Morning Report: October 25, 2010 Board Review Today ! 12:00 Topic: Genetics
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Transcript of Morning Report: October 25, 2010 Board Review Today ! 12:00 Topic: Genetics
Morning Report: October 25, 2010
Board Review Today!
12:00Topic: Genetics
Diabetes InsipidusPolydipsia, polyuria, dilute urine,Hypernatremia, dehydration
Diabetes InsipidusCentral or Neurogenic DI
Destruction of posterior pituitary (tumors/trauma) Deficiency of vasopressin
Nephrogenic DIRenal tubular resistance to vasopressinIntrinsic receptor defectMedications
Compulsive Water DrinkerPhysiologic inhibition of vasopressin
secretionFemale PredominanceUsually presents in adulthood
May be seen in adolescence>10% of patients with schizophrenia
Clinical PresentationInfants:
Poor feeding, FTTIrritability, seizures
hypernatremia, dehydrationVomiting after feedsDiapers “dripping wet”Less severe in breast fed babies (solute load)Inquire about family history
Clinical PresentationOlder Children:
Polyuria, polydipsia with normal glucose Hypernatremia
Neurologic deficits or precocious puberty Neurogenic DI
Consider obstructive uropathyMedicationsSystemic disorders
Laboratory TestsCompulsive water drinker
Low serum osmolality coupled with hypo-osmolar urine
Vasopressin deficiency/insensitivityHigh serum osmolality
In setting of normal serum glucose and ureacoupled with hypo-osmolar urine
Water Deprivation TestFollow specific protocol
close monitoringDiagnostic criteria of DI (short deprivation)
Plasma elevation >10mOsm/kg over baselineUrine SpG remains <1.010
DDAVP ChallengeIf urine osm increased > 450mOsm/kgEstablishes central DI
If urine osm remains < 200 mOsm/kgLikely nephrogenic DI
If urine osm incresed > 750 mOsm/kgLikely compulsive water drinker
DDAVP Intranasally
MRIVisualizes:
Anterior and posterior pituitaryPituitary stalk
Possible pathologySuprasellar massPituitary cystHypoplasiaEctopic pituitary
ManagementCentral DI
Intranasal DDAVPOral repletion of waterIf IV fluids used
No more than 3% dextrose Avoid worsening hyperosmolality Avoid glucosuria
ManagementNephrogenic DI
Low-Osmolar, low Na dietHuman milk in infancyThiazide diuretic
Increases Na lossNSAIDS may have benefit
Use only if other methods fail
PrognosisConsider genetic testing/counselingBehavioral problems
Short attention span, hyperactivity, learning delays ? Exacerbated by frequent trips to bathroom, water
source ?Nonobstructive functional hydronephrosis
May be transientCaution when pt cannot readily access water