Elevated ADH

Increased concentration of arginine vasopressin (antidiuretic hormone) above the reference level (<4.3 pg/mL), leading to enhanced renal water reabsorption, impaired free water excretion, and a tendency toward euvolemic hyponatremia.

Causes

• Syndrome of inappropriate antidiuretic hormone secretion (SIADH)

• Central nervous system (CNS) disorders

  • Stroke

  • Meningitis

  • Encephalitis

  • Head trauma

  • Brain tumors

• Medications

  • Selective serotonin reuptake inhibitors (SSRIs)

  • Anti-seizure medications

  • Opioids

• Malignancy

  • Small cell lung cancer

• Pulmonary diseases

  • Pneumonia

  • Tuberculosis

  • Lung abscess

• Physiologic stress

  • Major surgery

  • Intense pain

  • Severe nausea