Mrs. Gardner is 48 years old woman diagnosed with breast cancer. She has been enrolled in a
clinical research trial testing the effectiveness of a new chemotherapeutic agent. After her
second dose of the agent, she complains of feeling light-headed when she gets out of bed
in the morning. Her blood pressure is found to fall from 135/80 to 105/70 when she goes from
a supine to a standing position (i.e., orthostatic hypotension). She also complains of frequent
urination and nocturia. Routine urinalysis reveals her urine contains large quantities of sodium.
However, her serum creatinine level is within normal limits at 1.0 mg/dl.
1. On the basis of the urinalysis results, her doctor suspects that the chemotherapeutic agent damaged her kidneys. Based on the information above, which portion of the nephron is likely damaged, the glomerulus, the proximal tubule, distal tubule, or collecting duct? Explain the reason for your choice.
The major filteration is done by the glomerular capillaries present in the renal corpuscle. In the scenario mentioned it states that the serum creatinine levels are within the normal which indicates that the glomerular filteration rate is good however the large quantities of sodium are a result of damage of the proximal, distal and collecting tubule. Reason being as follows- Usually 60-70% of sodium reabsorption takes place in the proximal tubule of the nephron, the most essential substances are reabsorbed in the first half of the proximal tubule, by the time the filterate has reached the mid part of the proximal tubule 100% of filtered glucose, amino acids along with large amounts of sodium bicarbonate and phosphate have been absorbed. Sodium continues to be reabsorbed by loop of henle(25%), the early distal tube absorbs further 5% and the late distal tubule and the collection duct reabsorb a last lillte bit around 3% determining excatly how much sodium will be extracted. Therefore the proximal, distal and collectiong tubule all three play role in sodim reabsorption, damage to any of these three could affect the sodium levels, the promximal tubule in particular.
Mrs. Gardner is 48 years old woman diagnosed with breast cancer. She has been enrolled in...
Mrs. Gardner is 48 years old woman diagnosed with breast cancer. She has been enrolled in a clinical research trial testing the effectiveness of a new chemotherapeutic agent. After her second dose of the agent, she complains of feeling light-headed when she gets out of bed in the morning. Her blood pressure is found to fall from 135/80 to 105/70 when she goes from a supine to a standing position (i.e., orthostatic hypotension). She also complains of frequent urination and...
Mrs. Gardner is 48 years old woman diagnosed with breast cancer. She has been enrolled in a clinical research trial testing the effectiveness of a new chemotherapeutic agent. After her second dose of the agent, she complains of feeling light-headed when she gets out of bed in the morning. Her blood pressure is found to fall from 135/80 to 105/70 when she goes from a supine to a standing position (i.e., orthostatic hypotension). She also complains of frequent urination and...
Mrs. Gardner is 48 years old woman diagnosed with breast cancer. She has been enrolled in a clinical research trial testing the effectiveness of a new chemotherapeutic agent. After her second dose of the agent, she complains of feeling light-headed when she gets out of bed in the morning. Her blood pressure is found to fall from 135/80 to 105/70 when she goes from a supine to a standing position (i.e., orthostatic hypotension). She also complains of frequent urination and...
A.K., a 68-yr-old married Asian American woman, has been diagnosed with breast cancer. She is scheduled for surgery in the morning for a lumpectomy and sentinel lymph node biopsy with possible axillary node dissection. When she is seen in the preoperative clinic 1 week before surgery, she is crying uncontrollably and says, “My husband does not want to look at me anymore. He is afraid of what I am going to look like with a flat chest.” She says, “I...