PAUL M. SHANIUK, MD, PGY-4 JULY, 2015 UNIVERSITY HOSPITALS CASE MEDICAL CENTER WADE PARK VA MEDICAL...
-
Upload
ilene-cole -
Category
Documents
-
view
215 -
download
0
Transcript of PAUL M. SHANIUK, MD, PGY-4 JULY, 2015 UNIVERSITY HOSPITALS CASE MEDICAL CENTER WADE PARK VA MEDICAL...
Paul m. shaniuk, md, pgy-4July, 2015
University hospitals case medical centerWade park va medical center
Intern BootcampElectrolyte Management:
Disorders of Serum Sodium
Objectives
Categorize the differential diagnosis for disorders of sodium balance
Discuss approach to disorders of sodium balance
Acute Management of Hyponatremia
Acute Management of Hypernatremia
If time, an interlude on potassium & magnesium
Case 1
55 year old male with no significant PMHx except for known chronic alcoholism for 30 years (6 pack of beers daily and a 5th of vodka) who presents with recurrent falls for the past 2 months. His daughter took him to the doctor where his vital signs were stable (HR 74 and BP 116/74), and got the following labs
BMP 125/4.1/87/28/6/0.64<102. CXR & UA negative. He was admitted for further work-up.
Case 1 Continued
No significant family, medical or social history except for alcoholism. Only medication is celexa that he started 2 months ago.
How do we work up his hyponatremia?
Differential Diagnosis?
Beer PotomaniaSIADHCirrhosisPancreatitisSurreptitious Diuretic
UseRenal lossesGI losses
Glucocorticoid Deficiency
HypothyroidismDrug useAcute or Chronic
Kidney failureThird spacing of
fluidsType 2 RTADKAOsmotic diuresis
Classification of Hyponatremia
Classify based on physical examination and the patient’s volume status
Key Concept
“A key concept in sodium disorders is that the absolute plasma Na+ concentration tells one nothing about the volume status of a specific patient.”
Harrison’s Principles of Medicine, 18th Edition
Working Up Hyponatremia
Hypovolemic, Euvolemic, Hypervolemic? Based on History & Physical
Ratio of Total Body Water to Total Body Sodium Based on Serum & Urine Osmolarity
Is the body responding appropriately or inappropriately? Based on Urine Electrolytes
Case Continued
Physical exam showed a pale man who was A&Ox3 and in no distress. Normal cardiac, respiratory and abdominal exam. JVP not elevated
Neurologic exam showed b/l nystagmus with lateral gaze and impaired b/l proprioception in the lower extremities
Skin exam with normal turgor and multiple ecchymoses on his body.
How to Classify his Hyponatremia
Hypovolemic, Euvolemic or Hypervolemic? Euvolemic based on physical exam
Ratio of Total Body Water to Total Body Sodium? Excess of free water, based on low serum osmolarity
Is the body responding appropriately or inappropriately? Inappropriately (urine osm & urine sodium
elevated)
Case Conclusion
The patient was diagnosed with SIADH, most likely deemed to be due to his celexa.
Picture was clouded by the fact that he was presumed to have baseline hyponatremia due to alcohol use, but clinical picture did not fit beer potomania (Urine Osm/Na would be low)
Patient improved with 1.5 L a day fluid restriction & holding celexa
Case 2
46 y/o otherwise healthy male daycare worker who presents with severe nausea, vomiting and diarrhea for 3 days. Recent outbreak of rotavirus at his daycare who presents to the ED with orthostatic dizziness
No significant PMHx, Family or Social Hx, No medications or allergies
Vital signs are 37.7, HR 105, BP 108/64 (falls to 90/50 with standing and HR increases to 128), RR 16, O2 sats
Physical exam reveals dry mucus membranes, decreased skin turgor, mild tachycardia, otherwise normal.
How to Classify Hyponatremia
Hypovolemic, Euvolemic or Hypervolemic? Hypovolemic
Ratio of Total Body Water to Total Body Sodium? Both decreased (both dehydrated and
hyponatremic 2/2 GI losses and poor PO intake)
Is the body responding appropriately or inappropriately? Appropriately (urine osm elevated with low urine
sodium indicating kidneys are retaining both fluid & sodium)
Management?
He needs both water & sodium = IV fluids
What fluids do we give him? 0.45% NS? (72mM Na+) 0.9% NS? (154 mM Na+) 3% NS? (513 mM Na+)
Bolus or Proceed slowly?
Important Concepts with Fluid Replacement in Acute Hypovolemic
Hyponatremia
Calculate volume deficit and sodium deficit, usually with the assistance of an online calculator.
Replete SLOWLY. (Goal to increase by 4-6 mEq/L in a 24 hr period. No more quickly than 10mEq!)
Monitor! Check RFP Q6H-Q8H especially in the first 24.
Important Caveat #2
If the patient is encephalopathic or seizing, admit to MICU for 3% hypertonic saline (increase by 4-6 mEq in the first 6 hrs… do not reach normonatremia in the first 48 hrs)
Important Caveat #3
As you correct the volume deficit, intrinsic ADH secretion decreases and thus patient will start to autodiurese and you can overcorrect easily
Case 2 Continued
The patient was deemed to not be in shock and was not having seizures/encephalopathy, so was started on IV normal saline at 250cc/hr (calculated to increase serum sodium by 5 mEq in 24 hrs) and admitted to the ward
RFP slowly incremented, patients sodium increased back to normal over 3 days.
Patient discharged home, quit his job and now works at the CDC.
What about Hypervolemic Hyponatremia?
Principles are similar
Can try vaptans (vasopressin antagonists), especially in heart failure or cirrhosis
If you are giving a patient tolvaptan, the patient must be allowed to drink free water ad lib, or else could over-correct his serum sodium
Case 3
A 90 y/o female with advanced dementia is brought to the ED by her children with failure to thrive. She is non-verbal and had been having difficulty swallowing clear liquids and solid foods for the past few months. Family has been noting that she appears more confused and having very dark urine.
In the ED, vitals were 37.2, HR 110, BP 90/60, RR 14, O2 sats 93% on RA
Case 3 Continued
Physical exam shows a frail, elderly female who is responsive only to painful stimuli and loud voice, but does open her eyes to this. A&Ox1.
Dry, cracked mucus membranes, severely decreased skin turgor, incontinent of dark urine, stage 2 sacral decubitus ulcer present on admission
Case 3 Continued
Labs in the ED are pertinent for the following:
RFP 161/4.6/129/22/45/2.2 (baseline 1.4) <80
ED said she was dehydrated and gave a bolus of 1L normal saline, and admitted to Wearn.
Serum Osm 330, Urine Osm 850, Urine sodium 20
Basics on Hypernatremia
Less common than hyponatremia
Associated with high mortality (some studies suggest 40-60%)
Due to combined water & electrolyte deficit, but loss of free water exceeds the loss of electrolytes. (Hypertonic)
Most common in patients with decreased thirst AND decreased access to fluids Hypernatremia is a powerful thirst stimulant
Working up Hypernatremia
Also based on physical exam (typically though hypovolemia is seen)
Is the urine concentrated? If Yes – likely 2/2 free water deficit from insensible, GI
or renal losses
If No – likely 2/2 diuretics or diabetes insidipidus (either central or nephrogenic)
Management of Hypernatremia
Estimate Total body water: (50% of body weight in women and 60% in men)
Calculate Free Water Deficit [(Na -140)/140] x TBW Or use a handy calculator
Replete the free water deficit over 48-72 hrs without increasing the plasma sodium by > 10 mM in a 24 hr period
Don’t forget about potential for ongoing water losses from either diarrhea, diuresis or insensible losses!
Case 3 Continued
The patient was started on normal saline in the ED at 100 cc/hr and admitted to the floor
Upon arrival to the floor, repeat RFP shows a sodium of 162.
You calculate a free water deficit of 3.9L
Case Conclusion
You start the patient on D5W infusion at 65 cc/hr and monitor RFPs Q8H.
Her deficit improves appropriately over 72 hrs as does her mental status
Speech therapy finds that the patient has severe dysphagia. After extensive discussion, family opts for feeding orally for pleasure; they do not want a PEG. Patient made DNR and discharged to SNF near the oldest daughter’s home.
Key Concepts with Hypernatremia
Associated with high mortality! In patients with hx of head trauma, brain surgery or
pituitary resection, can represent DI/panhypopituitarism
If in shock, bolus with isotonic saline and correct fluids status later
Key Concepts with Hypernatremia
Enteral repletion is preferred if possible as there are risks with free water infusions (if our patient had a G-tube, free water flushes could have been given)
Some attendings or RNs are uncomfortable with D5W infusions outside the MICU. Realistically, any form of hypotonic saline can be used (0.45% NS, 0.2% NS, etc)
Quick Word on Potassium repletion
3 forms of oral potassium Tablet (horse pill) Oral packet Oral liquid
IV potassium Central Line formulation (more concentrated) Peripheral line formulation (cannot give more than
20mEq over 2 hrs, but can give x 2 doses to give 40mEq)
Quick word on Potassium Repletion
Replete orally if possible!If 3.1-3.4 mEq/l -> Give 40mEq
If 2.6 – 3.0 mEq/l -> Give 60-80mEq
If < 2.5 -> Give 80-120mEq
Final word on Potassium Repletion
Replete with caution in patients with AKI, ESRD, etc
Don’t forget to account for ongoing losses! Such as diarrhea, diuresis, etc
Quick word on Magnesium repletion
IV repletion is preferred
Oral forms Magnesium Chloride 64mg PO Magnesium Oxide 400mg PO
IV forms If Mg 1.0-1.6 give 2mg IV over 2 hrs If Mg < 1.0, give 4mg IV over 4 hrs
Some Endocrinologists would suggest that giving over a longer duration (such as 12-24 hrs) may help prevent rapid shifts and may overall increase effectiveness.
Remember your repletion goal
If a-fib, or cardiac arrhythmia Goal K > 4.0, Mg > 2.0
If in torsades, give IV Mg
Otherwise, aim for physiologic levels
References
Harrison’s 18th Edition
Braun et al. Diagnosis and Management of Sodium Disorders: Hyponatremia and Hypernatremia Am Fam Physician 2015 Mar 1;91(5):299-307.
Verbalis, Et Al. Diagnosis, Evaluation, and Treatment of Hyponatremia: Expert Panel Recommendations The American Journal of Medicine (2013) 126, S1-S42
Pocket Medicine Fourth Edition. Edited by Marc S. Sabatine