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SynopsisCodesLook ForDiagnostic PearlsDifferential Diagnosis & PitfallsBest TestsManagement PearlsTherapyDrug Reaction DataReferences
Emergency: requires immediate attention
Syndrome of inappropriate antidiuretic hormone
Other Resources UpToDate PubMed
Emergency: requires immediate attention

Syndrome of inappropriate antidiuretic hormone

Contributors: Shea A. Nagle MPH, Benjamin L. Mazer MD, MBA, Christine Osborne MD, Michael W. Winter MD
Other Resources UpToDate PubMed

Synopsis

The syndrome of inappropriate antidiuretic hormone (SIADH) is defined by inappropriate secretion of antidiuretic hormone resulting in hyponatremia and hypoosmolality in the setting of normal or increased plasma volume, leading to impaired water excretion. SIADH is caused either by inappropriate secretion of antidiuretic hormone (ADH) from the hypothalamus or from an ectopic source. SIADH may arise from postoperative stress, pain, or nausea. It also commonly manifests as a paraneoplastic syndrome.

Causes of SIADH can be divided into the following categories (more than one cause is often present, and sometimes no cause is identified):
Hyponatremia is the most common electrolyte derangement. Elderly patients, adults with cirrhosis or heart failure, patients with cancer, and children with pulmonary or gastrointestinal infections are at highest risk for developing SIADH.

Presenting symptoms relate to the rapidity of development of hyponatremia. Patients with slowly progressive hyponatremia are often asymptomatic, while those with rapid development of hyponatremia may present with headache, confusion, anorexia, malaise, or even seizures and coma. Physical examination often reveals a normotensive and euvolemic patient.

Codes

ICD10CM:
E22.2 – Syndrome of inappropriate secretion of antidiuretic hormone

SNOMEDCT:
55004003 – Syndrome of inappropriate vasopressin secretion

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Diagnostic Pearls

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Differential Diagnosis & Pitfalls

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Best Tests

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Management Pearls

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Therapy

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Drug Reaction Data

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References

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Last Reviewed:03/26/2019
Last Updated:10/31/2023
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Emergency: requires immediate attention
Syndrome of inappropriate antidiuretic hormone
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A medical illustration showing key findings of Syndrome of inappropriate antidiuretic hormone : Abdominal pain, Altered mental state, Fatigue, Headache, Nausea, Vomiting, Hyponatremia, Malaise, Confusion
Copyright © 2024 VisualDx®. All rights reserved.