Chemistries

Question 1

Serum osmolality >300 mOsm/kg, consider?

Answer 1

Hyperglycemia (DKA or hyperosolar hyperglycemic state [HHS])

Question 2

Serum osmolality <280 mOsm/kg, consider?

Answer 2

Thiazides, severe liver or heart disease

Question 3

What can cause metabolic acidosis?

Answer 3

Think SLUMPED: 
Salicylates
Lactate 
Uremia, underfed
Methanol
Paraldehyde
Ethanol, ethylene glycol
Diabetes

Question 4

How much potassium is lost per day via kidneys?

Answer 4

40 mEq K+ daily

Question 5

What does the blood urea nitrogen lab reflect?

Answer 5

The liver produces ammonia from protein breakdown, which results in nitrogen; this is then transformed into urea, which is excreted by the kidneys. Thus BUN can reflect liver or kidney dysfunction.

Question 6

BUN and creatinine will be increased with?

Answer 6

Renal failure

Question 7

BUN will be increased and creatinine normal with?

Answer 7

Dehydration, GI bleeding, high protein diet

Question 8

With GI bleeding, once the bleeding as stopped the BUN will return to normal within how many hours?

Answer 8

24 hours; draw BUN daily; if increases again you know the bleeding restarted

Question 9

Why would the BUN decrease?

Answer 9

Starvation (inadequate protein intake), liver failure (inadequate production of urea, and overhydration

Question 10

What is the normal BUN/creatinine ratio?

Answer 10

10; if over 10 consider prerenal azotemia and if under 10 consider renal failure

Question 11

What causes an increase in amylase but no lipase?

Answer 11

Perforated ulcer

Question 12

What causes lipase to increase >3x the normal?

Answer 12

Pancreatitis