Porth's Essentials of Pathophysiology, 4e

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Disorders of Renal Function

C h a p t e r 2 5

R E V I EW E X E R C I S E S 1. A 6-year-old boy is diagnosed with acute glomerulonephritis that developed after a streptococcal throat infection. At this time, the following manifestations are noted: decrease in urine output, increasing lethargy, hyperventilation, and generalized edema. Trace amounts of protein are detected in his urine. Blood analysis reveals the following: pH = 7.35, HCO 3 = 18 mEq/L, hematocrit = 29%, Na = 132 mEq/L, K = 5.6 mEq/L, blood urea nitrogen (BUN) = 62 mg/dL, creatinine = 4.1 mg/dL, and albumin = 2 g/dL. A. What is the probable cause of this boy’s glomerular disease? B. Use the laboratory values in the Appendix to interpret his laboratory test results. Which values are significant and why? C. Is he progressing to uremia? How can you tell? 2. A 36-year-old man is admitted to the emergency department with a sudden onset of severe, intermittent, cramping pain that makes him feel nauseated. He describes the pain as originating in the left groin and radiating toward the flank. Microscopic examination of his urine reveals the presence of red blood cells. His temperature is normal, and he does not exhibit signs of sepsis. A. What is the probable cause of this man’s pain? B. What diagnostic measure could be used to confirm the cause of his pain? C. A plain-film radiograph reveals a 4- to 5-mm kidney stone in the left ureter. What are the chances that this man will pass the stone spontaneously? D. What type of medications and other treatments should this man receive? E. Once the stone has been passed, what type of measures can he use to prevent stone recurrence? chemotherapy, and sometimes radiation therapy, with long-term survival rates of up to 96% with an aggressive plan of treatment. ■■ Cancer of the kidney accounts for about 3% of all cancers, with renal cell carcinoma accounting for 80% to 90% of cases.The neoplasms are a collection of tumors from different parts of the nephron, each with different genetic profiles and histologic features that challenge both diagnostic and treatment methods. Many of these cancers are characterized by a lack of early warning signs, diverse clinical manifestations, and resistance to chemotherapy and radiation therapy.

disease. Presenting features include hematuria, flank pain, and presence of a palpable flank mass. Gross or microscopic hematuria, which occurs in more than 50% of cases, is an important clinical clue. 4 It is, however, intermittent and may be microscopic; as a result, the tumor may reach considerable size before it is detected. One of the features of renal cell carcinoma is its abil- ity to metastasize. In about 25% of new cases, there is radiologic evidence of metastasis, with the most com- mon sites being lung and bone metastases. 35 Ultrasonography and CT scanning are used to confirm the diagnosis. MRI may be used when involvement of the inferior vena cava is suspected. Surgery (radical nephrec- tomy with lymph node dissection) is the treatment of choice for all resectable tumors. Nephron-sparing sur- gery may be done when both kidneys are involved or when the contralateral kidney is threatened by an associ- ated disease such as hypertension or diabetes mellitus. Single-agent and combination chemotherapy have been used with limited success. The 5-year survival rate is 90% if the tumor has not extended beyond the renal capsule, but drops to 30% if metastasis has occurred. 5 FIGURE 25-17. Gross pathology of a bisected kidney showing large renal cell carcinoma. Much of the kidney has been replaced by gray and yellow tumor tissue. A little remaining renal cortex and pericapsular fat are visible at the bottom of this surgical specimen. (From the Centers for Disease Control and Prevention Public Health Images Library. No. 863. Courtesy of Edwin P. Ewing, Jr.)

SUMMARY CONCEPTS

■■ There are two major groups of renal neoplasms: embryonic kidney tumors (i.e., Wilms tumor), which occur during childhood, and renal cell carcinoma, which occurs in adults. ■■ Wilms tumor is one of the most common malignant tumors of children.The most common presenting signs are a large abdominal mass and hypertension.Treatment methods include surgery,