uworld assessment block #2 4.15 Flashcards
(90 cards)
depletion of B12 stores? folate?
B12 depletes over years.
folate affected (by alcohol abuse) within weeks
MS: Lhermitte’s phenomenon
shock-like sensation radiating to the feet with neck flexion. also have cognitive defects.
B12 deficiency does this too.
guillain-barre syndrome presentation
acute postinfetious polyneuropathy. nonspecific prodome and nausea followed by progressive ascending paralysis.
sensory stroke presentation
numbness of face, arm, leg on one side of body w/o accompanying motor defect
pathophysiology of myasthenia gravis
acquired autoimmune condition. fluctuating weakness of facial, periocular, bulbar, pelvic girdle muscles.
antibody-mediated, T-cell dependent attach on postsynaptic NMJ.
myasthenia gravis is associated w/ what additional finding
60-70% have hyperplastic thymus tissue. 10-15% have thymomas.
removal of thymus helps.
loss of heterogeneity
inherit mutation in one tumor suppressor, and then develop somatic mutation later. allows for malignant transformation (i.e. Rb)
parental imprinting
preferential transcription of genes from one or the other homologous pair of chromosomes depending on parental origin of chromosome
common causative organisms for infective arthritis by age (children < 2, late adolescence & early adult, older children/older adults, sickle cell.
- children <2: H. flu
- late adolescence & early adult: N. gonorrhea (esp women)
- older children/adult: s. aureus
- sickle: salmonella
third pharyngeal arch
stylopharyngeus muscle, hyoid, glossopharyngeal n.
fourth pharyngeal arch
intrinsic muscles of pharynx + cricothyroid
CN X: superior laryngeal n.
hyperkalemia in DKA? hyponatremia
- acidemia drives K+H+ exchange
- insulin tends to drive K+ into cells
- note: total body K+ low bc osmotic diuresis and GI loss.
hyponatremia:
1. osmotic activity of glucose (serum Na drops 1.6 mEq/L for every 100mg/dl rise in glucose)
2. hyperglycemia-induced osmotic diuresis
arnold chiari malformation
downward displacement of elongated cerebellar tonsils through foramen magnum & into upper cervical canal. CSF flow blocked.
additional findings: small posterior fossa, caudal displacement of medulla, hydrocephalus, lumbar myelomeningocele
dandy-walker malformation
characterized by enlarged posterior fossa.
absent/shrunken vermis replaced by large midline cyst = expanded fourth ventricle
spina bifida cystica (myelomeningocele)
herniation of a sac containing CSF, spinal cord, nerve roots through defect in vertebral arches and dura
syringobulbia
fluid-filled cavities within medulla oblongata
inheritance of androgen insensitivity (testicular feminization syndrome)
rare X-linked disorder. 46 XY.
absence of testosterone receptors in target tissue.
testosterone and LH high (lack of receptors prevents negative feedback)
circulating androgens eventually peripherally converted to estradiol – feminization.
no mullerian duct (MIF from sertoli) so vagina = blind duct
testes: abdomen, inguinal canal, labia majora. make testosterone, but no spermatogenesis
normal testes descent
- transabdominal: MIF
- inguinoscrotal: hCG and androgens
mullerian agenesis
uterus, fallopian tubes, proximal vaginal fail to develop. LH, FSH, estrogen normal.
cause of primary ammenorrhea
when does the germinal matrix subside in prominence
after 32 weeks. decline in cellularity & vascularity.
why is germinal matrix prone to hemorrhage?
highly cellular & vascular (generates neurons & glia during fetal development).
no network fibers present to support vasculature in germinal matrix.
cephalhematoma
hemorrhage within circular region of scalp that inters the lower uterus during childbirth.
associated with sudden delivery, disproportion between diameter of fetal head & birth canal, inappropriate forceps use.
cisplatin toxicity
ototoxicity. damages apical stereocilia on hair cells
amiodarone toxicity in lungs? other toxicity?
insterstitial pneumonitis
dyspnea, cough, dry inspiratory crackles, patchy interstitial infiltration on radiograph.
other: hepatic necrosis, thyroid abnormalities, corneal deposits, bluish-gray skin discoloration