IM Flashcards
Calculated osmolality=
(Na x 2) + glucose/18 + BUN/2.8
Osmolar gap is the difference between the ___ and the ___ and is normally less than ___.
Measured and calculated osmolality…less than 10 mOsm/L
Osmolality refers to ___ where as tonicity describes ___
Osmolality refers to all particles, where as tonicity describes whether the particles are effective or ineffective osmoles. Effective osmoles (ex. Na, glucose) cannot penetrate cell membranes and thus can lead to changes in cell volume. Ineffective osmoles (ex. urea and alcohols) are ineffective osmoles because they pass freely into and out of cells and are unable to effect changes in cell volume.
Three causes of hyponatremia not associated with a hypo-osmolar state
1) Psydohyponatremia: Occurs in hyperglobulinemia or hypertryglyceridemia (plasma water relative to solids is decreased in blood leading to less Na in a given volume of blood)
2) True hyponatremia with elevations in [ ] of an effective osmole: Hyperglycemia (increased plasma glucose pulls water out of cells and dilutes serume Na)
3) Addition of an isosmotic non-Na containing fluid to the extracellular space: typically occurs during a TURP or laproscopic surgery
Hypotonic Hyponatremia implies that water intake ___ the abilit of the kidney to excrete water
Excedes
Hypotonic Hypatremia with dilute urine (Uosm <100), Ddx:
- Primary Polydipsia (consuming >20-30L per day)
- Beer potomania (mod fluid intake with extremely low solute intake)
- “Tea and Toaster” (mod fluid intake with extremely low solute intake)
Most common cause of drug induced hyponatremia
Thiazide diuretics
Symptoms of hyponatremia
Nausea, malaise, headache, lethargy muscle cramps, disorientation, restlessness, obtundation
General approach to hypernatremia
- Why has there been inadequate intake of water? (ex. altered LoC)
- Search for presence of accelerated water loss or increased Na gain (incensible losses from respiratory tract or skin result in concentrated urine, where as inappropriate water loss from DI results in dilute urine)
Urine osmolality >300 in the polyuric patient patient is suggestive of ____
Solute or osmotic diuresis
Central and nephrogenic DI often have this symptoms
Frequent nocturia
Central and nephrogenic Di are distinguished by
Change in urine osmolality following subcutaneous administration of AVP (increased in central no change in nephrogenic)
Signs and symptoms of hypernatremia include
Lethargy, weakness, fasciculations, seizures, coma
Water deficit can be calculated with this equation
Current body water (0.6 in med and 0.5 in women x body weight) x [( [Na plasma]/140) - 1]
Tx of uncomplicated hospital acquired pneumonia
Ceftriaxone 1g IV step down to Amox Clav PO
Examples of counterregulatory hormones released in catabolic and critical illnesses
Cortisol, Catecholamines, glucagon
Tb involving the spine is called…
Pott’s
Individuals who are likely to be malnourished include
Involuntary body weight loss 5% or more within weeks-months, weight less than 90% of ideal body weight, BMI <18.5
Equation to estimate energy requirements is called
Harris-Benedict equation
Adequate energy goal for most patients is estimated at ____ (using most recent prehospital clinic dry body weight)
20-25kcal/kg/day
When it comes to nutrition, if the ____ works use it!
When it comes to nutrition, if the gut works use it!
Complications of enteral tube feeding include
Diarrhea, aspiration, mechanical tube issues if placed in nose, leakage/skin issues if percutaneously placed, metabolic complications (fluid imbalances, hyperglycemia, lyte abnormalities, azotemia, refeeding syndrome)
Indications for parenteral nutrition include:
- Short bowel syndrome or other conditions causing intestinal failure
- Patient is stable, unlikely to get sufficient enteral feeding for 7-10 days
- Severe catabolic stress in ICU, enteral intake unlikely for 3-5 days
