Diabetes Insipidus
Sogol Mostoufi-Moab, MD
Sheela N. Magge, MD
Diabetes Insipidus - BASICS
Diabetes Insipidus - description
Polyuria and polydipsia caused by inability to produce or respond to antidiuretic hormone (ADH); also called arginine vasopressin
Diabetes Insipidus - incidence
Because most cases are secondary to another disease, the incidence depends on the primary causes.
Diabetes Insipidus - genetics
- Rare cases of autosomal-dominant transmission of antidiuretic hormone deficiency
- Nephrogenic diabetes insipidus (DI) is usually familial (autosomal recessive or dominant and X linked).
Diabetes Insipidus - pathophysiology
- Antidiuretic hormone stimulates the formation of cyclic adenosine monophosphate (cAMP) in the renal collecting ducts, thereby increasing water permeability and increasing reabsorption of free water.
- Lack of antidiuretic hormone effect results in urinary loss of free water.
- Patients with an intact thirst mechanism drink copiously (polydipsia) to compensate for free water loss.
- If the thirst mechanism is not present or if access to free water is limited (e.g., infants or vomiting), severe dehydration can occur.
Diabetes Insipidus - etiology
- Insufficient antidiuretic hormone secretion:
- Traumatic or postsurgical
- Nonaccidental injury in children
- Related to tumor invasion of posterior pituitary
- Extension from anterior pituitary/suprasellar: Optic glioma, rarely adenomas
- Hypothalamic: Germinoma, craniopharyngioma, meningioma
- Lymphoma
- Granulomas: Histiocytosis X, sarcoidosis
- Metastatic carcinoma
- Post–severe ischemic or hypoxic injury to the brain
- Familial (autosomal dominant)
- Congenital malformation of CNS
- Infection
- Viral encephalitis
- Meningitis
- Tuberculosis
- Increased metabolic clearance of antidiuretic hormone (gestational diabetes insipidus)
- Drug- or toxin-related: Snake venom, tetrodotoxin
- Autoimmune disorders: Hypophysitis
- Psychogenic: Excessive water drinking
- Idiopathic: Must observe for many years to exclude slow-growing tumors
- Unresponsive to antidiuretic hormone:
- Familial or nephrogenic (X-linked dominant and autosomal-recessive forms)
- Tumor related
- Urinary tract obstruction, especially in utero
- Renal medullary cystic disease
- Electrolyte disturbances: Hypokalemia, hypercalcemia (hypercalciuria)
- Drugs: Usually reversible (diuretics, diphenylhydantoin, reserpine, cisplatin, rifampin, lithium [may become permanent], demeclocycline, ethanol, chlorpromazine, volatile anesthetics, foscarnet, amphotericin B)
- Loss of the medullary concentrating gradient owing to excessive free water intake relative to solute intake
Pitfalls:
- Management of patients without an intact thirst mechanism and of newborns is difficult.
- Patients with psychogenic polydipsia may fail a water deprivation test because prolonged excessive water intake can wash out the renal medullary gradient required for concentrating the urine.
- Surreptitious water intake during water deprivation test
- Idiopathic, acquired diabetes insipidus can be caused by slowly growing brain tumors not visible on the initial magnetic resonance image.
Diabetes Insipidus - DIAGNOSIS
Diabetes Insipidus - signs & symptoms
Diabetes Insipidus - history
- Abnormal growth can be a sign of diabetes insipidus.
- Waking up during the night to drink or void:
- True diabetes insipidus is associated with polyuria throughout the day and night. Enuresis may be the first sign in a child who previously acquired bladder control. Patients, including infants, prefer water to other liquids such as juice, soda, or milk.
- Number of hours the patient goes without drinking:
- Patients with complete diabetes insipidus do not voluntarily stop drinking for >1–2 hours unless the thirst mechanism is also abnormal.
- Drinking everything including bath and toilet water:
- Patients with diabetes insipidus have such overwhelming thirst, they will drink anything.
- Volume of urine output in a day (not just frequency of urination):
- The daily volume of urine can be as high as 4–10 L. Younger or dehydrated children with diabetes insipidus tend to make less urine daily than older or hydrated children with diabetes insipidus.
- Familial history of diabetes insipidus:
- Nephrogenic diabetes insipidus will typically affect maternal uncles during infancy, and mothers may have a mild form
- Frequent episodes of dehydration requiring medical attention:
- Families may disregard the polydipsia as normal behavior. Repeated episodes of severe dehydration can damage the brain.
Diabetes Insipidus - physical exam
- Signs of dehydration:
- Diabetes insipidus is typically associated with dry, pale skin and mucous membranes. Because this is hyperosmolar dehydration, the patient may not look as severely dehydrated as she or he is.
- Complete neurologic examination:
- Check for impaired visual fields that can be the 1st sign of brain tumor.
Diabetes Insipidus - tests
Diabetes Insipidus - lab
- Morning urinary osmolality with simultaneous serum sodium and serum osmolality:
- If urine osmolality is at least 2 times higher than serum osmolality, patient does not have complete diabetes insipidus, but may still have partial diabetes insipidus.
- Water-deprivation test:
- Though definitive, it requires admission to the hospital for controlled testing under the close supervision of a pediatric endocrinologist. Patient fails test if urinary osmolality cannot concentrate more than twice serum osmolality at the same time that serum osmolality exceeds 305 mOsm/kg; serum osmolality exceeds 305 mOsm/kg at any time; patient loses >5% of body weight and becomes symptomatic from hypovolemia.
- Once patient fails the water-deprivation test, a dose of aqueous vasopressin should be given followed by close monitoring of urinary osmolality to document responsiveness to antidiuretic hormone.
- Never attempt a water-deprivation trial at home.
- Urinary specific gravity (nonspecific):
- Insufficient by itself and nondiagnostic during a water-deprivation test
- 24-hour urine collection (home testing):
- To obtain accurate urinary volume while patient has free access to water
Do not restrict water intake unless the patient is in the hospital under close surveillance!
Diabetes Insipidus - imaging
MRI of the head:
- To confirm the bright spot normally seen in the posterior pituitary and to search for tumors. Its absence is not pathognomonic of diabetes insipidus.
Diabetes Insipidus - differencial diagnosis
- Psychogenic polydipsia
- Abnormal thirst mechanism (dipsogenic diabetes insipidus)
- Hypernatremic dehydration
- Diabetes mellitus
- Polyuric renal failure (e.g., renal tubulopathy)
- Hypercalcemia
- Adrenal insufficiency
- Cerebral salt wasting
Diabetes Insipidus - TREATMENT
Diabetes Insipidus - general measures
Diabetes Insipidus - diet
- Patients with an intact thirst mechanism should drink only when thirsty.
- Patients without an intact thirst mechanism should drink only a carefully calculated fluid volume.
Diabetes Insipidus - medication
- DDAVP: Intranasal spray or oral tablets:
- Aqueous vasopressin: SC:
- Comes as 4 mcg/mL solution and doses range from 0.05 ์g up to 1 ์g SC b.i.d. daily. Titrate dose as you would with DDAVP.
- Duration of action of DDAVP is variable from patient to patient. Titration and frequency of dosing should be made by the family under the supervision of an endocrinologist.
- Control of diabetes insipidus in infants is more difficult because these patients may increase fluid intake because of hunger or increase caloric intake because of thirst, thereby causing an imbalance between free water intake and output. Some infants can be treated with diluted formula—the volume and frequency of feedings will be increased, but intake of free water will better match urine output. Strict record keeping of intake/output and accurate daily weighing are usually necessary for infants or patients without an intact thirst mechanism. All infants with diabetes insipidus must be treated by people experienced with diabetes insipidus of infancy.
- Nephrogenic diabetes insipidus may be treated with diuretics and solute restriction as these patients are resistant to DDAVP.
- Side effects:
- Facial flushing
- Increased BP
- Headache
- Nasal congestion
- Hyponatremia: Caused by water overdose (intoxication), not by overdose of drug. Taking a higher dose of DDAVP will generally extend the period of antidiuresis, but will not cause hyponatremia. Drinking too much water in the setting of antidiuresis causes hyponatremia. Water intoxication most often occurs in antidiuresed patients who also are on intravenous fluids, lack an intact thirst mechanism, or have psychogenic polydipsia.
- Duration:
- Lifelong generally. Some tumors regress with radiation, allowing recovery of antidiuretic hormone secretion.
- Possible conflicts with other treatments:
- Nasal congestion or GI illness can affect the absorption of DDAVP administered.
Diabetes Insipidus - FOLLOW UP
Diabetes Insipidus - prognosis
- Generally good, but depends on the primary cause
- May cause developmental delay if the hypernatremia is prolonged
Diabetes Insipidus - complications
- Without treatment and without access to water:
- Hypernatremia
- Dehydration
- Coma
- When overdosed with water:
- Hyponatremia
- Seizures
- Cerebral edema
Diabetes Insipidus - patient monitoring
- Depends on the patient and underlying disease causing diabetes insipidus
- When to expect improvement:
- Effects of DDAVP are immediate.
- Most cases of diabetes insipidus are lifelong. 1 exception is diabetes insipidus that occurs during the 7–10 days immediately after neurosurgery, since this postsurgical diabetes insipidus may resolve spontaneously within 1–2 weeks after surgery.
- Signs to watch for:
- Lethargy
- Somnolence
- Irritability
- Hyperpyrexia
- Any sign of dehydration
- Seizures
Diabetes Insipidus - bibliography
- Kirchlechner V, Koller DY, Seidl R, et al. Treatment of nephrogenic diabetes insipidus with hydrochlorothiazide and amiloride. Arch Dis Child. 1999;80(Jun):548–552.
- Leger J, Velasquez A, Garel C, et al. Thickened pituitary stalk on magnetic resonance imaging in children with central diabetes insipidus. J Clin Endocrinol Metab. 1999;84:1954–1960.
- Mootha SL, Barkovich AJ, Grumbach MM, et al. Idiopathic hypothalamic diabetes insipidus, pituitary stalk thickening, and the occult intracranial germinoma in children and adolescents. J Clin Endocrinol Metab. 1997;82:1362–1367.
- Robertson GL. Diabetes insipidus. Endocrinol Metab Clin North Am. 1995;24(Sep):549–572.
- Siegel AJ, Baldessarini RJ, Klepser MB, et al. Primary and drug-induced disorders of water homeostasis in psychiatric patients: Principles of diagnosis and management. Harv Rev Psychiatry. 1998;6(Nov–Dec):190–200.
Diabetes Insipidus - CODES
Diabetes Insipidus - icd9
253.5 Diabetes insipidus
Diabetes Insipidus - snomed
15771004 Diabetes insipidus (disorder)
Diabetes Insipidus - FAQ
- Q: In a patient with intact thirst mechanism and partial diabetes insipidus, is the use of DDAVP necessary?
- A: No, as long as the patient has constant access to free water.
- Q: How does therapy of diabetes insipidus affect daily life? Is it easily integrated into normal activity and eating patterns?
- A: DDAVP is used in a patient with intact thirst mechanism to facilitate the daily routine as well as to allow patients to sleep without the need to void frequently during the night.
- Q: Is there a longer-acting preparation or an implantable pump for dosing?
- A: The longest-acting form of antidiuretic hormone is an injected medication and can have effects for 3 days, increasing the risks of hyponatremia. Home use of the nasal spray or tablets, therefore, is easier and safer than the use of injections.
Book Source Details
- Book Title: The 5-Minute Pediatric Consult
- Author(s): M. William Schwartz MD; et al.
- Year of Publication: 2008
- Copyright Details: The 5-Minute Pediatric Consult, Copyright © 2008 Lippincott Williams & Wilkins.
Other Book Chapters Related to Diabetes insipidus
Read excerpts from these other book chapters related to Diabetes insipidus:
Medical Books Excerpts
- POLYDIPSIA
- "Algorithmic Diagnosis of Symptoms and Signs" (2003)
- [ read ]
- Polydipsia
- "Handbook of Signs & Symptoms (Third Edition)" (2006)
- [ read ]
- Polydipsia
- "Professional Guide to Signs & Symptoms (Fifth Edition)" (2006)
- [ read ]
- Polydipsia
- "The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter" (2000)
- [ read ]
- Polydipsia
- "Signs & Symptoms: A 2-in-1 Reference for Nurses" (2007)
- [ read ]
Copyright Details: The 5-Minute Pediatric Consult, Copyright © 2008 Williams & Wilkins.
More About Causes of Diabetes insipidus
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More About This Book:
Title: The 5-Minute Pediatric Consult
Authors: M. William Schwartz MD; et al.
Publisher: Lippincott Williams & Wilkins
Copyright: 2008
ISBN: 0-7817-7577-9
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