Uworld25 Flashcards
What is indicative of secondary hyperaldosteronism?
Elevated serum aldosterone levels can manifest with hypertension, hypokalemia, and muscle weakness.
Increased levels of both renin and aldosterone are indicative of secondary hyperaldosteronism, which can be caused by renovascular disease and renin-secreting tumors.
Fetal hyperinsulinemia causes what?
Neonates born to mothers with poorly controlled diabetes during pregnancy are exposed to high maternal glucose levels in utero, resulting in beta cell hyperplasia followed by excessive fetal insulin production.
Fetal hyperinsulinemia causes neonatal hypoglycemia, polycythemia, and macrosomia.
What is sporotrichosis?
Sporotrichosis typically presents as papulonodular lesions distributed along the lymphatics and is histologically characterized by granulomatous and neutrophilic inflammation.
It is caused by the dimorphic fungus Sporothrix schenckii, which is often inoculated into the skin during outdoor activities such as gardening.
Candida endophthalmitis typically occurs due to?
hematogenous dissemination to the choroid later in the setting of fungemia.
Most cases arise in hospitalized patients with indwelling central catheters. Patients usually have unilateral eye floaters and progressive vision loss.
What is neuroleptic malignant syndrome?
an adverse reaction to antipsychotic medication characterized by severe “lead pipe” rigidity, hyperthermia, sympathetic hyperactivity, and mental status changes.
NMS is charactered by severe rigidity rather than the neuromuscular irritability (eg, hyperreflexia, myoclonus) seen in serotonin syndrome.
Presentation and risk factors for renal cell carcinoma
Renal cell carcinoma may present with a combination of hematuria, abdominal mass, or flank pain; however, this triad occurs together in <10% of cases.
Pathology demonstrates rounded, polygonal cells with clear cytoplasm.
Risk factors: smoking, toxin exposure, and certain hereditary disorders (eg, von Hippel-Lindau syndrome)
Which drugs are susceptible to chelation?
Tetracyclines interact with polyvalent cations (eg, iron, calcium, aluminum, magnesium) to form nonabsorbable chelate complexes in the GI tract.
This can lead to significantly decreased drug absorption and therapeutic effect.
Fluoroquinolones and thyroxine are also susceptible to chelation.
What hormone inhibits lactation during pregnancy?
In pregnancy, progesterone is secreted by the corpus luteum and later by the placenta.
Although prolactin secretion increases as pregnancy progresses, high progesterone levels inhibit lactation by preventing binding of prolactin to receptors on alveolar cells in the breast.
Which type of cancer can obstruct the eustachian tube?
The eustachian tube connects the middle ear to the nasopharynx. Cancer located in the nasopharynx can lead to obstruction of the eustachian tube, causing a middle ear effusion.
What are the common adverse effects of nondihydropyridine calcium channel blockers (eg, diltiazem, verapamil)?
constipation, bradycardia, atrioventricular block (negative chronotropic effect), and worsening of heart failure in patients with left ventricular systolic dysfunction (negative inotropic effect)
What is the most important prognostic determinant for colorectal cancer?
Tumor stage (degree of invasion/spread).
Tumors confined to the basement membrane and lamina propria are early stage and have the best prognosis.
Outcomes generally deteriorate as the stage advances: spread of tumor into the muscularis propria –> regional lymph nodes –> distant sites.
What are risk factors for acne?
increased androgen levels, obstruction of pilosebaceous glands by oil based hair products, and mechanical irritation of skin follicles.
Sports participation frequently triggers acne due to the use to tight fitting clothing and protective gear.
What are the labs seen in multiple myeloma?
Multiple myeloma is associated with increased bone resorption due to the production of tumor-related cytokines.
This results in elevated serum calcium levels, which reduce parathyroid hormone production.
Low PTH decreases renal calcium reabsorption (hypercalciuria) and in combination with renal insufficiency, reduces 1,25-dihydroxyvitamin D synthesis.
What is methemoglobinemia?
causes dusky discoloration of the skin (similar to cyanosis), and because methemoglobin is unable to carry oxygen, a state of functional anemia is induced.
However, the blood partial pressure of oxygen will be unchanged as it is a measure of oxygen dissolved in plasma and is unrelated to hemoglobin function.
The risk for UTI can be reduced by?
UTIs are common in hospitalized patients with indwelling urinary catheters.
The risk for UTI can be reduced by avoiding unnecessary catheterization, using sterile technique when inserting the catheter, and removing the catheter as soon as possible.
Why is epinephrine often added to lidocaine?
Epinephrine is often added to lidocaine to produce vasoconstriction, which prolongs the duration of action of lidocaine, decreases bleeding during a procedure, and reduces systemic lidocaine absorption
What is cord factor?
Mycobacterium tuberculosis grows in long, serpentine cords due to the presence of cord factor, a surface glycolipid, on the cell wall.
Cord factor is a primary virulence factor of M tuberculosis; it protects the bacteria from digestion by macrophages and also leads to the formation of caseating granulomas.
What is SIADH- syndrome of inappropiate antidiuretic hormone secretion?
characterized by low plasma sodium and osmolality, inappropriately concentrated urine, and clinically normal volume status (euvolemic hyponatremia).
An important cause of SIADH is a paraneoplastic effect secondary to small cell carcinoma of the lung
MOA of milrinone
phosphodiesterase-3 inhibitor that reduces the degradation of cyclic adenosine monophosphate to provide 2 beneficial effects for treating systolic heart failure.
Calcium influx into cardiomyocytes is increased, which increases cardiac contractility.
In addition, calcium-myosin light chain kinase interaction is reduced, which causes vasodilation and reduces cardiac preload and afterload
What is familial hypercholesterolemia?
on of the most common AD disorders, is the result of heterozygous or homozygous LDL receptor gene mutations, which cause hepatocyte under expression of functional LDL receptors.
This condition can lead to accelerated atherosclerosis and early onset coronary artery disease
What can improve carpal tunnel syndrome?
The carpal tunnel is formed by the carpal bones and the transverse carpal ligament (flexor retinaculum).
Carpal tunnel syndrome results from compression of the median nerve as it passes through the carpal tunnel with 9 flexor tendons.
Longitudinal incision of the transverse carpal ligament can decrease pressure within the carpal tunnel, improving patients’ symptoms.
Why are women at high risk for UTIs?
Women are at high risk for urinary tract infections due to a shorter urethra that is close to the anus and vaginal introitus, which allows enteric pathogens to colonize the vagina and ascend to the bladder.
Acute simple cystitis is generally marked by dysuria, urinary frequency/urgency, suprapubic tenderness, and pyuria/bacteriuria on urinalysis.
What happens during a fasting state with glucagon, epinephrine and cortisol?
In a fasting state, glucagon and epinephrine bind to transmembrane receptors and prevent hypoglycemia by increasing hepatic glycogenolysis and gluconeogenesis.
Prolonged fasting increases the secretion of cortisol, a steroid hormone that binds to an intracellular receptor and acts to increase transcription of enzymes involved in gluconeogenesis, lipolysis, and proteolysis.
Cavernous hemangiomas carry an increased risk of?
Cavernous hemangiomas are vascular malformations that occur most commonly within the brain parenchyma; they carry an increased risk of intracerebral hemorrhage and seizure.
What causes the fibrosis in a myocardial infarction?
After myocardial infarction, transforming growth factor-beta reduces inflammation and promotes tissue remodeling due to fibroblast proliferation and collagen deposition, resulting in fibrosis in the area damaged by ischemia.
Abnormal myocardium at the scar border can predispose patients to sudden death as a result of arrhythmia.
Citrate anticoagulants in high volume blood transfusion can chelate what?
Citrate anticoagulants in high volume blood transfusion can chelate plasma calcium, leading to hypocalcemia which causes peripheral neuromuscular excitability (eg, paresthesia, muscle spasms).
This is most common with very rapid transfusion rates, but it can also be seen at lower rates in patients with hepatic insufficiency because citrate is metabolized by the liver
Function of IL-10
Of the cytokines released in the setting of tissue injury, IL-10 plays important anti-inflammatory and immunomodulatory roles, especially in the pathogenesis of inflammatory bowel disease.
IL-10 attenuates the immune response through the inhibition of Th1 cytokines, reduction of major histocompatibility complex class II expression, and suppression of activated macrophages and dendritic cells.
What do homeobox genes encode for?
DNA-binding transcription factors that play an important role in the segmental organization of the embryo along the craniotomy-caudal axis.
What is seen in diabetes insipidus following desmopressin adminstration during the water deprivation test?
Patients with diabetes insipidus are unable to concentrate their urine in response to dehydration.
Following desmopressin administration during the water deprivation test, urine osmolality increases to normal levels in central DI but does not change in complete nephrogenic DI.
Function of glucokinase
Insulin release by pancreatic beta cells is stimulated by increased glucose metabolism and ATP production.
Glucokinase functions as a glucose sensor in pancreatic beta cells by controlling the rate of glucose entry into the glycolytic pathway.
Mutations in the glucokinase gene lead to a state in which higher glucose levels are required to stimulate insulin secretion and are a cause of maturity-onset diabetes of the young.
What is health promotion?
the process of enabling people to increase control over their health and its determinants and thereby improve their health
What is intermittent explosive disorder?
characterized by recurrent episodes of explosive verbal or physical aggression.
The aggressive behaviors are impulsive and grossly out of proportion to the provocation.
What is the Ghon complex?
The Ghon complex describes the two initial sites (lower lobe of lung, ipsilateral hilar lymph node) of primary tuberculosis infection.
Over time, these sites become calcified and fibrosed and can be visualized on gross pathology and radiographic imaging (Ranke complex)
What is seen on EM and IF for membranous nephropathy?
Membranous nephropathy is a common cause of nephrotic syndrome in adults.
EM of the glomerular capillary demonstrates irregular, subepithelial, electron-dense immune deposits on the glomerular basement membrane with moderate effacement of the podocyte food processes.
Immunofluorescence microscopy demonstrates a diffuse granular pattern of IgG along the capillary loops
What is Guillain-Barre syndrome?
Guillain Barre syndrome represents a group of immune-mediated polyneuropathies that are thought to be caused by molecular mimicry, leading to demyelination of the peripheral nerves.
Up to 1/3 of GBS cases are preceded by a Campylobacter jejuni infection, which is a common cause of acute diarrheal illness.
Chronic aortic regurgitation is caused by?
a reduction in diastolic blood pressure and a compensatory increase in left ventricular stroke volume.
These changes create a high-amplitude, rapid fall pulsation (ie, widened pulse pressure) and the other characteristic findings of AR (head bobbing, “pistol shot” femoral pulses)
What is costosternal syndrome (costochondritis)?
usually occurs after repetitive activity and is characterized by pain that is reproducible with palpation and worsened with movement or changes in position.
What is congenital long QT syndrome?
Congenital long QT syndrome is most often caused by genetic mutations in a K+ channel protein that contributes to the outward-rectifying potassium current.
A decrease in the outward K+ current leads to prolongation of action potential duration and QT interval.
This prolongation predisposes to the development of life-threatening ventricular arrhythmias (eg, torsades de pointes) that can cause palpitations, syncope, seizures, or sudden cardiac death.
Function of tetrahydrobiopterin and impaired synthesis causes?
Tetrahydrobiopterin (BH4) is an essential cofactor for hydroxylase enzymes involved in the metabolism of phenylalanine, tyrosine, and tryptophan.
Impaired BH4 synthesis causes hyperphenylalaninemia and reduced levels of neurotransmitters (eg, dopamine, serotonin), causing progressive neurologic findings (developmental delay, seizures, microcephaly)
What is a case control study?
observation study design; it begins with individuals who have the outcome (cases) and compares them with individuals who do not have the outcome (controls) according to history of exposure to >1 risk factors.
