Download 11/4/16 - ERS 4 KIDS

Case discussion
ED conference 11/04/16
JELTE KELCHTERMANS
Case description:
A 5-year-old girl presents to the ED with a 4-day history of NBNB vomiting. The patient has
had several episodes of watery non bloody diarrhea over the first two days of illness but
has had well formed stools of the past two days. The patient also has a 5-day history of
rhinorrhea.
Mother reports that over the last 24 hours the patient has been less active. No associated
abdominal pain, dysuria, fever, chills, rash, cough, change in fluid intake or urine output.
The patient visited the ED on day 2 of illness and was diagnosed with a probable viral
Gastroenteritis and discharged after passing an oral tolerance test. No significant past
medical or surgical history. No significant family history. Not currently taking any
medications. No known allergies. Vaccinations are up to date.
Bp 100/50 mmHg, RR 30/min, HR 140/min. The patients’ urine specific gravity is 1.004 and
her blood sodium level is 146 mmol/L.
What test is most likely to reveal the
underlying diagnosis?
1. Brain MRI
2. Kidney MRI
3. ADH level
4. Water deprivation test
5. Stool culture
What test is most likely to reveal the
underlying diagnosis?
1. Brain MRI
2. Kidney MRI
3. ADH level
4. Water deprivation test
5. Stool culture
Diabetes insipidus
Polydipsia and polyuria:
◦ Central Diabetes insipidus (most common with 3/100,000)
◦ Nephrogenic diabetes insipidus
◦ Compulsive water drinking
Central (Hypothalamic/Pituitary Lesions Leading to
Insufficient Production or Release of ADH)
Postoperative brain surgery
Intracranial lesions (cysts, aneurysms, tumors of pituitary, brainstem)
Infiltrative malignancies (lymphoma, leukemia)
Infections, including encephalitis, meningitis, abscess
Head trauma
Hypoxic injury
Congenital, inherited as an autosomal dominant disorder
Nephrogenic (Resistance to ADH due to interference with the
Renal Concentrating Mechanism)
Acquired metabolic aberrations
◦ Hypokalemia (chronic, Bartter syndrome)
◦
Hypercalcemia
◦
Hypercalciuria (rare)
◦
Diabetes mellitus
Medullary damage
◦ Chronic pyelonephritis
◦
Infiltrative disease (leukemia, lymphoma, amyloidosis)
◦
Sickle cell disease
◦
Cystinosis
◦
Other forms of chronic renal failure
◦
Obstructive uropathy
Drugs (lithium, demeclocycline, amphotericin B, diphenylhydantoin)
Inherited
◦ X-linked
◦
Autosomal recessive
Autosomal dominant
Pathophysiology
Presentation
1. Poor feeding + failure to thrive due to excessive fluid consumption and
blunted appetite
2. Irritability due to hypernatremia and dehydration
3. Nocturia due to large urine volume
4. Constipation due to dehydration
5. Seizures and dehydration may develop with late recognition of the
disease
6. High urine output despite dehydration
Diagnosis
1. Blood/urine glucose (DD DM)
2. 24 hour urine
3. Urinary specific gravity
4. Water deprivation test (DD severe DI vs mild DI and polydipsia)
5. DDAVP intranasal test (DD Nephrogenic and Central DI)
6. MRI of the brain (Loss of bright T1-weighted signal within the sella)
Management
1. Sufficient water to maintain normal electrolytes
2. Low renal solute load to minimize water loss
◦ If urine concentrates to 1,000 mOsm/kg of water (normal), the kidney can
excrete a solute load of 300 mOsm in 300 mL of urine. However, if urine
concentrates only to 100 mOsm/kg of water, excreting 300 mOsm requires
3 L of urine.
3. Adequate calories to support growth. Pharmacotherapy (E.g Thiazide, NSAID)
usually is needed.
References
Diabetes Insipidus. Pablo Saborio, Gary A. Tipton, James C.M. Chan. Pediatrics in
Review Apr 2000, 21 (4) 122-129; DOI: 10.1542/pir.21-4-122
Back to Basics. Michael A. Linshaw. Pediatrics in Review Oct 2007, 28 (10) 372380; DOI: 10.1542/pir.28-10-372
Central diabetes insipidus misdiagnosed as acute gastroenteritis in a pediatric
patient. Laleh Gharahbaghian, MD et all. Canadian Journal of Emergency
Medicine, 10(5), pp. 488–492. doi: 10.1017/S1481803500010642.