Renal scenarios Flashcards
The earliest sign of CKD is
a) microscopic hematuria
b) HTN
c) proteinuria
d) abnormal creatinine
e) hyperkalemia
c: Injury to the nephron results in excessive protein leak and decreased protein reabsorption from the tubules. This occurs long before the creatinine becomes abnormal and 5 to 10 years before overt proteinuria, detectable by routine dipstick, develops. Persistent proteinuria eventually will results in an abnormal creatinine but, in the case of CKD, years later. Therefore, proteinuria, best assessed by the protein to creatinine ratio from a urine specimen, is considered the earliest marker of CKD. Microscopic hematuria can result from many processes, some transient, including infection, malignancy, calculi, acute GN, and IgA nephropathy, and is not, in and of itself, an indicator or permanent kidney damage. HTN , if not the cause of CKD, can occur early in the course of CKD, but proteinuria usually occurs before HTN develops. Chronic hyperkalemia develops later in the course of CKD, generally when GFR is
Assuming that a pt has maintained a normal baseline creatinine of 1.0 mg/dL with a normal DFR of 100 mL/min, which of the following indicates a more significant change in the GFR?
a) increase in creatinine from 1.0 to 2.0 mg/dL
b) increase in creatinine from 2.0 to 4.0 mg/dL
c) increase in creatinine from 4.0 to 8.0 mg/dL
d) increase in creatinine from 8.0 to 16.0 mg/dL
a: GFR describes the amount of blood passing through the kidneys per minute. There is an inverse relationship between GFR and serum creatinine. In a pt with normal renal function, doubling of the serum creatinine represents a loss of approx 50% GFR. Using this info, the loss of GFR can be estimated from changes in the serum creatinine. For example, assume normal creatinine levels of 1.0 mg/dL and normal GFR of 100 mL/min. A doubling of the serum creatinine from 1.0 to 2.0 mg/dL represents an approximate reduction in GFR from 100mL/min to 50 mL/min (50% GFR has been lost). Each additional doubling of the creatinine decreased the remaining GFR by approx on half. When renal function is severely impaired, large increases in the creatinine (i.e., from 8.0 to 16.0 mg/dL) represent only small decreases in GFR (i.e. from about 12 to 6 mL/min). This example emphasizes the importance of detecting increases in serum creatinine early. However, serum creatinine level does not become abnormal until ~25% of renal function is lost. Therefore, other methods of estimating GFR are more useful in detecting early decreases in GFR.
Which of the following urinary findings is suggestive of acute glomerulonephritis?
a) red cells and red cell casts
b) white cells and white cell casts
c) renal tubular epithelial cells
d) oval fat bodies
e) hyaline casts
a: Casts in the urine indicate a pathologic process, with the exception of the presence of rare hyaline cast. The acute inflammatory process of GN is characterized by red cells and red cell casts in the urine. White cells and white cell casts occur with an allergic or infectious process, s/a acute interstitial nephritis or pyelonephritis, respectively. Renal tubular epithelial cells indicate damage to the renal tubules, as with acute tubular necrosis. Oval fat bodies (Nephrotic syndrome) result from renal tubular cells that have absorbed fats or monocytes and macrophages that have ingested fats.
In pts with known CKD, which of the following is an absolute indication to initiate dialysis?
a) proteinuria >3g/24H
b) GFR5.0 mEq/L
d) seizures
e) hyperphosphatemia > 6.5 mg/dL
d: The development of seizures d/t uremia is an absolute indication to begin hemodialysis. The waste products of urea metabolism must be removed to abort the seizure activity. Proteinuria is a sign of kidney damage, poses no immediate threat to life, and hemodialysis will not correct it. Calculations of GFR are used to assess kidney function, predict when complications of CKD and ESRD will occur., and guide treatment plan but not to indicate when to initiate hemodialysis. Rather, the decision to initiate renal replacement therapy is a clinical one, based upon clinical assessment of functioning and physical manifestations of ESRD. A potassium level of >5 mEq/L does not represent an immediate threat to the pt and can be tx medically. Hyperphostphatemia is best tx with phosphate binders, s/a calcium carbonate and calcium acetate, and low phosphate diet.
A renal ultrasound would be most beneficial for dx which of the following?
a) nephrotic syndrome
b) polycystic kidney disease
c) glomerulonephritis
d) acute tubular necrosis
e) lupus nephritis
b: Renal ultrasound is useful for assessing kidney size and thickness of the cortex, and for the presence of masses, cysts, obstruction, and hydronephrosis. Intrinsic disease is best assessed by establishing the clinical context, analyzing the urine for protein, casts, and cells, and possibly by doing a biopsy. Loss of cortical thickness is a nonspecific finding, and ultrasound does not establish an etiology.
Which of the following types of renal calculi is associated with an infectious cause?
a) struvite
b) uric acid
c) calcium oxalate
d) cystine
e) calcium phosphate
a: Struvite stone form when urea-splitting organisms, such as Proteus, Klebsiella, Pseudoomonas, and Staphylococcus, are present in the urinary tract. Ammonia is formed when urease breaks down urea. This results in an alkaline urine, which decreases the solubility of strive, favoring the production of stones. Calcium stones result from hyper absorption of calcium in the intestine, impaired renal tubular reabsorption of calcium, primary hyperparathyroidism, intestinal hyper absorption of oxalate, and hypocitraturia. Uric acid stones are d/t hyperuricosuria or a urinary pH
Hyperphostphatemia is associated with stage 3 CKD. Which of the following is the appropriate tx for mild hyperphosphatemia in this pt population?
a) magnesium oxide
b) calcium carbonate once daily on an empty stomach
c) calcium carbonate 3 times daily on an empty stomach
d) calcium carbonate 3 times daily with meals
e) no tx indicated
d: Hyperphosphatemia develops in pts with CKD because of impaired renal excretion as GFR declines. Consequently, this results in down regulation of some phosphate transporters, a decrease in vitamin D production due to inhibition of an enzyme system that activates vitamin D, and an increase in PTH production. Also, as synthesis of 1,25 D declines in the kidney, calcium absorption decreases further. Excess phosphorus complexes with calcium in the blood, decreasing ionized calcium levels, which results in hypocalcemia. As a result, PTH is further stimulated in attempt to increase serum calcium levels. This eventually results in secondary hyperparathyroidism (sHPT), renal osteodystrophy as calcium is drawn out of the bones to maintain a normal serum level, and extraosseous calcification of soft tissues due to calcium -phosphorus complexes. Tx should be initiated early to prevent these long term complications. Calcium carbonate binds phosphorous in the intestine before it can be absorbed and decreases serum levels. This must be taken with meals to bind dietary phosphorous. A synthetic phosphate binder, sevelamer, can also be utilized. This most effective regimen is 0.5 to 1.5 g po taken at the start of each meal.
Which of the following complications are associated with stage 3 kidney disease?
a) no notable complications
b) acid-base abnormalities
c) HTN only
d) anemia, disorders of calcium and phosphorus metabolism
e) fluid and electrolyte abnormalities
d: Stage 3: GFR 30-59 mL/min; complications include anemia, HTN, malnutrition, disorders of calcium and phosphorus metabolism, reduced functioning and well-being, neuropathy; screen for and tx complications as appropriate, avoid nephrotoxins, control CVD risk factors, adjust doses of renally excreted meds.
A pt with an estimated GFR of 72 mL/min is in what stage of kidney disease?
a) Stage 1
b) Stage 2
c) Stage 3
d) Stage 4
e) Stage 5
b: enough said.
A 46yo man with a hx of ETOH abuse is brought to the ER in the morning by his wife. She has noted that he has developed tremors in both arms, and he seems mildly confused to her. He complains of feeling weak, with some cramping in the legs. On physical exam, his BP is 162/95, and his HR is 108 BPM. there is not asterixis. Which of the following electrolyte disorders are you likely to find in this pt?
a) hypercalcemia
b) hypocalcemia
c) hypermagnesemia
d) hypomanesemia
e) hyperphosphatemia
d: HYPOMAGNESEMIA is a common finding in a pt who abuses alcohol. Other leading causes include diarrhea, diuretics, ahminoglycosides, and amphotericin B. The etiology of hypomagnesemia in the pt with a hx of alcohol abuse is thought to be a combination of malabsorption and inadequate dietary intake, possibly with alcohol exerting an antagonistic effect of absorption. Signs and symptoms are those of neuromuscular and central nervous system hyper irritability including weakness, muscle cramps, tremors, nystagmus, positive babinski response, confusion, disorientation.
A 65yo woman with DM and PVD is about to undergo a diagnostic radiographic procedure involving the use of IV contrast dye. Her serum creatinine is 1.9. An appropriate action prior to the procedure would be to
a) start an ACE I
b) administer a 1000 cc bolus of normal saline and acetylceysteine po
c) administer a 1000 cc bolus of normal saline only
d) adminiter IV diuretic
e) no specific pre procedure tx is needed
b: This pt has CKD with an elevated creatinine feel of 1.9 mg/dL. Her kidney function can worsen if exposed to any nephrotoxins, including contrast dye and some medications s/a aminoglycosides, amphotericin B, NSAIDS, cisplatin, and cyclosporine. The mechanism of injury from contrast dye is thought to be d/t renal vasoconstriction, possibly mediated by alterations in the amount of NO and/or endothelin present, which results in ischemia. In addition, there are also direct toxic effects of the contrast ages on the renal cells. A byproduct of the renal injury is oxygen-free radicals, which are important modulators of renal perfusion and GFR. Maintaining adequate hydration protects the glomeruli in the presence of vasoconstriction, therefore, providing a pre procedure fluid bolus of 1L is appropriate. In addition, acetylcysteine has been found to have a potentially protective effect as well. It improves endothelin-dependent vasomotor function in the coronary peripheral circulation and is also a potent antioxidant that may result in scavenging of free radicals.
You have just received labs back on a 43yo woman with severe vomiting and no oral intake in the last 3 days. You not a metabolic alkalosis, based on her arterial blood gasses. You also note that compensatory changes are present. Which of the following best represents these changes? (Normal PCO2= 35-45 mmHg; normal HCO3= 24-31 mEq/L)
a) PCO2= 32
b) PCO2= 38
c) PCO2= 47
d) HCO3= 38
e) HCO3= 24
c: With any acid-base disorder, the body tries to compensate to restore pH to normal. BY definition, an alkalosis is characterized by a pH of >7.45. This pt has sustained losses of acid (HCl, NaCl, KCl) through vomiting. In addition, volume contraction results in a decrease in GFR, which causes avid sodium and bicarbonate reabsorption, further worsening the alkalosis. The body has two ways to increase serum levels of acid to try to decrease the pH to normal: the lungs slow the respiratory rate to retain CO2 and/or the kidneys reabsorb Cl and and H and increase excretion of bicarbonate (HCO3). The lungs can respond more quickly and therefore, PCO2 will rise before serum HCO3 will drop.
What is the most common electrolyte abnormality seen in hospitalized pts?
a) hypokalemia
b) hyperkalemia
c) hyponatremia
d) hypernatremia
e) hypomagnesemia
c: Hyponatremia affects approv 20% of hospitalized pts and is the MC electrolyte abnormality found in this population. Hypokalemia is 2nd at 13%
The most serious consequence of rapid correction of hyponatremia is
a) brainstem herniation
b) central pontine myelinolysis
c) muscle cramps
d) hypernatremia
e) fluid overload
b: Hyponatremia is defined as serum sodium concentration
When adjusting medication dosing for pts with CKD, which of the following factors is the least important?
a) serum BUN level
b) serum creatinine level
c) age
d) weight
e) gender
a: Because many drugs are excreted in the urine, knowledge of the final function is important when dosing medication, especially in pts with abnormal GFR. Drug toxicity or adverse SE may occur if the frug is dosed improperly. Estimation of creatinine clearance can help in making the proper drug adjustment for the degree of CKD. Use the Cockcroft-Gault equation. The BUN is not a reliable index, because several factors may alter tubular reabsorption, or generation, of urea. These include the patient’s hydration status, protein intake, and degree of catabolic activity occurring.
