SIADH Nursing Diagnosis & Care Plan

Syndrome of inappropriate antidiuretic hormone (SIADH) occurs when the body releases excessive amounts of antidiuretic hormone (ADH), resulting in the retention of excess water in the body, causing hyponatremia

ADH is a hormone produced by the hypothalamus and stored and released by the pituitary gland. It plays an essential role in various processes in the body, including the balance of salt and water in the blood, kidney function, and the regulation of blood pressure. 

The common causes of SIADH include the following: 

Clinical manifestations of SIADH typically involve hyponatremia which causes nausea and vomiting, muscle cramps, muscle weakness, headache, problems with balance, mental changes, and seizures or coma in severe cases. 

There is no single test that can diagnose SIADH. Physical examination and fluid status are assessed as they are integral in confirming the possibility of dehydration or overhydration. In addition, healthcare providers may order tests that can help confirm hyponatremia, such as a comprehensive metabolic panel, urine osmolality test, osmolality blood test, and urine sodium and potassium tests. 

The Nursing Process

Since SIADH may be caused by different conditions, its treatment will vary. The initial steps in the treatment process, however, will be to limit fluid intake to prevent further accumulation of excess water in the body. Nurses play a key role in the implementation of strict fluid restriction, fluid status monitoring, accurate patient education on the disease process, and treatment adherence.

Excess Fluid Volume

Fluid volume excess is the main problem in patients with Syndrome of Inappropriate Antidiuretic Hormone.

Nursing Diagnosis: Excess Fluid Volume

  • Disease process 
  • Excessive fluid intake
  • Compromised regulatory mechanism 
  • Endocrine regulatory dysfunction 
  • Renal dysfunction

As evidenced by:

  • Intake exceeds output
  • Concentrated urine
  • Oliguria
  • Low sodium levels
  • Decreased hematocrit

Expected outcomes:

  • The patient will maintain electrolytes within acceptable ranges
  • The patient will maintain balanced intake and output


1. Assess mental status changes.
Low sodium can result in confusion, delirium, and seizures in severe causes, which can lead to coma and death. Subtle changes in mental status must be monitored for prompt intervention.

2. Monitor lab values.
SIADH primarily affects the patient’s ability to eliminate water effectively. This can cause low sodium levels, low serum osmolality, and alterations in kidney values.


1. Monitor urine output.
Urinalysis is often ordered to measure the patient’s urine concentration, sodium, and osmolality levels. Water retention may cause poor urine output.

2. Restrict fluids.
Fluid restriction is vital in SIADH as this can prevent further fluid retention in the body.

3. Administer medications as indicated.
Vasopressin antagonist medications like tolvaptan and conivaptan are given to block the action of ADH.

4. Administer diuretics as ordered.
Furosemide can be given to decrease urine concentration and increase water excretion.

Imbalanced Nutrition: Less than Body Requirements

Hyponatremia is a significant complication of Syndrome of Inappropriate Antidiuretic Hormone. This causes symptoms like cramping, loss of appetite, nausea, and vomiting. With frequent nausea and vomiting, imbalanced nutrition can occur. 

Nursing Diagnosis: Imbalanced Nutrition

  • Food aversion
  • Altered taste perception
  • Nausea and vomiting
  • Disease Process
  • Misinformation

As evidenced by:

  • Electrolyte imbalances
  • Food intake less than recommended daily allowance
  • Hypoglycemia

Expected outcomes:

  • The patient will maintain laboratory values within expected limits
  • The patient will verbalize how their disease process affects nutrition


1. Assess the extent of the patient’s symptoms.
Nausea and vomiting may occur with SIADH and can cause problems with nutrition. Vomiting is a serious symptom that can further worsen their condition.

2. Assess for underlying conditions.
SIADH is a complication of a condition. Cancers, lung diseases, brain injuries, and more can cause SIADH and may also affect intake and appetite.


1. Administer sodium chloride IV.
Though free water may be restricted to prevent fluid overload, IV sodium chloride may be ordered to treat hyponatremia.

2. Provide frequent small feedings.
This will help the patients stabilize blood sugar levels, improve satiety, and reduce the incidence of nausea and vomiting.

3. Administer salt tablets.
Especially if receiving diuretics, prescribed salt tablets can be administered to treat hyponatremia.

4. Administer antiemetics.
Vomiting is a concerning symptom related to SIADH that can worsen hyponatremia. The nurse can administer antiemetics to prevent further imbalance of electrolytes.

Deficient Knowledge

Patient education is an essential part of the management of Syndrome of Inappropriate Antidiuretic Hormone to prevent complications and symptoms.

Nursing Diagnosis: Deficient Knowledge

  • Misinformation 
  • Inadequate access to resources 
  • Inadequate awareness of resources
  • Inadequate commitment to learning 
  • Inadequate information 
  • Inadequate interest in learning

As evidenced by:

  • Inaccurate follow-through of instructions
  • Inaccurate statements about a topic 
  • Development of symptoms
  • Worsening lab values
  • Development of seizures or coma

Expected Outcomes:

  • The patient will verbalize an understanding of the disease, prognosis, and treatments
  • The patient will not develop preventable complications


1. Assess the patient’s ability to learn.
Since SIADH is usually related to another cause (cancer, stroke, infection), ensure the patient is competent and capable of carrying out learned concepts.

2. Assess the patient’s learning needs.
It is important to determine the patient’s learning needs as this can help formulate the best approach to provide accurate information.


1. Educate the patient about the condition, symptoms, and treatments.
Provide accurate information about the condition, symptoms, and treatments in layperson’s terms that the patient can understand.

2. Teach the patient about fluid restriction and its relation to SIADH.
Fluid restriction is a priority in the management of SIADH, as the main issue with this disease is fluid excess and hyponatremia.

3. Educate the patient about medications and their uses.
Providing accurate information about medications and how they work as part of the SIADH treatment regimen to ensure better adherence.

4. Involve the support system.
The patient may require the assistance of a support person in managing this condition, monitoring for symptoms, and communicating with the healthcare team.

References and Sources

  1. ACCN Essentials of Critical Care Nursing. 3rd Edition. Suzanne M. Burns, MSN, RRT, ACNP, CCRN, FAAN, FCCM, FAANP. 2014. McGraw Hill Education.
  2. Medical-Surgical Nursing: Concepts for Interprofessional Collaborative Care. 9th Edition. Donna D. Ignatavicius, MS, RN, CNE, ANEF. 2018. Elsevier, Inc.
  3. Syndrome of Inappropriate Antidiuretic Hormone (SIADH). Ann Pietrangelo. Reviewed by Graham Rogers, M.D. Updated June 6, 2017. From:
  4. Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH). Children’s Hospital of Philadelphia. 2022. From:
  5. Syndrome of inappropriate antidiuretic hormone secretion. Medline Plus Trusted Healthcare Information for You. Updated by Brent Wisse, MD, Board Certified in Metabolism/Endocrinology, Seattle, WA. Reviewed May 1, 2021. From:
  6. Syndrome of Inappropriate Antidiuretic Hormone Secretion. Yasir M, Mechanic OJ. [Updated 2022 May 9]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from:
Published on
Photo of author
Maegan Wagner is a registered nurse with over 10 years of healthcare experience. She earned her BSN at Western Governors University. Her nursing career has led her through many different specialties including inpatient acute care, hospice, home health, case management, travel nursing, and telehealth, but her passion lies in educating through writing for other healthcare professionals and the general public.