Would hydronephrosis (fluid accumulation in the kidney) require a referral to Nephrology (kidney specialty)?

From the Guidelines

Hydronephrosis typically warrants a referral to nephrology, as it is a condition characterized by swelling of the kidney due to urine buildup from obstruction in the urinary tract, and a nephrologist should evaluate this condition to determine the underlying cause, assess kidney function, and develop an appropriate treatment plan. The severity of hydronephrosis, accompanying symptoms, and laboratory findings (such as elevated creatinine or signs of infection) influence the urgency of the referral 1. While mild cases might be monitored by primary care, moderate to severe hydronephrosis, especially with impaired kidney function, requires specialist intervention. Nephrologists can perform comprehensive evaluations including specialized imaging studies, such as CT urography (CTU) or scintigraphic evaluation with mercaptoacetyltriglycine (MAG3) imaging, and may coordinate with urologists if surgical intervention is needed to relieve obstruction 1. Early referral is important as prolonged hydronephrosis can lead to permanent kidney damage, particularly if both kidneys are affected or if the patient has underlying kidney disease.

Some key points to consider in the evaluation and management of hydronephrosis include:

• The cause of hydronephrosis, which can be classified as obstructive or non-obstructive, and can be due to various factors such as urolithiasis, malignant obstruction, or supravesical or bladder dysfunction 1
• The severity of hydronephrosis, which can be assessed using imaging studies such as CTU or MAG3 scintigraphy, and can be classified as mild, moderate, or severe
• The presence of accompanying symptoms, such as flank or groin pain, infection, nausea, or urinary urgency, which can influence the urgency of the referral
• The laboratory findings, such as elevated creatinine or signs of infection, which can indicate impaired kidney function and require specialist intervention.

In general, prompt referral to a nephrologist is recommended for uncertainty about the etiology of kidney disease, difficult management issues, and rapidly progressing kidney disease 1, and hydronephrosis is no exception. A nephrologist can provide comprehensive care and coordinate with other specialists, such as urologists, to ensure the best possible outcomes for patients with hydronephrosis.

From the Research

Hydronephrosis Referral to Nephrology

• Hydronephrosis is a condition characterized by the dilation of the renal collecting system, which can be diagnosed using various imaging modalities such as sonography, radiography, and magnetic resonance imaging 2.
• The management of hydronephrosis depends on the underlying cause and severity of the condition, with asymptomatic and stable cases potentially being observed, while acute or symptomatic cases may require intervention 3.
• In cases where hydronephrosis is suspected, referral to a urologist may be necessary, particularly if there are signs of infection or obstruction 3.
• However, there is evidence to suggest that patients with hydronephrosis may also be referred to a nephrologist, especially if there are concerns about kidney function or potential kidney damage 4, 3.
• The severity of hydronephrosis can be used to guide management and predict prognosis, with severe hydronephrosis being associated with a higher risk of passage failure and potentially requiring more urgent intervention 5.

Diagnostic Approaches

• Imaging modalities such as CT scans can be used to assess the severity of hydronephrosis and guide management decisions 5.
• Machine learning algorithms can also be used to recognize hydronephrosis in non-contrast CT images, potentially aiding in the diagnosis and management of the condition 6.
• The use of diuretic nuclear renography can help to exclude functional urinary obstruction in patients with hydronephrosis 3.