Diabetes Insipidus - Causes and Treatment
Diabetes Insipidus is a disorder in which the person produces a lot of dilute or light-colored urine even when he/she is not hydrated sufficiently. While a healthy adult produces around 2.84 liters of urine per day, an adult with Diabetes Insipidus (DI) will output as much as 19 liters of urine per day. Compared to other ailments, this is quite rare, affecting 1 in 25000 people. If ignored or left untreated, it can cause various complications over time. So it’s important to recognize the symptoms and seek timely medical help.
Diabetes Insipidus is often confused with Diabetes Mellitus because both of them cause thirst, frequent urination and more intake of fluids. However, the similarity ends there.
- In Diabetes Mellitus (DM), there is excess sugar or glucose in the blood, which the kidneys try to remove through the urine.
- In Diabetes Insipidus (DI), blood-sugar levels are normal but the kidneys are not able to concentrate the urine, which is what they normally do. In the process, a lot of fluid is excreted out of the body, in the form of urine.
Pathology of the condition
As much as 60 percent of the adult human body comprises of fluids, including water. Routines such as breathing, urinating and sweating help remove excess fluids from the body, while consuming food, beverages and water increases fluid content in the body. It is important to ensure proper fluid balance in the body for good physical and mental health. This is achieved through certain organs and hormones in the body.
- The kidney is the primary organ that regulates fluid content in the body by removing excess fluids in the form of urine. The urine produced is stored in the bladder and eliminated through an opening called the urethra.
- ADH, also called Vasopressin, is a hormone that is produced by the hypothalamus portion of the brain and stored in the pituitary gland that lies in the head, behind the bridge of the nose. When water must be retained in the body (when the person does not have access to water or the person is not consuming enough water), ADH is released into the blood, this way, less or concentrated urine is produced. When the person is consuming enough water, there is no need to retain water, so minimum to no ADH is released. Then, more or dilute urine is produced.
The above process happens constantly, on a daily basis. But in people with DI, there is an irregularity in the process, making the person produce a lot of dilute urine whether he/she is sufficiently hydrated or not. This leads to dehydration, electrolyte imbalance, etc.
Also Read: 6 Complications of Uncontrolled Diabetes
Symptoms of DI
- Polyuria or excess volume of urine
- Nocturia: Getting up frequently in the night to urinate
- Bed-wetting or urinating in sleep
- Light-colored or dilute urine
- The person prefers to consume cold drinks
- Dehydration accompanied by thirst
- Weakness and muscle pain
- Irritable behavior
- Dry skin
Symptoms of dehydration
- Polydipsia or extreme thirst – the person’s thirst for fluids or water is insatiable
- Fatigue and feeling dull or lazy
- Confused and disoriented state
- Dizziness followed by fainting (syncope)
- Nausea and vomiting
Types, Causes and Symptoms
DI is of 4 broad types, each with its unique causes and pathology.
1. Central DI
This is the most common type. In this, there is damage to either the pituitary or the hypothalamus or both. As a result, the mechanism for producing, storing and releasing ADH is impaired. In the process, the kidneys produce copious amounts of urine. The possible causes for this damage are:
- Trauma or injury to the head
- Any condition that causes swelling in the brain
- Tumor in the brain
- Brain surgery that has damaged some or all of the tissue in the pituitary or hypothalamus
- Any condition that is affecting blood-supply to the pituitary
- Inherited conditions or diseases
2. Nephrogenic DI
As the name implies, there is damage to the kidneys, and one of the consequences is DI. Possible causes include:
- Genetic mutations that are either inherited or acquired
- Drugs such as tetracycline or those that contain lithium
- A blockage anywhere in the urinary tract
- Electrolyte imbalances in the blood, such as hypercalcemia (too much calcium), or hypokalemia (inadequate potassium)
- Chronic kidney disease
3. Dipsogenic DI
In this type, the hypothalamus is not damaged, but its ability to regulate thirst is impaired. So the person feels thirsty all the time, consumes a lot of fluids and hence produces a lot of urine. Causes for this include:
- Certain medications
- Mental or neurological conditions
4. Gestational DI
As the name implies, this type occurs only during the term of pregnancy and disappears gradually after childbirth. The placenta is an organ that develops in the uterus during pregnancy. It is responsible for delivering nutrition to the fetus and removing wastes from the baby’s blood. To achieve these functions, the placenta secretes several hormones which sometimes can alter other body functions. So prominent causes of Gestational DI include:
- Certain enzymes secreted by the placenta destroy ADH or impair its function completely
- There is an increased production of prostaglandin in some pregnant women. This can make the kidney resistant or immune to the action of ADH.
One or more of the below tests are undertaken to confirm or rule out DI.
- Urine gravity test
- Urine analysis
- Blood test
- Fluid deprivation test
- MRI scan
- Genetic screening
- Stimulation tests
Also Read: How Diabetes affects the kidneys
Treatment for DI
1. Central DI
If the abnormality in the hypothalamus or pituitary is caused by a tumor or other reason, then that condition is resolved first. After that, a synthetic version of vasopressin called desmopressin is given as an injection or nasal spray. This takes over the function of natural ADH and decreases urination. The dosage of desmopressin will depend on the extent of Central DI. Also, to increase the availability of this synthetic vasopressin in the body, other drugs such as chlorpropamide may be given.
2. Nephrogenic DI
Since this type involves some impairment in the kidneys, measures are taken to address that.
- A low-sodium or low-salt diet to reduce the urine output
- Altering the dosage or stopping those medications currently taken for other conditions
- Diuretics like hydrochlorothiazide reduces urine output for people with Nephrogenic DI and increases the same for others.
3. Dipsogenic DI
There is no specific treatment for this condition. However, if a mental health condition is causing the ailment, treating the same will relieve the symptoms of this condition.
4. Gestational DI
Since this condition is temporary, treatment is not required for every patient. However, some women may be given Desmopressin which is safe for both mother and child.
5. Lifestyle changes (for all types of DI)
Diet and nutrition: The patient may be recommended a diet low in sodium and protein so that urine output reduces automatically.
Hydration: The person should carry a bottle of water with him/her all the time and consume beverages, or foods that are rich in fluid, from time to time.
Emergency response: The person should wear a medical bracelet or carry some card in the wallet that mentions his/her condition, all the time. In case of an emergency, a doctor or paramedic will notice the same and hydrate the person immediately.
Reviewed by Dr Suresh S Venkita, Group Medical Director, Kauvery Hospitals
NOTE: Take medications only when prescribed by your doctors, self-medication must be avoided under any circumstances.
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- Mar 13, 2023