BRIEF CLINICAL
operative in encouraging very rapid conduction rates. Castellanos et al [6] have shown that premature stimuli delivered soon after the atria1 ERP could precipitate runs of reciprocating tachycardia as well as flutter or fibrillation. In our patient, the chest wall trauma was probably the mechanoelectrical stimulus causing an extrasystole that fell upon the vulnerable period of atria1 depolarization. Thus, in this patient, it is reasonable to assume a causal relationship between the chest wall trauma and the induction of atria1 fibrillation and antidromic circus movement tachycardia. This is a unique presentation of the WPW syndrome. PAUL E. NATHAN, M.D.
tary tumors such as nasopharyngeal carcinoma (NPC) has been increasingly recognized [1,2]. While hyponatremia is known to occur in patients with hypopituitarism [3], the usual causes of hypopituitarism cited were Sheehan’s syndrome, pituitary tumors, and the empty sella syndrome. Severe hyponatremia occurring as the presenting feature of postirradiation hypopituitarism has not been previously reported. A 52-year-old man presented to the emergency room because of generalized weakness, dizziness, and progressive drowsiness for 3 days. He also had left ear pain associated with purulent discharge and fever for 7 days. Past medical records showed that he DOMINICK ANASTASIO, M.D. had received external radiation VICTORNAVARRO,M.D. HUGO ROSERO,M.D. therapy for stage II NPC [2] 4 TERRENCE J. SACCHI, M.D., F.A.C.C. years ago. A total dose of 5,040 WILLIAM J. SCARPA, M.D., F.A.C.C. cGy was delivered to the nasoLong Island College Hospital Brooklyn, New York pharyngeal region in 12 fractions over 38 days using the usual 1. Caldwell G, Millar G, Quinn E. Vincent R, Chamthree-field technique [4]. Direct berlain DA. Simple mechanical methods for cardioversion: defence of the precordial thump and cough questioning revealed the presversion, BMJ 1985; 291: 627-30. ence of cold intolerance, reduced 2. Standards and guidelines for cardiopulmonary refacial hair growth, and frequency suscitation (CPR) and emergency cardiac care of morning erection in the last (ECC). JAMA 1986; 255: 290. 3. Adgey AAJ, Webb SW. The treatment of ventricuyear. On admission, he was lar arrythmias in acute myocardial infarction. Br J drowsy but responsive to quesHosp Med 1979; 21: 356-79. tioning. No neck rigidity or focal 4. Lown B. Taylor J. “Thump-version.” N Engl J Med neurologic signs were present. 1970; 283: 1223-4. 5. Wellens HJ, Durrer D. Wolff-Parkinson-White synFundi and visual fields were nordrome and atrial fibrillation relation between refracmal. His skin was smooth and fair tory period of accessory pathway and ventricular and there was a definite paucity rate during atrial fibrillation. Am J Cardiol 1974; 34: of facial, axillary, and pubic hair. 777-82. 6. Castellanos A Jr, Myerburg RJ, Craparo K, BeThe testes and external genitalia feler B, Agha AS. Factors regulatingventricular rates were normal. There were signs of during atrial flutter and fibrillation in pre-excitation acute suppurative otitis media (Wolff-Parkinson-White) syndrome. Br Heart J affecting the left ear. His blood 1973; 35: 811-7. pressure was 130/80 mm Hg with Submitted May 2, 1991, and accepted May 18, 1991 no postural reduction, and the pulse rate was 72/minute. Investigations showed severe hyponaPOSTIRRADIATION tremia (103 nmol/L) associated HYPOPITUITARISM with normal potassium, urea, crePRESENTINGAS SEVERE atinine, and glucose levels. SeHYPONATREMIA rum and urine osmolalities were 213 and 289 mOsm/kg, respectively. Plasma cortisol and Hypopituitarism occurring after ACTH levels on the morning of cranial irradiation for nonpituiFebruary
1992
The American
OBSERVATIONS
admission were 176 nmol/L (normal, 80 to 500 nmol/L) and 17 pg/mL (normal, 10 to 52 pg/mL), respectively, in the presence of significant physical stress. Serum free thyroxine index and thyrotropin (TSH) level were 57 (normal, 76 to 152) and less than 1.5 mU/L (normal, up to 7 mu/L), respectively. He was treated with intravenous hydrocortisone 200 mglday and thyroxine 0.05 mgl day. Antibiotic therapy was also given. The serum sodium level increased to 130 mmol/L after 2 days and became normal after 5 more days of oral hydrocortisone at a reduced dosage (80 mglday to 30 mg/day). Anterior pituitary function tests were performed 2 weeks later, and confirmed the presence of panhypopituitarism (Table I). We have since encountered five more patients with hypopituitarism who presented with acute symptomatic hyponatremia associated with the inappropriate antidiuretic hormone (ADH) syndrome 2 to 14 years after cranial irradiation for NPC. Hypopituitarism was previously undiagnosed in all except one patient who presented with sexual dysfunction. In all patients, hyponatremia was associated with relative hypocortisolism on admission and was promptly corrected by replacement therapy with hydrocortisone. Thyroxine replacement was started in three patients 1 day after admission when hypothyroidism was confirmed. The clinical and biochemical findings in these patients are summarized in Table I. Anterior pituitary function tests were performed as described [2] after the correction of hyponatremia and included the measurement of basal sex hormone and prolactin levels, the growth hormone .and cortisol responses to insulin-induced hypoglycemia (using a reduced insulin dosage of 0.1 U/kg; glucose nadir less than or equal to Journal
of Medicine
Volume
92
219
BRIEF CLINICAL
OBSERVATIONS
TABLE I Clinical and Biochemical Findings in Six Patients With Severe Hyponatremia and Postirradiation Hypopituitarism Serum
Patient No.
Sex/ Age
TSH(TRHTest)
Interval FromRT (years)
Serum Sodium (mmol/L)
Serum FTI (N 76-152)
Basal (N 5 7 mu/L)
Peak (N 2 7 mu/L)
PlasmaCortisol(ITT) Basal Peak Yl:iy
%?ol~;;
Other Endocrine Deficiencies
Pret$b$ng
1
Ml52
4
103
57
operative in encouraging very rapid conduction rates. Castellanos et al [6] have shown that premature stimuli delivered soon after the atria1 ERP could precipitate runs of reciprocating tachycardia as well as flutter or fibrillation. In our patient, the chest wall trauma was probably the mechanoelectrical stimulus causing an extrasystole that fell upon the vulnerable period of atria1 depolarization. Thus, in this patient, it is reasonable to assume a causal relationship between the chest wall trauma and the induction of atria1 fibrillation and antidromic circus movement tachycardia. This is a unique presentation of the WPW syndrome. PAUL E. NATHAN, M.D.
tary tumors such as nasopharyngeal carcinoma (NPC) has been increasingly recognized [1,2]. While hyponatremia is known to occur in patients with hypopituitarism [3], the usual causes of hypopituitarism cited were Sheehan’s syndrome, pituitary tumors, and the empty sella syndrome. Severe hyponatremia occurring as the presenting feature of postirradiation hypopituitarism has not been previously reported. A 52-year-old man presented to the emergency room because of generalized weakness, dizziness, and progressive drowsiness for 3 days. He also had left ear pain associated with purulent discharge and fever for 7 days. Past medical records showed that he DOMINICK ANASTASIO, M.D. had received external radiation VICTORNAVARRO,M.D. HUGO ROSERO,M.D. therapy for stage II NPC [2] 4 TERRENCE J. SACCHI, M.D., F.A.C.C. years ago. A total dose of 5,040 WILLIAM J. SCARPA, M.D., F.A.C.C. cGy was delivered to the nasoLong Island College Hospital Brooklyn, New York pharyngeal region in 12 fractions over 38 days using the usual 1. Caldwell G, Millar G, Quinn E. Vincent R, Chamthree-field technique [4]. Direct berlain DA. Simple mechanical methods for cardioversion: defence of the precordial thump and cough questioning revealed the presversion, BMJ 1985; 291: 627-30. ence of cold intolerance, reduced 2. Standards and guidelines for cardiopulmonary refacial hair growth, and frequency suscitation (CPR) and emergency cardiac care of morning erection in the last (ECC). JAMA 1986; 255: 290. 3. Adgey AAJ, Webb SW. The treatment of ventricuyear. On admission, he was lar arrythmias in acute myocardial infarction. Br J drowsy but responsive to quesHosp Med 1979; 21: 356-79. tioning. No neck rigidity or focal 4. Lown B. Taylor J. “Thump-version.” N Engl J Med neurologic signs were present. 1970; 283: 1223-4. 5. Wellens HJ, Durrer D. Wolff-Parkinson-White synFundi and visual fields were nordrome and atrial fibrillation relation between refracmal. His skin was smooth and fair tory period of accessory pathway and ventricular and there was a definite paucity rate during atrial fibrillation. Am J Cardiol 1974; 34: of facial, axillary, and pubic hair. 777-82. 6. Castellanos A Jr, Myerburg RJ, Craparo K, BeThe testes and external genitalia feler B, Agha AS. Factors regulatingventricular rates were normal. There were signs of during atrial flutter and fibrillation in pre-excitation acute suppurative otitis media (Wolff-Parkinson-White) syndrome. Br Heart J affecting the left ear. His blood 1973; 35: 811-7. pressure was 130/80 mm Hg with Submitted May 2, 1991, and accepted May 18, 1991 no postural reduction, and the pulse rate was 72/minute. Investigations showed severe hyponaPOSTIRRADIATION tremia (103 nmol/L) associated HYPOPITUITARISM with normal potassium, urea, crePRESENTINGAS SEVERE atinine, and glucose levels. SeHYPONATREMIA rum and urine osmolalities were 213 and 289 mOsm/kg, respectively. Plasma cortisol and Hypopituitarism occurring after ACTH levels on the morning of cranial irradiation for nonpituiFebruary
1992
The American
OBSERVATIONS
admission were 176 nmol/L (normal, 80 to 500 nmol/L) and 17 pg/mL (normal, 10 to 52 pg/mL), respectively, in the presence of significant physical stress. Serum free thyroxine index and thyrotropin (TSH) level were 57 (normal, 76 to 152) and less than 1.5 mU/L (normal, up to 7 mu/L), respectively. He was treated with intravenous hydrocortisone 200 mglday and thyroxine 0.05 mgl day. Antibiotic therapy was also given. The serum sodium level increased to 130 mmol/L after 2 days and became normal after 5 more days of oral hydrocortisone at a reduced dosage (80 mglday to 30 mg/day). Anterior pituitary function tests were performed 2 weeks later, and confirmed the presence of panhypopituitarism (Table I). We have since encountered five more patients with hypopituitarism who presented with acute symptomatic hyponatremia associated with the inappropriate antidiuretic hormone (ADH) syndrome 2 to 14 years after cranial irradiation for NPC. Hypopituitarism was previously undiagnosed in all except one patient who presented with sexual dysfunction. In all patients, hyponatremia was associated with relative hypocortisolism on admission and was promptly corrected by replacement therapy with hydrocortisone. Thyroxine replacement was started in three patients 1 day after admission when hypothyroidism was confirmed. The clinical and biochemical findings in these patients are summarized in Table I. Anterior pituitary function tests were performed as described [2] after the correction of hyponatremia and included the measurement of basal sex hormone and prolactin levels, the growth hormone .and cortisol responses to insulin-induced hypoglycemia (using a reduced insulin dosage of 0.1 U/kg; glucose nadir less than or equal to Journal
of Medicine
Volume
92
219
BRIEF CLINICAL
OBSERVATIONS
TABLE I Clinical and Biochemical Findings in Six Patients With Severe Hyponatremia and Postirradiation Hypopituitarism Serum
Patient No.
Sex/ Age
TSH(TRHTest)
Interval FromRT (years)
Serum Sodium (mmol/L)
Serum FTI (N 76-152)
Basal (N 5 7 mu/L)
Peak (N 2 7 mu/L)
PlasmaCortisol(ITT) Basal Peak Yl:iy
%?ol~;;
Other Endocrine Deficiencies
Pret$b$ng
1
Ml52
4
103
57
