Doctor123.org

Diabetes Insipidus, Emergency Medicine

Basics

Description

- Disorder in which large volumes of dilute urine are excreted (polyuria) as an inappropriate response to argininevasopressin (AVP) - Polyuria defined as >3 L in 24 hr - Often characterized by excessive fluid intake (polydipsia) - 2 types: - Central diabetes insipidus (DI, CDI; failure or deficiency of AVP release): - 4 types: - No AVP to release (loss or malfunction of posterior pituitary neurons) - Defective osmoreceptors-release AVP only in response to severe dehydration - Elevated threshold for AVP release - Subnormal amount of AVP released

- Central DI: - Any condition that disrupts the osmoreceptor-hypothalamus-hypophyseal axis: - Highest incident in ages 10-20 yr - Trauma (skull fractures, hemorrhage) - Pituitary or hypothalamic surgery - CNS neoplasm: DI can be considered a tumor marker: - Pituitary adenomas - Craniopharyngiomas - Germinomas - Pinealomas - Meningiomas

- Transient in the 2nd trimester: - Unclear etiology, but there is an increase of circulating vasopressinase. - Leads to a decrease in AVP and transient DI - Watch patient closely during anesthesia and periods of water restriction. - Typically clears after 2-6 wk after delivery - Desmopressin (DDAVP) resists this vasopressinase.

- In children: - Enuresis - Difficulty with toilet training

- Clinical diagnosis in the ED: - Elevated serum sodium concentration - Copious amounts of dilute urine

- Electrolytes, BUN, creatinine, and glucose: - Hypernatremia - Hypercalcemia - Hypokalemia

- Primary sodium excess: - Excessive sodium bicarbonate during resuscitation - Hypernatremic enemas - Ingestion of seawater - Hypertonic saline administration - Accidental substitution of salt (sodium chloride) for glucose in infant formulas - Intentional salt poisoning - High breast milk sodium

- Primary polydipsia (psychogenic polydipsia): - Solute-induced polyuria - Diuretic use - Resolving acute renal failure - Osmotic diuresis - Uncontrolled DM

- Lysine vasopressin (lypressin): - Can be given intranasally - Frequent instillation needed

- Chlorpropamide (Diabinese): - Enhances effect of vasopressin at renal tubule - May stimulate AVP release - Useful only in partial CDI - Clofibrate stimulates the release of endogenous vasopressin.

- Nephrogenic DI: - Diuretics: - Induce natriuresis - Thiazides 1st line - Amiloride often used in combination with thiazides

- Dietary sodium restriction - Restrict solutes and avoid excessive drinking to prevent water intoxication. - Avoid alcohol (especially beer) intake. - Check daily weights. - NSAIDs (indomethacin)

  • Disorder in which large volumes of dilute urine are excreted (polyuria) as an inappropriate response to argininevasopressin (AVP)
  • Polyuria defined as >3 L in 24 hr
  • Often characterized by excessive fluid intake (polydipsia)
  • 2 types:Central diabetes insipidus (DI, CDI; failure or deficiency of AVP release):4 types:No AVP to release (loss or malfunction of posterior pituitary neurons)Defective osmoreceptors-release AVP only in response to severe dehydrationElevated threshold for AVP releaseSubnormal amount of AVP releasedFamilial cases have been reported (autosomal dominant).Nephrogenic DI (lack of renal response to AVP):Differentiate from primary polydipsia.Some cases are X-linked recessive in males.

Etiology

  • Central DI:Any condition that disrupts the osmoreceptor-hypothalamus-hypophyseal axis:Highest incident in ages 10-20 yrTrauma (skull fractures, hemorrhage)Pituitary or hypothalamic surgeryCNS neoplasm: DI can be considered a tumor marker:Pituitary adenomasCraniopharyngiomasGerminomasPinealomasMeningiomasMetastatic tumors:Granulomatous:Congenital CNS defectsCNS infections (e.g., meningitis, encephalitis)Pregnancy (Sheehan syndrome)Idiopathic (autoantibodies, occult tumor)Wolfram syndrome (DI, DM, optic atrophy, deafness)Ethanol
  • Nephrogenic DI:Any condition that disrupts the kidney:Congenital renal disordersObstructive uropathyRenal dysplasiaPolycystic kidney diseaseSystemic disease with renal involvementSickle cell diseaseSarcoidosisAmyloidosisDrugs:AmphotericinPhenytoinLithium (most common and persists past discontinuation of drug)AminoglycosidesMethoxyfluranceDemeclocyclineElectrolyte disorders:
  • Transient in the 2nd trimester:Unclear etiology, but there is an increase of circulating vasopressinase.Leads to a decrease in AVP and transient DIWatch patient closely during anesthesia and periods of water restriction.Typically clears after 2-6 wk after deliveryDesmopressin (DDAVP) resists this vasopressinase.
  • Sheehan syndrome may cause DI.

Diagnosis

Signs and Symptoms

History

  • Polyuria (up to 16-24 L/d of urine):Note the voiding frequency.
  • Polydipsia (often craves cold fluids):Note the amount of PO fluid intake per day.
  • Drug ingestion
  • Signs and symptoms of hypothalamic tumors:HeadacheVisual disturbancesGrowth disturbancesObesityHyperpyrexiaSleep disturbancesSexual precocityEmotional disturbances

Physical Exam

  • Dehydration
  • Cachexia
  • Head trauma
  • Visual field defects
  • Seizures
  • Polyuria and polydipsia may not be recognized by caregivers until symptoms of dehydration develop.
  • In neonates:Often present at birthIf unrecognized, dehydration and hypernatremia may cause permanent CNS damage.
  • In infants:IrritabilityPoor feeding/weight lossConstipationGrowth failureIntermittent high feverAbnormal behavior (hyperactivity, restlessness, excessive crying)
  • In children:EnuresisDifficulty with toilet training

Essential Workup

  • Clinical diagnosis in the ED:Elevated serum sodium concentrationCopious amounts of dilute urine
  • History:Usually an increased amount of PO fluid intake per dayVoiding frequencyMedication use history
  • Physical exam
  • Labs below

Diagnosis Tests & Interpretation

Lab

  • Urinalysis:Specific gravity will be low.
  • Serum and urine osmolality:High serum osmolalityLow urine osmolality
  • Electrolytes, BUN, creatinine, and glucose:HypernatremiaHypercalcemiaHypokalemia
  • CBC:Anemia may be a sign of a neoplasm.
  • Serum and urine AVP tests are expensive and unnecessary in the ED.

Imaging

  • As needed to evaluate for trauma or search for neoplasm
  • CXR
  • CT of brain
  • MRI of pituitary axis is usually outpatient.

Diagnostic Procedures/Surgery

Water deprivation test (dehydration test): пїЅ

  • Unnecessary in the emergency setting
  • Can be dangerous in cases of hypotension or small children
  • Performed as a confirmatory test for those receiving treatment
  • Measures urine and plasma osmolality after fluid restrictionUrine osmo <300 is significant for DIDesmopressin is administeredCentral DI-urine osmo increased by >50%Nephrogenic DI-urine osmo increased by <50%Further testing is needed if urine osmo 300-800Primary polydipsia if urine osmo >800

Differential Diagnosis

  • Primary water deficit:Inadequate access to free waterIncreased insensible water loss (e.g., premature infants)Inadequate breast-feeding
  • Primary sodium excess:Excessive sodium bicarbonate during resuscitationHypernatremic enemasIngestion of seawaterHypertonic saline administrationAccidental substitution of salt (sodium chloride) for glucose in infant formulasIntentional salt poisoningHigh breast milk sodium
  • Primary polydipsia (psychogenic polydipsia):Solute-induced polyuriaDiuretic useResolving acute renal failureOsmotic diuresisUncontrolled DM

Treatment

Pre-Hospital

  • ABCs
  • Immobilize if trauma is suspected.
  • Serum blood glucose
  • IV access and fluids if signs of dehydration exist
  • Control seizures according to medical direction guidelines.

Initial Stabilization/Therapy

  • Manage ABCs.
  • Manage traumatic injuries accordingly.
  • High index of suspicion for head trauma

Ed Treatment/Procedures

  • Correction of hypotension:Use of 0.9% NaCl is indicated for shock.Intravascular losses represent only about 1/12 of total water losses.
  • Central DI (vasopressin deficient):AVP (aqueous vasopressin):Half-life is too short.May induce coronary vasospasmUsed only for dehydration testLysine vasopressin (lypressin):Can be given intranasallyFrequent instillation neededDesmopressin:Drug of choice to control symptomsAdminister intranasally, SC, IV, or PO in 2 divided doses as necessary to control polyuria or polydipsia.Caution in postoperative patients as cerebral edema may developChlorpropamide (Diabinese):Enhances effect of vasopressin at renal tubuleMay stimulate AVP releaseUseful only in partial CDIClofibrate stimulates the release of endogenous vasopressin.
  • Nephrogenic DI:Diuretics:Induce natriuresisThiazides 1st lineAmiloride often used in combination with thiazidesDietary sodium restrictionRestrict solutes and avoid excessive drinking to prevent water intoxication.Avoid alcohol (especially beer) intake.Check daily weights.NSAIDs (indomethacin)
  • Parenteral correction of initial water deficit in cases where PO is not an option:Usually only in symptomatic hypernatremic casesFor fluid replacement, refer to "Hypernatremia."пїЅ

Medication

  • Aqueous AVP: 5-10 U SC in the unconscious patient from head trauma or postoperative
  • Amiloride: 2.5-10 mg PO BID
  • Chlorpropamide (Diabinese): 200-500 mg PO daily
  • Clofibrate (Atromid-S): 500 mg PO q6h
  • Desmopressin: 10-20 Ојg/d intranasally; 1-3 Ојg/d SC or IV; 0.1-1.2 Ојg/d PO
  • Hydrochlorothiazide (HCTZ): 50 mg PO daily (peds: 2-4 mg/kg QD-BID)
  • Lypressin nasal spray: 1-2 nasal spray TID-QID as needed

Follow-Up

Disposition

Admission Criteria

  • AMS
  • Seizure
  • Severe dehydration
  • Electrolyte abnormalities
  • Associated trauma
  • Patients requiring DDAVP testing or a trial of water restriction

Discharge Criteria

  • Known diagnosis of DI
  • Stable electrolytes
  • Adequately hydrated

Followup Recommendations

Referral to specialist depends on underlying etiology of DI. пїЅ

Pearls and Pitfalls

  • Check urine osmolality and consider DI in polyuria.
  • Central DI will typically respond to desmopressin.
  • Nephrogenic DI will not respond to ADH:Treat the underlying electrolyte abnormality, discontinue concerning drugs, and consult nephrology for further management.

Additional Reading

  • Di lorgi пїЅN, Napoli пїЅF, Allegri пїЅAE, et al. Diabetes insipidus - diagnosis and management. Horm Res Paediatr. 2012;77:69-84.
  • Fenske пїЅW, Allolio пїЅB. Current state and future perspectives in the diagnosis of diabetes insipidus: A clinical review. J Clin Endocrinol Metab. 2012;97(10):3426-3437.
  • Gardner пїЅDG, Shoback пїЅD, eds. Endocrine emergencies. In: Greenspans Basic & Clinical Endocrinology. 9th ed. McGraw-Hill Professional; 2011.
  • Kliegman пїЅRM. ed. Diabetes insipidus. In: Nelson Textbook of Pediatrics. 19th ed. Philadelphia, PA: Elsevier Saunders; 2011.
  • Makaryus пїЅAN, McFarlane пїЅSI. Diabetes insipidus: Diagnosis and treatment of a complex disease. Cleve Clin J Med. 2006;73:65-71.

See Also (Topic, Algorithm, Electronic Media Element)

Codes

ICD9

  • 253.5 Diabetes insipidus
  • 588.1 Nephrogenic diabetes insipidus

ICD10

  • E23.2 Diabetes insipidus
  • N25.1 Nephrogenic diabetes insipidus

SNOMED

  • 15771004 Diabetes insipidus (disorder)
  • 111395007 Nephrogenic diabetes insipidus (disorder)
  • 42021008 Familial diabetes insipidus
  • 45369008 Neurohypophyseal diabetes insipidus (disorder)
  • 77274005 Idiopathic diabetes insipidus (disorder)