Diabetes insipidus natural history, complications and prognosis

If left untreated, diabetes insipidus results in an elevation in serum sodium and osmolality. The hyperosmolarity seen in these patients may also present with neurologic symptoms such as confusion, altered mental status, seizures, coma, and death. The two major complications of diabetes insipidus are dehydration and electrolyte imbalance . Some research also demonstrates that there is decrease in bone mineral density seen in patients with diabetes insipidus. However, the mechanism of development is not clearly understood neither is the treatment clearly accounted for because treatment of diabetes insipidus does not reverse the disorder.

• Diabetes insipidus if left untreated results in an elevation in serum sodium and osmolality. The hyperosmolarity seen in this patients may also present with neurologic symptoms such as confusion, altered mental status, seizures, coma, and death.
• The serum sodium concentration in untreated central diabetes insipidus is often in the high to normal range. This is required in order to provide the sensation of thirst in a patient and stimulate drinking in order to replace the water lost in the urine. However, in patients that have some form of central nervous disorders, moderate to severe hypernatremia can develop as thirst is impaired or cannot be expressed. This can also occur in infants and young children who cannot independently access free water, and in the postoperative period in patients with unrecognized diabetes insipidus (DI).
• Patients with CDI may develop decreased bone mineral density at the lumbar spine and femoral neck, even in those treated with desmopressin (dDAVP).^[1] It is unclear how the deficiency of ADH results in bone loss, particularly since treatment fails to prevent bone disease. However, since ADH acts upon both V1 and V2 receptors and desmopressin principally upon V2 receptors, one possible mechanism is that activation of V1 receptors stimulates bone formation.

There are two major complications of untreated diabetes insipidus:

Due to the inability of the body to retain water, patients with diabetes insipidus are prone to dehydration if the water lost is not appropriately restored by giving IV fluids in the hospital as oral drinking of water may not be sufficient to restore lost water at the same rate especially in infants and the elderly. It is important to watch out for signs and symptoms of dehydration which include:

• Dizziness or light-headedness
• Headache
• Dry mouth and lips
• Sunken eyes and fontanelles in infants and children
• Confusion and irritability

Diabetes insipidus can also cause an electrolyte imbalance. Some of the electrolyte imbalances include:

• hypernatremia from polyuria (seen in both central and nephrogenic DI)
• hyponatremia from polydipsia (seen in psychogenic DI)
• hypokalemia
• hypercalcemia

Polydipsia can cause an increase in the concentration of these electrolytes simply because of decrease in the plasma concentration of the blood. Dehydration disrupts other functions of the body, such as the way muscles work. The most important symptoms that may be associated with electrolyte imbalance include:

• Headache
• Fatigue
• Irritability
• Myalgias
• Palpitations

The prognosis of diabetes insipidus is good as long as the underlying cause is identified early before the onset of complications and treated early.

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