Relief of bilateral kidney obstruction resulting in post-obstructive diuresis has associated risks?

• A. Hypertension
• B. Urinary tract infection
• C. Renal failure
• D. Fluid and electrolyte imbalance

Answer: (D)

Relief of bilateral kidney obstruction can unleash post-obstructive diuresis, a rapid and substantial urine flow as the kidneys resume normal filtration and excretion after a period of backup. This vigorous diuresis washes out water and solutes from the body, so the biggest danger is losing fluids and electrolytes faster than the body can replace them. Patients can become dehydrated and develop electrolyte disturbances such as low sodium, potassium, or other ions, and even shifts in acid-base balance if losses are large. That combination—volume depletion plus electrolyte derangements—is the main risk during this phase, which is why fluid and electrolyte imbalance is the best answer. Other concerns like infection or outright renal failure aren’t the defining immediate risks of post-obstructive diuresis, though they can occur in other contexts.