Uworld32 Flashcards
Most cases of cleft lip and/or cleft palate are from?
Most cases of cleft lip and/or cleft palate have a multifactorial pathophysiology related to complex interactions between genetic and environmental factors.
What is tracheoesophageal fistula with esophageal atresia?
typically presents in the immediate newborn period with choking/coughing with feeding.
A feeding tube cannot be passed into the stomach; curling of the distal end of the enteric tube in the proximal esophagus on x-ray is diagnostic.
What is seen on biopsy for subacute granulomatous (de Quervain) thyroiditis?
characterized by painful thyroid enlargement and usually follows a viral illness.
Biopsy shows a mixed inflammatory infiltrate with macrophages and multinucleated giant cells.
What is retinoblastoma?
Retinoblastoma is associated with inactivating mutations of the RB1 tumor suppressor gene, which normally restricts cells from passing the G1/S checkpoint until the cell is ready to divide.
Impaired function of the Rb protein allows unrestricted progression through the G1/S checkpoint, leading to uncontrolled cell division.
Tumor cells must develop adaptations to avoid destruction by the innate and adaptive immune response. A common adaptation is to?
overexpress programmed cell death 1 ligand (PD-L1), which converts effector T cells to exhausted T cells.
Other adaptations include down-regulating class I major histocompatibility complexes, blocking T cell costimulation, and increasing immunoinhibitory cytokine secretion.
What is an effect of St. John’s wort?
St John’s wort induced cytochrome P450 hepatic microsomal enzymes. As a result, a wide variety of drugs that are metabolized by these enzymes, such as warfarin, will have lower plasma concentrations and decreased efficacy.
Hereditary breast cancer is most commonly associated with mutations in?
BRCA1 and BRCA2. These tumor suppressor genes are involved in DNA repair, and their mutations increase the risk of developing breast and ovarian cancer.
The most important airway-protective movements during swallowing are?
the anterior/superior displacement of the larynx, the tilting of the epiglottis to block the airway, and vocal fold adduction.
A chin-tuck maneuver can be helpful in some patients with aspiration by stimulating the airway-protective movement of the larynx.
Large prolactin-secreting pituitary tumors can compress the optic chiasm, causing?
bitemporal hemianopsia. In addition, elevated prolactin levels suppress release of GnRH, leading to decreased LH secretion and subsequently impaired testosterone production in men.
What is odds ratio formula?
OR= odds of exposure in cases / odds of exposure in controls
OR = ad/bc
Labs for DIC
Disseminated intravascular coagulation commonly occurs in the setting of sepsis and is characterized by widespread activation of the coagulation cascade with formation of microthrombi.
Labs: prolonged PT/PTT, thrombocytopenia, low fibrinogen (ie, a consumptive coagulopathy) and patients usually have signs of bleeding (eg, oozing from venipuncture sites)
What is the earliest manifestations of diabetic nephropathy?
Moderately increased albuminuria (urine albumin 30-300 mg/day) is the earliest manifestation of diabetic nephropathy.
Screening for diabetic nephropathy is best achieved using an albumin-specific urine assay (regular dipstick urinalysis has low sensitivity).
What is confounding?
Confounding occurs when the exposure-disease relationship is muddled by the effect of an extraneous factor associated with both exposure and disease.
Confounding bias can result in the false association of an exposure with a disease.
Left-sided heart failure can cause secondary pulmonary hypertension via?
elevated left-sided diastolic filling pressures transmitting backward to the pulmonary veins, resulting in pulmonary venous congestion.
Over time, pulmonary arterial remodeling (medial hypertrophy and intimal thickening with fibrosis) can occur, but not to the extent that occurs in (primary) pulmonary arterial hypertension.
Pathogenesis of diphtheria exotoxin
inhibits host cell protein synthesis by catalyzing the ADP-ribosylation of host cell elongation factor-2
Physiologic age-related changes in the cardiopulmonary system can lead to reduced ability to cope with critical illness. These changes include?
reduced maximal heart rate and cardiac output due to decreased responsiveness to adrenergic stimuli, reduced retention of arterial blood volume due to decreased arterial compliance, and reduced respiratory strength and gas exchange efficiency.
What is aplastic anemia?
a form of bone marrow failure caused by direct toxic injury or cytotoxic T cell destruction of multipotent hematologic stem cells, which leads to pancytopenia.
Bone marrow examination will show profound hypocellularity, an abundance of fat cells, and small clusters of morphologically normal hematologic cells.
What is the most common manifestation of Francisella tularensis?
Francisella tularensis is a highly virulent, gram negative coccobacillus transmitted to humans during contact with an infected wild animal (eg, hare, rabbit, squirrel) or due to a bite with a tick or mosquito that recently fed on an infected animal.
The most common manifestation is ulceroglandular disease, which is characterized by rapid-onset fever, a single papuloulcerative lesion with central eschar at the site of inoculation, and painful regional lymphadenopathy.
What muscles are the major hip flexors?
The rectus femoris, iliopsoas, and sartorius are the major hip flexors.
Of these, only the rectus femoris and sartorius also affect knee movement. The sartorius flexes the knee while the rectus femoris extends the knee.
What is seen in a hookworm infection?
Hookworm infections are transmitted via direct contact between human skin and contaminated soil/sand (eg, walking barefoot).
Dermal penetration is often characterized by an intensely pruritic papule that may form serpinginous tracks due to the subcutaneous migration of hookworm larvae.
Coadministration of selective serotonin reuptake inhibitors and monoamine oxidase inhibitors can produce?
excessive synaptic serotonin levels secondary to decreased reuptake and decreased degradation of serotonin, potentially causing serotonin syndrome.
To avoid the risk, a 2 week washout period after discontinuing an MAO inhibitor and before initiating SSRI therapy is required to allow sufficient time for MAO regeneration.
The flow-volume loop for chronic obstructive pulmonary disease is characterized by?
increased residual volume and total lung capacity, as well as a “scooped-out” expiratory pattern due to reduced expiratory flow rates.
Both airway narrowing due to chronic bronchitis and decreased elasticity due to emphysematous destruction of interalveolar walls are responsible for the hyperinflation and airflow limitation.
Invasive vascular procedures can be complicated by atheroembolic disease, which may involve the kidneys, GI tract, CNS, and the skin. Light microscopy shows?
a partially or completely obstructed arterial lumen with needle shaped cholesterol clefts within the atheromatous embolus.
Name the inhibitors and inducers of the P450
Rifampin, phenobarbital, and phenytoin are potent enhancers of the cytochrome P450 pathway; concurrent use of warfarin with these medications results in decreased efficacy of warfarin.
In contrast, cimetidine, amiodarone, and trimethoprim-sulfamethoxazole inhibit warfarin metabolism, increasing the risk of bleeding.
