While both diabetes insipidus and diabetes mellitus share the term ‘diabetes’, they are different conditions that affect the body in different ways. Diabetes insipidus affects the fluid balance in the body, whereas diabetes mellitus causes sugar imbalances. “Diabetes mellitus and insipidus are two completely different conditions. The only thing common between them is the word ‘diabetes’,” says Dr Nisha Kaimal, consultant endocrinologist & diabetologist, Kokilaben Dhirubhai Ambani Hospital, Mumbai.
Origin of diabetes mellitus and insipidus
Dr Radhika Govil, consultant, nephrology, Fortis Escorts Hospital, Jaipur, explains that both conditions are classified as diabetes due to increased urine production in both. Diabetes in Latin means to pass through. The condition was discovered after detecting that the urine of some people contained excess sugar, making it sweet.
Dr Kaimal says, “In case of people diagnosed with diabetes insipidus, the urine won’t contain glucose, but will rather be dilute and bland– sort of insipid,” she adds.
So, people with sugary urine are diagnosed with diabetes mellitus, while those with insipid urine are diagnosed with diabetes insipidus.
Diabetes mellitus vs diabetes insipidus
Dr Giridhar Adapa, endocrinologist, Manipal Hospital, Vijayawada, explains that diabetes mellitus is characterised by blood glucose fluctuations due to impaired glucose metabolism in the body. It mainly occurs due to two factors: a lack of insulin production by the pancreas or high insulin resistance due to various co-morbidities, where insulin produced in the body is unable to break down sugar to be used as energy for various purposes.
There are two main variants of diabetes mellitus: type 1 diabetes, an autoimmune condition that occurs when the pancreas is unable to secrete insulin and type 2 diabetes, where factors like a sedentary lifestyle, obesity and hypertension could lead to impaired glucose metabolism despite insulin secretion in the body.
Dr Adapa explains that in case of diabetes insipidus, the problem lies with the pituitary hormone ADH (anti-diuretic hormone or vasopressin). “Diabetes insipidus is a condition where the body is not able to regulate the fluid balance,” says Dr Kaimal. This happens due to a deficiency of ADH that is produced in the brain, which is either not being produced enough or not acting effectively. “Diabetes insipidus is mainly characterised by excessive urination,” says Dr Govil.
“For people with diabetes insipidus, it is important to drink water only if they are thirsty,” says Dr Kaimal.
Types of diabetes insipidus
The two main types of diabetes insipidus are:
♦ Central diabetes insipidus
“Central diabetes insipidus is caused due to ADH deficiency,” says Dr Adapa. ADH regulates the fluid balance by ensuring that the kidneys don’t filter out excess fluid from the body, explains Dr Kaimal. As a result, people with diabetes insipidus might experience dehydration.
The ADH balance could also get altered due to certain factors affecting the brain, which include:
- Severe head injuries
- Brain surgery
- Pituitary gland inflammation
- Tumor in the pituitary gland
Hormonal therapy and medication are often prescribed to those diagnosed with central diabetes insipidus. “To control the condition, the person will be given a synthetic form of ADH [desmopressin],” says Dr Govil.
♦ Nephrogenic diabetes insipidus
In this form of diabetes insipidus, the ADH hormone is produced, but the kidneys are unable to respond to its signals and control fluid expulsion. “The kidneys are unable to retain urine, resulting in excessive urination,” says Dr Kaimal.
Kidney damage due to some hereditary factors or various complications is attributed to this condition. “Medications like thiazide diuretics are prescribed for nephrogenic diabetes insipidus,” says Dr Adapa.
Preventive measures for diabetes mellitus and insipidus
Dr Adapa explains that in case of type 2 diabetes, remission is initially possible with weight loss and lifestyle modifications. However, diabetes insipidus cannot be managed like that. Type 1 diabetes is also a lifelong condition that has to be managed through insulin injections.
Experts add that when it comes to type 1 diabetes and diabetes insipidus, early detection and the right treatment are important.
Takeaways
- Although diabetes insipidus and diabetes mellitus share the term ‘diabetes’, they affect the body in different ways. They are classified as diabetes because of common symptoms like excessive urination and thirst.
- The two main types of diabetes insipidus are central diabetes insipidus and nephrogenic diabetes insipidus.
- Type 1 diabetes and diabetes insipidus are lifelong conditions. So, timely diagnosis and the right treatment are important.
