Uworld2 Flashcards
How does carotid sinus hypersensititivity result in syncope?
Carotid sinus hypersensitivity is a common cause of syncope associated with tactile stimulation of the carotid sinus (eg, shaving).
The syncope results from an exaggerated vagal response stimulated by the carotid baroreceptors, which leads to slowed heart rate and marked peripheral vasodilation with a resulting transient loss of cerebral perfusion.
What is congenital toxoplasmosis treated with?
Sulfadiazine plus pyrimethamine.
These medications work synergistically to inhibit formation of tetrahydrofolate, a necessary cofactor for purine nucleotide synthesis
Prerenal acute kidney injury results from what? What are the lab findings?
Results from renal hypoperfusion (eg, dehydration due to poor oral intake).
Labs: elevated blood urea nitrogen/creatinine ratio (>20:1), low urine sodium (<20 mEq/L), low fractional excretion of sodium (<1%), high urine osmolality and specific gravity, and unremarkable urinalysis.
Vitamin D def in children causes what?
This causes rickets characterized by excessive unmineralized osteoid matrix at the epiphyseal cartilage.
What happens with vitamin D deficiency?
Vitamin D deficiency decreases intestinal absorption of calcium.
Parathyroid hormone secretion increases to maintain plasma calcium, which causes renal phosphate wasting and impaired bone mineralization.
What is the most effective agents for the treatment of hypertriglyceridemia?
Fibrates (eg, fenofibrate)
In patients with severe hypertriglyceridemia, pancreatic lipases can cause toxic levels of free fatty acids to be released within the pancreatic tissue, leading to acute pancreatitis.
What is the MOA of bisacodyl?
Bisacodyl is a commonly used stimulant laxative that stimulates the enteric neurons within the colonic myenteric plexus, thereby increasing peristaltic activity and enhancing colonic motility.
What is focal dystonia?
Focal dystonia is a neurologic movement disorder characterized by sustained, involuntary muscle contraction.
What is seen on muscle biopsy with focal dystonia?
Because these contractions are neurologically mediated, muscle biopsy may not show significant histologic changes, although muscle fiber hypertrophy is often present due to repetitive contractions.
What is the criteria for hospice?
Patients with advanced metastatic cancers or other terminal illnesses and a life expectancy of less than or equal to 6 months should be evaluated for hospice care.
What is leukocyte adhesion deficiency is due to what?
It due to the absence of CD18 antigens, which are necessary for the formation of integrins.
Failure of leukocyte adhesion and migration results in recurrent skin and mucosal infections without purulence, delayed umbilical cord separation, and peripheral leukocytosis.
What does Vitamin A def cause?
It causes night blindness and hyperkeratosis.
Deficiency of this lipid-soluble vitamin can develop in patients with fat malabsorption due to chronic biliary obstruction, exocrine pancreatic insufficiency, or small-bowel resection.
What can cause a traumatic pneumothorax?
Traumatic pneumothorax can involve puncture of either the chest wall (eg, penetrating chest trauma) or the lung (eg, by fractured ribs), allowing air to enter the pleural space.
What are the symptoms from traumatic pneumothorax?
Patients usually experience chest pain and diffuculty breathing. Crepitus, caused by air in the subcutaneous tissues of the chest wall, is often present on PE.
Where is the esophagus located on a CT?
The esophagus is located between the trachea and the vertebral bodies in the superior thorax.
It is typically collapsed with no visible lumen on CT images of the chest.
What is the leading cause of acute exacerbations of chronic obstructive pulmonary disease?
Viral and bacterial respiratory infections. The most common viral pathogens are: rhinovirus, influenza, and respirartory syncytial virus.
An aneurysm of the internal carotid artery can laterally impinge on the optic chiasm. This can cause what?
This can cause ipsilateral nasal hemianopia by damaging uncrossed optic nerve fibers from the temporal portion of the retina.
Hyper-IgM syndrome is usually caused by?
It is usually caused by a defect in CD40 ligand, which prevents B cells from undergoing class-switch recombination.
What are the clinical features of hyper-IgM syndrome?
Clinical features include recurrent sinopulmonary, gastrointestinal (eg, Giardia), and opportunistic infections,
Lab findings include elevated IgM and low/absent IgG, IgA, and IgE.
What is indicative of extramedullary hematopoiesis?
The presence of erythroid precursors in the liver and spleen.
What is extramedullary hematpoiesis?
A condition characterized by erythropoietin-stimulated formation and maturation of blood cells outside of the bone marrow.
It occurs in response to severe chronic hemolytic anemia (eg, beta thalassemia).
Patients with T1DM are increased risk of hypoglycemia because?
Because exogenous insulin will continue to be absorbed from the injection site despite falling glucose levels.
Those with long-standing diabetes may also have decreased glucagon secretion and therefore have an even greater risk of rapid hypoglycemia.
Infective endocarditis in IV drug users commonly affects what heart valve?
Commonly affects the tricuspid valve, often leading to septic pulmonary emboli.
Patietns can have an early- or holo-systolic murmur or tricupsid regurgitation, which is best ausculated in the 4th or 5th intercostal space at the left lower sternal border.
What is the MOA of nitroglycerin?
A venodilator that increases venous capacitance to reduce venous return and shift the vascular function curve to the left.
Alcoholic hepatitis presents how on histo?
Histopathology is characterized by marked intrahepatic neutrophil infilration, hepatocellular ballooning, Mallory bodies, and steatosis.
Typical labs of alcoholic hepatitis?
Elevated aminotransferases with an AST/ALT ratio >2:1
What is the presentation of congenital toxoplasmosis?
It is an infection acquired in utero that can present with hydrocephalus, intracranial calcifications, and chorioretinitis due to prolonged CNS inflammation.
What is the main pacemaker of the heart?
The sinoatrial node is the main pacemaker of the cardiac conduction system, typically initiating electrical impulses at a rate of 60-100/min.
What are the other pacemakers in the heart?
Other parts of the conduction system (eg, atriventricular node, His bundle) have their own intrinsic pacemakers, and they initiate impulses at a slower rate when impulses from the sinoatrial node are blocked.
What is MOA abciximab?
Abciximab is a blocker of glycoprotein (GP) IIb/IIIa receptor, which normally promotes platelet binding to fibrinogen.
What is defective in Glanzmann thrombasthemia?
GP IIb/IIIa.
What is hand-foot-and-mouth disease?
Hand-foot-and-mouth disease is a common childhood illness characterized by painful, vesicular mouth lesions; ulcers on the extremities; and low-grade fever.
It is caused by the ingestion and subsequent dissemination of an enterovirus (eg, Coxsackievirus)
Antidepressants monotherapy should be avoided in what patients?
Patients with bipolar disorder due to the risk precipitating mania.
Supine patients aspirate into which lung lobes?
Due to gravity, supine patients typically aspirate into the posterior segments of the upper lobes and superior segments of the lower lobes.
Patients who are upright will aspirate into what lung lobes?
Patients who are upright tend to aspirate into the basilar segments of the lower lobes.
Aspirated material will travel down which bronchus?
Aspirated material is more likely to travel down the right main bronchus.
Biliary atresia (obstruction of extrahepatic bile ducts) presents with what and on biopsy?
Presents with jaundice, dark urine, and acholic stools in the first 2 months of life due to conjugated hyperbilirubinemia.
Biopsy reveals intrahepatic bile duct proliferation, portal tract edema, and fibrosis.
Traits of enterococcus
Gram+, cocci in pairs and chains and when grown on blood agar, they do not cause hemolysis (gamma-hemolytic)
It is an important cause urinary tract infections.
Patients with cirrhosis complicated by abdominal ascites may develop what?
Hepatic hydrothorax, which is a transudative, usually right-sided pleural effusion that results from passage of intraabdominal fluid into chest cavity through small fenestrations in the diaphragm.
First generations antihistamines will have what kind of effects?
First generation antihistamines are nonspecific and interact with multiple receptors, including the muscarinic receptor. This leads to anticholinergic effects (eg, fever, flushing, mydriasis, urinary retention, tachycardia, altered mental status)
