A horseshoe kidney is a congenital condition where the two kidneys are fused together at their lower poles, forming a U-shape that resembles a horseshoe. This anomaly occurs during fetal development, typically between the 4th and 8th weeks of gestation, when the kidneys fail to ascend normally into their final positions in the abdomen.

Key Features:

1. Anatomy:

The kidneys are joined by a band of tissue called the isthmus, which may consist of renal tissue or fibrous tissue.

The isthmus typically lies anterior to the abdominal aorta and inferior vena cava.

2. Epidemiology:

Occurs in about 1 in 500 to 1 in 1,000 live births.

More common in males than females.

3. Clinical Presentation:

Many individuals are asymptomatic, and the condition is discovered incidentally during imaging studies.

Some may experience symptoms due to complications such as:

Urinary tract infections (UTIs).

Kidney stones.

Obstruction or hydronephrosis.

Abdominal pain.

4. Associated Conditions:

Turner syndrome.

Trisomy 18 and 21.

Other genitourinary anomalies.

5. Diagnosis:

Imaging studies, such as:

Ultrasound: Initial imaging to identify abnormal kidney shape and position.

CT scan or MRI: To better visualize the anatomy and assess complications.

Intravenous pyelogram (IVP): May be used to evaluate the urinary tract.

Nuclear medicine studies: To assess renal function.

6. Complications:

Increased risk of:

Kidney stones.

Pyelonephritis.

Hydronephrosis.

Wilms tumor (rarely).

Renal cell carcinoma (rarely).

7. Management:

Most cases do not require treatment unless complications arise.

Symptomatic management includes:

Treatment of UTIs or kidney stones.

Surgical correction for obstruction if necessary.