Kidney Function & Glomerular Filtration Practice Quiz

Practice Quiz #3 - Study Notes

• Question 1: Estimating glomerular filtration rate (GFR) using plasma creatinine concentration relies on the assumption that the person providing the sample has average muscle mass and activity. Creatinine levels are reduced in individuals with sarcopenia (muscle loss), especially older adults.

• Question 1 (Incorrect Options): Fasting and withholding fluids, normal cholesterol/lipid levels, and simultaneous BUN (blood urea nitrogen) measurement are not critical assumptions for GFR estimation using creatinine. Although BUN/creatinine ratio is used to identify prerenal failure, creatinine alone is sufficient for most GFR estimations.

• Question 2: Diuretics reduce edema by blocking the Na+/Cl− cotransporter in the distal tubule, which increases sodium excretion.

• Question 3: A large increase in serum creatinine in a septic patient suggests prerenal kidney damage due to inadequate renal blood flow. Acute, not chronic, kidney injury is more likely in this context.

• Question 4: A 43-year-old male with diabetes and a BMI of 38 is at highest risk for kidney stones (nephrolithiasis) due to the presence of three risk factors (male, obesity, and diabetes).

• Question 5: Hypertension is a potential renal complication of strep throat infection, potentially due to poststreptococcal glomerulonephritis.

• Question 6: Decreased glomerular filtration rate (GFR) is a major factor contributing to increased medication toxicity in older adults.

• Question 7: Increased urinary albumin to creatinine ratio in diabetic nephropathy is due to destruction of the glomerular filtration barrier by advanced glycation end products (AGEs).

• Question 8: Arginine vasopressin (AVP) or antidiuretic hormone (ADH) increases to compensate for hypervolemia and hypertension to reduce urine output and increase water retention.

• Question 9: An ICU patient with sepsis is at greatest risk for prerenal kidney injury due to decreased renal perfusion caused by hypotension.

• Question 10: Chronic hypertension causes kidney damage by increasing nephron hyperfiltration and thickening of the afferent arteriole walls. This is a consequence of elevated perfusion pressure and not the other way around.

• Question 11: A major factor associated with increased risk of later-life kidney disease after preterm birth is the lower number of nephrons present at birth.

• Question 12: A slow and regular pulse rate (bradycardia) is not a component of atrial fibrillation. Atrial fibrillation is characterized by high and irregular pulse rate.

• Question 13: Troponin is a key cardiac biomarker that becomes elevated within 6 to 12 hours from myocardial damage and peaks around 24 hours.

• Question 14: In left-sided heart failure with a reduced ejection fraction (HFrEF), dyspnea is caused by pulmonary congestion stimulating lung receptors. This leads to the sensation of shortness of breath.

• Question 15: Neurohormonal compensation in heart failure involves various mechanisms that worsen the condition.

• Question 16: Stable angina is chest pain upon exertion that improves upon rest. Symptoms such as syncope or diminished S2, often indicate another diagnosis, not angina.

• Question 17: Prolongation of the QT interval is the most concerning change in the aging heart due to increased risk of arrhythmias and mortality.

• Question 18: Supraventricular tachycardia due to Wolff-Parkinson-White (WPW) syndrome is associated with an accessory pathway between the atria and ventricles.

• Question 19: Atrial fibrillation is not characterized by a slow (bradycardic) and regular pulse rate.

• Question 20: Preload increases in HFrEF as a compensatory mechanism to shift ventricular volume to the right, improving stroke volume.

• Question 21: Elevated troponin levels differentiate a non ST-elevation myocardial infarction (NSTEMI) from unstable angina (UA).

• Question 22: Inhibiting the enzyme neprilysin, with drugs like sacubitril, increases blood levels of BNP and bradykinin, leading to vasodilation and natriuresis, which improves heart function.

• Question 23: A murmur beginning just after the S1 sound and ending just before the S2 sound is a common finding in chronic mitral regurgitation.

• Question 24: Administering NSAIDs to a pregnant mother can cause premature closure of the ductus arteriosus in the fetus and cause fetal hypoxia.

• Question 25: The unique elastic tissues in large arteries such as the aorta allows them to recoil and support diastolic pressure and flow. Elastin proteins assist the expansion of the vessel during ventricular ejection.

GFR estimation relies on normal muscle mass. Diuretics reduce edema by blocking the Na+/Cl− cotransporter, increasing sodium excretion. A large increase in serum creatinine in a septic patient suggests prerenal kidney damage.