Doctors at Delhi’s Sir Ganga Ram Hospital have removed what is believed to be the “largest kidney” in India and the third-largest in the world, from a 56-year-old man suffering from a genetic disorder called Autosomal Dominant Polycystic Kidney Disease (ADPKD).
The kidney weighed 7.4 kg (more than two newborn babies), and measured 32 cm x 21.8 cm. A human kidney on average weighs between 120 grams and 150 grams.
According to doctors at the hospital, the only two instances of kidneys heavier than this being removed are from the United States (9 kg) and the Netherlands (8.7 kg).
The Guinness Book of Records, however, acknowledges a 4.25 kg kidney removed from an ADKPD patient at a Dubai hospital in 2017 as the heaviest ever.
What is Autosomal Dominant Polycystic Kidney Disease (ADPKD)?
It is a rare disease that occurs in 1 out of 700-1,000 individuals. Globally, there are over 12.5 million such cases, but only a fourth of them are believed to be aware of their condition.
Even so, as inherited kidney disorders go, ADPKD is among the most common. It is also one of the most common causes of end-stage kidney disease (when kidneys can no longer function properly).
Numerous cysts grow in the kidneys, and the most common symptoms include pain in the back and between the ribs and hips, headaches, blood in the urine, high blood pressure, and kidney insufficiency.
Though a kidney disease, ADPKD can affect other organ systems leading to a multisystem disorder. Organs that can be affected include the liver, pancreas, prostrate and glands of the male reproductive tract.
The American non-profit National Organisation for Rare Diseases (NORD) says ADPKD was earlier known as adult polycystic kidney disease, since it usually occurs in the fourth or fifth decade of life — but it has been reported in children and infants as well.
ADPKD is caused by inherited mutations in one of the two genes that create proteins for the proper functioning of the kidneys and other parts of the body.
Even so, the precise role that these proteins play in the proper functioning of the kidney is not fully understood. Researchers believe they help in the development of tubes and blood vessels in the kidneys and other organs, and in increasing the flow of calcium through cell membranes.
The ADPKD cysts that can range in size from that of a pin-head to larger than a grapefruit, according to NORD. These cysts, which resemble blisters, form inside the kidneys on the walls of hair-sized structures called nephrons, which help to filter out waste from the blood.
The cysts can also continue to grow as isolated sacs of fluid, and this is what gives the kidney its abnormal size and weight.
How can the disease be treated?
Both men and women are equally likely to develop this disease. Over 6,000 new cases are diagnosed every year in the United States, according to NORD.
Treatment includes dialysis and renal (kidney) transplant. The diagnosis involves using imaging techniques such as ultrasonography and Magnetic Resonance Imaging (MRI).
In the case of the 56-year-old patient in Delhi, his other kidney weighed more than the one that was removed. One of them had to be removed because the patient had stopped responding to antibiotics, and was in pain.
The patient is on dialysis, and is expected to undergo a renal transplant. Typically, among patients with this disease who are undergoing dialysis, the kidney is not removed unless there are signs of bleeding, infection or tumours.