From the Guidelines
Hyperkalemia workup should begin with confirmation of the elevated potassium level through a repeat blood test to rule out pseudohyperkalemia from hemolysis or improper collection technique. The initial evaluation includes a comprehensive history focusing on medication use (particularly ACE inhibitors, ARBs, potassium-sparing diuretics, NSAIDs, and potassium supplements), dietary habits, and symptoms such as muscle weakness, palpitations, or paresthesias 1. A physical examination should assess for signs of underlying conditions. Laboratory tests should include serum electrolytes, BUN, creatinine, urinalysis, and an ECG to evaluate for cardiac manifestations like peaked T waves, widened QRS complexes, or flattened P waves. Additional testing may include urine potassium and creatinine to calculate the transtubular potassium gradient (TTKG), plasma renin activity, and aldosterone levels if adrenal dysfunction is suspected. In patients with renal impairment, assessment of glomerular filtration rate is essential. For those with unexplained hyperkalemia despite initial workup, further investigation for rare causes like hyporeninemic hypoaldosteronism, pseudohypoaldosteronism, or genetic disorders affecting potassium channels may be warranted 1. This systematic approach helps identify the underlying cause of hyperkalemia, which is crucial for appropriate management and prevention of recurrence.
Some key points to consider in the workup of hyperkalemia include:
- The risk of hyperkalemia is increased in patients with chronic kidney disease (CKD), diabetes, and heart failure (HF) and in individuals receiving renin-angiotensin-aldosterone system inhibitors (RAASis) 1
- Life-threatening hyperkalemia requires immediate treatment with a combination of calcium carbonate and hyperosmolar sodium to stabilize the myocardial cell membrane; insulin with or without glucose and/or beta adrenoceptor agonists to transfer K+ into the cells 1
- Treatment options for the management of acute and chronic hyperkalemia include intravenous calcium, insulin, beta-agonists, sodium bicarbonate, loop diuretics, and potassium binders 1
- Promoting potassium excretion through diuresis, Kayexalate, or dialysis may also be necessary in some cases 1
From the FDA Drug Label
Sodium Polystyrene Sulfonate Powder, for Suspension is indicated for the treatment of hyperkalemia.
The treatment of hyperkalemia with Sodium Polystyrene Sulfonate Powder, for Suspension does not provide a workup for hyperkalemia.
- Key points for treatment:
- The intensity and duration of therapy depend upon the severity and resistance of hyperkalemia.
- Monitor serum potassium during therapy because severe hypokalemia may occur.
- Monitor calcium and magnesium in patients receiving Sodium Polystyrene Sulfonate Powder, for Suspension. However, the FDA drug label does not provide information on the workup for hyperkalemia, only the treatment. 2
From the Research
Hyperkalemia Workup
- Hyperkalemia is defined as a serum potassium level >5.5 mmol/l 3
- It is associated with fatal dysrhythmias and muscular dysfunction, and certain medical conditions such as chronic kidney disease (CKD) and diabetes mellitus can lead to hyperkalemia 3
- A history and physical examination can be beneficial in the diagnosis of hyperkalemia, along with laboratory potassium levels and characteristic electrocardiogram findings 3
Electrocardiogram Findings
- Severe hyperkalemia can be identified through electrocardiogram (ECG) findings, which can be the most immediately available diagnostic tool in critically ill patients 4
- Peaking of the T waves is a widely appreciated ECG sign, but it is actually rarely a manifestation of life-threatening hyperkalemia 4
- Other ECG abnormalities associated with hyperkalemia include wide QRS, peaked T waves, and bradycardia 5, 6
- The prevalence of ECG alterations suggestive of hyperkalemia is higher in hyperkalemic patients compared to normokalemic patients, but a minority of patients with normal potassium levels may also exhibit these alterations 6
Diagnosis and Treatment
- Diagnosis of hyperkalemia involves laboratory potassium levels and ECG findings, and treatment includes glucose and insulin, bicarbonate, calcium gluconate, beta-2 agonists, hyperventilation, and dialysis 3, 7
- Certain drugs such as sodium polystyrene sulfonate (SPS), sodium zirconium cyclosilicate (SZC), and patiromer can aid in the reduction of serum potassium levels, but each has unique benefits and contraindications 3
- Failure to diagnose and manage severe hyperkalemia can require emergent hemodialysis 7