Pediatric Diabetes Insipidus Clinical Presentation

Updated: Sep 27, 2017
  • Author: Karl S Roth, MD; Chief Editor: Robert P Hoffman, MD  more...
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Presentation

History

Diagnosis of diabetes insipidus (DI) may be difficult in infants and children because of nonspecific presenting features (eg, poor feeding, failure to thrive, irritability). Accordingly, a high index of suspicion is necessary.

The earliest signs of DI include a vigorous suck with vomiting, fever without apparent cause, constipation, and excessively wet diapers from urination. In older infants and young children, irritability is generally due to a borderline state of dehydration coupled with hypernatremia and, sometimes, fever. Nocturia is common and expected because of increased urine production. Central DI tends to develop suddenly.

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Physical Examination

The typical examination reveals an irritable infant with a dripping wet diaper, along with detectable signs of dehydration (eg, dry mucous membranes, diminished skin turgor, decreased tearing, tachycardia). Often, skin turgor is not diminished in individuals with hypernatremic dehydration despite significant dehydration. In severely dehydrated patients, the pulse may be thready and rapid. Hypotension may be present because of hypovolemic shock. Mobile fecaliths may be palpable in the abdomen.

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Complications

Complications include the following:

  • Growth failure

  • Nocturia and enuresis

  • Hypernatremic dehydration

  • Seizures

  • Mental retardation

Dehydration results from an inability to reabsorb free water at a site distal to electrolyte reabsorption. Any patient unable to continuously replace water loss is vulnerable to dehydration, especially in warm weather when insensible water loss through perspiration and respiration substantially increases risk.

Electrolyte abnormalities are caused by the loss of urinary free water, which produces hyperosmolar dehydration, leading to hypernatremia, hyperchloremia, and prerenal azotemia. Diminished blood volume increases blood viscosity and the risk of sludging and thrombosis.

Failure to thrive occurs because of the patient’s constant thirst conferring a sense of fullness that offsets the sense of hunger. The affected individual eats less than necessary for normal growth.

Seizures are a consequence of the electrolyte abnormalities introduced in the central nervous system (CNS) by severe hypernatremia and hyperosmolar dehydration. Mental retardation results from the damage to the CNS caused by severe hyperosmolarity, seizures, and potential hypoxia, all of which are thought to account for the frequent occurrence of mental retardation. Death can occur from a hypovolemic shock or a hypernatremic seizure.

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