Hypocalcaemic tetany induced by hypertonic-phosphate enema

Serum electrolyte shifts following administration of sodium phosphates enema

The misuse of sodium phosphates enemas has resulted in reports of potentially severe metabolic and hemodynamic disturbances. Despite their long availability, these products have not been fully characterized pharmacokinetically. This trial sought to evaluate changes in the metabolic and hemodynamic parameters following the administration of one of two standard sodium phosphates enemas. Enema Casen (250 ml) is available only in Spain, and Fleet Enema (133 ml) is available in 66 countries in six continents of the world. These changes were correlated with scientific literature reports of hyperphosphatemia following phosphate enema use. Forty-five adult participants aged 50 years or older enrolled in the trial. Twenty-five participants were given one Enema Casen, whereas 20 participants received one Fleet Enema. Blood pressure, pulse, and serum chemistries were evaluated at screening; baseline; and 10, 60, and 120 minutes after receiving the enema. Each participant had a bowel movement within 10 minutes of receiving his enema. Asymptomatic, transient hyperphosphatemia was associated with increase in retention time but not with increase in volume of sodium phosphates enemas. Increased serum phosphate concentration and increased area under the curve of serum phosphate were associated with increased enema retention time. The Enema Casen induced a greater mean AUC of serum sodium concentration than did the Fleet Enema. There were no drug-related adverse events. Transient hyperphosphatemia following the use of sodium phosphates enemas correlates with retention time but not with dose. A scientific literature review of serious adverse events revealed that overdose, concomitant use of oral and rectal sodium phosphates products, and use in a contraindicated patient were associated with sodium phosphates enema and hyperphosphatemia.

Systematic review: the adverse effects of sodium phosphate enema

BACKGROUND

Sodium-phosphate enemas are widely used to treat constipation, and are rarely associated with side effects.

AIM

A systematic review of the literature was conducted to identify the most common adverse effects of sodium-phosphate enemas and associated risk factors.

METHODS

A systematic search was conducted in Internet (MEDLINE), and the Cochrane Library, from January 1957 to March 2007.

RESULTS

A total of 761 references were identified initially, and 39 relevant papers were finally selected. The most common therapeutic indications included constipation (63%). Sixty-eight per cent of the patients having adverse effects had associated conditions, the most common being gastrointestinal motility disorders, cardiological diseases and renal failure. Virtually, all side effects were due to water and electrolyte disturbances. Most patients were under 18 years of age (66%) or older than 65 years (25%). A total of 12 deaths were found.

CONCLUSION

The main side effects caused by sodium phosphate enemas are water and electrolyte disturbances. The main risk factors are extreme age and associated comorbidity.

Severe hyperphosphatemia and hypocalcemia following the rectal administration of a phosphate-containing Fleet pediatric enema

BACKGROUND

Toxicity secondary to rectally administered hypertonic phosphate solution in patients with normal renal function is rarely reported in the literature. We report a case of electrolyte disturbance and seizure secondary to the rectal administration of 2 Fleet pediatric enemas.

CASE REPORT

A 4-year-old white female with spinal muscular atrophy and chronic constipation was brought to the emergency department with complaints of lethargy and difficulty breathing following the administration of 2 Fleet pediatric enemas. In the emergency department, physical examination was significant for a depressed level of consciousness and shallow respirations. A basic metabolic profile was significant for a calcium of 3.3 mg/dL, phosphate of 23 mg/dL, and sodium of 153 mEq/L. Arterial blood gases revealed a pH of 7.24, Pco2 of 38 mm Hg, Po2 of 220 mm Hg. Electrocardiogram revealed a prolonged QT interval of 340 milliseconds with a corrected QT interval of 498 milliseconds. Sixteen hours postexposure, she experienced a generalized seizure unresponsive to multiple doses of lorazepam and responsive only to 100 mg of intravenous calcium chloride. Two days after presentation, the patient experienced complete resolution of symptoms.

CONCLUSION

Osmotically acting hypertonic phosphate enemas can result in severe toxicity if retained. This is true even in patients without predisposing risk factors.

Respiratory failure requiring extracorporeal membrane oxygenation after sodium phosphate enema intoxication

A variety of adverse effects are associated with the use of hypertonic sodium phosphate enemas and laxatives in children. We describe an unusual case of phosphate enema toxicity in a child that resulted in cardiopulmonary failure necessitating the use of extracorporeal membrane oxygenation. The toxicity associated with hypertonic sodium phosphate enemas is reviewed.

CONCLUSION

Hypertonic sodium phosphate enemas can cause cardiopulmonary failure.

Severe hyperphosphatemia following phosphate administration for bowel preparation in patients with renal failure: two cases and a review of the literature

Two cases of severe hyperphosphatemia following phosphate bowel preparation are described and a review of the literature is presented. Impairment of renal function appears to be a risk factor in those patients without primary bowel pathology. One of our patients died, and the mortality rate combining our cases with all other reported cases is 33%. Repeated doses of phosphate bowel preparations/purgatives can be dangerous in patients with renal impairment.

Effect of oral sodium phosphate colon preparation on serum electrolytes in patients with normal serum creatinine

BACKGROUND

Oral sodium phosphate is commonly used for colon preparation prior to colonoscopy. Several studies have demonstrated significant changes in serum electrolytes after sodium phosphate preparation, but failed to stratify patients with regard to renal function. The purpose of this study was to determine if electrolyte alterations are observed after sodium phosphate in patients with normal levels of serum creatinine.

METHODS

Thirty-two patients scheduled for elective colonoscopy who had a serum creatinine level of less than 1.5 mg/dL were enrolled. All patients had a panel of laboratory studies prior to and immediately after receiving oral sodium phosphate colon preparation.

RESULTS

Significant increases in serum phosphate and sodium and decreases in serum calcium and potassium were observed. Twenty-eight percent of patients had serum phosphate levels greater than 8.0 mg/dL, and 6% of patients had serum calcium levels less than 8.0 mg/dL after sodium phosphate colon preparation. There were no clinically apparent adverse events.

CONCLUSIONS

Significant changes in serum electrolyte levels occur after sodium phosphate colon preparation in patients with normal serum creatinine levels. Sodium phosphate could exacerbate pre-existing hypocalcemia or hypokalemia in patients with apparently normal renal function. Therefore, it may be prudent to evaluate serum electrolytes prior to administration of sodium phosphate.

Severe hyperphosphatemia induced by a phosphate-containing oral laxative

OBJECTIVE

To describe a case of severe hyperphosphatemia following unintentional overdosage with an oral phosphate laxative, and raise attention to the risk of using such medications in the elderly.

CASE SUMMARY

An 84-year-old white woman was admitted with confusion 8 hours after inadvertently ingesting 12 fluid ounces of Fleet Phospho-Soda (instead of the prescribed 1 1/2 fluid ounces) prior to a colonoscopy. Her serum phosphate and ionized calcium concentrations were 10.3 mmol/L and 0.56 mmol/L, respectively. She was treated conservatively with oral phosphate binders and made an uneventful recovery.

DISCUSSION

Several previous reports have described hyperphosphatemia in association with phosphate laxatives, especially in patients with renal or colonic disease. Our case again presents two important issues in the use of phosphate laxatives by the elderly: (1) the frequently overlooked underlying renal insufficiency in which, despite "normal" serum creatinine values, renal phosphate handling may be impaired; and (2) the potential for drug misuse and poor compliance in the elderly.

CONCLUSIONS

Caution should be taken with the use of phosphate laxatives in the elderly in the face of potentially serious metabolic abnormalities that may be generated.

Bowel preparation for colonoscopy: a randomized prospective trail comparing sodium phosphate and polyethylene glycol in a predominantly elderly population

Many patients find polyethylene glycol-based preparations (PEG) difficult to take because of the large volume of fluid they are required to consume. One hundred and sixteen predominantly elderly patients were randomized to receive either sodium phosphate (n = 61) or PEG (n = 55) bowel preparations before colonoscopy. Patients with a history of symptomatic ischaemic heart disease or cerebrovascular disease in the preceding 6 months, severe liver disease or heart failure, or serum creatinine above 200 micrograms/L were excluded from the study. Each patient filled in a questionnaire about the bowel preparation prior to the procedure. The colonoscopists, who were not aware which preparation had been used, were asked to complete a questionnaire about the quality of the bowel preparation after the procedure. The patients found the sodium phosphate preparation slightly more tolerable than PEG. Side effects were slightly more common with sodium phosphate. Neither difference was statistically significant. However, 91% of patients who had previously had PEG found sodium phosphate easier to take. Approximately 25% of patients in each group experienced at least one episode of incontinence. The colonoscopists found no difference in the overall quality of the bowel preparation. The amount of fluid in the colon was greater in patients prepared with PEG. As expected, patients taking sodium phosphate developed hyperphosphataemia (mean phosphate level before colonoscopy 1.56 mmol/L, normal 0.8 -1.3). They also had a lower mean serum potassium level (3.8 mmol/L) than the PEG group (4.2 mmol/L). However, there were no clinically significant consequences. Sodium phosphate was a safe and effective bowel preparation for colonoscopy in this carefully selected group of patients. It was preferred by patients who had previously had PEG. Many elderly patients were found to develop faecal incontinence, irrespective of the type of bowel preparation used.

Oral sodium phosphate versus sulfate-free polyethylene glycol electrolyte lavage solution in outpatient preparation for colonoscopy: a prospective comparison

BACKGROUND

Biochemical abnormalities induced by oral sodium phosphate and the risk of cardiac arrhythmias as potential sequelae have yet to be investigated.

METHODS

We studied 98 outpatients scheduled to undergo diagnostic colonoscopy and prospectively randomized them to receive oral sodium phosphate or sulfate-free polyethylene glycol electrolyte lavage solution (SF-PEG-ELS) as recommended by the manufacturers.

RESULTS

Forty-nine patients received sodium phosphate and 49 received SF-PEG-ELS. There was no significant difference in tolerance or quality of preparation as judged by blinded endoscopists. Significant changes in serum sodium, potassium, chloride, calcium, ionized calcium, and inorganic phosphorus levels were noted following sodium phosphate preparation when compared to values before preparation. A significantly greater number of patients who received sodium phosphate preparation had serum potassium and ionized calcium levels that fell into the abnormal range. Ambulatory electrocardiogram monitors placed 24 hours before the preparation and removed after colonoscopy showed no increase in ventricular premature contractions or other serious arrhythmias in either group during preparation or colonoscopy.

CONCLUSIONS

(1) Sodium phosphate and SF-PEG-ELS are equally well tolerated and effective in preparation for outpatient colonoscopy, and (2) sodium phosphate preparation at the recommended dose causes significant alterations in serum sodium, potassium, chloride, calcium, ionized calcium, and phosphorus levels.

Colonoscopic bowel preparations--which one? A blinded, prospective, randomized trial

For the past decade peroral, orthograde, polyethylene glycol-electrolyte lavage solutions (PEG-ELS) have been the preferred bowel-cleansing regimens before diagnostic and therapeutic procedures on the colon and rectum. The large volume and unpalatibility of these solutions may lead to troubling side effects and poor patient compliance.

PURPOSE

This study was undertaken to determine which of various colon-cleansing methods before colonoscopy would provide greater patient acceptance while maintaining similar or improved effectiveness and safety.

METHODS

Three hundred twenty-nine patients undergoing elective ambulatory colonoscopy were prospectively randomized to one of three bowel preparation regimens. Group 1 received 41 of PEG-ELS (n = 124). Group 2, in addition to PEG-ELS, received oral metoclopramide (n = 99). Group 3 received oral sodium phosphate (n = 106). All groups were evenly matched according to age and sex.

RESULTS

Ninety-one percent of all patients completed the preparation received. Sixteen percent of patients suffered significant sleep loss with a bowel preparation. When comparing the three groups, there was no difference in the assessment of nausea, vomiting, abdominal cramps, anal irritation, or quality of the preparation. Compared with other preparations, oral sodium phosphate was better tolerated. More patients completed the preparation (P < or = 0.001). Fewer patients complained of abdominal fullness (P < or = 0.001). More patients were willing to repeat their preparation (P < or = 0.02). Also, sodium phosphate was found to be four times less expensive than either of the PEG-ELS preparations.

CONCLUSION

All regimens were found to be equally effective. Abdominal symptoms and bowel preparation were not influenced by the addition of metoclopramide. The oral sodium phosphate preparation was less expensive, better tolerated, and more likely to be completed than either of the other preparations.

Serum electrolyte, mineral, and blood pH changes after phosphate enema, water enema, and electrolyte lavage solution enema for flexible sigmoidoscopy

Hypertonic sodium phosphate (Fleet) enema is a commonly used preparation for fiberoptic flexible sigmoidoscopy. Unfortunately, Fleet has been associated with complications in children and adults. The purpose of this study was to compare the serum electrolytes, mineral, and blood pH changes before and after the administration of Fleet with water and polyethylene glycol electrolyte lavage solution (Golytely) as enemas in an adult population undergoing flexible sigmoidoscopy. Sixty-six patients were randomized in a double-blind fashion to receive two enemas of either Fleet (N = 22), water (N = 20), or Golytely (N = 24). The cleansing ability was graded from 1 to 4 (1 = poor, 4 = excellent). The Fleet had significantly better optimal cleansing efficacy compared with water (p < 0.05) but not to Golytely (p > 0.05). There was a significant increase in the serum phosphorus in the Fleet group compared with water (p < 0.001) or Golytely (p < 0.001). However, absolute serum phosphorus values after Fleet enema always remained within normal range in all but one patient. The changes in other electrolytes, minerals, and venous pH were insignificant.

Hyperphosphataemia and hypocalcaemia induced by hypertonic phosphate enema--an experimental study and review of the literature

1. The study objective was to determine the hyperphosphataemic and hypocalcaemic effect of hypertonic phosphate enema. The study was conducted in a department of Internal Medicine at a University Medical Center. 2. Fourteen patients were studied. Patients' mean age (+/- s.d.) was 78.5 +/- 9 years. The creatinine clearance was 48.2 +/- 17.4 ml min-1 (mean +/- s.d.). 3. 500 ml (approx. 7 ml kg-1) of Fleet enema (FE - Na2HPO4.7H2O 224 mmol l-1 and NaH2PO4.H2O 1160 mmol l-1) were administered to each patient. Blood was drawn before FE administration and 1/2, 1, 3, 5, 12 and 24 h thereafter. Serum was analysed for levels of inorganic phosphorus and for calcium. 4. The serum inorganic phosphorus level rose from 1.01 +/- 0.3 mmol l-1 to 1.4 +/- 0.5 mmol l-1 (P = 0.001) 1 h after FE was administered. Serum calcium decreased from 2.32 +/- 0.12 mmol l-1 to 2.12 +/- 0.1 mmol l-1 (P less than 0.001) 12 h after FE was administered. 5. We conclude that FE carries a potential risk for acutely ill elderly patients. To avoid untoward effects due to hyperphosphataemia and hypocalcaemia, the phosphate load must be adjusted to the patient's renal function, i.e. enema volume is to be lowered when phosphate concentration is high, so that if renal function is compromised the amount of phosphate absorbed does not exceed renal excretion capacity.

Iatrogenic hypocalcemic tetany

The treatment of a patient with hypocalcemic tetany secondary to sodium phosphate enemas is reported. The patient presented with a serum calcium level of 5.2 mg/dL and a phosphate level of 17.5 mg/dL. Physical manifestations included tetanic contraction of the muscles of the legs and arms. There was rapid symptomatic resolution with IV calcium. The electrolyte imbalance normalized over the next two days with oral calcium supplementation.

Ionized calcium: pediatric perspective

Ionized calcium is a physiologically critical calcium pool. It is easily determined, although accuracy depends on sample handling. As a clinical parameter, directly measured ionized calcium has particular import in the care of neonates, patients with sepsis or other cardiovascular instability, massively transfused patients, and those undergoing cardiopulmonary bypass or liver transplantation. Disturbances of calcium occur in many other settings, however, and accurate diagnosis and research conclusions may depend on using the best measurement available. Clinical and investigational use of ionized calcium determinations represent appropriate applications of current proven technology. In the future, clinical calcium manipulation may include modifying specific transmembrane transport processes and intracellular calcium pools and movements. At the current time we are largely restricted to studies of extracellular calcium concentration and its interactions. Much is known, but Mother Nature still has too many secrets. The interested reader is referred to discussions of ionized calcium and hemodynamics, reviews of the endocrine disturbances of calcium and phosphorus, textbook discussions pertinent to general calcium disturbances, and critical care issues.