Uworld Sim 1 Flashcards
ARDS
characterized by hypoxemia and bilateral pulmonary edema in the absence of heart failure
most common in patients with severe systemic illness, trauma, or pulmonary injury
injury to alveolar pneumocytes and pulmonary endothelium leads to an inflammatory response resulting in increased capillary permeability, intraalveolar fluid accumulation, and hyaline membrane formation
diabetic nephropathy
occurs 10-15 years after diagnosis
characterized by mesangial expansion, glomerular basement membrane thickening, and glomerular sclerosis
if the sclerosis is nodular, it is described as a Kimmelstiel Wilson lesion
cardiac conduction system
fastest: bundle of His
slowest in the AV node and fastest in the Purkinje system
conduction speed of atrial muscle is higher than that of ventricular muscle
fastest: Purkinje>Atrial muscle>ventricular muscle>AV node
osteosarcoma
bone tumor most often associated with Paget’s disease, arising in the femur, tibia, humerus, and other bones
destruction of the normal trabecular bone pattern, mixed radiodense and radiolucent areas, periosteal new bone formation, lifting of the cortex, and Codman’s triangle.
globus sensation
common abnormal sensation of a foreign body, tightness, or fullness in the throat
often worse when swallowing saliva and may be alleviated with food or liquid
functional disorder of the esophagus associated with anxiety
endometriosis
old blood collections cause chocolate cyst
biopsy: endometrial glands and stroma
early menarche, shorter menstrual cycles, and longer days of menstrual flow
dysmenorrhea manifests after menstrual cycles and leads to infertility, significant pelvic pain, deep dyspareunia
tx: NSAIDs and hormonal contraceptives, laparoscopy last resort
vitamin A
not indicated in pregnancy; fat soluble vitamin that poses a toxicity risk
accumulates within stellate cells of the liver and not readily excreted in urine
teratogen during organogenesis: leads to spontaneous abortion and fetal defects
DNA laddering
sensitive indicator of apoptosis that occurs when regulating factors (interleukins) withdrawn from proliferating cells
arises from the action of specific endonucleases during karyorrhexis
cleave DNA at internucleosomal linker regions which occur at 180 base pair intervals in the genome
why do benzos lead to longer symptoms in the elderly?
elderly people have an increased volume of distribution secondary to decreased total body water, decreased total body mass, increased body fat, reduced liver size and blood flow
leads to increased side effects such as confusion, paradoxical agitation, anterograde amnesia, psychomotor retardation, ataxia, weakness, vertigo, syncope
anticholinergic syndrome
fever, dry skin and mucous membranes, flushing, mydriasis and cycloplegia, altered mental status
caused by jimson weed
germline mosaicisim
presence of multiple, genetically different cell lines within the body
the earlier the mutation occurs, the more daughter cells that are affected
achondroplasia
diabetes mellitus complications
careful and regular inspection of feet for diabetic foot infections
acute promyelocytic leukemia
young adult: fever, fatiguability, and sore throat
unresponsive to antibiotic treatment
on histo, large blast cells with auer rods azurophilic, needleshaped crytoplasmic inclusion formed by the fusion of primary granules
t(15;17) chromosomal translocation involving the retinoic acid receptor-alpha gene on chromosome 17 and the promyelocytic leukemia gene on chromosome 15
complications of pancytopenia and DIC
tx: all trans retinoic acid should be started ASAP
cadherins
adhesion molecules that bind epithelial cells together within tissues
transmembrane proteins that interact intracellularly with intermediate proteins which facilitate binding to intermediate filaments or microfilaments within the cytoplasm
Ca2+ dependent
molluscum contagiosum
32 y/o woman due to spots on her face for 3w eeks that are increasing in size and becoming more numerous
mildly pruritic, no pain, no fever, multiple papular lesions noted on trunk and face
MC: firm, flesh colored papules on the skin and mucous membranes with umbilicated centers
poxvirus; transmitted thru direct contact or fomites
epidermal hyperplasia with molluscum bodies, large eosinophilic cytoplasmic inclusions made of virus particles
gallbladder release
delivery of acidic chyme from the stomach to the duodenum triggers bile release and stimulates S cell sin the crypts of Lieberkuhn to release secretin into systemic circulation
pancreas is then prompted by secretin to generate HCO3 rich fluid which neutralizes the hydrogen ions in chyme`
knee dislocation
neurovascular examination distal to the point of dislocation is necessary because the popliteal artery, tibial nerve, and common peroneal nerve
popliteal artery is at high risk because it is deep in the popliteal fossa, close to the articular surface of the joint
politeal artery is especially sensitive to traction forces
postpartum endometritis
polymicrobial uterine infection that is especially common after c section
sx: fever, lower abdominal pain, malodorous lochia, uterine tenderness and leukocytosis
cervix is a portal of entry but is not the affected organ
varicella zoster
usually occurs in people over 50 can occur in kids if herpes zoster infection at <1 y/o
sublimation
patients channel impulses into socially acceptable behaviors
Her2/neu has intrinsic tyrosine kinase activity. What is the immediate effect of ligand binding to this receptor?
transduce signals from hormones such as insulin, EGF, PDGF, VEGF
transmembrane proteins that have a ligand binding extracellular region, hydrophobic transmembrane region, intracellular domain with inducible tyrosine kinase activity
ligand binding causes dimerization of 2 identical receptor subunits
each phosphorylates the other to expose the catalytic omain
reflection
facilitating interview technique in which the physician repeats what the patient has said either word for word or by paraphrasing
allows the patient to feel heard and understand and strengthen the physician-patient relationship
obstructing interventions decrease spontaneous communication and are not helpful in promotting discussion
cocaine abuse
vasoncstriction, impaired cell mediated immunity, reduced mucociliary clearance
presents as headaches, chronic nasal discharge, atrophic nasal mucosa, and perforation of the nasal septum
heminephrectomy
acute reduction of the total GFR by 50%, the nephrons undergo significant structural and hemodynamic adaptations to allow for the single nephron GFR to rise. end result is to approximately 80% of 2 kidney GFR
sildenafil
selective PDE5 inhibitor
PDE5 inhibition leads to augmentation of intracellular cGMP concentrations which mediates relaxation in teh smooth muscle cells that surround the cavernous venous sinuses of the corpora cavernosa
craniopharyngiomas
slow growing suprasellar tumors arising from remnants of Rathke’s pouch
bimodal age distribution
patients present insidiously with headaches, pituitary dysfunction, visual disturbances
bitemporal hemianopia can occur and a calcified mass is uually foudn in the suprasellar region
serratus anterior paralysis
originates on the 1st 8 ribs and inserts on the medial scapula
stabilizes and pulls the scapula upward to allow complete abduction of the arm over the head
paralysis results in in ability to raise the arm over the head and protrusion of the medial border of the scapula when the outstretched arm is pushed forward against resistance
innervation: long thoracic nerve
exocrine pancreas
secretes approximately 1L of fluid which consists of an aqueous portion an enzymatic portion and the ductal cells
contain fixed concentrations of sodium and potassium that are virtually identical to those of plasma
HCO3 and Cl- vary with the pancreatic flow rate, which increases in response to secretin
high flow: HCO3 increases which Cl dros and its opposite at low flow
schizophreniform disorder
2 month history of psychotic symptoms and negative symptoms
HSV encephalitis
pathogenesis: HSV1–> olfactory tract–>olfactory cortex
presentation: fever, headache, seizures, aphasia, mental status
diagnosis: temporal lobe hemorrhage and edema
tx: IV acyclovir
acute intermittent porphyria
autosomal dominant defect in PBG deaminase that can lead to elevated levels of PBG and ALA
sx: acute severe abdominal pain, nausea and vomiting, motor/sensory neuropathy, and neuropsychiatric manifestations
port wine colored urine that darkens on exposure to light and air
skin and photosensitivity are absent and patients are symptom free
cobalamin deficiency
confusion, irritability, shock like sensation that radiates to his feet on neck flexion
long history of alcohol abuse with acute pancreatitis
low blood sugar
decreased vibratory sensation over the feet and ankles
myasthenia gravis
usually young patient, autoantibodies against acetylcholine receptors at motor endplate of postsynaptic membrane of NMJ
thymic hyperplasia and thymoma
fluctuating and fatigable proximal muscle weakness; worse later in the day: ocular, bulbar, respiratory muscles
diplopia, bulbar muscle weakness, and ptosis on examination
thymic hyperplasia
thymus is thought to the site of autoimmunization in MG and contains muscle like cells that express AChRs
leads to a decrease in the number of functional AChRs with resultant fatigable musculoskeletal weakness
retinoblastoma
both copies of the RB1 gene must be lost for tumorigenesis to occur
reflects the 2 hit hypothesis
sporadic retinoblastoma develop 2 spontaneous somatic mutations in a single retinal cell resulting in a unilateral tumor
familial: born with a germline defect in one of their RB1 genes. All cells have hit their first hit required for tumor formation–> leads o bilateral and multifocal retinoblastoma, as well as osteosarcoma
DiGeorge syndrome
chromosome 22q11.2 deletion; defective development of third and fourth pharyngeal pouches (predecessors of thymus, parathyroid gland, and ultimobranchial body)
conotruncal cardiac defects, abnormal facies, thymic hypoplasia, craniofacial deformities, hypocalcemia/hypoparathyroidism
impaired T cell immunity and tetanus
susceptible to recurrent viral, bacterial and fungal infections such as candida and pneumocystis jiroveci
metabolic derangements in DKA
metabolic acidosis
ketonemia
ketonuria
hyperglycemia/glycosuria
hyponatremia
hypovolemia
hyperkalemia (due to increased K+/H+ and because insulin’s tendency to drive K+ into cells is missing)
total K+ are actually depleted due to urinary losses and GI losses
increased K+, increased glucose, decreased Na+
chiari I malformation
most common and mildest form of chiari malformations
defects in craniocervical and hindbrain development that results in downward displacement of cerebellar structures that are often associated with a small posterior fossa
occipital headache due to meningeal irritation and cerebellar dysfunction due to compression of the cerebellar tonsils
downward displacement of the elongated cerebellar tonsils through the foramen magnum and into the upper cervical canal
complete androgen insensitivity syndrome
rare X linked disorder for individuals with 46, XY karyotype with a female phenotype due to mutated testosterone receptors throughout the body
cryptorchid testes secrete testosterone and are located in the abdomen, inguinal canal, or labia majora
circulating testosterone is peripherally converted into estradiol to result in breast development
vagina ends abruptly in a blind pouch and Mullerian structures are absent as AMH stimulates regression of the Mullerian ducts
premature infants
at significant risk for intraventricular hemorrhage or germinal matrix hemorrhage
germinal matrix: dense cellular and vascular layer of the subependymal zone of the brain from which neurons and glial cells devleop in utero; begins to involute at 28 weeks gestation and absent by term
begins betweent he caudate nucleus and thalamus, extends into the lateral, third, and fourth ventricles—>hydrocephalus
primary risk factor: physiologic immaturiry, infants with very low birth weight and those born preterm are at the greatest risk
ototoxicity
caused by cisplatin; damages apical stereocilia within the Organ of Corti of the cochlear emmbranous labyrinth
amiodarone
in some patients can result in interstitial pneumonitis that presents with slowly progressive dyspnea and nonproductive cough
fever, dyspnea, cough, dry inspiratory crackles, patchy interstitial
reversible with reduction in dose or discontinuation of the drug
other AE: arrhythmias, hepatic injury, thyroid abnormalities and bluish gray skin discoloartion
ILD meds also include nitrofurantoin, methotrexate, and bleomycin
misoprostol
PGE1 analog that can be used to help prevent and treat NSAID induced peptic ulcers
NSAIDs inhibit COX1 and decrease PGE1 secretion, leading to decreased parietal cell acid secretion and no protection from acidic juices
aspirin induced airway disease
10% of people with asthma develop nasal congestion or bronchospasm after ingesting aspirin or nonsteroidal anti inflammatory drugs
result from dysregulation of AA metabolism due to COX inhibition
increases flow dow the 5-LO pathway and reduces inhibition of the pathway via PGE2 leads to increased formatino of bronchoconstrictive leukotrienes
tx: montelukast
HNSCC
strongly associated with the use of tobacco and alcohol
develop in the oral cavity with the ventral tongue, floor of the mouth, lower lip, soft palate and gingiva
infiltrates adjacent tissue and may eventually metastasize locally to lymph nodes or distally to mediastinal lymph nodes, lungs, liver, or bones
Marfan syndrome
autosomal dominant connective tissue disease the classically affects the CV and MSK systems as well as the eyes
muation in FBN1 which codes for a connective tissue protein responsible for the production and maintenance of elastic fibers
difference in phenotype is observed even among those who carry the same genetic mutation in variable expressivity
nitrates
direct vascular smooth muscle relaxation which causes systemic venodilation and decreased peripheral venous return–>EDV and pressure (decreased preload) which decreased myocardial oxygen demand by decreasing systolic wall stress
modest reduction in afterload due to systemic arterial vasodilation which further reduces left ventricular wall stress and myocardial oxygen demand
don’t affect cardiac chronotropy or inotropy but drop in systolic blood pressure typically leads to reflex tachycardia
cystic fibrosis
autosomal recessive
mutations cause dysfunction of epithelial chloride channel resulting in impaired electrolyte transport by exocrine glands
function varies from tissue to tisstue
eccrine: CFTR acts to reabsorb chloride from sweat fluid and also enhances sodium reabsorption by the epithelial sodium channel due to higher levels of sodium and chloride
intestinal and respiratory epithelium: CFTR normally secretes chloride into the lumen and has an inhibitory effect on ENaC
allelic heterogeneity
instances when different mutations at the same genetic locus causes similar phenotypes
ex: B thalassemia
presentations are similar but the exact phenotype can vary
hereditary hemochromatosis
autosomal recessive disease characterized by excessive GI absorption of Fe3+
store iron in the form of hemosiderin within the dermis and various parenchymal organs
typically silent in early adulthood, presenting only after significant amounts have accumulated (>40 y/o)
presents depending on what tissues the iron is being stored in and skin hyperpigmentation is also commonly seen, mild hepatomegaly, and atrophic testes
hepatic cirrhosis
irreversible process due to chronic injury to the hepatic parenchyma
hepatic necrosis and extensive fibrosis cause distortion of the hepatic vascular bed with formation of disorganized regenerative nodules
disruption of hepatic vasculature causes portal hypertension leading to portosystemic anastomoses and ascites
portal venous system is valveless therefore portal hypertension can cause retrograde flow of portal blood away from the liver and increased pressure within the splenic vein
leads to congestion of splenic red pulp and result sin splenomegaly
indirect ELISA
identifies the presence of serum antibody directed against a known target antigen
- known antigen is fixed to the surface of a well.
- patient’s serum is added and then the plate is washed.
- anti-human immunoglobulin antibody coupled to a substrate modifying enzyme is then added. This binds and the plate is then washed again.
- a substrate is added to elicit a signal. If quantitative, the intensity of color change is proportional to the amount of antibody present
impetigo
prolonged erythema and a yellow crust on a cutaneous wound
most common causes: staph aureus and strep pyogenes
efflux pumps
transport proteins that excrete toxic substances like Abs from cytoplasm/periplasm of bacteria into the external environment
energy dependent and use ATP, sodium gradients, or proton electrochemical gradients to pump H+ out leading to a transmembrane pH gradient of 2-3
high pH agars neutralize proton gradients by raising pH of external environment and limiting the H+ concentration difference between the exterior and interior of the cell
reduction in ciprofloxacin MIC with a high pH agar indicates that the underlying source of resistance was an efflux pump
achondroplasia
autosomal dominant disorder caused by a gain of function point mutation on FGFR3 gene which normally acts to inhibit excessive cartilage proliferation in the long bones
becomes const activated, leading to severely restricted chondrocyte proliferation in growth plate cartilage and decreased endochondral ossification
90% are denovo, 10% are inherited from affected parent
physical sx: rhizomelia, brachydactyly in a trident configuration, macrocephaly, midface hypoplasia, frontal bossing
increased risk of spinal stenosis andr resultant nerve compression which presents with proximal lower extremity weakness and paresthesia
maple syrup urine disease
characterized by a defect in the branched chain alpha keto acid dehydrogenase complex resulting in an inability to degrade branched chain alpha amino acids (leucine, isoleucine, and valine) and their alpha ketoacid metabolites
causes BCAAs and a-ketoacids to accumulate in the plasma and urine which cause CNS toxicity
early symptoms: poor feeding and vomiting
a-ketoacid dehydrogenase requires thiamine (b1) as a cofactor (transketolase does as well)
hydrops fetalis
due to alpha thalassemia major and loss of all 4 alpha globin genes and formation of hemoglobin barts (4 gamma chains)
extreme affinity for oxygen (>10x HgA) and unable to release O2 to the tissues
leads to this condition which is characterized by anasarca, ascites, pleural/pericardial effusions and intrauterine death
androgen binding protein
synthesized by sertoli cells in response to FSH and secreted into the seminiferous tubule lumen
normal circulating testosterone levels suggests normal HPG axis and normal secretory function of Leydig cells but low concentration of T in the seminiferous tubules suggests sertoli cell dysfunction
pulmonary embolism
causes V/Q mismatch that increases ventilation and heart rate via a chemoreceptor reflex
resulting hyperventilation lowers arterial CO2 but is unable to compensate fully for the hypoxemia. HIghly ventilated regions can excrete more Co2 to compensate. Hyperventilation results in hypocapnia and respiratory alkalosis with high pH
costosternal syndrome
occurs after repetitive activity and involves the upper costal cartilage at the costochondral or costosternal junctions
pain is typically reproduced with palpation and worsened with movement or changes in position
patients do not have palpable warmth, swelling, or erythema
verapamil
non DHP calacium channel blocker that works by blocking L type Ca2+ channels, which prevents the initial calcium influx into cardiac myocytes and vascular smooth muscle cells
skeletal muscle is not dependent on extracellular calsium influx and there fore Ca channel blockers don’t affect skeletal muscle contractility
RRR
(absolute risk control-absolute risk treatment)/absolute risk control
