Is hydronephrosis a component of Acute on Chronic Kidney Disease (CKD)?

From the Guidelines

Hydronephrosis is not part of acute on chronic kidney disease (CKD), but rather represents a separate condition that can potentially cause or worsen kidney dysfunction. Hydronephrosis refers to the swelling of a kidney due to urine backup from an obstruction in the urinary tract, such as kidney stones, tumors, or enlarged prostate 1. Acute on chronic kidney disease describes a sudden deterioration in kidney function in a patient with pre-existing CKD. While hydronephrosis can lead to acute kidney injury that may be superimposed on CKD (thus creating an acute on chronic situation), it is a distinct pathological process with its own causes and treatments.

Key Points to Consider

• Hydronephrosis is a condition characterized by the dilation of the renal pelvis and calyces due to urinary obstruction or reflux 1.
• Acute kidney disease (AKD) is a term used to describe functional and/or structural abnormalities of the kidneys with implications for health, and can occur in patients with or without pre-existing CKD 1.
• The management of hydronephrosis typically involves addressing the underlying obstruction through procedures like stent placement, nephrostomy tube insertion, or removal of the obstructing lesion.
• Prompt diagnosis and treatment of hydronephrosis is essential as prolonged obstruction can cause permanent kidney damage, potentially worsening existing CKD or precipitating acute kidney injury in patients with already compromised renal function 1.

Diagnostic Considerations

• Ultrasound (US) is a valuable diagnostic tool for detecting hydronephrosis, with a high sensitivity for detecting urinary tract obstruction 1.
• The evaluation of renal size, echogenicity, and morphology can help differentiate acute kidney injury from chronic kidney disease, and determine prognosis 1.

Treatment and Outcomes

• The primary goal of treatment is to relieve the underlying obstruction and prevent further kidney damage. This can be achieved through procedures such as stent placement, nephrostomy tube insertion, or removal of the obstructing lesion.
• Prompt treatment of hydronephrosis is essential to prevent long-term kidney damage and improve patient outcomes 1.

From the Research

Definition and Relationship with Acute Kidney Injury

• Hydronephrosis is a condition characterized by the dilation of the renal collecting system, which can lead to acute kidney injury (AKI) if not corrected 2, 3.
• The relationship between hydronephrosis and AKI is well-established, with hydronephrosis being a potential cause of AKI 4.

Hydronephrosis as Part of Acute on CKD

• There is evidence to suggest that hydronephrosis can be a component of acute on chronic kidney disease (CKD), as it can exacerbate existing kidney damage and lead to further deterioration of renal function 2, 4.
• A study found that patients with AKI and hydronephrosis had a higher risk of developing CKD, highlighting the importance of prompt diagnosis and treatment of hydronephrosis in patients with AKD 4.

Diagnosis and Management

• Hydronephrosis can be diagnosed using various imaging modalities, including ultrasound, CT, and MRI 2, 3.
• Management of hydronephrosis typically involves relieving the obstruction and restoring normal urine flow, which can be achieved through ureteral stenting or percutaneous nephrostomy 5, 6.
• The choice of management strategy depends on the underlying cause of the hydronephrosis, as well as the patient's overall clinical condition 5, 6.