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Syndrome of Inappropriate ADH Secretion (SIADH)

A clinical picture of hyponatremia driven by ADH excess independent of osmotic stimulation.

Written by: Saygı Hospital Health Guide Editorial Board
Last updated:

This content has been compiled by the Saygı Hospital Health Guide Editorial Board and is periodically reviewed by a specialist physician.

References (5)

This content is for informational purposes only and does not constitute medical advice. You can book an appointment at our Endokrinoloji department. Book Appointment →

What is Syndrome of Inappropriate ADH Secretion (SIADH)?

Syndrome of inappropriate antidiuretic hormone secretion (SIADH) is a disorder in which secretion or action of ADH (vasopressin) is increased in the absence of an appropriate osmotic or volume stimulus, leading to water retention, hyponatremia, and concentrated urine.

Main causes include small cell lung cancer, central nervous system disorders (meningitis, stroke, trauma), pulmonary diseases (pneumonia, tuberculosis), drugs (SSRIs, carbamazepine, cyclophosphamide), and postoperative states.

Diagnostic criteria include euvolemic hypotonic hyponatremia, inappropriately concentrated urine (>100 mOsm/kg), urine sodium >30 mEq/L, an euvolemic state, and normal adrenal/thyroid function.

Symptoms

Headache, fatigue, and weakness
Nausea and vomiting
Difficulty concentrating and lethargy
Muscle cramps and weakness
Balance disturbance and falls
Confusion and memory impairment
Seizures and coma (in severe cases)

Risk Factors

Small cell lung cancer and other malignancies
Central nervous system diseases
Pulmonary infections and diseases
Use of SSRIs, carbamazepine, cyclophosphamide
Older age and hospitalization
Ecstasy (MDMA) use
Postoperative period

When to See a Doctor?

If you experience any of the following symptoms, seek medical attention promptly:

  • When unexplained hyponatremia is detected
  • If headache, confusion, and vomiting are present
  • Weakness and dizziness after starting a medication
  • New symptoms in patients with lung cancer
  • Seizures or change in consciousness (urgent)

Treatment Methods

01
Treatment of the underlying cause (tumor, infection, drug withdrawal)
02
Fluid restriction (first step), usually <1 L/day
03
High-salt foods and urea supplementation
04
3% hypertonic saline in severe/symptomatic cases (controlled)
05
Vaptans (tolvaptan) — in selected cases
06
Avoidance of osmotic demyelination syndrome

Which Department to Visit?

You can visit our Endokrinoloji department for these complaints. Our specialist physicians will create the most suitable treatment plan for you.

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Health Disclaimer: The information on this page is prepared for general informational purposes only. It does not replace medical diagnosis and treatment. Please consult your physician for your complaints. Saygı Hospital does not accept responsibility for actions taken based on the information on this page.