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Delayed fatal hyperkalemia in a patient with acute fluoride intoxication.

A 19-year-old man presented with acute fluoride poisoning. Initially his serum electrolytes were normal, but two hours later he developed ECG evidence of hyperkalemia followed by refractory ventricular fibrillation, suggesting that hyperkalemia may be important in the cardiotoxicity of acute fluoride intoxication. Treatment of fluoride-induced hyperkalemia consists of removal of fluoride from the body by dialysis, binding fluoride with aluminum or calcium, or enhancing fluoride excretion by inducing a metabolic alkalosis. Direct treatment of the hyperkalemia with glucose, insulin, and bicarbonate is ineffective. Quinidine may be an effective therapy for the hyperkalemia and ventricular irritability, but is as yet untested in human beings.

Adult↗

Hyperkalemia in acute glomerulonephritis due to transient hyporeninemic hypoaldosteronism.

Transient hyperkalemia has been reported to occur in patients with acute glomerulonephritis, but the pathogenetic mechanism has not been investigated systematically. We studied the mechanism of hyperkalemia (5.7 to 6.7 mmol/liter) in four men with post-infectious glomerulonephritis. All four patients had clinical findings consistent with acute glomerulonephritis (edema, hypertension, proteinuria, hematuria, and an elevated ASO titer) and a renal biopsy performed in three of the patients confirmed the diagnosis. In comparison to normal subjects (N = 18), plasma aldosterone (5.4 +/- 1.6 vs. 22.8 +/- 2.6 ng/dl, P less than 0.005) and plasma renin activity (0.3 +/- 0.2 vs. 4.3 +/- 0.6 ng/ml/hr, P less than 0.005) were reduced. Hyperkalemia resolved within one to two weeks in two patients as the nephritis resolved and diuresis ensued, and aldosterone and renin levels obtained at follow-up visits were normal. Hyperkalemia persisted despite furosemide-induced diuresis in the other two patients, but resolved with fludrocortisone treatment. Thus, hyperkalemia in patients with acute glomerulonephritis is a manifestation, in part, of hyporeninemic hypoaldosteronism. It is ameliorated by mineralocorticoid therapy and improves spontaneously with resolution of the glomerulonephritis.

Acute Disease↗

Hyperkalemia: An adaptive response in chronic renal insufficiency.

BACKGROUND: Hyperkalemia is a common feature of chronic renal insufficiency, usually ascribed to impaired K+ homeostasis. However, various experimental observations suggest that the increase in extracellular [K+] actually functions in a homeostatic fashion, directly stimulating renal K+ excretion through an effect that is independent of, and additive to, aldosterone. METHODS: We have reviewed relevant studies in experimental animals and in human subjects that have examined the regulation of K+ excretion and its relation to plasma [K+]. RESULTS: Studies indicate that (1) extracellular [K+] in patients with renal insufficiency correlates directly with intracellular K+ content, and (2) hyperkalemia directly promotes K+ secretion in the principal cells of the collecting duct by increasing apical and basolateral membrane conductances. The effect of hyperkalemia differs from that of aldosterone in that K+ conductances are increased as the primary event. The changes in principal cell function and structure induced by hyperkalemia are indistinguishable from the effects seen in adaptation to a high K+ diet. CONCLUSIONS: We propose that hyperkalemia plays a pivotal role in K+ homeostasis in renal insufficiency by stimulating K+ excretion. In patients with chronic renal insufficiency, a new steady state develops in which extracellular [K+] rises to the level needed to stimulate K+ excretion so that it again matches intake. When this new steady state is achieved, plasma [K+] remains stable unless dietary intake increases, glomerular filtration rate falls, or drugs are given that disrupt the new balance.

Adaptation, Physiological↗

Electrocardiographic manifestations of hyperkalemia.

Hyperkalemia is one of the more common acute life-threatening metabolic emergencies seen in the emergency department. Early diagnosis and empiric treatment of hyperkalemia is dependent in many cases on the emergency physician's ability to recognize the electrocardiographic manifestations of hyperkalemia. The electrocardiographic manifestations commonly include peaked T-waves, widening of the QRS-complex, and other abnormalities of altered cardiac conduction. Peaked T-waves in the precordial leads are among the most common and the most frequently recognized findings on the electrocardiogram. Other "classic" electrocardiographic findings in patients with hyperkalemia include prolongation of the PR interval, flattening or absence of the P-wave, widening of the QRS complex, and a "sine-wave" appearance at severely elevated levels. A thorough knowledge of these findings is imperative for rapid diagnosis and treatment of hyperkalemia.

Adult↗

Rates of hyperkalemia after publication of the Randomized Aldactone Evaluation Study.

BACKGROUND: The Randomized Aldactone Evaluation Study (RALES) demonstrated that spironolactone significantly improves outcomes in patients with severe heart failure. Use of angiotensin-converting-enzyme (ACE) inhibitors is also indicated in these patients. However, life-threatening hyperkalemia can occur when these drugs are used together. METHODS: We conducted a population-based time-series analysis to examine trends in the rate of spironolactone prescriptions and the rate of hospitalization for hyperkalemia in ambulatory patients before and after the publication of RALES. We linked prescription-claims data and hospital-admission records for more than 1.3 million adults 66 years of age or older in Ontario, Canada, for the period from 1994 through 2001. RESULTS: Among patients treated with ACE inhibitors who had recently been hospitalized for heart failure, the spironolactone-prescription rate was 34 per 1000 patients in 1994, and it increased immediately after the publication of RALES, to 149 per 1000 patients by late 2001 (P<0.001). The rate of hospitalization for hyperkalemia rose from 2.4 per 1000 patients in 1994 to 11.0 per 1000 patients in 2001 (P<0.001), and the associated mortality rose from 0.3 per 1000 to 2.0 per 1000 patients (P<0.001). As compared with expected numbers of events, there were 560 (95 percent confidence interval, 285 to 754) additional hyperkalemia-related hospitalizations and 73 (95 percent confidence interval, 27 to 120) additional hospital deaths during 2001 among older patients with heart failure who were treated with ACE inhibitors in Ontario. Publication of RALES was not associated with significant decreases in the rates of readmission for heart failure or death from all causes. CONCLUSIONS: The publication of RALES was associated with abrupt increases in the rate of prescriptions for spironolactone and in hyperkalemia-associated morbidity and mortality. Closer laboratory monitoring and more judicious use of spironolactone may reduce the occurrence of this complication.

Adrenergic beta-Antagonists↗

Reversible hemiplegia as a consequence of severe hyperkalemia and cocaine abuse in a hemodialysis patient.

Severe hyperkalemia may cause weakness that typically is ascending and symmetric. In an isolated case report, hemiplegia occurred after the development of hyperkalemia in a patient with a known central nervous system lesion. We describe a patient requiring long-term hemodialysis who had near-fatal hyperkalemia, hemiplegia, and rhabdomyolysis after abuse of crack cocaine. The hemiplegia resolved after normalization of serum potassium using emergency dialysis. No brain lesion could be identified during computed tomography or by electroencephalography, and the patient had no residual neurologic deficits. We conclude that this patient had hemiplegia secondary to cocaine-induced cerebral vasoconstriction because no structural lesion could be found and that the neurologic deficit was worsened by severe hyperkalemia, which probably resulted from cocaine-induced rhabdomyolysis. Hence, despite the absence of a structural lesion of the brain, severe hyperkalemia, typically associated with symmetric, ascending muscle weakness, may contribute to causing focal weakness in the condition of cocaine-induced vasoconstriction.

Adult↗

Drug-induced hyperkalemia.

After reviewing the available data on drug-induced hyperkalemia, we conclude that the situation has not improved since Lawson quantitatively documented the substantial risks of potassium chloride over a decade ago (90). As discussed, the risk of developing hyperkalemia in hospital remains at least at the range of 1 to 2% and can reach 10%, depending on the definition used (Table 2). Potassium chloride supplements and potassium-sparing diuretics remain the major culprits but they have been joined by a host of new actors, e.g., salt substitutes, beta-blockers, converting enzyme inhibitors, nonsteroidal antiinflammatory agents, and heparin, among others. Readily identifiable risk factors (other than drugs) for developing hyperkalemia are well-known but seem to be consistently ignored, even in teaching hospitals. The presence of diabetes mellitus, renal insufficiency, hypoaldosteronism, and age greater than 60 years results in a substantial increase in the risk of hyperkalemia from the use of any of the drugs we have reviewed. If prevention of hyperkalemia is the goal, as it should be, the current widespread and indiscriminate use of potassium supplements and potassium-sparing diuretics will need to end. We remain intrigued by Burchell's prescient pronouncement of over a decade ago that "more lives have been lost than saved by potassium therapy" (28).

Adrenergic Agonists↗

Effects of chronic hyperkalemia on renal production and proximal tubule transport of ammonium in rats.

Free-flow micropuncture experiments were performed to examine directly the effects of chronic hyperkalemia on renal ammonium production, urinary ammonium excretion, and proximal convoluted tubule ammonium transport in the rat in vivo. Munich-Wistar rats were pair-fed either a control or a high-K+ diet for 6-11 days. Chronic K+ loading was associated with an increase in plasma K+ concentration and significant systemic metabolic acidosis. Renal blood flow did not differ in control and high-K+ rats. In the hyperkalemic rats, urinary ammonium excretion was reduced by 40% and whole kidney ammonium production was reduced by 50% compared with controls. In contrast, chronic hyperkalemia had no significant effect on net ammonium transport by either the early or late segment of the proximal convoluted tubule. Chronic hyperkalemia also had no effect on the absolute rate of ammonium delivery to early or late proximal convoluted tubule sites. These results indicate that a change in renal ammonium production does not necessarily correlate with a change in proximal tubule ammonium transport and that reduced urinary ammonium excretion in chronic hyperkalemia is not due to impaired secretion of ammonium by the proximal convoluted tubule. Chronic hyperkalemia may reduce ammonium excretion by decreasing transfer of ammonium from proximal tubules to collecting ducts in the renal medulla.

Ammonia↗

Role of Ca2+ in protecting the heart from hyperkalemia and acidosis in the rabbit: implications for exercise.

Catecholamines can offset the negative effect of acidosis and raised extracellular K+ concentration in the isolated rabbit heart when these factors are changed with similar kinetics and concentrations as those observed in exercise. This effect appears to be mediated by changes in Ca2+ handling in the heart. To test the role of Ca2+ in vivo, we studied the interactive effects of infusions of KCl, lactic acid, norepinephrine (NE), and CaCl2 on cardiovascular performance in the anesthetized rabbit. After propranolol, CaCl2 was given during acidosis and hyperkalemia. Acidosis (arterial pH 7.17 +/- 0.3) markedly reduced cardiac performance, and its effects were exacerbated by hyperkalemia (7.3 +/- 0.4 mM). NE reversed the cardiac response to combined acidosis and hyperkalemia. After propranolol, arterial pH and arterial K+ concentration changed more rapidly with acidosis and hyperkalemia, combined with a faster fall in cardiac performance, but CaCl2 offset these negative hemodynamic effects. The rises in plasma Ca2+, NE, and sympathetic activity during exercise may therefore interact to ameliorate the harmful effects of acidosis and hyperkalemia.

Acidosis↗

Trimethoprim-sulfamethoxazole therapy in outpatients: is hyperkalemia a significant problem?

A prospective, randomized clinical study was undertaken to determine the effect of standard-dose trimethoprim-sulfamethoxazole combination treatment on serum potassium concentrations in outpatients treated in an ambulatory clinic. Ninety-seven patients were treated with oral antibiotics for a variety of infections. Fifty-one patients treated with trimethoprim-sulfamethoxazole (trimethoprim, 320 mg/day; sulfamethoxazole, 1,600 mg/day) constituted the treatment group, while 46 patients treated with other antibiotics served as controls. Serum potassium, sodium, and chloride concentrations, serum carbon dioxide content, blood urea nitrogen level, serum creatinine level, and serum glucose concentration were measured. The baseline serum potassium concentration in the treatment group was 4.30 +/- (SD) 0.36 mmol/l, and it increased significantly (p < 0.001) to 4.66 +/- 0.45 mmol/l on day 5 of therapy. Subgroup analysis of mean serum potassium concentration on day 5 of therapy failed to detect clinically relevant hyperkalemia. In patients with a serum creatinine level equal to or greater than 1.1 mg/dl (K+, 4.83 +/- 0.48 mmol/l), a nonsignificant difference (p = 0.3) in the potassium concentration was noted on day 5 as compared with patients with a serum creatinine level <1.1 mg/dl (K+, 4.63 +/- 0.44 mmol/l). Although diabetics had a higher serum potassium concentration (K+, 4.91 +/- 0.44 mmol/l) than nondiabetics (K+, 4.61 +/- 0.44 mmol/l), the difference was not statistically significant (p = 0.055). Patients aged >/=50 years (K+, 4.82 +/- 0.59 mmol/l) had a significantly different (p = 0.046) serum potassium concentration on day 5 than patients aged <50 years (K+, 4.55 +/- 0.28 mmol/l). In contrast, the baseline serum potassium concentration in the control group was 4.37 +/- 0.45 mmol/l, and it decreased (p = 0.1) to 4.22 +/- 0.4 mmol/l on 5 days of drug therapy. Trimethoprim-sulfamethoxazole therapy, when used to treat a variety of infections, leads to an increase in serum potassium concentration in most patients. After 5 days of therapy with this drug, the treatment group developed a statistically significant rise in the serum potassium concentration as compared with the control group. However, severe hyperkalemia (K+ >/=5.5 mmol/l) occurred in only 3 patients (6%) treated with trimethoprim-sulfamethoxazole. In addition, none of the subgroups of treated patients developed clinically important hyperkalemia. This suggests that outpatients, in contrast to acquired immunodeficiency syndrome patients and hospitalized patients with mild renal insufficiency, develop severe or life-threatening hyperkalemia less commonly when treated with this antimicrobial regimen. However, outpatients having risk factors which may predispose to the development of hyperkalemia should be carefully monitored when treated with trimethoprim-sulfamethoxazole.

Ambulatory Care↗

Labetalol-induced hyperkalemia in renal transplant recipients.

BACKGROUND: Labetalol is a commonly used agent for perioperative hypertension in renal transplant recipients. A previous report suggested that labetalol may cause life-threatening hyperkalemia after renal transplantation. METHODS: We performed a retrospective review of 103 consecutive renal transplants to determine whether labetalol was an independent predictor of hyperkalemia treatment. Thirty-eight patients (36.9%) received labetalol, and 65 patients (63.1%) had no labetalol medication. RESULTS: Of the 103 patients, 24 (23.3%) required treatment for hyperkalemia. Thirteen (34.2%) of the patients who had labetolol medication and 11 (16.9%) of the patients who did not receive labetalol were treated for hyperkalemia (p = 0.045). Factors considered for a logistic regression model included: the use of labetalol, cold ischemia time, diabetes, and dialysis method; intake of tacrolimus, beta blockers, angiotensin-converting enzyme inhibitors, or other antihypertensives prior to admission; the mannitol dose given intraoperatively, and the 24-hour urine output postoperatively. Intravenous labetalol (odds ratio OR = 4.52, confidence interval CI = 1.33-15.28; p = 0.02), 24- hour urine output (OR = 4.4, CI = 0.97-20.1: p = 0.47), increasing cold ischemia time (OR = 1.09, CI = 1.01-1.17; p = 0.02), and continuous ambulatory peritoneal dialysis (OR = 0.17, CI = 0.29-0.98; p = 0.036) were independent predictors. CONCLUSION: Labetalol appears to increase the risk of hyperkalemia in patients after renal transplantation.

Adrenergic alpha-Antagonists↗

Therapeutic approach to hyperkalemia.

The foremost step in the initial clinical management of hyperkalemia is to decide whether a hyperkalemic patient requires immediate treatment to avoid a life-threatening situation (serum potassium concentration >6.0 mEq/l and EKG changes). When the decision for urgent treatment of hyperkalemia is based on EKG changes, an important caveat for clinicians is that absent or atypical EKG changes do not exclude the necessity for immediate intervention. Once an urgent situation has being handled with intravenous push of a 10% calcium salt, the initiation of short-term measures can be launched by either a single or combined regimen of the three agents that cause a transcellular shift of potassium - insulin with glucose, beta(2)-agonist (albuterol), and NaHCO(3). As the first choice among these available options, we favor an intravenous bolus of 10 units of insulin with 50 ml of 50% glucose alone or in combination with 10-20 mg of albuterol by nebulizer. These can be repeated as required until the institution of hemodialysis. The combination of insulin with glucose and NaHCO(3) as an another option needs further clarification for its additive effects. However, NaHCO(3) has lost its favor because of its poor efficacy as a potassium-lowering agent when used alone. The next step is to remove potassium from the body - diuretics (furosemide), cation exchange resin (kayexelate) with sorbitol, and dialysis (preferably hemodialysis). The final important step for the managements of hyperkalemia is a long-term plan to prevent its recurrence or worsening. In addition to every effort to elucidate underlying causes and pathophysiologic mechanisms for hyperkalemia, an extensive search must be made to uncover overt or sometimes covert medications that may have led to the development of hyperkalemia. Furthermore, one must obtain detailed dietary and medical history of hyperkalemic patients.

Adrenergic beta-Agonists↗

Primary role of hyperkalemia in the acidosis of hyporeninemic hypoaldosteronism.

A 65-year-old woman with mild renal insufficiency had persistent hyperkalemia and hyperchloremic acidosis. Her plasma aldosterone level was relatively low for her hyperkalemia, and her urine pH was low. Fludrocortisone acetate administration corrected both hyperkalemia and acidosis by increasing urinary excretion of potassium and net acid, implicating deficient mineralocorticoid activity in the distal renal tubule in this patient. During this medication urinary ammonium excretion increased, but urine pH remained low, so that urinary titratable acid excretion did not decrease. On the other hand, correction of hyperkalemia by administration of a potassium-calcium exchange resin alone also resolved the acidosis by increasing urinary ammonium excretion. This increment exceeded the decrement of urinary titratable acid excretion, which was caused by raised urine pH secondary to increased urinary ammonium excretion, and resulted in increase of net acid excretion. Thus, in this patient, hyperkalemia appears to be a decisive causative factor in the acidosis, with deficient mineralocorticoid effect only contributing in part to the reduction of net acid excretion and the acidosis.

Acidosis, Renal Tubular↗

Chronic hyperkalemia impairs ammonium transport and accumulation in the inner medulla of the rat.

Previously we demonstrated in rats that chronic hyperkalemia had no effect on ammonium secretion by the proximal tubule in vivo but that high K+ concentrations inhibited ammonium absorption by the medullary thick ascending limb in vitro. These observations suggested that chronic hyperkalemia may reduce urinary ammonium excretion through effects on medullary transport events. To examine directly the effects of chronic hyperkalemia on medullary ammonium accumulation and collecting duct ammonium secretion, micropuncture experiments were performed in the inner medulla of Munich-Wistar rats pair fed a control or high-K+ diet for 7-13 d. In situ pH and total ammonia concentrations were measured to calculate NH3 concentrations for base and tip collecting duct and vasa recta. Chronic K+ loading was associated with significant systemic metabolic acidosis and a 40% decrease in urinary ammonium excretion. In control rats, 15% of excreted ammonium was secreted between base and tip collecting duct sites. In contrast, no net transport of ammonium was detected along the collecting duct in high-K+ rats. The decrease in collecting duct ammonium secretion in hyperkalemia was associated with a decrease in the NH3 concentration difference between vasa recta and collecting duct. The fall in the NH3 concentration difference across the collecting duct in high-K+ rats was due entirely to a decrease in [NH3] in the medullary interstitial fluid, with no change in [NH3] in the collecting duct. These results indicate that impaired accumulation of ammonium in the medullary interstitium, secondary to inhibition of ammonium absorption in the medullary thick ascending limb, may play an important role in reducing collecting duct ammonium secretion and urinary ammonium excretion during chronic hyperkalemia.

Ammonia↗

Hyperkalemia: a review.

Potassium is the principal intracellular cation, and maintenance of the distribution of potassium between the intracellular and the extracellular compartments relies on several homeostatic mechanisms. When these mechanisms are perturbed, hypokalemia or hyperkalemia may occur. This review covers hyperkalemia, that is, a serum potassium concentration exceeding 5 mmol/L. The review includes a discussion of potassium homeostasis and the etiologies of hyperkalemia and focuses on the prompt recognition and treatment of hyperkalemia. This disorder should be of major concern to clinicians because of its propensity to cause fatal arrhythmias. Hyperkalemia is easily diagnosed, and rapid and effective treatments are readily available. Unfortunately, treatment of this life-threatening condition is often delayed or insufficiently attentive or aggressive.

Algorithms↗

A case of aldosterone-producing adenoma with severe postoperative hyperkalemia.

It is known that some patients with primary aldosteronism show postoperative hyperkalemia, which is due to inability of the adrenal gland to secrete sufficient amounts of aldosterone. However, hyperkalemia is generally neither severe nor prolonged, in which replacement therapy with mineralocorticoid is seldom necessary. We report a case of a 46-year-old woman with an aldosterone-producing adenoma associated with severe postoperative hyperkalemia. After unilateral adrenalectomy, the patient showed episodes of severe hyperkalemia for four months, which required not only cation-exchange resin, but also mineralocorticoid replacement. Plasma aldosterone concentration (PAC) was low, although PAC was increased after rapid ACTH test. Histological examination indicated the presence of adrenocortical tumor and paradoxical hyperplasia of zona glomerulosa in the adjacent adrenal. Immunohistochemistry demonstrated that the enzymes involved in aldosterone synthesis, such as cholesterol side chain cleavage (P-450scc), 3beta-hydroxysteroid dehydrogenase (3beta-HSD), and 21-hydroxylase (P-450c21), or the enzyme involved in glucocorticoid synthesis, 11beta-hydroxylase (P-450c11beta), were expressed in the tumor, but they were completely absent in zona glomerulosa of the adjacent adrenal. These findings were consistent with the patterns of primary aldosteronism. Serum potassium level was gradually decreased with concomitant increase in PAC. These results suggest that severe postoperative hyperkalemia of the present case was attributable to severe suppression of aldosterone synthesis in the adjacent and contralateral adrenal, which resulted in slow recovery of aldosterone secretion. It is plausible that aldosterone synthesis of adjacent and contralateral adrenal glands is severely impaired in some cases with primary aldosteronism, as glucocorticoid synthesis in Cushing syndrome.

Adenoma↗

Hyperkalemia in end-stage renal disease: mechanisms and management.

Clinical investigations in the past few years have enhanced the understanding of the mechanisms of hyperkalemia in patients with ESRD. The results of these studies have led to modifications in the acute treatment and prevention of hyperkalemia in this patient population. They have confirmed the efficacy of intravenous insulin, while raising doubts about the utility of intravenous bicarbonate, for the acute treatment of hyperkalemia. Moreover, the beta-adrenergic agonist albuterol has been shown to be a useful adjunct to insulin for acutely lowering plasma potassium. Finally, there has been enhanced recognition of nondietary factors that can predispose to hyperkalemia in patients with ESRD, including prolonged fasting and the use of nonselective beta-adrenergic blockers. These new insights may improve the clinical management of hyperkalemia in patients with renal failure.

Humans↗

Hyperkalemia-induced ECG abnormalities in patients with reduced renal function.

Hyperkalemia is a potentially lethal condition to be aware of in the presence of ECG abnormalities especially in patients with reduced renal function. However, ECG abnormalities are not always dependent on the degree ofhyperkalemia but may be aggravated by the rapidity of the development of hyperkalemia and by associated electrolyte disorders. We describe 3 patients with renal failure and different ECG changes induced by hyperkalemia. More severe changes were observed when hyperkalemia developed rapidly, but not in presence of electrolyte disorders. Even minor ECG abnormalities must alarm physicians in patients with renal failure since severe hyperkalemia is not always associated with critical ECG changes.

Aged↗