Week 2 Flashcards
Which of the following would you predict to worsen an individual’s edema? 1) Malnutrition 2) Elevated blood pressure 3) Local infection 4) Tight socks
Malnutrition (decreased plasma protein content), increased blood pressure (increased capillary hydrostatic pressure) and local infection (increased capillary protein permeability) might worsen edema. Can think about it as: forces pushing fluid out of capillary are capillary hydrostatic pressure (mean arterial pressure) and interstitial osmotic pressures, forces keeping fluid in capillary are capillary osmotic pressure (plasma protein content) and interstitial hydrostatic pressure (stocking). Capillary barrier protein “leakiness” aka the reflection coefficient is influenced by inflammation (eg, infection, burns).
You are taking care of a patient who is taking an a1 blocker for benign prostatic hyperplasia. As such, your preceptor tells you to make sure to take the patient’s blood pressure standing as well as sitting. Why?
Standing leads to blood pooling in the lower extremities, decreasing venous return, decreasing mean arterial pressure, and activating the baroreceptor reflex to increase sympathetic outflow (constrict arterioles and veins, increase heart rate/contractility). Blocking the alpha-1b receptors on blood vessels will mitigate the ability to respond to BP changes, thus these drugs can lead to postural hypotension.
A patient with heavy menses and persistent bleeding after a wisdom tooth extraction presents for evaluation. A ristocetin test reveals no platelet aggregation (abornmal), and she is found to lack a protein involved in platelet rolling. She responds to desmopressin. What is the protein deficit in this case, and what is the drug’s mechanism of action?
von Willebrand Factor (VWF) – normally functions in platelet rolling, activated by ristocetin (thus in vitro assay will cause platelet clumping if VWF and GP1b are present – GP1b can be absent in Bernard-Soulier disease). Von Willebrand disease is relatively common and response to desmopressin, which stimulates VWF release from endothelial cells, confirms the diagnosis.
Which of the following factors is likely to decrease the affinity of Hb for oxygen? 1) Increased pH 2) Increased 2,3-BPG 3) Increased temperature
Factors that will decrease Hb oxygen affinity (facilitate O2 offloading from Hb) include decreased pH, increased 2,3 bpg, and increased temperature. Can be helpful to think about the contexts where this might happen: exercising tissue will need more oxygen – it will be warm and have low pH from accumulated lactate. The fetus needs to steal oxygen from mom’s circulation, and it does this by having more 2,3BPG.
You are rotating on hematology and are preparing to see a patient who has a prolonged PT but normal aPTT. Which factor(s) or clotting cascade proteins might be abnormal in this patient?
Most likely Factror VII – the only unique factor to the extrinsic pathway (tested by PT). Isolated aPTT abnormalitiy would suggest hemophilia, von Willebrand disease, or heparin use. If both are prolonged, consider FV, FX, fibrinogen, or oral anticoagulant use.
A patient with afib is started on an anticoagulant to prevent thromboembolic events. The next day, they go to the ER with massive skin and soft tissue necrosis. What drug were they started on, and what is the mechanism of this adverse effect?
Warfarin is a cheap and common anticoagulant. A feared adverse effect is warfarin gangrene/necrosis. Of the vitamin K-dependent factors, FVII and Protein C are the most quickly degraded. In a patient with low levels of Protein C or Protein S (anticoagulant factors) to begin with, whether due to diet or genetics, inhibiting vit K activity reduces the remaining anticoagulant protein levels and favors thrombosis. The orhter procoagulant factors will be cleared over a few days, thus this effect happens usually in the first day. Treatment: stop warfarin, give plasma and vit K.
Of the major lipid-lowering drug classes – statins, bile acid resins, ezetimibe, fibrates, niacin, PCSK9 inhibitors – which (2) have the strongest LDL-lowering effects? Which (1) can result in increased triglyceride levels? Which (1) most strongly increases HDL?
Statins and PCSK9 inhibitors most affect LDL. Bile acid resins can increase TG levels. Niacin is most strong increase in HDL, though most will have modest effects to increase HDL.
Are the biggest atherosclerotic plaques the most likely to rupture? Are young or old plaques more likely to lead to aneurysm (eg, AAA)?
The weakest (not necessarily biggest, and often not the biggest) plaques are most likely to rupture. That is, plaques with weak fibrous caps from matrix metalloproteases released by inflammatory cells. This can expose collagen and activate the coagulation cascade. Longstanding/old plaques are more likely than young plaques to give rise to aneurysms because the plaque increases the oxygen diffusion area to get through the media, and over time, this leads to atrophy/weakness of that musculature.
A group of 60 year-old men volunteered for evaluation in a cardiovascular study. All appeared healthy with no history of cardiovascular disease. The loop-labeled “Patient A” was recorded from a 60-year-old man who recounts a mild viral infection four weeks ago. The loop labeled “Control” was from another volunteer. When compared to the control loop, the left ventricular pressure-volume loop from patient A demonstrates which of the following changes?
a. Drug related increased contractility
b. Viral myocarditis-related increased end-systolic pressure
c. Increased pulmonary artery wedge pressure due to valvular diseased. Increased systemic vascular resistance from age-related vessel stiffening
e. Valve disease-related ventricular dilation
e. Valve disease-related ventricular dilation
Explanations:
E – Pt has incompetent aortic valve resulting in AR and LV dilatation. Regurgitant flow is evident from the isovolumetric phases of the graph (which are not isovolumetric – the volume increases when the valves should be closed). Pulse pressure also increases on the graph due to retrograde flow through an incompetent valve decreased DBP. Volume overload leads to increased compliance as the heart dilates.
A – Contractility decreases, B – end systolic pressure decreases, C – mean pulmonary artery wedge pressure is estimated by the end diastolic pressure – which is identical in both loops, D – DBP (which is largely determined by SVR) is lower in patient A than in the control
Card from 2018-2019 lectures
A 72-yr-old man with a history of type II diabetes and hypertension is brought to the ED because of sudden onset chest pain and dyspnea. His pulse is 110/min and blood pressure is 90/60 mm Hg. Cardiac auscultation reveals no murmurs, rubs, or gallops. Because of his hemodynamic instability, a central venous catheter is placed. The image shows the central line tracings from a normal patient during one cardiac cycle with corresponding aortic, left ventricular, and left atrial pressures. At which of the following points on the curve is the sarcomere length of the left ventricular muscle fibers the smallest?
A
B
C
D
E
F
C
Explanation: Sarcomere length is smallest when the left ventricle is at maximal contraction
Card from 2018 - 2019 lectures
A 65-yr-old woman presents to the ER with shortness of breath. She has a history of diabetes and myocardial infarction 2 years ago. Cardiac exam reveals a displaced point of maximal impulse. Pulmonary auscultation reveals bilateral crackles and decreased breath sounds. Examination of her neck reveals normal JVP. Which of the following physical exam findings is most likely associated with this patient’s condition?
a. S3
b. Ascites
c. Pedal edema
d. Spleen and liver enlargement
a. S3
Explanation: Left heart failure. C, and D are all right heart failure.
Card from 2018 - 2019 lectures
A middle-aged woman reports episodes of fainting and dizziness while standing at her job. Her seated blood pressure is 123/72 mm Hg and pulse is regular at 75/min. Hemodynamic studies are performed to evaluate her. Her blood volume is 4.2 L and resting cardiac output is 4.2 L/min. In the supine posture at rest, which of the following vascular structures will most likely contain the largest proportion of the total blood volume in this patient?
a. Aorta and larger arteries
b. Arterioles
c. Capillaries
d. Chambers of the heart
e. Pulmonary vasculature
f. Vena Cavae
g. Venules and veins
g. Venules and veins
Explanation: Just a fact that venous system has the most capacitance and is the reservoir for blood
Card from 2018 - 2019 lectures
A healthy 25-yr-old woman begins a program that includes weight lifting and high-intensity static exercise. Which of the following is most likely to occur within her skeletal muscles during contraction while performing this type of exercise?
a. Decreased blood flow and increased vascular resistance
b. Decreased extracellular potassium concentration
c. Increased arteriolar diameter and increased flow
d. Increased ADP/ATP ratio
e. Increased intracellular potassium concentration
a. Decreased blood flow and increased vascular resistance
Muscle contraction compresses and collapses vessels leading to increased resistance and decreased blood flow.
Card from 2018 - 2019 lectures
A 51-yr-old woman is admitted to the hospital for an elective cardiac catheterization because of a 9-month history of worsening fatigue and shortness of breath. The results of cardiac catheterization are shown:
Pulmonary artery pressure: 45/25 mmHg
Pulmonary wedge pressure: 30 mmHg
Left ventricular pressure: 120/5 mmHg
Aortic pressure: 120/80 mmHg
What is the most likely diagnosis?
a. Aortic regurgitation
b. Aortic stenosis
c. Mitral regurgitation
d. Mitral stenosis
e. Myocardial infarction
d. Mitral stenosis
Explanation: Elevated pulmonary capillary wedge pressure and elevated pulmonary artery pressure. Normal LVEDP that is unequal to the pulmonary wedge pressure. A pressure gradient between 5-30 mmHg is indicative of mitral stenosis.
Card from 2018 - 2019 lectures
A 25-year old woman comes to the physician for a routine exam. She is healthy and experiences no symptoms however on cardiac examination a mid-systolic click is heard. Which of the following valvular abnormalities is most likely present in this patient?
a. Ballooning of valve leaflets
b. Fibrous bridging between thickened, leaflets
c. Irregular beads of calcification in annulus
d. Large, bulky vegetation with adjacent leaflet perforatione. Tiny vegetations along the line of closure of valve leaflet
a. Ballooning of valve leaflets
Explanations
A – mitral valve prolapse, B – Mitral stenosis (rheumatic fever), C – Elderly individuals (normal aging), D – Acute bacterial endocarditis, E – Marantic (nonbacterial thrombotic) endocarditis
Card from 2018 - 2019 lectures
