Usmle Step 2 Secrets

Front 1

What does CO2 tell you with an ABG?

Back 1

CO2--> if high, either it's respiratory acidosis, or compensating for met alk.
If low, either resp alk, or compensating for met acidosis

Front 2

What does Bicarb tell you with an ABG?

Back 2

If high, either met alk, or compensating for resp acidosis. If low, either met acidosis, or compensating for resp alk

Front 3

T/F, the body doesn't compensate beyond normal pH?

Back 3

True, overcorrection doesn't occur

Front 4

Common causes of respiratory acidosis?

Back 4

COPD,asthma,drugs, just what problems, and sleep apnea

Front 5

Common causes metabolic acidosis?

Back 5

Ethanol, diabetic ketoacidosis, uremia, lactic acidosis, methanol/ethylene Glycol , aspirin overdose , diarrhea, and carbonic anhydrase inhibitors

Front 6

What does CO2 tell you with an ABG?

Back 6

CO2--> if high, either it's respiratory acidosis, or compensating for met alk.
If low, either resp alk, or compensating for met acidosis

Front 7

What does Bicarb tell you with an ABG?

Back 7

If high, either met alk, or compensating for resp acidosis. If low, either met acidosis, or compensating for resp alk

Front 8

T/F, the body doesn't compensate beyond normal pH?

Back 8

True, overcorrection doesn't occur

Front 9

Common causes of respiratory acidosis?

Back 9

COPD,asthma,drugs, and sleep apnea

Front 10

Common causes of metabolic acidosis?

Back 10

Ethanol, diabetic ketoacidosis, uremia, lactic acidosis, methanol/ethylene Glycol , aspirin overdose , diarrhea, and carbonic anhydrase inhibitors

Front 11

Common causes of Respiratory alkalosis?

Back 11

anxiety/hyperventilation and aspirin/salicylate overdose

Front 12

Common causes of metabolic alkalosis ?

Back 12

Diuretics (except carbonic anhydrase inhibitors),vomiting, volume contraction, antacid use, and Hyperaldosteronism

Front 13

What type of acid-base disturbance does aspirin overdose cause ?

Back 13

Respiratory alkalosis and metabolic acidosis

Front 14

What happens to the blood gas of patients with chronic lung conditions?

Back 14

in certain people with chronic lung conditions pH may be alkaline during the day because they breathe better when awake

Front 15

Should you give bicarbonate to a patient with acidosis?

Back 15

For purposes of the step two boards almost never. First, try IV fluids and correction of the underlying disorder

Front 16

List the signs and symptoms of Hyponatremia ?

Back 16

Lethargy, mental status changes, anorexia, seizures, cramps, coma

Front 17

What are the causes of Hypovolemic hyponatremia?

Back 17

Dehydration, diuretics, diabetes, hyperaldosteronism.

Front 18

what are the causes of Euvolemic hyponatremia?

Back 18

SIADH, psychogenic polydipsia, Oxytocin use

Front 19

what are the causes of hypervolemic hyponatremia?

Back 19

Heart failure, Nephrotic syndrome, Cirrhosis , toxemia , renal failure

Front 20

how his hyponatremia treated?

Back 20

For hypovolemic hyponatremia the treatment is normal Saline. For euvolemic and hypervolemic hyponatremia treat with water/fluid restriction

Front 21

What happens if hyponatremia is corrected too quickly?

Back 21

You may cause brain stem damage (central pontine myelinolysis).hypertonic saline is used only when a patient has seizures from severe hyponatremia. N. S. is a better choice 99% of the time

Front 22

What medication is used to treat SIADH if water restriction fails?

Back 22

DEMECLOCYCLINE which induces nephrogenic diabetes insipidus

Front 23

what causes false hyponatremia?

Back 23

Hyperglycemia (once glucose is over 200mg/dl, Na decreases by 1.6mEq/L for each rise of 100mg/dl in glucose),Hyperproteinemia, hyperlipidemia

Front 24

What causes hyponatremia in postoperative patients?

Back 24

Most common cause is the combination of pain and narcotics, with aggressive administration of IV fluids

Front 25

what is the classic cause of hyponatremia in pregnant patients about to deliver ?

Back 25

Oxytocin, which has an antidiuretic hormone-like effect

Front 26

What are the S/Sx of hypernatremia?

Back 26

basically the same as hyponatremia; mental status changes/confusion, hyperreflexia, seizures, and/or coma

Front 27

What causes hypernatremia?

Back 27

Most common is dehydration. Watch for diuretics, diabetes insipidus, diarrhea, and renal dz as well as iatrogenic causes.

Front 28

How is hypernatremia treated?

Back 28

Water replacement, most of NS

* D5W should not be used for hypernatremia

Front 29

S/Sx of hypokalemia?

Back 29

Muscular weakness, paralysis and Ventilatory failure went smooth muscles are also affected, patients may develop ileus and/or hypotension. EKG findings include a loss of T. wave or T. wave flattening,other arrhythmias may also occur

Front 30

what is the effect of pH on serum potassium?

Back 30

Changes in pH caused changes in serum potassium as a result of cellular shift. alkalosis Causes hypokalemia, acidosis causes hyperkalemia. For this reason bicarbonate is given to severely hyperkalemic patients

Front 31

Describe the interaction between digitalis and potassium?

Back 31

The heart is particularly sensitive to hypokalemia in patients taking digitalis. Potassium levels should be monitored carefully

Front 32

How should potassium be replaced?

Back 32

Slowly, like all electrolyte abnormalities. Oral is preferred, but if I. V. is necessary do not give more than 20mEq/hr. put the patient on an EKG monitor when giving IV potassium

Front 33

When hypokalemia persists even after administration of significant amounts of potassium, what should you do?

Back 33

check the magnesium level. when magnesium is low, the body cannot retain potassium effectively

Front 34

what are the signs and symptoms of Hyperkalemia?

Back 34

Weakness and paralysis may occur, but the cardiac effects are best known. EKG changes include tall, peaked T waves, widening of QRS, prolonged PR, loss of P waves, and sine-wave pattern. Asystole, and V-fib happen

Front 35

what causes hyperkalemia?

Back 35

Renal failure, severe tissue destruction,hyperaldosteronism, medications, and adrenal insufficiency

Front 36

What should you suspect If an asymptomatic patient has hyperkalemia?

Back 36

with hyperkalemia, the first consideration is whether the labsand specimen is hemolyzed,which causes a false hyperkalemia

Front 37

if the specimen was not hemolyzed, what is the first treatment?

Back 37

get EKG to look for Cartdiotoxicity. In general the best therapy for hyperkalemia is decreased potassium intake, and oral sodium polystyrene resin.

Front 38

If the potassium level is greater than 6.5 and/or cardiotoxicity is present what do you do?

Back 38

Immediate IV therapy, first give calcium gluconate, then give sodium bicarb, and glucose with insulin.

Front 39

What are the S/Sx of hypocalcemia?

Back 39

neuro findings; tetany. Tapping of the facial nerve elicits Chvostek's sign (contraction of facial muscles). Trousseau's sign can also happen (BP cuff elicits hand spasms)

Front 40

Classic EKG findings with hypocalcemia?

Back 40

QT-interval prolongation

Front 41

What should you do if the calcium level is low?

Back 41

First, remember that hypoproteinemia can cause it, but these pts are asymptomatic. So check albumin, and/or ionized or free Ca.

Front 42

What causes hypocalcemia?

Back 42

DiGeorge's syndrome (tetany 24-48 hrs after birth), Renal failure, hypoparathyroidism, Vit D deficiency, pseudohypoparathyroidism, acute pancreatitis, renal tubular acidosis

Front 43

Describe relationship between low calcium and low magnesium?

Back 43

It's difficult to correct hypocalcemia until hypomagnesemia also is corrected.

Front 44

How does pH affect Ca levels?

Back 44

alkalosis causes Ca to shift intracellularly.

Front 45

What's the relationship betweeen Ca and Phosphorus?

Back 45

The levels usually go in opposite directions,

Front 46

What are the S/Sx of hypercalcemia?

Back 46

Often aSx, but if present; Bones (osteopenia), Stones (kidney and polyuria), Groans (abd pain, anorexia, constipation, ileus, N/V), Psychiatric overtones (depression, psychosis, delirium/confusion)

Front 47

EKG changes with hypercalcemia?

Back 47

classically QT-interval shortening

Front 48

What causes hypercalcemia?

Back 48

Most commonly hyperparathyroidism. In inpatients, it's malignancy. Others include Vit A, or D intox, sarcoidosis, thiazide diuretics, familial hypocalciuric hypercalcemia, and immobilization

Front 49

Why is aSx hypercalcemia usually treated?

Back 49

If prolonged, it can cause nephrocalcinosis and renal failure d/t Ca salt deposits in the kidney and may result in bone dz secondary to loss of Ca

Front 50

How do you Tx hypercalcemia?

Back 50

First, IV fluids, then when well hydrated give Lasix to cause calcium diuresis. (Thiazides are contraindicated). For hyperparathyroidism, surgery is Tx of choice

Front 51

In what clinical scenario is hypomagnesemia usually seen?

Back 51

Alcoholism, Mg is wasted through the kidneys

Front 52

S/Sx of hypomagnesemia?

Back 52

Prolonged QT interval and possible tetany (similar to those of hypocalcemia)

Front 53

In what clinical scenario is hypermagnesemia seen?

Back 53

classically iatrogenic in pregnant pts who are tx for preeclampsia with Mag sulfate. Also common in renal failure.

Front 54

S/Sx of hypermagnesemia?

Back 54

Initial sign is decrease in DTR, then hypotension and respiratory failure occur sequentially

Front 55

How is Hypermagnesemia Tx?

Back 55

First stop any Mag. Remember ABCs and intubate if necessary. If stable, can give IV fluids, and Lasix can be given to cause Mg diuresis. Last resort is dialysis.

Front 56

In what clinical scenarios is hypophosphatemia seen?

Back 56

Seen primarily in pts with uncontrolled DM (esp diabetic ketoacidosis), and alcoholics.

Front 57

S/Sx of hypophosphatemia?

Back 57

Neuromuscular disturbances, rhabdo, anemia, and WBC and platelet dysfxn

Front 58

What is the IV fluid of choice in trauma patients?

Back 58

Lactated Ringers, second is NS

Front 59

What is the IV fluid of choice in nontrauma, hypovolemic pts?

Back 59

NS or Lactated Ringers. First fill the tank, then correct imbalances that kidney can't get fixed

Front 60

What is the maintenance fluid of choice for pts who aren't eating?

Back 60

1/2 NS with 5% dextrose in adults, and 1/4 or 1/3 NS with 5% dextrose in children

Front 61

Should anything be added to the IV fluid for pts who aren't eating?

Back 61

Usually KCl, 10 or 20 mEq, to a liter of IV fluid each day to prevent hypokalemia