Endocrine

Syndrome of Inappropriate ADH

Reading Time:

Pathology

Inappropriate anti-diuretic hormone secretion leading to water retention and relative hyponatraemia. 

Aetiology

Idiopathic
Endocrine: Hypothyroidism, Addison’s Disease
Ectopic Production: Small cell lung cancer, pneumonia, abscess, TB
Malignancy: Lung, pancreas, ovary, lymphoma, thymoma
CNS: Tumour, trauma, infection, strike, multiple sclerosis, Guillain-Barre 
Syndrome, meningitis, encephalitis, subarachnoid haemhorrhage
Drugs: SSRIs, TCAs, opiates, haloperidol, MAOIs, diuretics, NSAIDs

Signs

Weakness, coma, euvolaemia, papilloedema, myoclonus, ataxia, tremor

Symptoms

Fatigue, confusion, falls, seizures, inappropriate thirst, headache, nausea

Investigations

Bloods: U&E – hyponatramia, serum osmolarity, TFTs and Cortisol
MSU: Urinary sodium (raised) and osmolarity
Imaging: CT head to assess for malignancy

Treatment

Fluid restriction, Demeclocycline

Prognosis

Usually good for idiopathic or drug related causes
Central pontine myelinolysis with rapid correction; to prevent this a sodium 
correction rate of 0.5-1mmol/hour should be used

Key Facts

Lorem ipsum dolor sit amet, sapien platea morbi dolor lacus nunc, nunc ullamcorper. Felis aliquet egestas vitae, nibh ante quis quis dolor sed mauris.

Key Images

Lorem ipsum dolor sit amet, sapien platea morbi dolor lacus nunc, nunc ullamcorper. Felis aliquet egestas vitae, nibh ante quis quis dolor sed mauris.

Key References

Lorem ipsum dolor sit amet, sapien platea morbi dolor lacus nunc, nunc ullamcorper. Felis aliquet egestas vitae, nibh ante quis quis dolor sed mauris.