Syndrome of inappropriate antidiuretic hormone secretion

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The syndrome of inappropriate antidiuretic hormone secretion (SIADH or SIAD) (also known as Schwartz-Bartter syndrome) was initially described in patients withlung cancer who developed hyponatraemia associated with continued urinary sodium loss. The result is often dilutional hyponatremia in which the sodium remains normal but total body fluid increases.

Pathology

Aetiology

Inappropriate (excessive) release of antidiuretic hormone (ADH), now known as arginine-vasopressin (AVP), may be caused by^4,6:

malignant tumours, in particular: head and neck cancer, non-small cell lung cancer, small cell lung cancer (representing a paraneoplastic syndrome)
- also: GU and GI malignancies, lymphoma, Ewing sarcoma,
lung diseases
- infections
  - pneumonia (bacterial/viral)
  - lung abscess
  - tuberculosis
  - aspergillosis
- asthma
- cystic fibrosis
- positive pressure ventilation
~~conditions with decreased left atrial pressure~~CNS disease
- infections
  - encephalitis
  - meningitis
  - brain abscess
  - HIV/AIDS
- haemorrhage
- miscellaneous
  - head injury
  - hydrocephalus
  - cavernous sinus thrombosis
  - multiple sclerosis
  - Guillain–Barré syndrome
  - Shy–Drager syndrome
  - delirium tremens
  - acute intermittent porphyria
drugs
- antidepressants
  - selective serotonin reuptake inhibitors (SSRIs)
  - tricyclic antidepressants (TCA)
- carbamazepine, oxcarbazepine
- cyclophosphamide, ifosfamide
- hydrochlorothiazide, thiazides
- non-steroidal anti-inflammatory drugs (NSAIDs)
- vincristine
- neuroleptic agents
- AVP analogues: desmopressin, vasopressin
- , oxytocin
- chlorpropamide
- clofibrate
- MDMA ("ecstasy")

Treatment and prognosis

The optimal therapy for SIADH is to treat the underlying cause. If this is not possible, or if the disease has become refractory, other treatment methods are available such as water restriction, demeclocycline therapy, or in severe cases infusion of hypertonic saline together with furosemide during careful monitoring.

History and etymology

In 1957 William B Schwartz and colleagues (including the American endocrinologist Frederic Bartter) an American nephrologist, first described the syndrome of inappropriate antidiuretic hormone secretion. ‘Inappropriate’ was employed because of the observed loss of the normal linkage between ADH secretion and serum osmolality ^4,5.

-<p>The <strong>syndrome of inappropriate antidiuretic hormone secretion </strong>(<strong>SIADH</strong> or <strong>SIAD</strong>) (also known as <strong>Schwartz-Bartter syndrome</strong>) was initially described in patients with<strong> </strong><a href="/articles/lung-cancer-3">lung cancer</a> who developed hyponatraemia associated with continued urinary sodium loss. The result is often dilutional hyponatremia in which the sodium remains normal but total body fluid increases.</p><h4>Pathology</h4><h5>Aetiology</h5><p>Inappropriate (excessive) release of antidiuretic hormone (ADH), now known as arginine-vasopressin (AVP), may be caused by: </p><ul>
-<li>malignant tumours, in particular: head and neck cancer, <a href="/articles/non-small-cell-lung-cancer-2">non-small cell lung cancer</a>, <a href="/articles/small-cell-lung-cancer-4">small cell lung cancer</a> (representing a <a href="/articles/paraneoplastic-syndromes">paraneoplastic syndrome</a>)</li>
~~-<li>infections</li>~~
+<p>The <strong>syndrome of inappropriate antidiuretic hormone secretion </strong>(<strong>SIADH</strong> or <strong>SIAD</strong>) (also known as <strong>Schwartz-Bartter syndrome</strong>) was initially described in patients with<strong> </strong><a href="/articles/lung-cancer-3">lung cancer</a> who developed hyponatraemia associated with continued urinary sodium loss. The result is often dilutional hyponatremia in which the sodium remains normal but total body fluid increases.</p><h4>Pathology</h4><h5>Aetiology</h5><p>Inappropriate (excessive) release of antidiuretic hormone (ADH), now known as arginine-vasopressin (AVP), may be caused by <sup>4,6</sup>: </p><ul>
+<li>malignant tumours, in particular: head and neck cancer, <a href="/articles/non-small-cell-lung-cancer-2">non-small cell lung cancer</a>, <a href="/articles/small-cell-lung-cancer-4">small cell lung cancer</a> (representing a <a href="/articles/paraneoplastic-syndromes">paraneoplastic syndrome</a>)<ul><li>also: GU and GI malignancies, <a title="Lymphoma" href="/articles/lymphoma">lymphoma</a>, <a title="Ewing sarcoma" href="/articles/ewing-sarcoma">Ewing sarcoma</a>, </li></ul>
+</li>
+<li>lung diseases<ul>
+<li>infections<ul>
+<li>
+<a href="/articles/pneumonia">pneumonia</a> (bacterial/viral)</li>
+<li><a href="/articles/lung-abscess">lung abscess</a></li>
+<li><a href="/articles/tuberculosis-pulmonary-manifestations-1">tuberculosis</a></li>
+<li><a href="/articles/pulmonary-aspergillosis">aspergillosis</a></li>
+</ul>
+</li>
+<li><a href="/articles/asthma-1">asthma</a></li>
+<li><a href="/articles/cystic-fibrosis">cystic fibrosis</a></li>
~~-<li>conditions with decreased left atrial pressure</li>~~
+</ul>
+</li>
+<li>CNS disease<ul>
+<li>infections<ul>
+<li>encephalitis</li>
+<li><a href="/articles/leptomeningitis">meningitis</a></li>
+<li><a href="/articles/brain-abscess-1">brain abscess</a></li>
+<li><a href="/articles/hivaids">HIV/AIDS</a></li>
+</ul>
+</li>
+<li>haemorrhage<ul>
+<li><a href="/articles/subdural-haemorrhage">subdural haematoma</a></li>
+<li><a href="/articles/subarachnoid-haemorrhage">subarachnoid hemorrhage</a></li>
+<li><a href="/articles/stroke">stroke</a></li>
+</ul>
+</li>
+<li>miscellaneous<ul>
+<li>head injury</li>
+<li><a title="Hydrocephalus" href="/articles/hydrocephalus">hydrocephalus</a></li>
+<li><a href="/articles/cavernous-sinus-thrombosis">cavernous sinus thrombosis</a></li>
+<li><a href="/articles/multiple-sclerosis">multiple sclerosis</a></li>
+<li><a href="/articles/guillain-barre-syndrome-2">Guillain–Barré syndrome</a></li>
+<li><a href="/articles/shy-drager-syndrome-2">Shy–Drager syndrome</a></li>
+<li>delirium tremens</li>
+<li>acute intermittent porphyria</li>
+</ul>
+</li>
+</ul>
+</li>
~~-<li>desmopressin, vasopressin</li>~~
~~-<li>oxytocin</li>~~
+<li>AVP analogues: desmopressin, vasopressin, oxytocin</li>
+<li>MDMA ("ecstasy")</li>