obsolete multicystic dysplastic kidney

Definition and Overview

Multicystic dysplastic kidney (MCDK) is a rare congenital anomaly of the kidney and urinary tract, characterized by large, non-functional kidneys distended by multiple cysts. This condition can affect one or both kidneys, resulting in significant impairment of renal function.

Key Features

• Large, non-functional kidneys
• Multiple cysts replacing normal kidney tissue
• Can be unilateral (affecting one kidney) or bilateral (affecting both kidneys)
• Non-communicating cysts, without functional renal tissue

Prevalence and Prognosis

MCDK is a rare condition, occurring in approximately 1 in 4300 live births. When unilateral and isolated, the prognosis is generally favorable, with most children experiencing an excellent outcome. However, when bilateral or associated with other anomalies, the prognosis may be considerably worse.

References

• [1] Multicystic dysplastic kidney disease (MCDK) is one of the most common renal abnormalities that can be identified during fetal ultrasound evaluation.
• [2] Bilateral MCDK has a worse prognosis than unilateral MCDK.
• [3] A rare congenital anomaly of the kidney and urinary tract (CAKUT), in which one or both kidneys are large, distended by multiple cysts, and non-functional.

Abdominal Obstructive Signs

Multicystic dysplastic kidney (MCDK) can cause abdominal obstructive signs, particularly when the cysts in the affected kidney put pressure on surrounding structures [1][2]. This may lead to symptoms such as:

• Swelling in the abdomen
• Abdominal pain or discomfort

Other Possible Symptoms

In some cases, MCDK may also present with other nonspecific symptoms, including:

• Hematuria (blood in the urine)
• Proteinuria (excess protein in the urine)
• Urinary tract infections [9]

However, it's essential to note that many children with MCDK are asymptomatic and only discovered through prenatal imaging or routine ultrasound examinations.

Impact on Kidney Function

When one kidney is affected by MCDK, the remaining healthy kidney usually takes over all kidney function. In cases where both kidneys are affected, the condition can be lethal due to severe kidney dysfunction [4].

It's worth noting that MCDK does not cause any symptoms in many children and

Diagnostic Tests for Multicystic Dysplastic Kidney

Multicystic dysplastic kidney (MCDK) can be diagnosed through various imaging tests and examinations. Here are some of the diagnostic tests used to confirm the condition:

• Ultrasound examination: This is a non-invasive test that uses high-frequency sound waves to create images of the kidneys. It is usually performed during pregnancy, around 20 weeks (5 months), and can detect multiple fluid-filled cysts replacing the entire kidney with no function [8][13].
• Voiding cystourethrogram (VCUG): This specific x-ray examines the urinary tract and can be used to diagnose MCDK [5].
• Intravenous pyelogram (IVP): This test involves injecting a contrast dye into a vein, which is then excreted by the kidneys. X-rays are taken to visualize the kidneys and urinary tract [5].
• Nuclear scan: In some cases, a nuclear scan may be required to differentiate MCDK from other kidney conditions [6].

Additional Tests

After birth, additional imaging tests such as ultrasound, CT scans, or MRIs can confirm the diagnosis and help determine the health of the affected kidney and the unaffected one [9]. Blood tests for creatinine, urea, and electrolytes should also be performed to assess kidney function [2].

It's essential to note that diagnostic testing with chromosomal microarray analysis (CMA) may be offered when MCDK is detected, as it can identify a pathogenic copy number variant in 14%

Differential Diagnoses for Obsolete Multicystic Dysplastic Kidney

The differential diagnosis for obsolete multicystic dysplastic kidney (MCDK) includes several conditions that can mimic its appearance on imaging studies. These include:

• Hydronephrosis with calyceal involvement: This condition, characterized by a dilated renal pelvis and calyces, can be mistaken for MCDK on ultrasound or other imaging modalities [15].
• Obstructive renal dysplasia: Severe urinary tract obstruction can lead to cystic changes in the kidney, making it difficult to distinguish from MCDK [15].
• Renal agenesis or hypodysplasia: Congenital anomalies of the kidney and urinary tract (CAKUT) can include renal agenesis or hypodysplasia, which may present with cystic changes in the affected kidney [6].

It's essential to note that a definitive diagnosis of MCDK requires a combination of clinical presentation, imaging studies, and histopathological examination. A thorough evaluation by a qualified healthcare professional is necessary to rule out these differential diagnoses and confirm the presence of obsolete MCDK.

References:

[1] Multicystic dysplastic kidney disease (MCDK) is one of the most common renal abnormalities that can be identified during fetal ultrasound evaluation [10].

[2] Bilateral MCDK has a worse prognosis than unilateral MCDK, especially when associated with other anomalies [10].

[3] Hydronephrosis with calyceal involvement can be mistaken for MCDK on imaging studies [15].

[4] Obstructive renal dysplasia due to severe urinary tract obstruction can cause cystic changes in the kidney, similar to MCDK [15].

[5] Renal agenesis or hypodysplasia is a congenital anomaly that may present with cystic changes in the affected kidney [6].