From the Guidelines
Post renal obstruction requires prompt diagnosis and treatment to prevent kidney damage, and the management depends on the cause, location, and severity of the obstruction. The condition occurs when there is a blockage in the urinary tract that prevents the normal flow of urine from the kidneys to the bladder and out of the body. According to the study by 1, acute kidney injury (AKI) is common, affecting up to 20% of hospital inpatients, and postrenal AKI results from ureteral, bladder, or urethral obstruction.
Causes and Treatment
The causes of post renal obstruction include kidney stones, prostate enlargement, and tumors. For kidney stones causing obstruction, medical expulsive therapy with alpha-blockers like tamsulosin 0.4mg daily may help pass smaller stones, as mentioned in the example. Larger stones might require surgical intervention such as ureteroscopy, extracorporeal shock wave lithotripsy, or percutaneous nephrolithotomy. A prospective, randomized, controlled trial by 1 demonstrated the safety and efficacy of emergent nephrolithotomy compared with diverting PCN in the initial management of obstructing ureteropelvic stone disease in the setting of related sepsis.
Monitoring and Complications
After relieving the obstruction, monitoring kidney function with blood tests (BUN, creatinine) and imaging studies is essential, as stated in the example. Complications of prolonged obstruction include urinary tract infections, which may require antibiotics, and kidney damage, which can be permanent if the obstruction isn't promptly addressed. The pathophysiology involves increased pressure in the collecting system backing up to the kidney, leading to hydronephrosis and eventual nephron damage if not corrected.
Key Points
- Post renal obstruction requires prompt diagnosis and treatment to prevent kidney damage
- The management depends on the cause, location, and severity of the obstruction
- Causes include kidney stones, prostate enlargement, and tumors
- Treatment options include medical expulsive therapy, surgical intervention, and monitoring of kidney function
- Complications include urinary tract infections and permanent kidney damage if left untreated, as highlighted by 1 and 1.
From the Research
Definition and Causes of Post Renal Obstruction
- Post renal obstruction refers to a blockage in the urinary tract that occurs after the kidneys, typically in the ureters, bladder, or urethra 2.
- The causes of post renal obstruction can be diverse, including ureteral obstruction, bladder outlet obstruction, and other conditions that lead to urinary tract obstruction 3, 2.
Treatment Options for Post Renal Obstruction
- Treatment options for post renal obstruction include percutaneous nephrostomy (PCN) and retrograde ureteral stenting (RUS) 4, 3, 5, 6.
- PCN involves the insertion of a catheter into the kidney to drain urine, while RUS involves the placement of a stent in the ureter to allow urine to flow around the blockage 4, 3.
Comparison of PCN and RUS
- Studies have compared the efficacy and safety of PCN and RUS for the treatment of post renal obstruction, with some finding no significant difference in most outcomes 4, 5, 6.
- However, PCN may be preferable to RUS due to its reduced impact on post-operative quality of life, with fewer symptoms of haematuria and dysuria 4, 5, 6.
- RUS may be associated with more urinary symptoms and a lower quality of life, particularly in the long term 5, 6.
Complications of Post Renal Obstruction
- Postobstructive diuresis is a rare but potentially lethal complication that can occur after the relief of urinary obstruction, characterized by a polyuric response and potential dehydration and electrolyte imbalances 2.
- Early diagnosis and treatment of postobstructive diuresis are crucial to prevent mortality, and primary care physicians should be aware of this potential complication 2.