Horseshoe kidney, also referred to as renal fusion, is a congenital condition where the two kidneys are fused into a U-shaped structure resembling a horseshoe. In terms of position, it is placed much lower compared to the normal kidneys.
“A horseshoe kidney is seen in one out of 500 people,” says Dr Guru Balaji, urologist, Prashanth Hospital, Chennai. “While some may face certain issues, others may not have any symptoms or problems due to the condition.”
Horseshoe kidney: Location and complications
A horseshoe kidney is located in the lower part of the pelvis and is closer to the front of the body, deviating from its normal position — above the pelvis and towards the back. Dr Mohan Keshavamurthy, director, urology, uro-oncology and robotic surgery, Fortis Hospital, Bangalore, explains, “During fetal development, the kidneys develop around the umbilicus (navel) and get positioned on either side of the spine. In the case of a horseshoe kidney, however, the kidneys get fused, forming a U-shaped structure. They stay in front of the body, centrally among all other organs.” In most cases, it is asymptomatic and detected incidentally.
According to Dr Balaji, the fusion sometimes obstructs the urinary passage. As a result, the kidney swells up due to the buildup of urine, causing pain. “This obstruction can cause recurrent urinary infections. However, if the individual has no symptoms and the kidney is functioning effectively, they need not worry about it,” he informs.
As per a recent media report, a woman from Delhi born with a horseshoe kidney successfully donated a portion of it to her husband.
Symptoms of renal fusion
According to experts, some common symptoms observed in people with horseshoe kidney include:
- Abdominal pain
- Recurrent UTIs accompanied by fever
- Increased risk of kidney stones
- Nausea
- Impaired kidney function
- Vesicoureteral reflux — a condition where urine flows back into the kidney from the bladder.
Renal cancer can be a complication for those with horseshoe kidney. Dr Keshavamurthy recalls encountering such a case in 2023. Sumathi (name changed), a 54-year-old woman from Bangalore, had not experienced any issues due to her horseshoe kidney until recently, when she started to feel severe pain in her upper abdomen. She learned about her condition during her younger years while undergoing tests for recurring UTIs. “She was diagnosed with a malignant tumor in the upper part of her left kidney in early 2023 after complaining of acute abdominal pain. Cancer occurring in a horseshoe kidney is extremely rare, accounting for one in every two lakh cases,” shares Dr Keshavamurthy.
Horseshoe kidney: How does it complicate treatment?
The horseshoe kidney is often overlapped by blood vessels from surrounding organs, which makes surgeries difficult, say doctors. “It’s located deep in the abdomen, towards the middle of the intestines and other vital organs, making it tough to carry out a surgery,” says Dr Keshavamurthy.
In Sumathi’s case, Dr Keshavamurthy performed a robotic-assisted laparoscopic partial nephrectomy where the tumor from the left kidney along with a 1 mm margin was removed, minimizing the damage to the healthy kidney tissue. She also needed a ureteral stent (also known as a JJ stent), which was temporarily placed before the procedure to help transfer urine from her kidneys to the bladder.
Diagnosis and treatment
Diagnostic tests like a renal ultrasound, X-ray, CT scan and MRI can detect the condition. With advancements in ultrasounds, the anomaly can be detected during the antenatal tests (tests conducted throughout the course of pregnancy) itself. The condition can neither be prevented nor corrected, clarifies Dr Balaji. “Fusion of the kidneys is not a problem. We should only intervene if any complications arise. For example, there can be issues with the filtration capacity of the kidney. In addition, kidney stones may also form, affecting kidney function. Such issues can be addressed and treated,” he explains.
Takeaways
- Horseshoe kidney or renal fusion is a congenital condition where the two kidneys fuse to form a U-shaped structure resembling a horseshoe. The condition occurs in one out of 500 people.
- As it’s located towards the lower end of the pelvis, it may lead to issues with urinary flow, causing recurrent infections or kidney stones.
- Not everyone with the condition will face issues. In most cases, intervention isn’t required until there’s a complication.
