USMLE and COMLEX Review Nephrology Supplement Glomerulonephritis, Acute Tubular Necrosis and Acute Interstitial Nephritis Northwestern Medical Review www.northwesternmedicalreview.com Lansing, Michigan 2014-2015 1. What is Tamm-Horsfall glycoprotein (THP)? Matching (4 – 15): Match the following urinary casts with the descriptions, conditions, or questions _______________________________________ presented hereafter: _______________________________________ A. Bacterial casts _______________________________________ B. Crystal casts _______________________________________ C. Epithelial casts D. Fatty casts _______________________________________ E. Granular casts _______________________________________ F. Hyaline casts G. Pigment casts H. Red blood cell casts 2. What is a urinary cast? I. Waxy casts J. White blood cell casts _______________________________________ _______________________________________ 4. These types of casts are by far the most common _______________________________________ urinary casts. They are composed of solidified Tamm-Horsfall mucoprotein and secreted from _______________________________________ tubular cells under conditions of oliguria, _______________________________________ concentrated urine, and acidic urine. _______________________________________ _______________________________________ _______________________________________ 5. These types of casts are pathognomonic of acute tubular necrosis (ATN) and at times are 3. What are the major types of urinary casts? described as “muddy brown casts”. _______________________________________ _______________________________________ _______________________________________ _______________________________________ _______________________________________ 6. A 6-year-old girl is admitted to the emergency department with fever, and puffy face, eyes, and trunk. Blood pressure taken on admission is 180/120. Her mother states that 10 days ago she had a sore throat, and she has voided very little urine within the past 24 hours. Serology of the patient is significant for high antistreptolysin O titers and low Complement C3. Urinalysis of the child is most likely indicative of which type of cast? _______________________________________ 7. Presence of these types of urinary casts is often indicative of tubulointerstitial nephritis. _______________________________________ 8. Distinction of leukocytic casts from epithelial casts is sometimes difficult. What urinary test often helps to confirm presence of leukocytic casts? _______________________________________ _______________________________________ _______________________________________ _______________________________________ 13. These types of urinary casts are often seen in 9. What urinary test is indicative of bacteriuria? patients with rhabdomyolysis and conjugated urobilinemia. _______________________________________ _______________________________________ _______________________________________ _______________________________________ 14. What is the best description for the cast seen in the picture below? _______________________________________ _______________________________________ _______________________________________ _______________________________________ 10. These casts are the second most common casts. The "muddy brown cast" seen in acute tubular necrosis is a type of this cast. 15. What do these two pictures depict and what is wrong with them? _______________________________________ _______________________________________ 11. These casts are indicative of very low urine flow and they are associated with severe, 16. What is the description of acute tubular necrosis longstanding kidney disease and renal failure. (ATN)? They are notably larger than hyaline casts. _______________________________________ _______________________________________ _______________________________________ _______________________________________ 17. What is the most common cause of acute renal injury (AKI)? 12. These caricature urinary casts are seen with _______________________________________ polarized microscopy of the urine of a patient with nephrotic syndrome. 18. What are the common causes of ATN? _______________________________________ _______________________________________ _______________________________________ 24. Distinguishing prerenal azotemia from acute tubular necrosis is important in clinical settings _______________________________________ because fluid resuscitation often alleviates _______________________________________ prerenal azotemia but is ineffective for treating ATN. What lab measurement would help to _______________________________________ differentiate the two conditions from each other? _______________________________________ _______________________________________ _______________________________________ _______________________________________ _______________________________________ 19. What are the key findings in ATN? _______________________________________ _______________________________________ _______________________________________ _______________________________________ _______________________________________ _______________________________________ _______________________________________ 25. How do we measure FeNa+? _______________________________________ _______________________________________ _______________________________________ 20. What is the key pathognomonic cast seen in _______________________________________ urinalysis of patients with ATN who present _______________________________________ urinary tubular epithelial cells? _______________________________________ _______________________________________ _______________________________________ 21. What is the treatment for ATN? _______________________________________ _______________________________________ _______________________________________ 22. Of the two types of ATN, ischemic and toxic, one 26. Which of the two improves rapidly in response to of the two causes “skip” lesions at various parts administration of large volume of IV fluids; ATN, of the nephrons, including proximal and distal or prerenal azotemia? tubules. Which type is it? _______________________________________ _______________________________________ _______________________________________ _______________________________________ _______________________________________ 23. Kidney failure is defined as prerenal, renal, and 27. What is the difference between blood urea and postrenal. Which of the three types is similar to blood urea nitrogen? ATN? _______________________________________ _______________________________________ _______________________________________ _______________________________________ _______________________________________ _______________________________________ 28. What is the source of blood urea? BUN to Creatinine Ratios and their Attributes _______________________________________ Greater than 20:1 _______________________________________ Prerenal BUN reabsorption is increased. _______________________________________ BUN is disproportionately elevated relative to creatinine in serum. Dehydration is suspected. 29. What is the source of blood creatinine? _______________________________________ Between 10:1 and 20:1 Normal or postrenal _______________________________________ Normal range. Can also be postrenal disease. BUN reabsorption is within normal limits. 30. What is the physiologic significance of the BUN to creatinine ratio? Less than 10:1 _______________________________________ Intrarenal _______________________________________ Renal damage causes reduced reabsorption _______________________________________ of BUN, therefore lowering the BUN:Cr ratio. _______________________________________ 34. A 25-year-old African-American medical student _______________________________________ plans on visiting Kenya as part of his international medical training program. He received a prescription for chloroquine and was 31. What is the normal BUN to creatinine ratio? advised to start the medication 10 days prior to _______________________________________ his departure. Two days after taking the medication the patient is admitted to the hospital _______________________________________ with the complaint of shortness of breath, pallor, jaundice, and low volume and dark urine. Serology of the patient is significant for 32. What major factors increase or decrease BUN to bilirubinemia and inclusions within the red cells. creatinine ratio? What is the LEAST LIKELY urinary finding in this _______________________________________ patient? _______________________________________ _______________________________________ _______________________________________ _______________________________________ A. Hemoglobinuria 33. What is the most important clinical value of the B. Unconjugated bilirubinuria BUN to creatinine ratio? C. Epithelial casts _______________________________________ D. Muddy brown casts E. High levels of urinary sodium _______________________________________ _______________________________________ _______________________________________ 35. Why does urinalysis show epithelial and muddy 39. In addition to FeNa of more than 2% in ATN and brown casts in ATN? less than 1% in prerenal azotemia, the two _______________________________________ conditions are often characterized by their urinary sediments. How are they differentiated by their _______________________________________ sediments? _______________________________________ _______________________________________ _______________________________________ _______________________________________