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Page 22 of 33 Berardi et al. J Cancer Metastasis Treat 2019;5:79 I http://dx.doi.org/10.20517/2394-4722.2019.008

Table 6. Causes of hyperkalemia
Causes of hyperkalemia
Increased intake Iatrogenic (excessive potassium infusion, parenteral nutrition, etc.)
Redistribution into extracellular Massive tissue catabolism (hemolysis, sepsis, diffuse trauma, rhabdomyolysis,
compartment chemotherapies, lysis syndrome)
Drugs (beta-blockers, arginine, digital)
Metabolic acidosis
Insulin deficiency and hyperglycemia
Severe muscular exercise
Pseudo-hyperkalemia (in vitro hemolysis, leukocytosis, thrombocytosis)
Reduction of renal excretion of potassium Renal injuries:
Acute or chronic renal failure
Depletion of effective circulating volume
Tubulopathies
Selective alteration of potassium excretion (acute transplant rejection, lupus nephritis,
cyclosporine, analgesic nephropathy, lead poisoning)
Nephrotoxic drugs (cisplatin, ifosphamide, mitomycin C, gemcitabine, methotrexate,
bisphosphonates, interferon, somatostatin analogs)
Corticosurrenal insufficiency:
Iporeninemic hypoaldosteronism (diabetic nephropathy, chronic interstitial nephritis, drug
nephropathy)
Primitive hypoaldosteronism (M. Addison)
Use of potassium-sparing diuretics

(3) Concomitant drugs: diuretics, potassium-sparing diuretics, angiotensin-converting enzyme, inhibitors,
and NSAIDs might induce hypokalemia.

(4) Concomitant diseases: renal failure, diabetes mellitus, sepsis, and parenteral nutrition might induce
hypokalemia.

However, causes of hyperkalemia might be resumed in different mechanisms, such as excessive intake,
redistribution into extracellular compartment, or abnormal renal elimination, that might depend on
aldosterone deficiency or on renal parenchyma damage [Table 6].

Rarely, hyperkalemia depends only on increased potassium intake, and it is often associated with other risk
factors: renal failure, diabetes mellitus, and concomitant medications that inhibit potassium excretion (e.g.,
potassium-sparing diuretics, angiotensin-converting enzyme inhibitors, and NSAIDs). Furthermore, in
cancer patients, parenteral nutrition rich in potassium might induce to life-threatening hyperkalemia [141] .

Tumor lysis syndrome (TLS) represents an important cause of acute hyperkalemia in cancer patients. It is a
rare but serious oncological emergency characterized by hyperuricemia, hyperkalemia, hyperphosphatemia,
hypocalcemia, and azotemia. It usually appears 48-72 h after the commencement of anticancer-therapy
(chemotherapy, radiotherapy, and radiofrequency ablation) as a consequence of massive cell necrosis
and acute release of intracellular factors into the systemic circulation [142] . In particular, elevated uric
acid and calcium phosphate release tend to precipitate into renal tubules, causing local damage with
glomerular filtration rate reduction until acute kidney injury (AKI). AKI worsens metabolic disorders and
hyperkalemia, which might induce severe cardiac arrhythmias until death; low serum calcium levels and
acidosis may exacerbate this risk [143] . In high-grade hematologic malignancies and childhood cancers, it
[144]
might also occur spontaneously .

Several predisposing factors to tumor lysis syndrome were detected, such as elevated tumor burden, rapid-
growing neoplasms, high tumor sensibility to anti-cancer treatment, concomitant renal failure, elevated
lactate dehydrogenase serum level, hyperuricemia, and hyperazotemia. These factors should be investigated
[145]
before starting treatment, in order to set up a preventive therapy .