Polyuria: When your kidneys get a sugar rush

If you experience frequent and increased urination, it could be due to high blood sugar levels. Polyuria is one of the common symptoms of uncontrolled and undiagnosed diabetes.

Polyuria refers to excessive production or passing of urine. Prof Dr Pradeep Talwalkar, a senior diabetologist from Mumbai says, “The total amount and frequency of urine is very high in people with uncontrolled diabetes as more amount of glucose is filtered through the urine.”

He adds that a person should normally pass around 500–1500 ml of urine per day. “If the urine volume is more than that, or a person urinates several times a day, particularly two to three times at night, then it can be polyuria,” he adds.

Common causes of polyuria

Dr Garima Aggarwal, nephrologist and renal transplant physician, Bengaluru, says, “Polyuria can result from an increased amount of solute in the urine, causing more water to pass along with it. It’s called solute diuresis.” Increased urination can be caused due to the following issues:

• Uncontrolled or undiagnosed diabetes
• High sodium level in blood
• Certain psychological conditions
• Use of diuretics
• Disorders of antidiuretic hormone, which controls how much water is excreted in the urine
• Kidney failure

Polyuria and diabetes

The most common cause of this kind of solute diuresis is high sugar level. Dr Aggarwal says one of the ways a lot of people find out about their diabetes is when they experience frequent urination. Their urine is also more concentrated due to high sugar levels. Hyperglycemia can lead to polyuria, as it causes glucosuria, which refers to the leakage of glucose in urine. She explains, “There is something known as a renal threshold. When sugar level in our blood is about 180 mg/dL, it won’t leak into the urine. However, when it exceeds 180 mg/dL, the kidney cannot handle that sugar load and glucose starts leaking into the urine. The kidney then starts acting as an osmotic agent (any substance that pulls water with it). When a high amount of sugar is being filtered out, the kidney keeps pulling more water towards urine.”

Polyuria and associated complications

Not all cases of hyperglycemia cause increased urination. Dr Talwalkar says when hyperglycemia is mild to moderate (blood sugar level of around 170–180 mg/dL pre-meal and 200–220 mg/dL post-meal), it doesn’t usually cause any symptoms. “When diabetes is undiagnosed or when one doesn’t take the necessary steps after diagnosis, resulting in their blood sugar levels shooting up to more than 400 mg/dL, then symptoms usually manifest. And one of the common symptoms is polyuria,” he adds. Dr Garima adds there’s no exact mechanism as to why only some diabetics get polyuria and some don’t. “It has a lot to do with your genetic makeup, kidney health and a lot of other factors,” she says.

Polyuria can also be accompanied by polydipsia (excessive thirst), as one loses more water in the urine. High blood sugar levels can also cause polyphagia (excessive hunger). If left untreated, it can lead to dehydration. Dr Garima says, “It can lead to very high sodium levels in the body. As dehydration is harmful for the kidneys, it can cause acute kidney injury. It can affect the brain and slow down its functioning. In a way, the complications of polyuria will be same as that of dehydration, with all that water leaking through your urine.”

The most common cause of kidney failure is diabetes. If a person with diabetes does not take proper precautions, it can damage the blood vessels in the kidneys, leading to kidney failure over a period of time, says Dr Talwalkar. “At that point, the only modes of treatment are either regular dialysis— two or three times a week– or a kidney transplant,” he says.

Managing increased urination

To manage polyuria and other complications, the key is to ensure proper control of diabetes through diet, exercises and medication. Dr Garima says they will most likely require insulin administration to bring down the sugar levels quickly. “Because of reduced fluid in the body, we administer IV hydration. They should be kept under observation for monitoring the urine output, and making sure that their fluid intake is appropriate,” she says.

Experts say some medications for diabetes can cause polyuria, as their mode of action is to release excess glucose through urine. However, they’re manageable. Dr Talwalkar says, “There are 20 different types of tablets for diabetes, divided into eight different groups or classes of medications along with insulin produced by several manufacturers. So, an experienced doctor — depending on the duration and severity of diabetes, one’s response to medications and associated conditions — will prescribe a drug or some drugs in combination to control their diabetes.”

Takeaways

• Polyuria, which refers to excessive production or passing of urine, is one of the common symptoms of uncontrolled and undiagnosed diabetes.
• The condition can also result from high sodium levels in blood, certain psychological illnesses and kidney issues.
• Polyuria is often accompanied by polydipsia (excessive thirst), as it causes dehydration.
• Ensuring good control of diabetes through diet, exercises and medication can help in managing polyuria.