Serum potassium
imbalance
Potassium:
It
is a major intracellular cation.
The
normal plasma potassium concentration is 3.5-5.0 mEq/L whereas that inside the
cells is about 150 mmol/L.
Disorders of
Potassium includes
Hypokalemia
Hyperkalemia
HYPOKALEMIA
DEFINTION:
Hypokalemia
is defined as a plasma potassium concentration level of less than 3.5mEq/L. It
is a common disorder especially in older adult population.
CAUSES
1.Potassium
loss:
·
GI
losses - Vomiting and Diarrhea, fistulas, NG suction
·
Renal
losses - potassium wasting Diuretics
(thiazide, loop and osmotic diuretics) hyperaldosteronism
(mineralocorticoid excess), magnesium depletion.
·
Skin
losses - Diaphoresis
·
Dialysis
2.Shift
of potassium into cells:
·
Increased
insulin
·
Alkalosis
- potassium exchange with hydrogen ion
across the cell wall, thus increasing the level of hydrogen but decreasing the
level of potassium in the plasma
·
Tissue
repair
·
Beta
adrenergic agonists (basically K goes inside the cells)
3.Lack
of potassium intake:
·
Starvation
·
Potassium
restricted diet.
·
Failure
to include potassium in parenteral fluids if NPO
CLINICAL
FEATURES
·
Slowed
skeletal muscle contraction
·
Slowed
smooth muscle contraction
·
Deterioration
of respiratory muscle contraction
·
Decrease
in myocardial contraction
·
Increased
conduction of nerve impulses
·
Slowed
smooth muscle contraction leads to GI manifestations - anorexia, abdominal
distension and constipation.
·
Slowed
Skeletal muscle contractions - weakness muscle cramps, may progress to
paralysis.
·
Decreased
nerve conduction - Fatigue, paresthesia,
hyporeflexia and irritability
·
Decreased
myocardial contractility - hypotension
weak and slow pulse. If K less than
·
2.5
mEq/L
·
ventricular
fibrillation and cardiac arrest.
·
Pulmonary
- Shallow respiration, shortness of breath, apnea and respiratory arrest.
ECG Changes:
·
ST
segment depression
·
Flattened
T wave
·
Presence
of U wave
·
Ventricular
dysrhythmias
·
Bradycardia
·
Enhanced
digitalis effects
In Progressive stage
·
Confusion,
depression, convulsions, areflexia, and coma
·
Vomiting,
urinary retention
·
Paralysis
·
Inability
of kidney to concentrate urine leads to Polyuria, nocturia, and decreased
plasma osmolality.
DIAGNOSIS:
History
and physical examination:-A detailed history and physical examination
Serum
potassium levels
ECG
MANAGEMENT
Medical Management:
·
It
is focused on identifying and correcting the cause of the imbalance.
·
The
aggressiveness of the therapy depends on the potassium level and the clinical
manifestations.
Minor potassium
deficit
·
Administering
foods high in potassium helps correct the deficit and offsets losses.
Mild to moderate
potassium deficits:
·
Oral
potassium replacement
·
Oral
potassium is extremely irritating to the gastric mucosa and can produce small
bowel lesion and must be taken with a glass of water or juice or with meals.
Severe hypokalemia:
·
KCl
supplement added to IV solution.
·
Should
not add more than 60 mEq/L.
·
The
preferred level is 40 mEq/L.
·
The
rate of administration should not exceed 10 to 20 mEq per hour to prevent
hyperkalemia and cardiac arrest.
·
Potassium
given intravenously must always be diluted in IV fluids
Nursing management:
Assessment
Physical
examination
Nursing diagnosis
·
Hypokalemia
related to nausea, vomiting or prolonged use of diuretics
·
Risk
for injury related to muscle weakness and hypotension or seizures secondary to
hypokalemia.
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