Hyponatremia By Brent Lee Lechner DO MAJ MC
Hyponatremia By Brent Lee Lechner, DO MAJ, MC, USA
Basic Concepts in Sodium Handling • Why is the sodium low? – Too much water – Too little salt • What aids in this decision? – Patient volume status clinically • Weight – Urine Na+ – Urine Osm
Basic Concepts in Sodium Handling Kidney preserves volume with highest priority!
Basic Concepts in Urine Evaluation • U Na+ reflects renal perfusion independent of S Na+: – Low U Na+ (<10 to 20 m. Eq/L) • Renal Perfusion is decreased – High U Na+ (>20 m. Eq/L) • Renal Perfusion is increased or normal • Defect in tubule reabsorption – If U Na+ elevated in clinical circumstance when renal blood flow is expected : Identify renal reabsorption defective.
Basic Concepts in Urine Evaluation • U OSM reflects H 20 removal from tubule fluid: – Normal U OSM • (200 -1200 m. Osm/L) – SG in urine 1. 010 = U OSM 300 m. Om/L
Basic Concepts in Urine Evaluation • ADH Secretion – U OSM > 1. 5 X S OSM: ADH must be acting on collecting duct – irrespective of S OSM – Physiologic stimuli for ADH release • Increase S OSM/ S Na+ • Decrease intravascular volume – If U OSM/S OSM > 1. 5 without increased S OSM or decreased intravascular volume: • ADH secretion is non-physiologic – irrespective of urine volume.
Case One • 14 month infant • Four day history of nausea/vomiting/diarrhea and fever. • Decreased urine output • 3 lb weight loss
Case One Labs 127 3. 0 100 16 43 0. 5 • Urine – Na+: <10 m. Eq/L – OSM: 800
Question Set One • What is the diagnosis? • Explain how you reached this diagnosis? • Does the patient seem to have more vomiting or diarrhea?
Bonus Question • What “state” was the bar in which Maverick and Goose frequently attended and sang “Great Balls of Fire” in Fighter Town, USA? • Movie: TOP GUN
Case Two • • • 14 month old Patient in case one tried oral rehydration Waited 10 hours Nausea/Vomiting/ diarrhea persisted Weight is decreased by 4 lbs.
Case Two • Urine 125 92 65 6. 5 9. 4 1. 2 – Na+: 60 m. Eq/L – OSM: 250
Question Set Two • The patient appears even more volume depleted but renal perfusion appears adequate with urine Na+ at 60 m. Eq/L. Is renal perfusion adequate? • Explain low bicarbonate.
Bonus Question • In the movie “A scent of a woman, ” how did the infantry colonel played by Al Pacino lose his sight?
Case Three • • • Five year old male Periorbital Edema and ankle swelling Weight gain 5 lb in 4 days Recent URI Decreased urine output Blood Pressure: 92/54
Case Three Labs 123 90 4. 9 16 40 0. 9 • Urine – Na+: <20 m. Eq/L – OSM: 560
Case Three Question • What is the child’s diagnosis? • What one lab test would confirm your answer to the above question? • How do you fix the serum Na+?
Bonus Question • In the movie “An officer and gentleman, ” what does Mayo’s (Richard Gere) friend (the guy from Oklahoma) tell his “girlfriend” (the girl faking the pregnancy) job is waiting at home?
Case Four • • • 17 year old Female Cheerleader Weight loss: 4 lbs in past week Lives with Grandmother and Parents Distorted body image
Case Four Labs • Urine 126 2. 7 88 32. 5 34 0. 7 – Na+: 77 m. Eq/L – OSM: 280
Case Four Questions • What is differential diagnosis? • What can you test in the urine to help determine the diagnosis?
Bonus Question • In the movie “A Few Good Men, ” what law school did Tom Cruise’s character graduate from?
Case Five • 14 year old male with ALL • Chemotherapy: – Vincristine, Cytoxan, and Decadron • 1 and ½ Maintenance fluid : ½ NS for 3 days • No edema • Slight weight gain: 4 -7 lbs in 7 days
Case Five labs 122 96 5 3. 0 20. 5 0. 4 • Urine – Na+: 65 m. Eq/L – OSM: 780
Case Five Questions • Diagnosis? • Change to NS, Right? – What is the treatment?
Bonus Question • What is the occuption and home state of Tom Hanks character in the movie “Saving Private Ryan, ” prior to him entering the U. S. Army?
Case Six • • • 15 year old female Polyuria Thirsty all the time Decreased weight Some increased respiratory rate
Case Six Labs • Urine 125 114 40 6. 8 12. 6 1. 3 450 – Na+: 45 m. Eq/L – OSM: 450
Case Six Questions • What is the diagnosis? • What is driving the urine output and loss of Na+ in the urine?
Bonus Question • At the end of basic training in the movie “Full Metal Jacket, ” what job in the U. S. Marine Corps does “Joker” obtain?
Clinical Utilization of U Na and U OSM Increased Weight U Na U OSM Decreased Weight Hypoalbuminema Nephrosis/Cirrhosis AGN <10 >500 Dehydration/Volume Depletion Acute Volume expansion <10 <300 Diabetes Insipidus >50 <= 300 Adrenal Insufficiency Cystic Fibrosis Water Intoxication Excess IV Fluid Acute Renal Failure Sepsis, Shock, Nephrotoxin Salt-losing Nephropathy Interstitial Nephritis/Cystic Dz/ Urinary Tract Obstruction Non-Physiologic ADH >500 DKA Osmotic Diuretics
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