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Flashcards in Firecracker - Electrolytes Deck (38):
1

hyponatremia - value

<135

2

SIADH - explanation

inapproriate secretion of ADH --> water retention, hyponatremia

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Causes of SIADH

Organic CNS disease: Meningitis, encephalitis, cerebrovascular accident, head trauma
Acute Psychosis
Tumors, especially small cell lung cancer (paraneoplastic)
Other pulmonary diseases (pneumonia, acute respiratory failure)

4

Meds that cause SIADH

Antidepressants (SSRIs) and Antipsychotics
Narcotics and NSAIDs
Chlorpropamide

5

hyponatremia (big picture) =

increase in intracellular osmolality relative to extracellular osmolality.
As result, water shifts into cells,
and in the CNS can cause brain edema.

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hyperglycemia & hyponatremia

Glucose is osmotically active, and it draws water into the extracellular space. Increased vascular volume increases diuresis, leading to hyponatremia.

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Corrected Serum Sodium

Measured serum sodium + 0.016 * (Serum glucose – 100)

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symptoms of hyponatremia

nausea and malaise. Symptoms can progress to lethargy, and confusion.

9

Na <115

seizures + coma

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plasma osmolality in hyponatremia

Plasma osmolality is normally low in hyponatremia. The exception is in the case of osmotically active solutes, such as glucose, sorbitol, and mannitol.

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urine in hyponatremia

kidneys should secrete a dilute urine (< 100 mOsm/L) in response to hyponatremia. If the urine is not diluted, it is suggestive of SIADH.

12

sodium correction

sodium correction should not exceed 12 meq in 24 hour
raise the serum sodium level by 1 meq per hour the first few hours to a level of 120 meq/L.

13

treatment of euvolemic hyponatremia

fluid restriction, loop diuretics ( to lower the urine osmolality), and/or salt tablets. The use of tolvaptan (Samsca) can also be prescribed in cases of refractory hyponatremia

14

Samsca

refractory hyponatremia. It causes a free water diuresis through its action on the aquaporin receptor.

15

hyperkalemia value

>5

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hypokalemic transcellular shift (cause hyperkalemia)

insul def, acidosis
b blockers
massive cell destruction - tumor lysis syndrome

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drugs that cause hyperkalemia through transcellular shift

digitalis, succinylcholine
Nsaids
ACEIs, ARBs, K sparring diuretcis

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symptoms of hyperkalemia

palpitations, syncope, sudden cardiac death
excitability of skeletal muscles --> weakness, flaccid paralysis, hypoventilation

19

TTKG

trans-tubular potassium gradient
evaluate renal K+ loss

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TTKG>10

increase in renal excretion

21

TTKG <7

def of aldosterosone/decreased response

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hypercalcemia values

total serum calcium >10.3
ionized calcium >5.2

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majority of causes of hypercalcemia

primary hyperparathyroidism
malignancy

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primary hyperparathyroidism

elevated Ca, decreased Po4
benign adenoma, hyperplasia, carcinoma

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hypercalcemia - malignacy

osteoclast stimulation by tumor cells
PTHrP from tumor cells
calcitriol from tumor cells

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malignacies associated with hypercalcemia

small cell lung cancer
multiple myeloma
leukemias
lymphomas

27

chronic granulomatous inflamm

increased calcitriol --> increased calcium
tuberculosis, sarcoidosis

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pharmacological causes of hypercalcemia

milk-alkali syndrome
vit d intox
thiazide dirutetics
lithium

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rare causes of hypercalcemia

adrenal insuff
paget's disease
hyperthyroidism

30

when do symptoms of hypercalcemia appear

>12

31

hypercalcemia due to what bone cell

increased osteoclast
can lead to osteopenia, fractures, osteitis fibrosa cystica

32

EKG findings of hypercalcemia

shorted QT interval
severe - AV block

33

corrected calcium

ca + .8 x 4-albumin

34

etiology of hypercalcemia - stepwise approach

1) serum pth
2) PTHrp if normal PTH
3) vit d
4) phosphorus

35

phosphorus and hypercalcemia

decreased in hyperparathyroidism
increased in paget's, vit d excess

36

treatment of hypercalcemia

1) correct hypovolemia with 0.9% saline
2) loop diuretics
3) bisphosphonates
4) calcitonin
5) glucocorticoids
6) gallium nitrate
7) dialysis

37

bisphosphonates

inhibit osteoclast

38

gallium nitrate

inhibit osteoclasts
nephrotoxic