Renal tubular defects: Pathology review

7,218views

00:00 / 00:00

Questions

USMLE® Step 1 style questions USMLE

of complete

A 58-year-old woman comes to the clinic complaining of headaches, palpitations, and muscle pain for the last 2 months. The patient’s medical history is non-contributory, and she is not currently taking any medications. The patient’s temperature is 37°C (98.6°F), pulse is 80/min, respirations are 16/min, and blood pressure is 186/92 mmHg. The physician prescribes lisinopril 10 mg and recommends a follow up in one month. One month later, the patient returns to the clinic with persistent symptoms. Upon further questioning, the patient admits to consumption of five cups of Egpytian licorice tea daily for the past six months. Laboratory tests are obtained, and the results are shown below:  
 
Laboratory value  Result 
Blood, serum, plasma 
Potassium   3.2 mEq/L 
 Bicarbonate  44 mEq/L 
 Aldosterone  decreased 
 Renin  decreased 
Which of the following enzymes is most likely inhibited in this patient?

Summary

Renal tubular defects refer to a group of disorders that affect the tubules of the kidneys. These tubules are responsible for filtering waste products from the blood, reabsorbing essential nutrients, and regulating the balance of electrolytes in the body. When these tubules are damaged or malfunctioning, they can lead to a variety of symptoms and complications, such as electrolyte imbalances, acid-base disturbances, and kidney failure. Some examples of renal tubular defects include Fanconi syndrome, Bartter syndrome, and Gitelman syndrome.

In Fanconi syndrome, there is a dysfunction of the proximal convoluted tubule (PCT), which results in the excretion of all substances normally reabsorbed by the PCT, such as glucose, bicarbonate, etc. In Bartter syndrome, there are defects in Na+/K+/2Cl- cotransporter in the thick ascending loop of Henle, which lead to metabolic alkalosis, hypokalemia, and hypercalciuria. Finally, in Gitelman syndrome, there is defective reabsorption of sodium chloride in the distal convoluted tubules (DCT), which leads to metabolic alkalosis, hypomagnesemia, hypokalemia, and hypocalciuria. Treatment options may include medications, dietary changes, and in some cases, kidney transplants.

Sources

  1. "Robbins Basic Pathology" Elsevier (2017)
  2. "Harrison's Principles of Internal Medicine, Twentieth Edition (Vol.1 & Vol.2)" McGraw-Hill Education / Medical (2018)
  3. "Practical Renal Pathology, A Diagnostic Approach E-Book" Elsevier Health Sciences (2012)
  4. "Physiology E-Book" Elsevier Health Sciences (2017)
  5. "The Renal System" Churchill Livingstone (2010)
  6. "Nephrolithiasis related to inborn metabolic diseases" Pediatric Nephrology (2009)
  7. "Hnf4a deletion in the mouse kidney phenocopies Fanconi renotubular syndrome" JCI Insight (2018)
  8. "Fanconi Syndrome" Pediatric Clinics of North America (2019)
Elsevier

Copyright © 2024 Elsevier, its licensors, and contributors. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

Cookies are used by this site.

USMLE® is a joint program of the Federation of State Medical Boards (FSMB) and the National Board of Medical Examiners (NBME). COMLEX-USA® is a registered trademark of The National Board of Osteopathic Medical Examiners, Inc. NCLEX-RN® is a registered trademark of the National Council of State Boards of Nursing, Inc. Test names and other trademarks are the property of the respective trademark holders. None of the trademark holders are endorsed by nor affiliated with Osmosis or this website.

RELX