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Another case of excessive caffeine and hypokalemia in pregnancy
LETTERS TO THE EDITOR
Another Case of Excessive Caffeine and Hypokalemia in Pregnancy To the Editor: In follow-up to the recent report of caffeine-induced hypokalemic paralysis in pregnancy (Obstet Gynecol 2001; 97:805–7), we report our experience in treating a similar patient. The patient was a multigravid woman who presented at 38 1/2 weeks’ gestation with a complaint of weakness and muscle aching of 2 days duration. She described polyuria but denied nausea, vomiting, or diarrhea. Medical and family histories were unremarkable. She denied clay and ethanol ingestion but did describe 8 to 9 servings per day of caffeinated colas or ice tea in 12–16-ounce cups. Medication included prenatal vitamins. On examination, she was afebrile and normotensive. Upper and lower extremity tone was decreased without fasiculations and patellar reflexes were decreased. Uterus was term size with mild to moderate contractions, and both fetal movement and heart tones were evident. Laboratory data included serum potassium 1.8 mmol/L (normal 3.7–5.2 mmol/L), sodium 147 mmol/L (normal 137–145 mmol/L), bicarbonate 24 mmol/L (normal 21–32 mmol/L), creatinine 0.7 mg/dL (normal 0.5– 1.2 mg/dL), magnesium 1.7 mg/dL (normal 1.6 –2.4 mg/dL), phosphorus 3.6 mg/dL (normal 2.2– 4.6 mg/ dL), creatinine phosphokinase more than 5294 U/L (normal 30 –135 U/L), albumin 2.4 g/dL (normal 3.9 –5.0 g/dL), and thyroid-stimulating hormone 1.73 IU/mL (normal 0.35–5.00 IU/mL). Random urine potassium was 19.6 mmol/L and urine pH 7.0 with specific gravity 1.013. A urine drug screen was negative for cocaine. Intravenous potassium and hypotonic fluid were started. Her serum potassium level was 2.3 mmol/L several hours after admission when she delivered vaginally a 6 lb 4 oz infant with a serum potassium level of 5.4 mmol/L. The patient’s dehydration (reflecting impaired renal concentration) and rhabdomyolysis were considered secondary to the hypokalemia. On hospital day 2 the patient’s serum potassium level remained low at 2.2 mmol/L, and serum bicarbonate decreased to 20 mmol/L with a normal anion gap. This finding, along with the increased urinary potassium, urine pH 7.0, and an elevated transtubular potassium gradient of 7.98 suggested type 1 (distal) renal tubular
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acidosis of unclear etiology.1 Alternatively, caffeine-induced hypokalemia was considered. By hospital day 4 the patient had received approximately 400 mmol of potassium, and her serum potassium level was normal at 4.5 mmol/L. Creatinine phosphokinase level was decreasing. She was discharged without potassium supplementation and was instructed to abstain from all caffeinated products. Four days after discharge the patient had a serum potassium 4.2 mmol/L, sodium 141 mmol/L, and bicarbonate 28 mmol/L. Random urine potassium had decreased to 11.8 mmol/L. Resolution of hypokalemia with restriction of caffeine intake suggests that this was a case of caffeine-induced hypokalemia in pregnancy. Stephen L. Young, MD Marvin L. Hage, MD Jinxing Li, MD Coastal AHEC of the University of North Carolina School of Medicine Wilmington, NC REFERENCE 1. Braunwald E, Fauci AS, Kasper DL, Hauser SL, Longo DL, Jameson JL, eds. Harrison’s principles of internal medicine. 15th ed. U.S.: McGraw-Hill, 2001.
Outcomes After Rollerball Endometrial Ablation for Menorrhagia To the Editor: We read the paper by Dutton et al (OBSTET GYNECOL 2001;98:35–9) with great interest. There was an increased risk of hysterectomy after a total rollerball endometrial ablation (TREA) in patients who had a previous tubal ligation, which was probably due to post-ablationtubal-sterilization syndrome (PATSS). Along with Dr. Townsend, we were the first to describe PATSS. We found that a total ablation causes significant intrauterine scarring.1 Turnbull performed magnetic resonance imaging (MRI) studies on patients after endometrial resection/ablation and found regrowth of fundal or cornual endometrium in 95%, cornual hematometra in 18%, PATSS in 3%, and abundant peritoneal fluid suggesting retrograde menstruation in 54%.2
OBSTETRICS & GYNECOLOGY
Another Case of Excessive Caffeine and Hypokalemia in Pregnancy To the Editor: In follow-up to the recent report of caffeine-induced hypokalemic paralysis in pregnancy (Obstet Gynecol 2001; 97:805–7), we report our experience in treating a similar patient. The patient was a multigravid woman who presented at 38 1/2 weeks’ gestation with a complaint of weakness and muscle aching of 2 days duration. She described polyuria but denied nausea, vomiting, or diarrhea. Medical and family histories were unremarkable. She denied clay and ethanol ingestion but did describe 8 to 9 servings per day of caffeinated colas or ice tea in 12–16-ounce cups. Medication included prenatal vitamins. On examination, she was afebrile and normotensive. Upper and lower extremity tone was decreased without fasiculations and patellar reflexes were decreased. Uterus was term size with mild to moderate contractions, and both fetal movement and heart tones were evident. Laboratory data included serum potassium 1.8 mmol/L (normal 3.7–5.2 mmol/L), sodium 147 mmol/L (normal 137–145 mmol/L), bicarbonate 24 mmol/L (normal 21–32 mmol/L), creatinine 0.7 mg/dL (normal 0.5– 1.2 mg/dL), magnesium 1.7 mg/dL (normal 1.6 –2.4 mg/dL), phosphorus 3.6 mg/dL (normal 2.2– 4.6 mg/ dL), creatinine phosphokinase more than 5294 U/L (normal 30 –135 U/L), albumin 2.4 g/dL (normal 3.9 –5.0 g/dL), and thyroid-stimulating hormone 1.73 IU/mL (normal 0.35–5.00 IU/mL). Random urine potassium was 19.6 mmol/L and urine pH 7.0 with specific gravity 1.013. A urine drug screen was negative for cocaine. Intravenous potassium and hypotonic fluid were started. Her serum potassium level was 2.3 mmol/L several hours after admission when she delivered vaginally a 6 lb 4 oz infant with a serum potassium level of 5.4 mmol/L. The patient’s dehydration (reflecting impaired renal concentration) and rhabdomyolysis were considered secondary to the hypokalemia. On hospital day 2 the patient’s serum potassium level remained low at 2.2 mmol/L, and serum bicarbonate decreased to 20 mmol/L with a normal anion gap. This finding, along with the increased urinary potassium, urine pH 7.0, and an elevated transtubular potassium gradient of 7.98 suggested type 1 (distal) renal tubular
874
0029-7844/01/$20.00
acidosis of unclear etiology.1 Alternatively, caffeine-induced hypokalemia was considered. By hospital day 4 the patient had received approximately 400 mmol of potassium, and her serum potassium level was normal at 4.5 mmol/L. Creatinine phosphokinase level was decreasing. She was discharged without potassium supplementation and was instructed to abstain from all caffeinated products. Four days after discharge the patient had a serum potassium 4.2 mmol/L, sodium 141 mmol/L, and bicarbonate 28 mmol/L. Random urine potassium had decreased to 11.8 mmol/L. Resolution of hypokalemia with restriction of caffeine intake suggests that this was a case of caffeine-induced hypokalemia in pregnancy. Stephen L. Young, MD Marvin L. Hage, MD Jinxing Li, MD Coastal AHEC of the University of North Carolina School of Medicine Wilmington, NC REFERENCE 1. Braunwald E, Fauci AS, Kasper DL, Hauser SL, Longo DL, Jameson JL, eds. Harrison’s principles of internal medicine. 15th ed. U.S.: McGraw-Hill, 2001.
Outcomes After Rollerball Endometrial Ablation for Menorrhagia To the Editor: We read the paper by Dutton et al (OBSTET GYNECOL 2001;98:35–9) with great interest. There was an increased risk of hysterectomy after a total rollerball endometrial ablation (TREA) in patients who had a previous tubal ligation, which was probably due to post-ablationtubal-sterilization syndrome (PATSS). Along with Dr. Townsend, we were the first to describe PATSS. We found that a total ablation causes significant intrauterine scarring.1 Turnbull performed magnetic resonance imaging (MRI) studies on patients after endometrial resection/ablation and found regrowth of fundal or cornual endometrium in 95%, cornual hematometra in 18%, PATSS in 3%, and abundant peritoneal fluid suggesting retrograde menstruation in 54%.2
OBSTETRICS & GYNECOLOGY