Flashcards in Diseases Test 1 Deck (63):
Failure of a significant portion of the neural tube to close resulting in exposure of the malformed neural tissue along back of head and body
Anencephaly or Merocephaly
Failure of the Rostral Neuropore to close
Failure of the caudal neuropore to close.
1.) Spina Bifida Occulta malformant spinal canal; fauns hair
2.) Meningiocele - Bulge canal in back with CSF only
3.) Myelomeningiocele - Bulge in back with nervous tissue in cele. Most severe.
Linked to low folic acid intake during pregnancy.
Tubular cavitation of the spinal cord -- generally cervical/upper thoracic
Neural deficits begin w/ loss of pain and temp. sensation over shoulders and upper arms. Can grow and move downward.
Forebrain does not divide into two hemispheres; leads to death and often single eye.
Dialation of ventricles due to CSF overproduction, obstruction of flow or failure of CSF reabsorbtion.
Partial or complete absence of cerebellar vermis.
Cerebellum drops down. Can range from asymptomatic to lack of cerebellar development.
Prenatal alcohol exposure
Marked decrease in child brain development w/ fetal alcohol syndrome. Thought to be due to alcohol interfering w/ migration of axons, so connections do not happen properly. May lack corpus callosum.
Neural crest did not migrate properly. Melanocyte abnormalities.
Hirschsprung Disease or congenital megacolon
Due to failure of neural crest cells t o migrate into the colon - most common in rectum and sigmoid.
Parasympathetic ganglia do not form, so normal peristalsis does not occur
Fecal retention with ballooning of the colon and abdomen.
Vit B1/ Thiamine deficiency doesn't allow transketolases in Pentose Phosphate Pathway to function limiting NADPH production, 5 carbon sugars, and glutathione production.
Destruction of mamillary bodies.
Symptoms: "Can of beer" Alcoholics (unless in developing world), Present with confusion, no formation of new memories, and confabulation.
Occur at the bifurcations in the circle of willis. Most common site is bifurcation of the anterior communicating artery. Rupture cal lead to hemorrhagic stroke/ subarachnoid hemmorrhage.
Rupture of middle meningeal artery often secondary to fracture of temporal bone. Lucid interval. Rapid expansion under systemic arterial pressure --> transtentorial herniation, CN III palsy.
CT Shows "biconvex disk" not crossing suture lines. Can cross falx, tentorium.
Rupture of bridging veins. Slow venous bleeding (less pressure = hematoma develops over time) with delayed symptoms. Acute (hours) or chronic (months)
Seen in elderly individuals, alchoholics, blunt trauma, shaken baby.
CT - crescent-shaped hemorrhage that crosses suture lines. Gyri are preserved, since pressure is equally distributed. Cannot cross falx, tentorium.
Rupture of an aneurysm (usually berry aneurysm) or an AVM.
Patients complain of "worst headache of my life"
Bloody or yellow (xanthochrompic) spinal tap. 2-3 days afterward, there is a risk of vasospasm due to blood breakdown products, which irritate vessels (treat with calcium channel blockers)
Normal Pressure Hydrocephalus
"Wet, wobbly, and wacky." Doesn't result in increased subarachnoid space volume. Expansion of ventricles distorts the fibers of the corona radiata and leads to the clinical triad of dementia, ataxia, and urinary incontinence.
Very important to rule out for dementia vs. AD because normal pressure hydrocephalus is reversible.
Decreased CSF absorption by arachnoid villi, which can lead to increased intracranial pressure, papilledema, and herniation.
(e.g. arachnoid scarring post meningitis)
Obstructive (non-communicating) hydrocephalus
Caused by structural blockage of CSF circulation within the ventricular system.
(e.g. tumor or stenosis of the aqueduct of sylvius.)
Hydrocephalus ex vacuo
Appearance of increased CSF in atrophy (i.e. AD, advanced HIV, Pick's disease) Intracranial pressure is normal; triad is not seen.
Autoimmune inflammation and demyelination of CNS. Patients can present with optic neuritis (sudden loss of vision), MLF syndrome (internuclear opthalmoplegia), hemiparesis, hemisensory symptoms, or bladder/bowel incontinence. Relapsing and remitting course. Most often affects women in their 20s and 30s; more common in whites.
Findings: increased protein (IgG) in CSF. Oligoclonal bands are diagnostic. MRI is gold standard. Periventricular plaques (areas of oligodendrocyte loss and reactive gliosis) with preservation of axons.
Charcot's triad: SIN Scanning speech, Intention tremor, Incontinence, Internuclear opthalmoplegia, Nystagmus.
Treatments: Beta- Interferon or immunosuppressant therapy. Symptomatic treatment for neurogenic bladder, spasticity, pain.
Guillain- Barre Syndrome
Acute inflammatory demyelinating polyradiculopathy
Inflammation and demyelination of peripheral nerves and motor fibers of ventral roots following flu like infection (sensory effect less sever than motor), causing symmetric ascending muscle weakness beginning in distal lower extremities. Facial paralysis in 50% of cases. Autonomic function may be sererely affected (i.e. cardiac irregularities, hypertension, and hypotension). Almost all patients survive; the majority recover completely after weeks to months.
Findings: Increased CSF protein with normal cell count. Increased protein --> papilledema.
Respiratory support is critical until recovery. Additional treatment: plasmapheresis, IV immune globulins.
Also known as hereditary motor and sensory neuropathy (HMSN). Group of progressive hereditary nerve disorders related to the defective production of proteins involved in the structure and function of peripheral nerves or myelin sheath.
High arches, hammer toes, muscle atrophy.
Normal life span.
Most common primary brain tumor. Average life expectancy is less than a year. Found in cerebral hemishperes. Can cross corpus collosum ("butterfly glioma")
Linear skull fracture
Most common. Straight crack. Usually not serious.
Depressed skull fracture
Bone displaced inward. Comminuted (in pieces). Can damage brain.
Diastatic skull fracture
Across a suture causing the suture to widen. Usually in children.
Basal skull fracture
More force required than others. Distant hematomas (often behind ear or around eyes) = Battle Sign. CSF drainage from nose or ear.
Altered consciousness from head injury due to change in momentum of head. Unknown mechanism.
Symptoms: amnesia, confusion, headache, visual disturbances, nausea, vomiting, dizziness.
Second Impact Syndrome
Second concussion before first one healed. Brain swells rapidly, catastrophically. Young athletes at greater risk.
Chronic Traumatic Encephalopathy (CTE)
Progressive degenerative disease of the brain. Athletes/ others with repetitive brain trauma.
Symptoms: Poor judgement, memory loss, apathy, confusion, depression, aggression.
Progress to dementia.
Histologically looks like AD except buildup of Tau protein.
Direct Parenchymal Injury
Laceration, contusion, blows can result in coup injury (contusion at point of contact) and countercoup injury (contusion on opposite side.)
Diffuse Axonal Injury
Injury of axons in deep white matter of brain. Twisting of axons caused by angular acceleration.
i.e. shaken baby syndrome, boxing
Common cause of persistent deficits or coma after trauma.
Leprosy (Hansen Disease)
Slowly progressive infx of skin and nerves caused by M. leprae. Transmitted through respiratory droplet although 95% of pop. is immune. Causes disabling deformities.
Acid fast, obligate intracellular bacterium. Hard to kill in normal ways due to body's granulomas and slow growing nature.
Less severe, localized form. Dry scaly skin lesions. Nerve degeneration. Nice T-cell response to the bug with nice granuloma formation.
More severe, widespread form. Skin, nerves, eye, mouth, testes, hands, feet. Patient's immune system doesn't respond.
Leonine facies, autoamputation, foamy histiocytes,high bug counts.
Peripheral neuropathy in DM
Most common manifestation: symmetric sensory and motor neuropathy involving distal nerves. Decreased pain sensation in distal extremeties.
Some patients also have autonomic neuropathy and or asymmetric neuropathy.
Neuropathies associated with malignancy
Common cause of mononeuropathy:
Brachial plexopathy in lung cancer.
Obturator palsy from pelvic neoplasms.
Cranial nerve palsies from brain tumors.
Polyneuropathies can occur in paraneoplastic syndrome.
Neuronal Ceroid Lipofuscinoses
Rare neuronal storage disease in which lipofuscin accumulates in the nerves resulting in neuronal dysfunction.
Key symptoms: blindness, mental and motor deterioration, and seizures (varies)
Tay Sachs Disease
Deficiency in Hexosamidase A which breaks down ganglisides. Gangliosides accumulate in all tissues.
Autosomal recessive. High prevalence in Ashkenazi Jews.
Begins in infancy --> developmental delays then paralysis then loss of neuro function. Death within several years.
Cherry-red spot is diagnostic.
Group of disorders characterized by myelin abnormalities. Most are autosomal recessive. Deterioration of motor skills, hypotonia, ataxia (motor probs > cognitive)
Defeciency of galactosylceramidase which leads to accumulation that is toxic to oligodendrocytes. Loss of myelin. Globoid cells (fat macrophages) in brain. Onset at 3-6 months. Rapid muscle stiffness, weakness
Megaloblastic anemia. (reversible)
Subacute combine degeneration of spinal cord. (irreversible)
General term for premature closure of sutures (no room for brain to grow); may not impact neural function.
Type of Craniosynostosis: Saggital sutures; long front to back diameter (narrow)
Type of Craniosynostosis in which coronal and saggital sutures resulting in tower skull
Type of Craniosynostosis with bilateral coronal suture fusion. Wide skull "flathead syndrome"
Type of Craniosynostosis with one side of coronal or lamboidal suture fusion; asymetric or twisted.
Type of Craniosynostosis with fusion of frontal suture.
Positional malformation of skull usually due to laying baby on back to avoid SIDS. Will usually resolve with time. Some cases require helmet therapy. Brain development is usually not affected.
Autosomal dominant trait; mutation in fibroblast growth factor receptor 2 gene.
Symptoms: Under-developed mid face, symmetric syndactly, hearing loss, frequent ear infx, short stature, possible delayed development.
similar to apert w/o syndactly.
small head, underdeveloped brain. Due to infx, drugs, etoh, rubella, chicken pox in utero.
absence of cranial vault
partial or complete absence of cranial vault.
Cranial vault fails to close due to failure of cranial neuropore to close; usually in occipital region. Brain version of spina bifida.
Subfalcine (Cingulate) Herniation
expansion of one hemisphere displaces cingulate gyrus
o Can cause compression of branches of anterior cerebral artery weakness of
limbs, aphasia, etc.
Transtentorial (Uncinate) Herniation
temporal lobe compressed against tentorium
o CN III (oculomotor) fixed, dilated pupil; impaired ocular movements
o Brainstem duret hemorrhages, impaired consciousness
o Posterior cerebral artery ischemia in primary visual cortex
o Contralateral cerebral peduncle hemiparesis
displacement of cerebellar tonsils through the foramen magnum
o Compresses medulla compromises vital respiratory and cardiac centers life-threatening
Patient was unconscious then fell
Patient fell then became unconscious due to impact
Vasogenic Cerebral Edema
Cause: increased vascular permeability
Fluid Shifts into intercellular spaces in brain.
Localized or generalized
Rx: Dexamethasone and Mannitol