Disorders Of The Nervous System

Front 1

Epidural hematoma

Back 1

*-an arterial hemorrhage associated with *skull fracture* (e.g. temporal fracture) and most often with laceration of branches of the *middle meningeal artery*
-characterized clinically by a short period of consciousness (lucid interval) followed by rapidly developing signs of cerebral compression
-is amenable to emergency surgical intervention because bleeding into the brain substance itself does not occur

Front 2

Subdural hematoma

Back 2

*-caused by venous bleeding, most often from bridging veins joining the cerebrum to the venous sinuses within the dura
-characterized clinically by *gradual signs of cerebral compression* occuring hours to days or even weeks after a head injury; venous hemorrhage typically arrests early, but he volumw of the hematoma gradually increases as a result of osmotic imbibement of water, resulting in a slowly enlarging tumor-like mass

Front 3

Subarachnoid hemorrhage

Back 3

-consists of bleeding into the subarachnoid space
*-is frequently associated with *berry aneurysm* of the circle of Willis
-is also caused by arteriovenous malformations, trauma, or hemorrhagic diatheses.

Front 4

Bacterial meningitis
-Clinical manifestations and pathogens involved

Back 4

-is manifest clinically by fever, prostration, and nuchal rigidity
*-can lead to reactive fibroblastic arachnoiditis, with scarring, obliteration of the subarachnoid space, and hydrocephalus caused by impedance of the flow of cerebrospinal fluid (CSF)
*-can lead to leptomeningeal venulitis with venous occlusion and hemorrhagic infarcts
-can also lead to brain abcess
-has its peak incidence in children (almost 75% of cases), with a second high incidence peak in the elderly.
-is characterized by purulent exudate in the subarachnoid space. *CSF findings* of diagnostic significance include:
*1) numerous neutrophils *2) decreased glucose (less than 2/3 of the serum glucose concentration) *3) Increased protein
*-in neonates and infants, is most frequently caused by *group B streptococci, E. Coli, and Listeria*
*-in older infants, children, and younf adults, is most frequently caused by *Neisseria meningitidis and Streptococcus pneumoniae*
-N. menigitidis occurance may be sporadic and may be accompanied by meningococcemia and secondary to a primary infection in the nasopharynx
*-Meningococcemia can also be associated with purpuric skin lesions and is sometimes complicated by the *Waterhouse-Friedrichsen syndrome* (hemorrhagic destruction of the adrenal cortex, acute hypercorticism with circulatory collapse, and DIC)
*-in older adults, is most frequently caused by S. pneumoniae and gram-negative rods

Front 5

Multiple sclerosis

Back 5

INCIDENCE
-is by far the most common of the demyelinating diseases
-most often begins between ages 20-30 years of age
-is more common in women
ETIOLOGY
-is of unknown etiology; immune or viral factors are suspected but unproven causes; multiple sclerosis is thought to be multifactorial in origin, with both *environmental and genetic factors* playing a role, a view supported by the following:
*1) frequent occurence of increased CSF immunoglobulin, often manifest as *multiple oligoclonal bands* on electrophoresis, suggests that viral or immune factors may play a role.
*2) Increased incidence in association with certain HLA haplotypes (A3, B7, DR2, and DW2) suggests that immune factors may play a role
3) highest incidence occurs in persons of northern European ancestry.
*4) Incidence is directly proportional to the geographic distance from the equator; predisposition remains when persons move to a low-incidence geographic site if the move is made after age 15.
MORPHOLOGIC CHANGES
*-is confined to the CNS
*-characterized by the *depletion of myelin-producing oligodendrocytes*, with multiple focal areas of demyelination (plaques) that are irregularly scattered in the brain and spinal cord; the *optic nerve, the brain stem, and paraventricular areas* are favored sites; helper CD4+ and cytotoxic CD8+ T lymphocytes and macrophages infiltrate plaques; reactive gliosis occurs later.
CLINICAL MANIFESTATIONS
*-is characterized by *exacerbations* with long asymptomatic *remissions* and often a progressive course, leading to invalidism with mental deterioration.
*-manifests by early findings: weakness of the lower extremities, visual disturbances and retrobulbar pain, sensory disturbances, and possible loss of bladder control.
*-may be manifest with the classic *Charcot triad: nystagmus, intention tremor, and scanning speech*, which is significant for diagnosis

Front 6

Huntington disease

Back 6

*-an *autosomal dominant*, fatal progressive degeneration and atrophy of the striatum (*caudate nucleus and putamen*) and frontal cortex with neuronal depletion and gliosis.
-is characterized by the *delay of clinical abnormalities until age 30-40*; course extends 15-20 years, beginning with athetoid movements, followed by progressive deterioration leading to hypertonicity, fecal and urine incontinence, anorexia and weight loss, and eventially dementia and death.
-especially affects cholinergic and GABA-ergic neurons.
*-is characterized by *increased numbers (more than the normal of 11-34) of CAG trinucleotide repeats* within the HD (huntingtin) gene on the short arm of chromosome 4, Paternal transmission results in an increased number of CAG repeats and correspondingly earlier onset of disease manifestations in successive generations (*anticipation*)

Front 7

Medulloblastoma

Back 7

*-is one of the most common neoplasms of childhood
*-is a highly *malignant tumor of the cerebellum*
-is characterized histologically by sheets of closely packed calles with scant cytoplasm arranged in a *rosette or perivascular pseudorosette pattern*.

Front 8

Meningioma

Back 8

*-is the *second most common primary intracranial neoplasm*.
*-is a *benign, slowly growing tumor*
*-originates in arachnoidal cells of the meninges; the tumor is external to the brain and can often be successfully removed surgically.
-occurs most frequently in the convexities of the cerebral hemispheres and the parasagittal region; other common locations include the falx cerebri, sphenoid ridge, olfactory area, and suprasellar region.
-is characterized histologically by a *whorled pattern of concentrically arranged spindle cells and laminated calcified psammoma bodies
-occurs more frequently in women than in men
*-most often occurs after age 30

Front 9

Craniopharyngioma

Back 9

*-is a *benign childhood tumor* derived from remnants of the *Rathke pouch*
-is not a true pituitary tumor.
-is similar to ameloblastoma of the jaw.
*-is characterized by nests and cords of squamous or columnar cells in a loose stroma, closely resembling the appearance of the *embryonic tooth bud enamel organ*.
*-is often cystic; lining epithelium of flat or columnar cells often expands into papillary projections.
-is often detected radiographically because of calcification