The key difference between diabetes insipidus and SIADH is that in diabetes insipidus, the body does not have enough ADH hormone, leading to increased urine output and dehydration, while in SIADH, the body has too much ADH hormone, preventing the production of urine and leading to the retention of excess water.
Diabetes insipidus and SIADH (syndrome of inappropriate antidiuretic hormone secretion) are two medical disorders that are centered on the changes in the activity of ADH (antidiuretic hormone). They require immediate attention and treatment.
CONTENTS
1. Overview and Key Difference
2. What is Diabetes Insipidus
3. What is SIADH
4. Similarities – Diabetes Insipidus and SIADH
5. Diabetes Insipidus vs SIADH in Tabular Form
6. Summary – Diabetes Insipidus vs SIADH
What is Diabetes Insipidus?
Diabetes insipidus is a medical condition of not having enough ADH hormone in the body, leading to increased urine output and dehydration. Diabetes insipidus is an uncommon medical disorder. It causes an imbalance in the fluids of the body. Moreover, this imbalance leads to the production of large amounts of urine. It also makes patients very thirsty even when they have something to drink. Diabetes insipidus is caused by problems in a hormone called ADH. ADH is produced by the hypothalamus and stored in the pituitary glands.
ADH plays a key role in regulating the amount of fluid in the body. When the amount of water in the body becomes too low, pituitary glands release ADH. It helps retain water in the body by reducing the amount of water lost through the kidneys, allowing the kidney to make more concentrated urine. Therefore, in diabetes insipidus, the lack of ADH means the kidneys cannot make enough concentrated urine. Therefore, too much water is passed from the body.
Figure 01: Diabetes Insipidus
The symptoms of diabetes insipidus include being extremely thirsty, producing large amounts of pale urine, frequently needing to urinate during the night, preferring cold drinks, infants or young children having heavy, wet diapers, bedwetting, trouble sleeping, fever, vomiting, constipation, delayed growth, and weight loss. This condition can be diagnosed through water deprivation tests, MRI scans, and genetic screening if other family members also suffer from the same disorder. Furthermore, treatments for diabetes insipidus are synthetic hormone called desmopressin (DDAVP) that replaces ADH, a low salt diet, drinking enough water to reduce dehydration, drug hydrochlorothiazide to improve symptoms and managing underlying conditions like mental illnesses.
What is SIADH?
SIADH (syndrome of inappropriate antidiuretic hormone secretion) is a medical condition involving too much ADH hormone in the body, which prevents the production of urine and leads to the retention of excess water. ADH is commonly released into the blood excessively due to medicines such as seizure drugs, antidepressants, cancer drugs, opiates, surgery under general anesthesia, disorders of the brain (injury, infection, stroke), brain surgery in the region of the hypothalamus, tuberculosis, cancer, chronic infections, lung disease, substance abuse, leukemia, cancers of the small intestine, and pancreas and mental disorders.
The symptoms of this condition include nausea or vomiting, cramps or tremors, depressed mood, memory impairment, irritability, personality changes (combativeness, confusion, and hallucinations), seizures, stupor, and coma. SIADH can be diagnosed through medical history, physical examination, and blood and urine tests to measure sodium, potassium, and osmolality. Furthermore, treatments for SIADH include fluid and water restriction, certain medications inhibiting ADH, surgical removal of tumors that cause high ADH, and other medicines that regulate blood fluid volume.
What are the Similarities Between Diabetes Insipidus and SIADH?
- Diabetes insipidus and SIADH are two medical disorders that are centered on the changes in the activity of ADH.
- Both disorders come under endocrine diseases.
- They are triggered by tumors and mental illnesses.
- Both disorders can be diagnosed by measuring the appropriate level of ADH in the human body.
- They are treated by endocrinologists by regulating the normal level of ADH in the human body.
What is the Difference Between Diabetes Insipidus and SIADH?
Diabetes insipidus is the medical condition of not having enough ADH hormone in the body, which leads to increased urine output and dehydration, while SIADH is the medical condition of having too much ADH hormone in the body, which prevents the production of urine and leads to the retention of excess water. Thus, this is the key difference between diabetes insipidus and SIADH.
Furthermore, diabetes insipidus is caused by low levels of ADH hormones due to damage to the pituitary or hypothalamus by a surgery or tumor, damage to the structure of the kidney by inherited conditions or certain medications, placental enzymes that destroy ADH, and damage to the thirst regulating mechanism in the hypothalamus. On the other hand, SIADH is caused by high levels of ADH hormone due to medicines such as seizure drugs, antidepressants, cancer drugs, opiates, surgery under general anesthesia, disorders of the brain (injury, infection, stroke), brain surgery in the region of hypothalamus, tuberculosis, cancer, chronic infections, lung disease, substance abuse, leukemia, etc.
The following table summarizes the difference between diabetes insipidus and SIADH.
Summary – Diabetes Insipidus vs SIADH
Diabetes insipidus and SIADH are two medical disorders that happen due to changes in the activity of ADH. In diabetes insipidus, the body does not have enough ADH hormone, which leads to increased urine output and dehydration, while in SIADH, the body has too much ADH hormone, which prevents the production of urine and leads to the retention of excess water in the body. So, this is the key difference between diabetes insipidus and SIADH.
Reference:
1. “Diabetes Insipidus.” Mayo Clinic, Mayo Foundation for Medical Education and Research.
2. “Syndrome of Inappropriate Antidiuretic Hormone Secretion.” MedlinePlus, U.S. National Library of Medicine.
Image Courtesy:
1. “Management of Hypernatremia” By en:User:HarishV – http://en.wikipedia.org/wiki/Image:Management_of_Hypernatremia.jpg (CC BY-SA 3.0) via Commons Wikimedia
2. “ADH Abnormalities” By Maen K. Househ – Own work (CC BY-SA 3.0) via Commons Wikimedia