Step 1 Flashcards
The most common cause of pericarditis is ______
Coxsackie B virus, which causes inflammation of the pericardial membrane. This is a picornovirus, the smallest RNA virus. Positive, single-stranded, naked, icosohedral virus.
Tertiary syphilis can cause what cardiac problems?
Tertiary syphilic disrupts the vasa vasorum of the aorta, dilating the aortic root and the aortic valve ring. This can lead to aneurysm and aortic valve insufficiency. “Tree barking” of the aorta may also occur which is due to the wrinkling of the tunica intima.
Cystic fibrosis
Autosomal recessive causing a defect in CFTR gene, leading to dysfunctional chloride channel that secretes Cl- into lungs and GI tract and reabsorbs Cl- in sweat glands. This often leads to mucus plugging and recurrent pulmonary infections, chronic bronchitis, and bronchiectasis. Often present with meconium ileus in newborns. N-acetylcysteine can be used to loosen mucus plugs (it cleaves disulfide bonds within mucus glycoproteins).
CF can lead to problems associated with absorption of fat-soluble vitamins. Which condition can arise from this?
Fat soluble vitamins include A, D, E, and K. Deficiency in D can cause rickets in children due to decreased bone formation. Hypocalcemic tetany and muscle spasm can also occur. Vitamin A deficiency can result in night-blindness and dry skin. Deficiency in E and K can lead to RBC dysfunction and defective coagulation, respectively.
Which antitumor antibiotic can cause pulmonary fibrosis?
Bleomycin - it induces free radical formation resulting in breaks in DNA strands. It is used to treat testicular cancer and Hodgkin’s lymphoma. Skin changes may also occur on this drug such as darkening.
What is osteomalacia?
It is a disorder of bone mineralization/calcification of osteoid in adults. It is often due to vitamin D deficiency (rickets in children), which leads to low to normal levels of calcium, low vitamin D, and low phosphate. Bone matrix can be laid down but it cannot be mineralized. These patients have reduced bone densities and prone to pathologic fractures. Lab profiles might show elevated alkaline phosphatase or increased PTH secretions (this decreased phosphate levels in serum and tries to increase calcium levels). There is a hyperactivity of osteoblasts which require an alkaline environment hence why alkaline phosphatase is increased.
What is osteoporosis?
This is a decreased synthesis of new bone matrix, which is contrasted from osteomalacia, where bone matrix is laid down but not mineralized.
What time of chronic gastritis (nonerosive) affects the first part of the stomach?
Type A - it affects the fundus/body of stomach and spares the antrum. It is an autoimmune condition where antibodies attack parietal cells in the stomach.
What is Gerstmann’s syndrome?
(1) an inability to distinguish right from left; (2) an inability to identify fingers; (3) a writing disability known as agraphia or dysgraphia; and (4) a lack of understanding the rules for calculation or arithmetic known as acalculia or dyscalculia. Reading ability remains intact. The syndrome results from damage to the visual association cortex (angular gyrus).
Name one enzyme responsible for renal gluconeogenesis.
Fructose-1,6-bisphosphatase
Stable angine usually presents at what percentage of artery stenosis?
75% and greater.
What is most likely cause of death a few hours post-MI?
Fatal arrythmia, specifically polymorphic ventricular tachycardia. Cardiac arrythmia is an important cause of death before reaching hospital. Cardiogenic shock may also arise when heart completely fails and cannot supply vital organs.
What causes arrythmia post-MI?
It is due to a disruption of the vascular supply to the conduction system, combined with myocardial irritability after injury.
What are some etiologies of dilated cardiomyopathy?
ABCCCD: Alcohol abuse, Beriberi (lack of thiamine pyrophosphate - active form of thiamine or B1), Coxsackie B myocarditis (direct toxicity via receptor-mediated entry of virus into cardiac myocytes), chronic Cocaine use, Chagas’ disease, and Doxorubicin toxicity.
What is the S3 heart sound?
S3, or ventricular gallop, occurs in early diastole, following opening of the AV valves during rapid ventricular filling phase. In adults, it is a sign of volume overload owing to congestive heart failure, or increased transvalvular flow that accompanies advanced mitral or tricuspic regurgitation.
What is the S4 heart sound?
S4, or atrial gallop, occurs in late diastole and coincides with contraction of atria. It is generated by the left or right atrium contracting vigorously against stiffened ventricle. It is a sign of decreased compliance due to ventricular hypertrophy or MI.
A cocaine user is exeriencing an MI. Physicians decide not to give a beta-blocker. Why?
Beta blockers are not given with cocaine use due to unopposed alpha effects. By blocking presynaptic uptake of norepinephrine and increased release of catecholamines from the adrenal gland, cocaine results in a high degree of adrenergic activity. Beta blockers will isolate these effects to a-receptors amplifying the a-1-agonists activity leading to vascular smooth muscle contraction.
Which beta blockers are nonselective antagonists?
Think “N to Z” for “n”onselective: nadolol, pindolol, propranolol, timolol
What is a classic histologic finding of rheumatic fever?
It can lead to damage of the heart valves (mitral > aortic»_space; tricuspid). Aschoff bodies (granulomas with giant cells), Anitschkow cells (enlarged macrophages with ovoid, wavy, rod-like nucleus) are commonly seen. The murmur is usually a late diastolic murmur with delayed rumbling.
Which heart valve is most likely damaged in IV drug users?
The tricuspid valve, usually tricuspid regurgitation due to tricuspid endocarditis. This results in a holosystolic, high-pitched blowing murmur. It is enhanced by maneuvers that increase RA return (like inspiration).
What are characteristics of septic shock?
Patients generally have high cardiac output and low SVR. The low SVR is due to inflammatory mediators released causing vasodilation, often presenting as flushing of the skin. Cardiac output is generally 4-8 L/min.
Which lipid-lowering agent results in most significant decrease in triglycerides?
Fibrates (like gemfibrozil). The are ligands for the peroxisome proliferator-activated receptor-alpha (PPAR-alpha) protein, a receptor that regulates the transcription of genes involved in lipid metabolism. Increase PPAR results in increased expression of LPL on endothelial cells and thus increased clearance of TG-rich lipoproteins. Also has the effect of increasing HDL synthesis.
What is the mechanism of calcium-channel blockers?
Amlodipine, nimodipine, nifedipine (dihydropyridine); diltiazem, verapamil (non-DHP) - block voltage-gated Ca++ channels (L-type) of cardiac and smooth muscle, thereby reducing muscle contractility. They close the channels during Phase 2 of the AP. Drugs like verapamil slows conduction through AV node via calcium channel blocking.
What is Kawasaki’s disease?
It is an acute necrotizing vasculitis of medium to small muscular arteries, usually affecting children <5 years old. This is the only condition in which you should given children aspirin with a high fever. IV immunoglobins should also be considered. The condition can present with fever, cervical lymphadenitis, conjuctival infection, strawberry tongue, and hand-foot erythema.
What is first line therapy for severe hypertriglyceridemia (increased blood levels of VLDL, TG)?
Fibrates and nicotinic acid.
What is secreted by carcinoid tumors?
Serotonin. This leads to flushing, watery diarrhea, and right-side valvular lesions. 5-HIAA is a metabolite of serotonin that can be detected in urine. Carcinoid tumors and IV drug use are likely pathology with pathology involving right-sided valves.
What is quinidine?
This is a sodium-channel blocker, Class I antiarrythmic. It slows or blocks conduction especially in depolarized cells. It decreased slope of Phase O and increases threshold of firing in abnormal pacemaker cells. Toxicity can cause torsades de pointes.
What is torsades de pointe?
It is a polymorpic ventricular tachycardia, characterized by shifting sinusoidal waveforms. Often caused by prolonged QT interval due to drugs, decreased K+, decreased Mg++, and other abnormalities. Treat with magnesium sulfate.
What is the most effective treatment for low HDL cholesterol levels?
Niacin is excellent for patients with low HDL (normal is >40 mg/dL for men). Niacin inhibits lipolysis in adipose tissue, reduces hepatix VLDL synthesis. It can cause hyperglycemia (FFA have undergone “rebound” from suppression and TG increase in skeletal muscle –> some lipase breaks this down into diacylglycerol, which activated PKC –> insulin receptors become flooded with serine phosphorylation, which impairs tyrosine phosphorylation, thus limiting the uptake of glucose) and hyperuricemia.
How does amiodarone work and what are potential complications?
It is a class III antiarrythmis - K+ channel blocker. It serves to increase AP duration and increase effective refractory period. It can increase QT interval, lead to pulmonary fibrosis, hepatotoxicity, hyper or hypothyroidism, corneal deposits, skin deposits resulting in photodermatitis, neurological effects, constipation, cardivascular effects (bradycardia, heart block, CHF)
What can cause a hypertensive crisis in a patient being treated with depression?
Taking an MAOI like tranylcypromine, phenelzine, iscocarboxazid, or selegiline with a food containing tyramine (eg. wine, cheese, chocolate, soy sauce, aged meats). Hypertensive crisis has the following symptoms: headache, disorientation, dilated pupils, tachycardia, and systolic blood pressure >170.
What is polyarteritis nodosa (PAN)?
It is characterized by necrotizing immune complex inflammation of medium-sized, muscular arteries. PAN typically is associated with fever, malaise, weight loss, abdominal pain, headache, myalgias, and hypertension. Inflammation of the arterial wall and surrounding connective tissue, resulting from immune complex formation and deposition, is associated with fibrinoid necrosis and leads to loss of elasticity. This fibrinoid necrosis can also lead to transmural inflammation of the arterial wall.
What is the most common cause of subacute bacterial endocarditis?
Viridans streptococci. It can be treated with penicillin. It leads to endocarditis commonly affecting the mitral valve. The tricuspid valve is associated with IV drug abuse.
What is the sympathetic effect on dromotropy of the heart?
There is a positive dromotropic effect due to increased inward Ca++ current. This is an increase in conduction velocity through the AV node.
What is Kussmaul’s sign?
It is a paradoxical rise in JVP on inspiration. It is usually a sign of limited right ventricular filling due to RHF or pericardial effusion (blood cannot enter the RA upon inspiration because of all the fluid surrounding the heart)
What is fibrinoid necrosis?
It is amorphous and pink on H&E. Examples are vasculitides (Henoch-Schonlein purpura, Churg-Strauss syndrome), malignant hypertension. It is usually a result of leakage of fibrin from epithelial cells.
An MI presents with ____.
ST-segment elevations on ECG. Also substernal chest pain with diaphoresis and dyspnea.
What are the features of type IIa-familial hypercholesterolemia?
There is increased blood levels of LDL and cholesterol due to absent or defective LDL receptors. Homozygotes have cholesterol levels over 700. Patients can present with xanthomas (plaques or nodules composed of lipid-laden histiocytes in the skin, especially eyelids). or on the Achiles tendon (tendinous xanthomas). Corneal arcus is also common - opaque ring around iris - it is a lipid deposit in the cornea.
What are the derivatives of each aortic arch?
1st - part of maxillary artery (branch of external carotid); 1st arch is maximal
2nd - stapedial artery and hyoid artery, Second = Stapedial
3rd - Common carotid artery and proximal part of the internal carotid artery, “C is the 3rd letter of the alphabet”
4th - on the left, aortic arch; proximal part of right subclavian artery, “4th arch (4 limbs) = systemic”
6th - proximal part of pulmonary arteries and (on left) ductus arteriosus
Where does intermittent claudication normally occur?
It usually occurs in arteries particularly where there is high turbulent flow like the iliac, femoral, popliteal, tibial, and peroneal arteries. Calf pain while walking is usually narrowing of popliteal artery. Medical therapy such as antiplatelet drugs may help and revascularization may be left for more severe cases.
What does massaging the carotid sinus do?
This stimulates the firing of baroreceptors in the carotid sinus (respond to stretching of the arterial wall - if arterial pressure rises, the walls of these vessels passively expand and the receptors fire). The baroreceptors synapse in the medulla, leading to autonomic changes that leads to decrease in heart rate due to slowed conduction through SA and AV nodes as a result of increased parasympathetic activity.
What drug can cause peaked T waves and prolonged PR intervals?
Spironolactone (aldosterone receptor antagonist - aldo normally aids in secretion of K+ and reabsorption of water and Na+). This is a potassium-sparing diuretic that inhibits potassium secretion at the cortical collecting duct leading to hyperkalemia.
What beta blocker used to treat arrythmias prolongs the repolarization phase of the cardiac action potential?
Sotelol - an antiarrhythmic with classes II and III properties. As a class III, it prolongs repolarization by blocking outward K+ conductance. This can lead to long QT. Amiodarone is another class III.
What is MPA?
It is microscopic polyangiitis. This is a small vessel vasculitis (like Wegener’s). It commonly involves the kidneys, skin, and lungs with pauci-immune glomerulonephritis and palpable purpura. MPO-ANCA/p-ANCA are detectable.
What is a common cause of aortic dissection?
HTN, cystic medial necrosis associated with Marfan’s syndrome, which typically causes ascending aortic aneurysms.
What is an aortic dissection?
It is a longitudinal intraluminal tear forming a false lumen. It can present with tearing chest pain of sudden onset, radiating to back with markedly unequal BP in arms. CXR shows mediastinal widening.
What heart medication should be (theoretically) avoided in diabetic patients?
Beta-blockers like metoprolol because they can mask the effects of hypoglycemia like tachycardia.
What is Beck’s triad and what is it a sign of?
It is jugular venous distention, hypotension, and muffled heart sounds which is a sign of tamponade. Patients will often also have pulsus paradoxus.
What is cardiac tamponade and what is the treatment?
It is compression of heart by fluid in pericardium, leading to decreased CO. There is an equilibration of diastolic pressure in all 4 chambers. It is treated with a pericardiocentesis.
What is a complication of nitroglycerine withdrawal?
It is a vasodilator, so withdrawal can lead to vasoconstriction, which can be unopposed in critical areas such as the coronary vessels, leading to nonatherosclerotic-related ischemia. Toxicity can lead to reflex tachycardia, hypotension, flushing, and headache.
What is cinchonism?
It is a pathologic condition caused by an overdose of quinidine of its natural source. Symptoms include flushed or sweaty skin, ringing of ears, blurring of vision.
