urine or feces; Contamination from household pets (ie cats)
What are three neurologic characteristics of congenital toxoplasmosis infection
What is the characteristic finding of toxoplasmosis on radiologic studies
Periventricular calcifications
Name the 3 areas of toxoplasma involvement in the brain
Cerebral cortex; Basal ganglia; Retina
What is the most common site of toxological infection in adults
Lymph nodes
What is another name for viral meningitis
Aseptic meningitis
How are the clinical findings in viral meningitis different from bacterial meningitis
None; they are the same: fever, headache, and nuchal rigidity
What are the CSF findings in viral meningitis
Increased lymphocytes
Moderate increase in protein
Normal glucose
What are the changes found in the brain substance occurring in meningoencephalitis or encephalitis
Perivascular cuffing (mononuclear cell infiltrate in the Virchow-Robin spaces around the vasculature)
Inclusion bodies in neurons or glial cells
Glial nodules (nonspecific proliferation of microglia)
Name 6 examples of CNS viral infection
Arbovirus encephalitis (St. Louis, Eastern equine, Western equine); Herpes simplex; Poliomyelitis; Rabies; Cytomegalovirus; HIV
What part of the brain is affected in Herpes simplex encephalitis
Temporal lobe
What happens to the brain in Herpes simplex encephalitis
It becomes swollen, hemorrhagic, and necrotic
What deteriorates in poliomyelitis
Anterior horn cells of spinal cord
What are the clinical manifestations of rabies
Severe encephalitis with increased excitability of the CNS. Muscle contractions and convulsions can occur after minimal stimuli
What are three histologic findings of rabies
Neuronal degeneration
Perivascular cuffing in brainstem and spinal cord
Negri bodies (eosinophilic intracytoplasmic inclusion bodies)
Where are Negri bodies found
Hippocampus and cerebellum (Purkinje cells)
What is the characteristic histology of CMV infection
Giant cells with eosinophilic inclusions involving nucleus and cytoplasm
What can be seen on radiologic evaluation of the brain in CMV infection
Periventricular calcifications
What is the most common clinical presentation of HIV nervous system involvement
AIDS dementia complex
Name 4 examples of suspected slow virus infection
Kuru; Creutzfeldt-Jakob disease; Subacute sclerosing panencephalitis; Progressive multifocal leukoencephalopathy
What characterizes slow virus infections
Long incubation period, little inflammatory response, and progressive deterioration
What is the histology of slow virus infections
Spongiosis, with numerous clusters of small cysts in the CNS gray matter
What 2 diseases do you suspect if dementia occurs acutely
Creutzfeldt-Jakob disease
Normal pressure hydrocephalus
Where was kuru first documented
A cannibal tribe in New Guinea, which ritualized the practice of consuming the human brain
What is subacute sclerosing panencephalitis
Persistent infections with measles virus, usually infected in infancy but asymptomatic until late childhood or early adolescence. Prognosis is slowly progressive and usually fatal
What is atypical about the measles virus
Lack of M component of the virus, responsible for extracellular spread; perhaps responsible for slow infection
What is PML
Rapidly progressive demyelination in multiple foci throughout the brain
What percentage of all nervous system disorders are neoplasms
About 10%
What is the incidence of neoplastic disease of the spinal cord
Very rare
In adults, are the majority of intracranial neoplasms above or below the tentorium
In children, are the majority of intracranial neoplasms above or below the tentorium
Are CNS tumors the most common malignancy in children
No, but they are the 2nd most common after leukemia
Where do most primary malignant CNS tumors metastasize
They usually don’t metastasize
What can be some direct effects of intracranial tumors
Neurologic dysfunction, with focal deficits depending on location of neoplasm; Electrically unstable neurons, with predisposition to epileptiform activity
Name 6 secondary effects of intracranial tumors
Brain edema; Compression with resultant deficiency of vascular supply; Ischemia; Necrosis; Herniation of brain and/or cerebellar tonsils; Hydrocephalus
What can often be seen on funduscopic examination in a patient with intracranial tumors
Papilledema (swelling caused by edema of optic nerve papillae) and retinal vein engorgement
Name the 4 most common intracranial tumors in adults
Glioblastoma multiforme
Metastatic tumors (from extracranial primary sites)
Acoustic neuroma
Name the 4 most common intracranial tumors in children
Name 3 other neoplasms of the CNS found in children
How does a glial tumor grow differently from a non-glial tumor
Glial tumors grow by infiltration, and thus cannot be completely removed. Non-glial tumors grow by expansion and are more likely to be totally resected
What is the function of a normal astrocyte
In reaction to injury, astrocytes expand their cytoplasm and form glial fibrils
What is the most common location of astrocytomas in adults
Central white matter of the cerebrum
What is the most common location of astrocytomas in children
How are astrocytomas characterized
Based on histology; Grade I-Grade IV
What is the treatment of astrocytoma
Surgical resection, with excellent prognosis if completely removed
What is another name for Grade IV astrocytoma
Glioblastoma multiforme, the most common primary intracranial neoplasm
What is the peak age group for glioblastoma multiforme
Later middle age
Describe the histology of glioblastoma multiforme
Marked anaplasia and pleomorphism
Vascular changes with endothelial hyperplasia
Many mitoses
What pattern of tumor cells encompass areas of necrosis and hemorrhage
Pseudo-palisade arrangement at the periphery
What is the prognosis of glioblastoma multiforme
Very poor, usually death within 1 year
What is an oligodendrocyte
A neuroglial cell, whose surface membrane coils around neuronal axons to form the myelin sheath in white matter
How fast does oligodendroglioma proliferate
Very slowly
What age group is most commonly affected by oligodendroglioma
Middle age
What is the most common site of origin of oligodendroglioma
Cerebral hemispheres
Describe the typical morphology of oligodendroglioma
Large round nuclei surrounded by a halo of clear cytoplasm, often called “fried egg appearance”
What is seen as typical morphology on oligodendroglioma
Foci of calcification
Where is the most common location of ependymoma
Fourth ventricle
What is the peak age group of ependymoma
Children and adolescents, but any age group can be affected
What may result from ependymoma growth
Hydrocephalus due to obstructed CSF flow
What is the pattern of the histology of ependymoma
Rosettes with cells encircling vessels, or tubules with cells pointing toward a ventral lumen
What is the proliferating cell type in a meningioma
Arachnoid cell
Characterize meningiomas
Commonly benign and slow growing
What is the second most common primary intracranial neoplasm
Why is surgery a feasible option with a meningioma
Meningioma is external to the brain, and thus can be surgically removed
Name common locations of meningioma
Convexities of the cerebral hemispheres
The parasagittal region
Falx cerebri
Sphenoid ridge
Olfactory area
Suprasellar region
What is the gross appeareance of meningioma
Firm, rubbery tumors, white or reddish colored, clearly distinguished from brain parenchyma
What is the appearance of a meningioma under the microscope
Whorled pattern spindle cells
Ovoid nuclei
Intranuclear vacuoles
Calcified psammoma bodies
What are psammoma bodies
Microscopic concentric laminated mass of calcified material
What is the age group most commonly affected by medulloblastoma
Young children under 14 years of age
Is medulloblastoma benign or malignant
Highly malignant
What area of the brain is usually involved in medulloblastoma
What is the gross pathology of medulloblastoma
Reddish gray, granular mass arising from roof of 4th ventricle
What is the histology of medulloblastoma
Rosette-patterned sheets of closely packed cells with little cytoplasm and a pseudorosette pattern
What is meant by a pseudorosette
Perivascular arrangement of tumor cells
What does PNET stand for
Primitive neuroectodermal tumor. Medulloblastoma is one of the small cell tumors of the nervous system
What is the prognosis of medulloblastoma
Poor; survival of 1-2 years after onset of symptoms is typical
What is the age group most commonly affected by retinoblastoma
Young children
What percentage of cases of retinoblastoma results from sporadic mutation
Approximately 60%
How are 40% of retinoblastomas cases inherited
What is the genetic defect in retinoblastoma
Homozygous deletion of retinoblastoma gene (chromosome 13)
Is an attenuated form of retinoblastoma present if only one deletion exists
No; both deletions are required for tumor to develop
What is hemangioblastoma
Tumor of blood vessel origin
What area of the brain is most frequently affected by hemangioblastoma
What are common clinical complaints of hemangioblastoma
Difficulty with balance and walking
What disease is associated with hemangioblastoma
von Hippel-Lindau disease, with similar lesions in retina and other organs
What are 3 neoplasms associated with von Hippel-Lindau disease
Renal cell carcinoma
What protein is sometimes produced by neoplastic hemangioblastoma cells
What can result from release of erythropoietin from hemangioblastoma cells
Secondary Polycythemia
What is the microscopic pathology of hemangioblastoma
Variable presentation, from purely vascular to highly cellular, with large polygonal cells full of lipids
What are two other names for schwannoma
Neurilemoma, acoustic neuroma (if localized to CN VIII)
What is the cell of origin in a schwannoma
Schwann cell
Are schwannomas benign or malignant
How fast do schwannomas proliferated
They are slow growing, encapsulated tumors
Where are schwannomas commonly located
Posterior nerve roots and peripheral nerves
What are 2 patterns of histology seen with schwannomas
Antoni type A neurilemoma: elongated cells with palisade nuclei, grouped in bundles
Antoni type B neurilemoma: less cellularity, similar pattern
What disease is associated with multiple neurofibromas
von Recklinghausen disease
From what cell are neurofibromas derived
Schwann cells, involving peripheral nerves
What are the 6 most common primary sites of malignancy that metastasize to the brain
Lung; Breast (usually dura and skull); Skin; Kidney; GI tract; Thyroid
How do most malignancies metastasize to the brain
Usually metastasis to the brain is hematogenous, but direct invasion is also possible
From what tissues is a craniopharyngioma derived
The hypophyseal trunk or Rathke pouch
What is a Rathke pouch
Diverticulum from the embryonic buccal cavity, from which the anterior lobe of the pituitary develops
What age group is most commonly affected by craniopharyngioma
Children, averaging between 4-16 years old
What clinical signs are evident with craniopharyngioma
Visual complaints, hypothalamic syndromes
What is the gross appearance of a craniopharyngioma
Calcified, multiloculated mass of several centimeters, sometimes encapsulated by the surrounding brain, with cystic areas
What is seen on skull radiograph of a craniopharyngioma that can suggest the diagnosis
Plain films of the head will show characteristic calcifications
What conditions increase the risk of developing primary lymphoma of the brain
Conditions that cause patients to be Immunocompromised (eg AIDS, status post transplant)
What is the most common primary brain neoplasm of Immunocompromised patients
In the absence of immune deficiency, in what age group do primary lymphomas most commonly occur
Patients in their 60s or 70s
What are 3 clinical features of lymphoma of the brain
Deficiency of higher neural function such as problems with memory
What is the gross pathology of lymphoma of the brain
Usually multifocal, seen most often in the cerebrum, arising in the perivascular spaces
What is the microscopic appearance of lymphoma of the brain
Similar to the classic forms of lymphoma
What are 2 characteristics of demyelinating diseases
Destruction of myelin
Preservation of axons
Which in primarily affected in demyelinating diseases, white or gray matter
White matter
Which is the most common of the demyelinating diseases
Multiple sclerosis
What are three common examples of demyelinating diseases
Multiple sclerosis
Acute disseminated encephalomyelitis
Guillain-Barre’ syndrome
What is the age group of peak incidence of MS
20-30 years old
What is the etiology of MS
Unknown; immune or viral theory postulated but not proven. It is thought to be multifactorial
Is MS more common in men or women
Slightly more common in women
What evidence supports the theory of an immune system etiology in MS
Increased incidence associated with HLA A3, B7, DR2, and DW2
What is increased in the CSF in patients with MS and how is it detected
Immunoglobulin, seen as multiple oligoclonal bands on electrophoresis
What is the relationship of incidence of MS to geographic location
Incidence is directly proportional to distance from the equator
What are the morphologic changes of MS in the brain and spinal cord
Multiple focal areas of demyelination known as plaques
What is the microscopic appearance of areas of demyelination in MS
Localized edema, congestion, and microglial proliferation
Progressive astrocytosis and infiltration
Eventually, sclerotic plaque and reactive gliosis
What 3 sites are particularly affected in MS
Optic nerve
Paraventricular areas
What cells infiltrate MS plaques before reactive gliosis occurs
Helper CD4+ cells
Cytotoxic CD8+ T lymphocytes
What are the early clinical findings of MS
Motor deficits of the distal lower extremities, visual disturbances and retrobulbar pain, sensory deficits, and sometimes bladder incontinence
What is the classic Charcot triad of MS symptoms
Intention tremor
Scanning speech

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