A tumor of the juxtaglomerular apparatus (JGA) of the kidneys (renal system) produces an excess of an enzyme called renin, which, through downstream effects, results in retention of water and sodium in the blood and constriction of blood vessels. The combined result is increased blood pressure.
Disease Mechanism
According to the seventh edition of "Vander's Renal Physiology," the renal system provides long-term regulation of blood pressure through the production of renin. Renin is made in the JGA of the kidneys. Renin production is stimulated by low blood pressure and decreased passage of sodium chloride (salt) through the kidney tubules. The result of renin production is increased blood pressure through fluid retention and constriction of blood vessels. JGA tumors produce an overabundance of renin, and the mechanism described is perpetuated despite the consequence of a higher than normal blood pressure.
Symptoms
The typical symptoms of a JGA tumor are headaches, increased urination and high blood pressure.
Diagnosis
In the Fall 2002 issue of "Reviews in Urology," Dr. Rubenstein and colleagues assert that diagnosis of a JGA tumor generally follows identification of plasma renin levels that are two to seven times higher than normal. The overproduction of renin is localized to the JGA through diagnostic imaging and microscopic examination of a tissue sample.
Treatment
The definitive cure for JGA tumors, state Dr. Rubenstein and colleagues, is surgical excision. Medical management of a JGA tumor is reasonable because these tumors are considered benign, with no reports of metastases. Angiotensin-converting enzyme inhibitors are a logical choice to control blood pressure before surgery.
Prognosis
Although JGA tumors are benign, the condition can be fatal if not treated. Surgical excision eliminates tumor recurrence, but, as reported by Dr. Rubenstein and colleagues, 12 to 27 percent of patients continue to have high blood pressure after surgery due to vascular damage caused by previous high blood pressure.
Tags: blood pressure, blood pressure, Rubenstein colleagues, blood pressure through, blood vessels, constriction blood, constriction blood vessels
