Clinical Endocrinology (1979) 10,443-449.
SERUM T 3 AND T 4 LEVELS I N PATIENTS WITH ANOREXIA NERVOSA SHOWING TRANSIENT HYPERTHYROIDISM DURING WEIGHT GAIN
Department ofMedicine, Addenbrooke’s Hospital, Hills Road, ambridge CB2 2QQ (Received 16 August 1978; revised 5 October 1978;accepted 9 October 197%)
SUMMARY
Serum thyroxine (T4) and triiodothyronine (T3) levels were measured in a group of thirty-three patients with anorexia nervosa (AN) and compared with twenty-five control women presenting with hirsutism and twenty-one patients with primary myxoedema. T3 levels in the AN patients were significantly lower thanin the control subjects and in the patients with myxcedema while T4 levels were significantly higher than in the patients with hypothyroidism but significantly lower than in the control group. Seventeen anorexia patients had further T3 and T4 levels measured following an arbitrary 25% weight gain and both levels had increased significantly. For individual patients, the absolute rise in T3 levels was significantly correlated with the rate of weight gain. Thirteen patients had serial T3 and T4 levels measured during their periods of weight gain. Eight of these subjects showed a gradual rise in T3 levels from subnormal or low normal levels to values in the upper normal range. Four subjects showed a distinct and self limiting overshoot of T3 levels and, associated with this, the patients had clinical features of mild hyperthyroidism. The precise thyroid status of patients with anorexia nervosa has, until recently, been the subject of considerable debate. Studies by Bliss& Migeon (1957), Crisp (1965), Rowland (1970) and Mills et ul. (1973) failed t o demonstrate any consistent abnormality in thyroid function tests available at the time, except for a low basal metabolic rate (BMR). Following the development of radio-immunoassay in the measurement of T4, T3 and thyrotrophin (TSH), several reports have appeared all confirming the presence of consistently low T3 levels and to a variable extent, T4 (Miyai etal., 1975;Moshang etal., 1975; Croxson & Ibbertson, 1977; Boyer, 1978). Lundberg e t ul. (1970) reported a normal or delayed TSH response to thyrotrophin releasing hormone fTRH). Burman et ul. (1977) additionally reported raised reverse T3 (rT3) levels at the time of diagnosis. Only Croxson & Ibbertson’s paper showed a rise in T3 following weight gain based on a single repeat measurement. None of these papers has reported serial measurements in response to appropriate weight Correspondence: Dr R. Moore, Anglesea Road Hospital, Ipswich, Suffolk.
0300-0164/79/0500-0443$02.00 o 1979 Blackwell Scientific Publications
443
444
R.Moore and I. H. Mills
gain which is the purpose of the present paper. The prospective study was prompted by the observation of a temporary clinically hyperthyroid state in the occasional patient who had gained weight rapidly in that she had a tachycardia, a fine tremor, was peripherally vasodilated and heat intolerant and was putting on a disappointingly small amount of weight in spite of a large dietary intake. Previous studies in a similar group of patients had shown an elevated BMR at this stage, but a normal free thyroxine index (Mills et al., 1973).
MATERIALS AND METHODS
Patients Between 1976 and 1978, thirty-three patients with anorexia nervosa referred to a general medical clinic run by one of us (IHM) with a special interest in this condition, were studied. All patients were female with a mean age of 19.9 years (range 12-36 years) and gave a typical history of food aversion and secondary amenorrhoea with a weight loss of at least 25% of original body weight (Feighner et al., 1972). All patients gave informed consent to the blood tests being performed and all had blood taken for T3 and T4 levels on presentation. In eighteen patients, the condition was thought to be serious enough to warrant inpatient treatment and in this group of patients, further T3 and T4 estimations were performed in response to weight gain, In fourteen patients blood was taken at weekly intervals, but in the other four, insufficient data was collected serially although further blood was taken after a 25% weight gain. The patients were treated in a general medical ward with a reward and punishment regime supported by psychotherapy. All were given a tricyclic antidepressant, usually amitriptyline in doses ranging from 50-300 mg/day in divided doses. A dietary intake of 3000-4000 Kcal was aimed for, containing approximately 55% carbohydrate and 15-20% fat. The control group of patients matched for age and sex were twenty-five consecutive patients referred to an endocrine clinic with hirsutism. All were clinically euthyroid when first seen and all had thyroid hormone levels within the normal range for our laboratory (T3 1.0-2.8 nmol/l, T4 55-144 nmol/l). The initial T3 and T4 levels of twenty-one patients referred with primary myxoedema (TSH level greater than 10 mU/l) were also collected over this 2-year period. Methods Serum concentrations of T3, T4 (Challand et al., 1975) and TSH (Hall et al., 1971) were determined by radio-immunoassay. The TSH response to TRH was determined by the measurement of TSH at 0, 20, and 60 min after 200 pg of intravenous synthetic TRH (Roche, Welwyn Garden City). Student’s paired 1 test was used for the statistical analyses. RESULTS
Serum T3 The initial serum T3 level (mean f SEM) was 1.00 +- 0.047 nmol/l in the 33 anorexia patients, significantly lower (PgO.001) than in the twenty-five control subjects, 1.95 f 0.08 nmol/l and the twentyane patients with primary hypothyroidism, 1.20 k 0.05 nmol/l (P
SERUM T 3 AND T 4 LEVELS I N PATIENTS WITH ANOREXIA NERVOSA SHOWING TRANSIENT HYPERTHYROIDISM DURING WEIGHT GAIN
Department ofMedicine, Addenbrooke’s Hospital, Hills Road, ambridge CB2 2QQ (Received 16 August 1978; revised 5 October 1978;accepted 9 October 197%)
SUMMARY
Serum thyroxine (T4) and triiodothyronine (T3) levels were measured in a group of thirty-three patients with anorexia nervosa (AN) and compared with twenty-five control women presenting with hirsutism and twenty-one patients with primary myxoedema. T3 levels in the AN patients were significantly lower thanin the control subjects and in the patients with myxcedema while T4 levels were significantly higher than in the patients with hypothyroidism but significantly lower than in the control group. Seventeen anorexia patients had further T3 and T4 levels measured following an arbitrary 25% weight gain and both levels had increased significantly. For individual patients, the absolute rise in T3 levels was significantly correlated with the rate of weight gain. Thirteen patients had serial T3 and T4 levels measured during their periods of weight gain. Eight of these subjects showed a gradual rise in T3 levels from subnormal or low normal levels to values in the upper normal range. Four subjects showed a distinct and self limiting overshoot of T3 levels and, associated with this, the patients had clinical features of mild hyperthyroidism. The precise thyroid status of patients with anorexia nervosa has, until recently, been the subject of considerable debate. Studies by Bliss& Migeon (1957), Crisp (1965), Rowland (1970) and Mills et ul. (1973) failed t o demonstrate any consistent abnormality in thyroid function tests available at the time, except for a low basal metabolic rate (BMR). Following the development of radio-immunoassay in the measurement of T4, T3 and thyrotrophin (TSH), several reports have appeared all confirming the presence of consistently low T3 levels and to a variable extent, T4 (Miyai etal., 1975;Moshang etal., 1975; Croxson & Ibbertson, 1977; Boyer, 1978). Lundberg e t ul. (1970) reported a normal or delayed TSH response to thyrotrophin releasing hormone fTRH). Burman et ul. (1977) additionally reported raised reverse T3 (rT3) levels at the time of diagnosis. Only Croxson & Ibbertson’s paper showed a rise in T3 following weight gain based on a single repeat measurement. None of these papers has reported serial measurements in response to appropriate weight Correspondence: Dr R. Moore, Anglesea Road Hospital, Ipswich, Suffolk.
0300-0164/79/0500-0443$02.00 o 1979 Blackwell Scientific Publications
443
444
R.Moore and I. H. Mills
gain which is the purpose of the present paper. The prospective study was prompted by the observation of a temporary clinically hyperthyroid state in the occasional patient who had gained weight rapidly in that she had a tachycardia, a fine tremor, was peripherally vasodilated and heat intolerant and was putting on a disappointingly small amount of weight in spite of a large dietary intake. Previous studies in a similar group of patients had shown an elevated BMR at this stage, but a normal free thyroxine index (Mills et al., 1973).
MATERIALS AND METHODS
Patients Between 1976 and 1978, thirty-three patients with anorexia nervosa referred to a general medical clinic run by one of us (IHM) with a special interest in this condition, were studied. All patients were female with a mean age of 19.9 years (range 12-36 years) and gave a typical history of food aversion and secondary amenorrhoea with a weight loss of at least 25% of original body weight (Feighner et al., 1972). All patients gave informed consent to the blood tests being performed and all had blood taken for T3 and T4 levels on presentation. In eighteen patients, the condition was thought to be serious enough to warrant inpatient treatment and in this group of patients, further T3 and T4 estimations were performed in response to weight gain, In fourteen patients blood was taken at weekly intervals, but in the other four, insufficient data was collected serially although further blood was taken after a 25% weight gain. The patients were treated in a general medical ward with a reward and punishment regime supported by psychotherapy. All were given a tricyclic antidepressant, usually amitriptyline in doses ranging from 50-300 mg/day in divided doses. A dietary intake of 3000-4000 Kcal was aimed for, containing approximately 55% carbohydrate and 15-20% fat. The control group of patients matched for age and sex were twenty-five consecutive patients referred to an endocrine clinic with hirsutism. All were clinically euthyroid when first seen and all had thyroid hormone levels within the normal range for our laboratory (T3 1.0-2.8 nmol/l, T4 55-144 nmol/l). The initial T3 and T4 levels of twenty-one patients referred with primary myxoedema (TSH level greater than 10 mU/l) were also collected over this 2-year period. Methods Serum concentrations of T3, T4 (Challand et al., 1975) and TSH (Hall et al., 1971) were determined by radio-immunoassay. The TSH response to TRH was determined by the measurement of TSH at 0, 20, and 60 min after 200 pg of intravenous synthetic TRH (Roche, Welwyn Garden City). Student’s paired 1 test was used for the statistical analyses. RESULTS
Serum T3 The initial serum T3 level (mean f SEM) was 1.00 +- 0.047 nmol/l in the 33 anorexia patients, significantly lower (PgO.001) than in the twenty-five control subjects, 1.95 f 0.08 nmol/l and the twentyane patients with primary hypothyroidism, 1.20 k 0.05 nmol/l (P
