Gitelman's Not-So-Benign Syndrome
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《新英格兰医药杂志》
To the Editor: Gitelman's syndrome, or congenital hypokalemic hypomagnesemic hypocalciuria with metabolic alkalosis, is widely described as a benign1 or milder2 variant of Bartter's syndrome. Despite symptoms including presyncope, vertigo, ataxia, and blurred vision, few data have been accumulated regarding formal cardiac evaluation for patients with Gitelman's syndrome.3
We report a case of Gitelman's syndrome in a patient presenting with presyncope coincident with long runs of ventricular tachycardia at 230 beats per minute that was decidedly malignant. An otherwise well 39-year-old woman taking no medications (not even thiazides) presented with recurrent presyncope. An echocardiogram and the results of a stress test were normal. A computed tomographic (CT) scan of the abdomen showed no mass lesion, and CT angiography of the chest showed normal coronary-artery anatomy with no stenoses. Holter monitoring revealed recurrent 2-to-8-second runs of monomorphic ventricular tachycardia with a cycle length of 260 msec coincident with presyncope.
On admission, the patient's serum electrolyte levels were as follows: potassium, 2.9 mmol per liter; magnesium, 0.9 mg per deciliter; sodium, 144 mmol per liter; chloride, 102 mmol per liter; and carbon dioxide, 34 mmol per liter. Urine electrolyte levels were as follows: sodium, 80 mmol per liter; chlorine, 128 mmol per liter; potassium, 83 mmol per liter; and magnesium, 10 mg per deciliter. Hypokalemic hypomagnesemic hypercalciuria persisted for several days in the hospital. An electrocardiogram showed sinus rhythm with a PR interval of 148 msec, a QRS interval of 94 msec, a QT interval of 424 msec, and a prolonged corrected QT interval (QTc) of 470 msec. Blood urea nitrogen and serum creatinine levels were normal. Plasma renin and aldosterone levels were 63 U per milliliter and 24.3 ng per deciliter, respectively, while the patient was in a recumbent position. An electrophysiological study was negative for inducible, sustained ventricular tachycardia; however, the patient continued to have ventricular tachycardia with presyncope despite aggressive potassium and magnesium supplementation and treatment with amiloride (an aldosterone antagonist), captopril (an angiotensin-converting–enzyme inhibitor), and lidocaine.
Amiodarone was initiated, in place of lidocaine, to control symptomatic runs of rapid, nonsustained ventricular tachycardia, and a defibrillator was implanted to guard against a potential breakthrough of sustained ventricular arrhythmia. The arrhythmia subsided and the patient was discharged to her home in good condition.
Gitelman's syndrome is an autosomal recessive disorder with an inactivating mutation of the thiazide-sensitive sodium–chloride cotransporter in the distal renal tubule. Scant literature exists regarding cardiac evaluation3,4 and suggests that about half the patients with Gitelman's syndrome have QTc prolongation. Although Gitelman's syndrome is described as an asymptomatic or benign disorder with characteristic electrolyte abnormalities, most reports of clinical series document presyncope, vertigo, ataxia, and blurred vision. The present case suggests that more diligent investigation into ventricular arrhythmia, particularly in patients with prolonged QTc, may be warranted.
Roman T. Pachulski, M.D.
South Texas Heartbeat Associates
San Antonio, TX 78229
rtpach@mac.com
Fernando Lopez, M.D.
Alamo Heart Associates
San Antonio, TX 78229
Rashid Sharaf, M.D.
South Texas Nephrology
San Antonio, TX 78229
References
Schepkens H, Lameire N. Gitelman's syndrome: an overlooked cause of chronic hypokalemia and hypomagnesemia in adults. Acta Clin Belg 2001;56:248-254.
Cruz DN, Shaer AJ, Bia MJ, Lifton RP, Simon DB. Gitelman's syndrome revisited: an evaluation of symptoms and health-related quality of life. Kidney Int 2001;59:710-717.
Foglia PE, Bettinelli A, Tosetto C, et al. Cardiac work up in primary renal hypokalemia-hypomagnesaemia (Gitelman syndrome). Nephrol Dial Transplant 2004;19:1398-1402.
Bettinelli A, Tosetto C, Colussi G, Tommasini G, Edefonti A, Bianchetti MG. Electrocardiogram with prolonged QT interval in Gitelman disease. Kidney Int 2002;62:580-584.
We report a case of Gitelman's syndrome in a patient presenting with presyncope coincident with long runs of ventricular tachycardia at 230 beats per minute that was decidedly malignant. An otherwise well 39-year-old woman taking no medications (not even thiazides) presented with recurrent presyncope. An echocardiogram and the results of a stress test were normal. A computed tomographic (CT) scan of the abdomen showed no mass lesion, and CT angiography of the chest showed normal coronary-artery anatomy with no stenoses. Holter monitoring revealed recurrent 2-to-8-second runs of monomorphic ventricular tachycardia with a cycle length of 260 msec coincident with presyncope.
On admission, the patient's serum electrolyte levels were as follows: potassium, 2.9 mmol per liter; magnesium, 0.9 mg per deciliter; sodium, 144 mmol per liter; chloride, 102 mmol per liter; and carbon dioxide, 34 mmol per liter. Urine electrolyte levels were as follows: sodium, 80 mmol per liter; chlorine, 128 mmol per liter; potassium, 83 mmol per liter; and magnesium, 10 mg per deciliter. Hypokalemic hypomagnesemic hypercalciuria persisted for several days in the hospital. An electrocardiogram showed sinus rhythm with a PR interval of 148 msec, a QRS interval of 94 msec, a QT interval of 424 msec, and a prolonged corrected QT interval (QTc) of 470 msec. Blood urea nitrogen and serum creatinine levels were normal. Plasma renin and aldosterone levels were 63 U per milliliter and 24.3 ng per deciliter, respectively, while the patient was in a recumbent position. An electrophysiological study was negative for inducible, sustained ventricular tachycardia; however, the patient continued to have ventricular tachycardia with presyncope despite aggressive potassium and magnesium supplementation and treatment with amiloride (an aldosterone antagonist), captopril (an angiotensin-converting–enzyme inhibitor), and lidocaine.
Amiodarone was initiated, in place of lidocaine, to control symptomatic runs of rapid, nonsustained ventricular tachycardia, and a defibrillator was implanted to guard against a potential breakthrough of sustained ventricular arrhythmia. The arrhythmia subsided and the patient was discharged to her home in good condition.
Gitelman's syndrome is an autosomal recessive disorder with an inactivating mutation of the thiazide-sensitive sodium–chloride cotransporter in the distal renal tubule. Scant literature exists regarding cardiac evaluation3,4 and suggests that about half the patients with Gitelman's syndrome have QTc prolongation. Although Gitelman's syndrome is described as an asymptomatic or benign disorder with characteristic electrolyte abnormalities, most reports of clinical series document presyncope, vertigo, ataxia, and blurred vision. The present case suggests that more diligent investigation into ventricular arrhythmia, particularly in patients with prolonged QTc, may be warranted.
Roman T. Pachulski, M.D.
South Texas Heartbeat Associates
San Antonio, TX 78229
rtpach@mac.com
Fernando Lopez, M.D.
Alamo Heart Associates
San Antonio, TX 78229
Rashid Sharaf, M.D.
South Texas Nephrology
San Antonio, TX 78229
References
Schepkens H, Lameire N. Gitelman's syndrome: an overlooked cause of chronic hypokalemia and hypomagnesemia in adults. Acta Clin Belg 2001;56:248-254.
Cruz DN, Shaer AJ, Bia MJ, Lifton RP, Simon DB. Gitelman's syndrome revisited: an evaluation of symptoms and health-related quality of life. Kidney Int 2001;59:710-717.
Foglia PE, Bettinelli A, Tosetto C, et al. Cardiac work up in primary renal hypokalemia-hypomagnesaemia (Gitelman syndrome). Nephrol Dial Transplant 2004;19:1398-1402.
Bettinelli A, Tosetto C, Colussi G, Tommasini G, Edefonti A, Bianchetti MG. Electrocardiogram with prolonged QT interval in Gitelman disease. Kidney Int 2002;62:580-584.