Hypokalemia 55 y/o male CC: chronic diarrhea Farmer in La Trinidad, Benguet Noted progressive weakness for the past weeks Blood Test Na140 meq/L Cl110 meq/L K2.0 meq/L

Hypokalemia Urine potassium: 15 meq/L Arterial Blood Gas pH7.28 pCO239 mmHg HCO316

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

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

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

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

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

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

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 arrhythmi a

Symptoms of Hypokalemia Palpitations Skeletal muscle weakness or cramping Paralysis, paresthesias Constipation 4 Nausea or vomiting Abdominal cramping Polyuria, nocturia, or polydipsia Psychosis, delirium, or hallucinations Depression

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)

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