938 results
Physiologic Approach to Hypotonic Hyponatremia
The next time you have a case of hypotonic hyponatremia, give the
• ADH Present (Uosm ... be high or low Uosm ... ADH Not Present (Uosm ... • ADH Present (Uosm ... differential #diagnosis #table
Hyponatremia Diagnosis Algorithm
UOsm ≥ POsm - Vasopressin-Dependent
 • UNa < 20 mEq/L - Appropriate (↓ EABV)
Diagnosis Algorithm UOsm ... ≥ POsm - Vasopressin-Dependent ... Cortisol deficiency UOsm ... < POsm - Vasopressin-independent
Polyuria - Differential Diagnosis Algorithm
Urine Output > 3L /day
Water Diuresis (Urine Osm <100 mOsm/kg)
 • Primary
Diuresis (Urine Osm ... <100 mOsm/kg) ... Diuresis (Urine Osm ... 100-200 mOsm/kg ... 300-500 mOsm/kg
Hypo-osmolar Hypotonic HypoNatremia Algorithm (Serum Na+ < 135 meq/L, serum Osm < 275 mosm/kg)
Assess Volume Status,
135 meq/L, serum Osm ... < 275 mosm/kg) ... Urine Na, Urine Osm
Hyponatremia - Diagnostic Evaluation Algorithm

Step 1: Consider whether Posm may actually be normal or elevated
Step 2:
Consider whether Posm ... Step 2: Check Uosm
Hyponatremia Differential Diagnosis Table

 • Step 1: Correct for hyperglycemia. Corrected Na = [(glucose - 100)/
Differential Diagnosis Table ... BMP • Serum Osm ... • Urine Osm ... Differential #Diagnosis #Table
Central vs Nephrogenic Diabetes Insipidus - Desmopressin Challenge
Give desmopressin (intranasal, SQ, IV) and monitor UOsm every
IV) and monitor UOsm ... • No Rise in UOsm ... < 45% rise in UOsm ... 15-50% rise in UOsm ... CDI • Rise in UOsm
Hypernatremia - Diagnostic Evaluation Algorithm
Step 1: Consider history. Most patients presenting with hypernatremia are either very
Step 2: Check Uosm ... using initial Uosm
Urine chemistry tests for the diagnostic evaluation of a patient with polyuria
UOsm <100 mOsm/Kg (H2O diuresis)
with polyuria UOsm ... nephrogenic) UOsm ... 2 × (Na + K) = UOsm ... × (Na + K) << UOsm ... diagnosis #nephrology #Uosm
Pathophysiology Based Approach to Hyponatremia - Diagnostic Algorithm

Not the "classic" Volume based approach. 

#Hyponatremia #Algorithm #Pathophysiology
Differential #Nephrology #UOsm