Acid-Base

Question 1

What are common causes of respiratory acidosis?

Answer 1

COPD, asthma, drugs (opioids, benzos, barbiturates, alcohol); chest wall problems (paralysis, pain); sleep apnea

Question 2

What are common causes of metabolic acidosis?

Answer 2

gap = MUDPILERS
methanol
uremia
DKA
propylene glycol
iron poisoning/isoniazid
lactic acidosis
ethylene glycol
rhabdomyolysis
salicylates

non-gap: diarrhea, carbonic anhydrase inhibitors

Question 3

What are the common causes of metabolic alkalosis?

Answer 3

respiratory: aspirin overdose (along with metabolic acidosis, tinnitus, hypoglycemia, vomiting); hyperventilatoin
metabolic: diuretics (except carbonic anhydrase inhibitors, vomiting, volume contraction, antacid abuse/milk alkali syndrome (overabundance of calcium), hyperaldosteronism

Question 4

What are the different etiologies of hyponatremia?

Answer 4

hypovolemic: Dehydration, diuretics, hyperaldosteronism, Addison’s disease
euvolemic: SIADH, psychogenic polydypsia, oxytocin use
hypervolemic: CHF, nephrotic syndrome, cirrhosis, renal failure
spurious: hyperglycemia (if sugar over 200, sodium decreases by 1.6 every 100 mg/dL of sugar), hyperproteinemia, hyperlipidemia can make sodium look low

Question 5

What should be the rate of correction for hyponatremia?

Answer 5

Should not exceed 0.5-1 meq/L/h

Question 6

What causes hyperkalemia?

Answer 6

1) kidney failure
2) tissue lysis
3) hypoaldosteronism (in diabetes, can have hyporeninemic hypoaldosteronism)
4) medications (K sparing diuretics, ACEis)
5) adrenal insufficiency

Question 7

What are signs/symptoms of hypocalcemia?

Answer 7

Chvostek’s sign (spasm with tap facial nerve); Trousseau’s sign (carpal spasm with inflation of BP cuff); prolongation of QT

depression, seizures, encephalopathy

Question 8

What causes hypocalcemia?

Answer 8

hypoparathyroidism (post-thyroidectomy (if parathyroid’s removed); renal failure, acute pancreatitis; vit D deficiency; etc

Question 9

Hypocalcemia can also be caused by (acidosis/alkalosis)

Answer 9

alkalosis. Alkalosis causes calcium to shift intercellularly. This is why when people hyperventilate, they get perioral numbness.

Question 10

What are the signs of hypercalcemia?

Answer 10

Bones, groans, stones, psychiatric overtones

bones: osteopenia, pathologic fractures
groans: abdominal pain, anorexia, constipation, n/v
stones: kidney stones, polyuria
psychiatric: delirium, depression, psychosis

QT interval shortening

Question 11

What fluids do you give to an adult not eating?

Answer 11

1/2 NS with 5% dextrose and 10-20 mEq of K/L of fluid to prevent hypokalemia