Endocrine Abstracts

Human obesity is characterized by abnormalities in sympathetic cardiovascular control. We present two cases to demonstrate the relationship between weight, BP and catecholamines (UC).

Case 1: A 39 year-old man reported symptoms of flushing and palpitations. His BMI was 50 kg/m², consistent BP of 240/140 mmHg, with normal renal, thyroid function and normal fasting glucose. Urinary noradrenaline (UNA820 nmol/24 hrs) and dopamine (UDA-4500 nmol/24 h) were elevated, adrenaline (UA-48 nmol/24 hrs) levels were normal [24 hr normal ranges-UA<190 nmol, UNA120-590 nmol, UDA 650–2700 nmol]. A MIBG scan and abdominal CT-scan were normal. Following 6 weeks of dietary modification, graduated exercise programme and α-blockade, his weight decreased by 12 kgs, BP to 180/110 mmHg and UC decreased (UNA-600 nmol/24 h, UDA-3700 nmol/24 h). At subsequent visits weight and BP improved further. After 4 months, UC had normalised (UNA-270 nmol/ 24 h, UDA-2100 nmol/24 h).

Case 2: A 38-year-old lady was referred with episodes of palpitations and sweating. Her BMI was 41 kg/m², pulse was 72/m, BP190/110 mmHg on calcium channel blocker and baseline renal and thyroid function normal. 24 hour UA (8 nmol/24 h) and UNA (510 nmol /24 h) were normal but UDA (3900 nmol/24 h)was elevated. MIBG and abdominal CT scans were normal. She was advised on a low-fat diet with α blocker for BP control. At 9 months follow-up, she had gained 15 kgs, UNA excretion had increased(850 nmol/24 h) and BP normalised. Dietary and exercise education was reinforced whence a simultaneous reduction in weight and UC (UNA-300 nmol/24 h) was noted.

Discussion: Our cases clearly demonstrate the relationship between weight, BP and UC. In the first case, weight reduction was consistently associated with decreases in BP and UC while in the second, weight changes correlated more with UC excretion than BP. Studies examining weight loss have noted a high correlation between BP reduction and a fall in NA, as was seen in our cases. Primary intervention of weight loss following diet and exercise resulted in reduction in BP and UC, thus emphasising the role of weight reduction in the management of hypertension in obese patients.