Causes of Hypokalemia
1.Decreased intake
A. Starvation
B. Clay ingestion
2. Redistribution into cells
C. Acid-base
I. Metabolic alkalosis
B. Hormonal
1. Insulin
2. Increased By-adrenergic sympathetic activity: post-myocardialinfarction, head
injurv
3. B, Adrenergic agonists -bronchodilators, tocolytics
4. a-Adrenergic antagonists
5. Thyrotoxic periodic paralysis
6. Downstream stimulation of Na-/K+-ATPase: theophylline, caffeine
7.
C. Anabolic state
a)Vitamin B, or folic acid administration (red blood cell production)
b) Granulocyte-macrophage colony-stimulating factor (white blood
cellproduction)
c) Total parenteral nutrition
d) Other
1. Pseudohypokalemia
2. Hypothermia
3. Familial hypokalemic periodic paralvsis
4. Barium toxicity: systemic inhibition of "leak" K* channel
8.
3. Increased loss
A.Nonrenal
1. Gastrointestinal loss (diarrhea)
2. Integumentary loss (sweat)
B. Renal
1.Increased distal flow and distal Na+ delivery: diuretics, osmotic diuresis, salt-
wasting nephropathies
2. Increased secretion of potassium
a. Mineralocorticoid excess: primary hyperaldosteronism ,Aldosterone-producing
adenomas, primary or unilateral adrenal hyperplasia, idiopathic hyperaldosteronism
due to bilateral adrenal hyperplasia, and adrenal carcinoma), genetic
hyperaldosteronism (familial hyperaldosteronism types V/I/II, congenital adrenal
hyperplasias), secondary hyperaldosteronism (malignant hypertension, renin-secreting
tumors, renal artery stenosis, hypovolemia), Cushing's syndrome, Barter's syndrome,
Gielman’s syndrome
b. Apparent mineralocorticoid excess: genetic deficiency of11-dehydrogenase-2
(syndrome of apparent mineralocoricoid excess
c. Distal delivery of nonreabsorbed anions vomting, nasogastric suction proximal renal
tubular acidosis, DKA, penicilin derivatives
3. Magnesium deficiency
9.
Clinical Features
1. Muscularweakness.
2. Tiredness
3. Fatigue
4. Myalgia
5. Abdominal distention due to paralytic ileus
6. Features of arrhythmia: Palpitation, irregular pulse, hypotension
11.
Investigations:
1. Measurement ofplasma electrolytes
2. Plasma bicarbonate
3. Arterial Blood Gas (ABG) Analysis
4. Urine potassium and sometimes calcium and
magnesium
5. ECG.
12.
Figure-2: ECG changesin Hypokalaemia
ECG changes in hypokalaemia:
Flattened T wave
ST-depression
Appearance of U wave
Type of HypokalaemiaSerum level of K+
Correction of K+
Mild Hypokalaemia 3-3.5 mmol/L Oral Correction by-
• Green coconut water
• Fruit and fruit juice
• Banana
• Orange
• Pineapple
• Potato
• Bean etc.
Moderate Hypokalaemia 2.5- 3.0 mmol/L Oral K+
Supplementation by potassium tablet (must be with half
glass of water and in full stomach) and syrup (in full stomach)
Severe Hypokalaemia 2.5 mmol/L
˂ I/V correction
• Intravenous potassium diluted in normal saline
• Not more than 10 mmol/hour
• 1 ampoule contains 20 mmol of potassium
• 1 litre of normal saline should not be mixed with more than 40
mmol (i.e. 2 ampoules)
Treatment
Note: Never Administer Potassium Directly via IV Route
Direct IV push can cause severe cardiac complications
Causes of HYPERKALAEMIA
1.Pseudohyperkalemia
A. Cellular efflux, thrombocytosis, erythrocytosis, leukocytosis, in vitrohemolysis
B. Hereditary defects in red cell membrane transport
2. Intra- to extracellular shift
A. Acidosis
B. Hyperosmolality; radiocontrast, hypertonic dextrose, mannitol
C. B2,- Adrenergic antagonists (noncardioselective agents)
D. Digoxin and related glycosides (yellow oleander, foxglove, bufadienolide)
E. Hyperkalemic periodic paralysis
F. Lvsine, arginine, and e-aminocaproic acid (structurally similar, positivelycharged)
G. Succinylcholine; thermal trauma, neuromuscular injury, disuse atrophy. mucositis, or
prolonged immobilization si
H. Rapid tumor lysisII.
19.
3. Inadequate excretion
A.Inhibition of the renin-angiotensin-aldosterone axis; I risk of hyperkalemia
when used in combination
1. Angiotensin- converting enzyme (ACE) inhibitors
2. Renin inhibitors, aliskiren (in combination with ACE inhibitors or angiotensin
receptor blockers ARBs])
3. ARBs
4. Blockade of the mineralocorticoid receptor: spironolactone, eplerenone,
drospirenone
5. Blockade of the epithelial sodium channel (ENaC): amiloride, triamterene,
trimethoprim, pentamidine, nafamostat
B. Decreased distal delivery
1. Congestive heart failureINSPIOBO
2. Volume depletion
Management Approach
History:
Historyof potassium containing drug intake
History of intake of drugs that can increase serum potassium e.g.
spironolactone, ACE inhibitors etc.
History of CKD
History of any condition that can cause renal impairment
Any condition that can cause metabolic acidosis
History of crush injury or soft tissue damage
Massive blood transfusion.
29.
Treatment: Treatment ofhyperkalaemia depends on the severity and the rate of development
1. In the absence of neuromuscular symptoms or ECG changes, reduction of potassium intake and correction of
underlying abnormalities may be sufficient.
2. Acute &/or severe hyperkalaemia more urgent measures must be taken:
Mechanism Therapy
Stabilization of the cell
membrane potential
• I/V calcium gluconate (10 ml of 10% solution) is to be given very
slowly over 10-20 minutes.
To shift into K+
cells • Inhaled ß2 agonist: Nebulization with Salbutamol.
• Glucose with Insulin: 50 ml of 50% glucose with 5-10 IU Insulin-R
[or 100 ml 25% glucose + Inj. Insulin-R 10 IU in Bangladesh].
• Correction of acidosis: I/V sodium bicarbonate (100ml of 8.4%
solution)
To remove K+
from
body
• Intravenous furosemide and normal saline.
• Ion-exchange resin (e.g. Resonium) orally or rectally.
• Newer Cation Exchange resin (Ex. Sodium zirconium cyclosilicate)
• Dialysis.