Nephrology, mineral, fluid, electrolyte, acid-base disorders Flashcards Preview

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Flashcards in Nephrology, mineral, fluid, electrolyte, acid-base disorders Deck (63)
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1

Hypocalcemia:

5 etiologies

1. hypoparathyroidism e.g. postthyroidectomy

2. vitamin D deficiency

3. chronic renal failure

4. accelerated net bone formation e.g. postparathyroidectomy

5. calcium sequestration e.g. pancreatitis

purple book 7-12

2

Hypocalcemia:

Clinical manifestations

1. Neuromuscular irritability:

  • --Chvostek sign (tapping facial nerve -> contraction of facial muscles)
  • --Trousseau sign (inflation of BP cuff -> carpal spasm)
  • --Irritability, depression, psychosis
  • --Long QT

2. Osteomalacia

 

purple book 7-12

3

Hypocalcemia:

Diagnostic studies

1. Ca, ionized Ca

2. albumin

3. PTH

4. 25(OH)D, 1,25(OH)2 D

5. Cr, Mg, PO4

6. Urine calcium

 

purple book 7-12

4

Hypocalcemia:

Treatment

1. Treat concomitant vit D deficiency

2. Symptomatic: IV Ca gluconate + calcitriol, +/- Mg

3. Asymptomatic: oral Ca

4. In chronic renal failure: phosphate binder, oral Ca, calcitriol

5

Hypercalcemia:

5 etiologies

1. Hyperparathyroidism

2. Malignancy (PTH-related peptides, or cytokines -> increased osteoclast activity, or incr vit D, or local osteolysis)

3. Vitamin D excess, e.g. granulomas, which increase 1,25(OH2 D

4. Increased bone turnover, e.g. hyperthyroidism, Paget disease

5. Thiazides

purple book 7-11

6

Hypercalcemia:

Clinical manifestations

1. Hypercalcemic crisis:

  • polyuria
  • dehydration
  • AMS

2. Osteopenia

3. Nephrolithiasis

4. Abd pain, N/V, constipation, anorexia, pancreatitis

5. Calciphylaxis: calcification of small-med blood vessels of dermis and subq fat -> ischemia & skin necrosis

7

What 2 causes account for over 90% of cases of hypercalcemia?

1. hyperparathyroidism

2. malignancy

8

Hypercalcemia:

Diagnostic studies

1. Ca, ionized Ca

2. albumin

3. PTH

4. PO4

5. Urine calcium

 

purple book 7-11

9

Hypercalcemia:

Acute treatment

1. Normal saline

2. Furosemide

3. Bisphosphanates

4. Calcitonin

 

purple book 7-12

10

Hypokalemia:

3 main etiologies

1. Transcellular shifts: alkalemia, insulin, etc.

2. GI potassium losses: diarrhea, laxative abuse, etc.

3. Renal potassium losses:

--Hypertensive: hyperaldosteronism

--Hypotensive or normotensive:

----acidosis: DKA

----alkalosis: diuretics, vomiting, Gitelman syndrome

purple book 4-10

11

Hypokalemia:

Clinical manifestations

1. N/V, ileus, weakness, muscle cramps, rhabdomyolysis, polyuria

2. EKG: U waves, flattened T waves

 

purple book 4-10

12

Hypokalemia:

Workup

1. Rule out transcellular shifts

2. Get 24 hr urine potassium, compare urine and plasma osm and K -> transtubular potassium gradient (TTKG), which is (Urine K / Plasma K) / (Urine osm / Plasma osm)

3. HIgh TTKG = renal loss, Low TTKG = extrarenal loss

4. If renal, check BP, acid-base status, Urine Cl

purple book 4-10

13

Hypokalemia: Treatment

1. Potassium supplementation

2. Treat underlying cause

3. Supplement Mg (can't fix hypokalemia if there's hypomag)

purple book 4-10

14

Hyperkalemia: 3 main etiologies

1. Transcellular shifts

2. Decreased GFR, e.g. AKI, ESRD

3. Normal GFR with decreased renal K excretion, e.g. CHF, hypoaldosteronism

 

purple book 4-11

15

Hyperkalemia: Clinical manifestations

1. Weakness, nausea, paresthesias, palpitations

2. EKG: peaked T waves, increased PR interval, widening of QRS, loss of P wave

 

purple book 4-11

16

Hyperkalemia: Workup

1. Rule out pseudohyperkalemia

2. Rule out transcellular shift

3. Assess GFR

4. If GFR normal, check TTKG - (Urine K / Plasma K) / (U osm / P osm); if < 6, consider hypoaldosteronism

 

purple book 4-11

17

Hyperkalemia: Treatment

1. Calcium supplementation

2. Insulin

3. Bicarb

4. B agonists e.g. albuterol

5. Kayexalate

6. Diuretics

7. Hemodialysis

purple book 4-11

18

Hypomagnesemia: 3 main etiologies

1. Diminished absorption or intake

--Malabsorption, chronic diarrhea, ALCOHOLISM

--Proton pump inhibitors

2. Increased renal loss

--Diuretics

--Hyperaldosteronism, Gitelman syndrome

--Hyperparathyroidism, hyperthyroidism

--Hypercalcemia

--Drugs (aminoglycoside, cetuximab, cisplatin, amphotericin B, pentamidine)

3. Miscellaneous

--Diabetes mellitus

--Post-parathyroidectomy (hungry bone syndrome)

--Respiratory alkalosis

--Pregnancy

CURRENT

19

Hypomagnesemia: s/s

--Causes neurologic symptoms and arrhythmias (like hypokalemia & hypocalcemia).

--Impairs release of PTH.

CURRENT

20

--Hypermagnesemia is almost always the result of ______.

 

--______ and ______ are underrecognized sources of magnesium.

 

--Pregnant patients may have severe hypermagnesemia from intravenous magnesium for ______.

--Hypermagnesemia is almost always the result of advanced CKD and the impaired magnesium excretion.

--Antacids and laxatives are underrecognized sources of magnesium.

--Pregnant patients may have severe hypermagnesemia from intravenous magnesium for preeclampsia and eclampsia.

CURRENT

21

Hypermagnesemia: s/s

--Muscle weakness

--Decreased deep tendon reflexes

--Mental obtundation, and confusion

--Weakness, flaccid paralysis, ileus, urinary retention, and hypotension

--Serious findings include respiratory muscle paralysis and cardiac arrest

 

CURRENT

22

Hypermagnesemia: Treatment

1. Calcium chloride

2. Hemodialysis

23

Hyperphosphatemia: Most common cause

Advanced CKD

24

Hyperphosphatemia: Treatment

Calcium carbonate (binds phosphate)

25

Hypophosphatemia: Causes

26

Hypophosphatemia: s/s

rhabdomyolysis, paresthesias, and encephalopathy

27

Hyponatremia, hypernatremia

Self - go read about hyponatremia and hypernatremia in the purple book, 4-6

28

Approach to interpreting an arterial blood gas

1. Anticipate the disorder (what is the clinical picture?)

2. Acidemic or alkalemic? (pH < 7.40 or > 7.40?)

3. Metabolic or respiratory?

--acidosis with HCO3/PCO2 down = Metabolic

--alkalosis with HCO3/PCO2 up = Metabolic

--acidosis with PCO2/HCO3 up = Respiratory

--alkalosis with PCO2/HCO3 down = Respiratory

4. If metabolic acidosis, is there an anion gap?

-- [Na - (Cl + HCO3)]

5. Is compensation appropriate? (use formulas)

6. Is there more than one disorder present? (use formulas)

Dr. Anderson handout

29

Acid-base disturbance of: PE

respiratory alkalosis

30

Acid-base disturbance of: Hypotension/decreased perfusion

metabolic acidosis