Diabetes insipidus: Is it same as diabetes? Know symptoms of this rare disorder
Diabetes insipidus is a rare disorder that causes frequent urination and thirst because of problems with kidney. Here's all you want to know.
Diabetes insipidus is an uncommon disorder that leads to frequent urination and thirst as the body loses its ability to concentrate urine resulting in large amounts of fluid loss during the day putting one at risk of dehydration. Diabetes insipidus is not the same as diabetes mellitus and has nothing to do with your blood sugar levels. However, some symptoms of diabetes insipidus and diabetes mellitus may be common. (Also read: Diabetes: Signs that your blood glucose levels are too low)
Diabetes insipidus occurs due to problems with a hormone called vasopressin that helps kidneys to maintain fluid balance. It may also be due to malfunctioning of a part of brain that controls thirst or can also occur temporarily during pregnancy when the mother’s placenta NIH external link makes too much of an enzyme that breaks down her vasopressin.
"Normal kidneys are able to produce concentrated urine due to a hormone called vasopressin. When the body loses its ability to concentrate urine due to either deficiency of this hormone or due to lack of sensitivity to it, large amounts of dilited urine is produced resulting in >3L of fluid loss from thr body per day. The concentration of normal urine is 800-1200mOsmoles/L but in case of diabetes insipidus, the concentration of urine falls below 300mOsmoles/L which translates into large volume of urine losses per day," says Dr Anurag Aggarwal, Sr. Consultant, internal medicine, Marengo QRG Hospital.
Diabetes insipidus should not be confused with psychogenic polydypsia wherein a person voluntarily consumes large amounts of plain water causing him to urinate large volumes of urine.
TYPES OF DIABETES INSIPIDUS
According to Dr Anupam Biswas, Consultant - Endocrinology, Fortis Hospital, Noida, there are 4 types of diabetes insipidus.
1. Central DI – Damage to pituitary gland or hypothalamus caused by head injury/surgery/tumours - occurs due to deficiency of ADH (antidiuretic hormone)
2. Nephrogenic DI – Inability of the kidney to concentrate urine in response to ADH due to inherited or acquired causes.
3. Dipsogenic DI – due to excess fluid intake.
4. Pregnancy Related DI – A substance muscle by placenta that prevents the mother's ADH from working properly.
SYMPTOMS OF DIABETES INSIPIDUS
Symptoms of diabetes insipidus as per Dr Anurag Aggarwal and Dr Anupam Biswas are:
1. Polyuria- patient passes a lot of urine ranging from 3-20L/day.
2. Polydypsia- due to excessive loss of large volumes of dilute urine, patient feels excessive thirst. due to increase in concentration of solutes in the body and to replenish lost fluids.
3. Nocturia- patient gets frequent urge to pass urine even at bedtime and in night.
4. Irritability and fatigue.
5. Headache or visual problems in case of pituitary tumour.
6. In children bed wetting at night is one of the symptoms.
Dr Aggarwal says the following laboratory tests to diagnose diabetes insipidus.
1. A 24-hour urine collection for determination of urine volume
2. Serum electrolyte concentrations and glucose level
3. Simultaneous plasma and urinary osmolality
4. Plasma ADH level
5. Urinary specific gravity
6. Pituitary studies, including magnetic resonance imaging (MRI) and measurement of circulating pituitary hormones other than ADH
Most patients are able to replace the lost fluids by drinking a lot of fluids but in case of reduced oral intake of liquids and when hypernatremia i.e. increased concentration of sodium happens in the blood, following measures are taken:
- Dextrose and water or an intravenous fluid that is less concentrated with respect to the patient’s serum.
- Administer fluids at 500-750 mL/hr; to reduce serum sodium by approximately 0.5 mmol/L (0.5 mEq/L) every hour.
- Synthetic vasopressin
- Thiazide diuretics
- NSAIDS like indomethacin (used when nothing else available)