Diabetes Insipidus View online at http://pier.acponline.org/physicians/diseases/d145/d145.html Module Updated: 2013-01-29 CME Expiration: 2016-01-29 Author Robert J. Ferry, Jr., MD Table of Contents 1. Diagnosis ..........................................................................................................................2 2. Consultation ......................................................................................................................8 3. Hospitalization ...................................................................................................................10 4. Therapy ............................................................................................................................11 5. Patient Counseling ..............................................................................................................16 6. Follow-up ..........................................................................................................................17 References ............................................................................................................................19 Glossary................................................................................................................................22 Tables ...................................................................................................................................23 Figures .................................................................................................................................39 Quality Ratings: The preponderance of data supporting guidance statements are derived from: level 1 studies, which meet all of the evidence criteria for that study type; level 2 studies, which meet at least one of the evidence criteria for that study type; or level 3 studies, which meet none of the evidence criteria for that study type or are derived from expert opinion, commentary, or consensus. Study types and criteria are defined at http://smartmedicine.acponline.org/criteria.html Disclaimer: The information included herein should never be used as a substitute for clinical judgement and does not represent an official position of the American College of Physicians. Because all PIER modules are updated regularly, printed web pages or PDFs may rapidly become obsolete. Therefore, PIER users should compare the module updated date on the offical web site with any printout to ensure that the information is the most current available. CME Statement: The American College of Physicians is accredited by the Accreditation Council for Continuing Medical Education (ACCME) to provide continuing education for physicians. The American College of Physicians designates this enduring material for a maximum of 1 AMA PRA Category 1 CreditTM. Physicians should claim only credit commensurate with the extent of their participation in the activity. Purpose: This activity has been developed for internists to facilitate the highest quality professional work in clinical applications, teaching, consultation, or research. Upon completion of the CME activity, participants should be able to demonstrate an increase in the skills and knowledge required to maintain competence, strengthen their habits of critical inquiry and balanced judgement, and to contribute to better patient care. Disclosures: Robert J. Ferry, Jr., MD, current author of this module, has no financial relationships with pharmaceutical companies, biomedical device manufacturers, or health-care related organizations. Deborah Korenstein, MD, FACP, Co-Editor, PIER, has no financial relationships with pharmaceutical companies, biomedical device manufacturers, or health-care related organizations. Richard B. Lynn, MD, FACP, Co-Editor, PIER, has no financial relationships with pharmaceutical companies, biomedical device manufacturers, or health-care related organizations. PIER is copyrighted ©2013 by the American College of Physicians. 190 N. Independence Mall West, Philadelphia, PA 19106, USA. Diabetes Insipidus Top 1. Diagnosis Confirm the diagnosis of DI with appropriate laboratory testing in patients with chronic thirst, increased fluid intake (polydipsia) or increased urination (polyuria), urinary frequency, enuresis, or nocturia. 1.1 Perform a complete history and physical exam to identify characteristics associated with DI and to identify its etiology. Recommendations • Ask about: Persistent thirst, particularly craving water or cold liquids Urinary frequency, enuresis, or nocturia Duration or persistence of symptoms (typically of insidious onset, unless postoperative) Appearance of the urine (typically very light colored or clear with DI) Family history of similar symptoms or diagnosis of DI or diabetes mellitus Headaches Head trauma Recent neurosurgery History of pituitary disease and anterior pituitary hormone deficiencies Menstrual irregularity Pregnancy-related polyuria and polydipsia History of renal or systemic disease Medications and nutritional supplements • Look for: Signs of focal neurologic deficits Congenital anomalies, particularly facial malformations Visual field deficits and examination of optic nerve Galactorrhea Signs of secondary adrenal insufficiency or secondary hypothyroidism Growth failure or delayed puberty in pediatric patients Signs of dehydration, including hemodynamic and mental status changes (rare) • See table Etiologies of Central Diabetes Insipidus. • See table Etiologies of Nephrogenic Diabetes Insipidus. • See table Definitions of Diabetes Insipidus. Evidence • The risk for DI is highest with procedures near the pituitary, which are most often performed to debulk neoplasms (e.g., craniopharyngioma, astrocytoma, or retinoblastoma) (1). • A 1999 review from a German university hospital documented postoperative DI in 59.4% of adult patients undergoing transsphenoidal procedures (2). • Gestational DI is transient and typically remits by 2 months postpartum (3); it is usually responsive to desmopressin administration, but not AVP, because the placenta metabolizes AVP; desmopressin resists placental degradation. Pregnancy may exacerbate preexisting DI (4). PIER is copyrighted ©2013 by the American College of Physicians. 190 N. Independence Mall West, Philadelphia, PA 19106, USA. Page 2 of 37 Diabetes Insipidus • Less than 5% of patients with DI present with hypernatremia; their manifestations include altered mental status, lethargy, irritability, restlessness, seizures (more common in children), muscle twitching, spasticity, fever, nausea, or vomiting (5). • The defects most associated with DI appear to be holoprosencephaly or optic nerve hypoplasia with absence of the septum pellucidum (6). • The funduscopic exam may reveal papilledema due to increased CSF production or blocked CSF circulation from a CNS lesion (7). Rationale • The specific etiology of DI directs treatment and follow-up management. • Although rare, hemodynamic instability and mental status changes should be addressed emergently as evaluation of the polyuria proceeds, because hemodynamic instability occurs only when fluid intake is impaired and severe hypernatremic dehydration develops. • Nephrogenic DI can be induced by certain drugs Comments • DI is a disorder characterized by the inability to appropriately concentrate the urine, resulting from either deficient release of AVP (pituitary or central DI) or resistance to vasopressin action at the level of the distal renal tubule and collecting duct (nephrogenic DI). In the first half of the 20th century, Professor Ernest Verney first linked DI to a decrease in AVP secretion or action (8). • Historical or physical evidence of an injury, disorder, or therapy known to be a frequent cause of DI should prompt evaluation for DI. • DI itself does not usually result in any appreciable abnormal physical sign; however, absence of historical or physical evidence of a known cause does not exclude the diagnosis of DI. • Dehydration associated with DI most often occurs as a result of coexistent morbidity, such as anorexia, malabsorption, adrenal insufficiency, or cerebral salt wasting. 1.2 Measure urinary output from patients after neurosurgery or head trauma to anticipate the development of central DI. Recommendations • Measure urinary output hourly and urinary specific gravity every 4 hours throughout the initial 72 hours after head trauma or neurosurgery to monitor for dilute polyuria, which is defined as: Urine specific gravity <1.010 Urine output >3 mL/kg·h • See table Laboratory and Other Studies for Diabetes Insipidus. Evidence • Increased incidence of DI has been reported after transsphenoidal procedures to approach parasellar masses (9); however, the incidence appears to be lower than that with other craniotomies. • Several studies suggest that frequent, serial assessments of urinary output and serum sodium concentrations after transsphenoidal surgery reduce the severity of complications associated with DI by facilitating prompt diagnosis and early intervention (10; 11). • In a cohort study, 102 consecutive patients (85 males) who suffered severe or moderate traumatic brain injury were evaluated for DI at a median of 17 months after the injury using the 8-hour water deprivation test. Permanent DI was present in 6.9% of the patients who survived the injury (12). Rationale PIER is copyrighted ©2013 by the American College of Physicians. 190 N. Independence Mall West, Philadelphia, PA 19106, USA. Page 3 of 37 Diabetes Insipidus • After neurosurgery or head trauma, patients may