1. Hypokalemia 55 y/o male CC: chronic diarrhea
Farmer in La Trinidad, Benguet
Noted progressive weakness for the past weeks
Blood Test Na
140 meq/L Cl
110 meq/L K
2.0 meq/L

2. Hypokalemia Urine potassium: 15 meq/L Arterial Blood Gas pH 7.28 pCO2
39 mmHg
HCO3 16

3. Diagnostic approach to hypokalemia
Urinary K+ excretion
<15 mmol/d
Assess acid-base status
>15 mmol/d
Assess K+ secretion

4. Diagnostic approach to hypokalemia
Assess acid-base status
Metabolic acidosis
Lower gastrointestinal K+ loss
Metabolic alkalosis
Remove diuretic use, vomitting and K+ loss via sweat

5. Diagnostic approach to hypokalemia
Assess K+ secretion
Transtubular K+ concentration gradient > 4
Acid-base status
Transtubular K+ concentration gradient < 2
Na+ wasting nephropathy, osmotic diuresis, diuretic

6. Diagnostic approach to hypokalemia
Acid-base status
Metabolic acidosis
Diabetic ketoacidosis, proximal RTA, distal RTA, amphotericin B
Metabolic alkalosis
Hypertension?

7. Diagnostic approach to hypokalemia
Hypertension?
YES
Mineralocor-ticoid excess, Liddle’s syndrome NO
Vomiting,Bartter’s syndrome, exclude diuretic use, hypomagnesemia

8. Significance of Urinary K levels
This can be established after eliminating decreased intake and intracellular shift as potential causes of hypokalemia
Appropriate response to K+ depletion is to excrete less than 15 mmol/d of K+ in the urine, due to increased reabsorption and decreased distal excretion
This is exemplified by the diagnostic approach shown previously

9. Adverse medical implications
More severe hypokalemia may lead to progressive weakness, hypoventilation (due to respiratory involvement involvement, and even complete paralysis
Impaired muscle metabolism and blunted hyperemic response to exercise leads to rhabomyolysis
Leads to prolonged PR interval, decreased voltage and widening of the QRS complex, with increased risk of ventricular arrhythmia

10. Symptoms of Hypokalemia
Palpitations
Skeletal muscle weakness or cramping
Paralysis, paresthesias
Constipation4
Nausea or vomiting
Abdominal cramping
Polyuria, nocturia, or polydipsia
Psychosis, delirium, or hallucinations
Depression

11. Signs of Hypokalemia Signs of ileus Hypotension
Ventricular arrhythmias
Cardiac arrest
Bradycardia or tachycardia
Premature atrial or ventricular beats
Hypoventilation, respiratory distress
Respiratory failure
Lethargy or other mental status changes
Decreased muscle strength, fasciculations, or tetany
Decreased tendon reflexes
Cushingoid appearance (eg, edema)

12. Treatment ECG monitoring Establish IV access Assess respiratory status
Infuse potassium chloride, since his serum potassium is < 2.5 meq/L, in other cases oral is the preferred route for potassium repletion because it is easy to administer, safe, inexpensive, and readily absorbed from the GI tract
Check serum Mg levels since it is difficult to restore K if the former is low