Renal malrotation is a rare congenital anomaly of the kidneys caused by a defect in the positioning during the intrauterine stage. The kidney that is formed in the pelvic region must ascend and rotate to the center of the abdomen between the 10th and 12th week of pregnancy.
In the intrauterine stage, the early formation of the kidney takes place near the pelvic region. “In the nascent stage, the kidney will be positioned lower in the pelvic region which gradually must ascend upwards and rotate to occupy its place in the abdomen region,” says Dr Nithin J, Consultant Nephrologist, BGS Gleneagles Global Hospitals, Bangalore.
It is termed renal malrotation if one or both kidneys
- Rotates in the reverse direction.
- Hyper rotates or rotates excessively.
- Rotates partially also known as incomplete rotation.
Of the many kidney diseases in children, renal malrotation is caused by incorrect positioning of the kidneys. Experts suggest that, in most cases, it does not affect the everyday functioning of the kidney, however, the risk of hypertension, kidney stones, or UTIs is on the rise. “While it remains asymptomatic largely, the ultrasound of the kidneys can detect malrotation,” adds Dr Jatin Kothari, Director of Nephrology and Chief Consultant, Renal Transplant Medicine at Nanavati Max Hospital in Mumbai.
Why is it called Mal-rotation?
Dr Kothari says that renal malrotation begins at the embryonic development in all the affected persons. “It is a rare phenomenon. It can be seen in one of the 5000 live births.”
“It is nothing but the incorrect positioning of kidneys during the fetal development stage. This is mostly genetic caused due to a defect in the genes that play a role in movement and positioning of the kidney,” explains Dr Nithin.
Diagnosis of renal malrotation
Experts opine that most cases of renal malrotation are incidental diagnoses. Dr Kothari explains, “Prenatal identification of congenital kidney diseases in children is possible during the routine sonography (ultrasound test) conducted between 16-18 weeks. In this, renal malrotation is identified in rare cases.” Otherwise, it is mostly identified in adulthood, says Dr Kothari. Those with a genetic history of renal issues can undergo genetic testing. The incorrect positioning, however, can increase the risk of hypertension or other kidney-related issues.
Risks associated with kidney malrotation
Dr Kothari suggests that despite being a congenital defect, it does not hamper kidney functioning mostly. “Nevertheless, the positioning of the kidney can increase the risk of vascular issues (abnormalities of the veins or arteries) which further can induce hypertension,” explains Dr Kothari. He describes, “A hyper rotation or reverse rotation of the kidney can stretch the blood vessels that can result in early onset of blood pressure (hypertension).”
Also, renal malrotation, in rare cases, increases the risk of urinary tract infections (UTIs) or kidney stones. “This happens when the kidney will be positioned in a way that blocks the drainage of urine from the kidneys to the bladder,” explains Dr Nithin.
Dr Nithin recalls an IT professional in his early 30s had developed kidney stones. An abdominal ultrasound (sonography) and CT (computerised tomography) scan revealed he had renal malrotation.
Who is at risk of developing kidney malrotation
Dr Nithin explains this rare condition is most often seen in people with genetic conditions like Turner’s syndrome or Down’s syndrome. However, other individuals also can be at risk of developing it.
Malrotation is not always bilateral
Malrotation can be unilateral or bilateral, meaning it can affect one or both kidneys, say experts. Men and women are equally at risk. In comparison to the left and right kidneys, there is more malrotation of the left kidney than the right. Dr Kothari explains the underlying cause could be the longer blood vessels and bigger size of the left kidney compared to the right.
In most cases, it remains asymptomatic and it is largely an incidental diagnosis,” says Dr Kothari.
- Renal malrotation is a congenital defect that does not affect the normal functioning of kidneys.
- Based on kidney positioning, the risk of hypertension, kidney stones or UTIs increases.
- Parents whose children are at risk of genetic kidney conditions can do genetic testing for better management of kidney health.