What are the symptoms of Syndrome of Inappropriate Antidiuretic Hormone (SIADH) secretion?

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Last updated: April 14, 2025View editorial policy

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From the Guidelines

Symptoms of SIADH primarily include general weakness, confusion, headache, and nausea, which can progress to life-threatening manifestations such as seizures, coma, and death if left untreated. According to the study by 1, the degree of hyponatremia and the acuity of hypoosmolality determine the signs and symptoms of SIADH.

Common Symptoms

  • General weakness
  • Confusion
  • Headache
  • Nausea

Severe Symptoms

  • Seizures
  • Coma
  • Death At serum sodium concentrations of 125 to 130 mEq/L, patients usually experience mild symptoms, while serum sodium levels below 120 mEq/L can lead to life-threatening manifestations 1.

Diagnostic Criteria

  • Hyponatremia (serum sodium < 134 mEq/L)
  • Hypoosmolality (plasma osmolality < 275 mosm/kg)
  • Inappropriately high urine osmolality (> 500 mosm/kg)
  • Inappropriately high urinary sodium concentration (> 20 mEq/L)
  • Absence of hypothyroidism or adrenal insufficiency or volume depletion Early detection and appropriate management of SIADH are crucial to prevent severe hyponatremia and its associated morbidity and mortality 1.

From the Research

Symptoms of SIADH

The symptoms of the Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH) are not explicitly listed in the provided studies. However, the studies discuss the condition and its treatment in relation to hyponatremia, which is a common electrolyte disorder characterized by low sodium levels in the blood.

Hyponatremia and SIADH

  • Hyponatremia is frequently associated with neurologic disorders and neurosurgical procedures 2.
  • SIADH is the most common cause of hyponatremia in hospitalized patients 2, 3, 4.
  • The available treatment options for SIADH are limited and not completely effective 3.
  • Vasopressin-receptor antagonists, such as conivaptan and tolvaptan, have been shown to be effective in treating hyponatremia secondary to SIADH 2, 5, 3, 4.

Treatment of SIADH

  • Conivaptan, an intravenous vasopressin-receptor antagonist, has been used to treat SIADH-induced hyponatremia in neurosurgical patients 2.
  • Tolvaptan, an oral vasopressin V2-receptor antagonist, has been shown to improve hyponatremia in patients with SIADH 5, 4.
  • The use of vasopressin-receptor antagonists, such as conivaptan and tolvaptan, may safely correct mild or moderate hyponatremia in patients with SIADH 4.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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