This is a rare disorder that causes the affected individual to pass an abnormally large quantity of urine that is dilute and odorless. This occurs with the imbalance of fluids in the body and includes the need to consume a large amount of liquid. The diabetes insipidus is not related to diabetes mellitus but the affected individual can experience similar symptoms.
Causes
This occurs as the result of abnormalities with the hormone called vasopressin (AVP), also known as antidiuretic hormone (ADH) which is essential for the regulation of fluid in the body. The ADH is produced by the hypothalamus and stored in the pituitary gland. When the fluid content in the body decreases, the ADH is secreted from the pituitary gland to cease urine production. Among the affected individuals, this hormone is not regulated properly resulting in too much urine output.
The two main forms of diabetes insipidus include cranial diabetes insipidus when the body is not able to produce sufficient quantity of AVP and nephrogenic diabetes insipidus occurs when the kidney isn’t responding normally. The cranial diabetes insipidus can develop as the result of three main causes that includes brain tumour, severe head injury and complications during brain surgery. In around third of all the cases of cranial diabetes insipidus, the cause is often not identified. The nephrogenic diabetes insipidus can develop when the nephrons that filter the waste products from the blood, does not respond well to the AVP signal. The AVPR2 gene mutation is responsible for the congenital nephrogenic diabetes insipidus that is estimated to affect 1 in 250,000 births. The acquired nephrogenic diabetes insipidus can be caused by the result of a medication used to treat bipolar disorder, hypercalcemia (high level of calcium in the blood), hypokalemia (insufficient amount of potassium) and kidney infection.
Symptoms
The two common symptoms of this condition are extreme thirst and the excessive amount of urine output. The severe cases can urinate as much as 15 liters a day when the average output is 3 liters. Symptoms in infants and children can include weight loss, excessive crying, delayed growth, fever, trouble sleeping, irritability, fatigue, loss of appetite and diarrhea.
Diagnosis
The diagnosis may involve various tests to determine the type of diabetes insipidus. A physical examination can help with detecting signs of dehydration and other tests can include water deprivation test, blood tests and MRI. The water deprivation tests involve the individual not taking any liquid for several hours while the amount of urine output is measured and analyzed for glucose, calcium and potassium. The urine of Individuals with diabetes insipidus is very dilute with low levels of various substances. The blood tests can identify the levels of sodium and can in some cases help determine the type of diabetes insipidus. The magnetic resonance imaging can be used to evaluate if any abnormalities of the hypothalamus or pituitary gland can be the cause.
Treatment
The treatment is focused on reducing the amount of urine produced by the body. The treatment is determined by the type of diabetes insipidus. For instance, a mild form of cranial diabetes insipidus usually does not require any treatment but the severe form can be treated with medication to replace the shortage of vasopressin. Stopping the medication that causes nephrogenic diabetes insipidus usually is considered with alternative drugs. However, the mild form of this condition requires reducing the amount of salt and protein to help the kidneys produces less quantity of urine.
References
http://www.nhs.uk/Conditions/Diabetes-insipidus/Pages/Treatment.aspx
https://medlineplus.gov/ency/article/000377.htm
