Endocrine manifestations of systemic disease

Laboratory tests and nutritional assessment. Protein-energy status

1. There is no one definitive laboratory test, group of tests, or indices that are satisfactory for the assessment of protein-calorie status. 2. Clinical evaluation remains the simplest, most widely available, most reproducible, and wisest method. It is satisfactory for the majority of clinical situations. 3. The laboratory should be used selectively and to complement clinical evaluation. Routine testing must be relegated to research protocols. 4. Always include some assessment of inflammation (for example, C-reactive protein, erythrosedimentation rate [ESR]), because its presence affects the interpretation of all the other tests. 5. The pathophysiologic effects of the underlying disease, especially in hospitalized patients, will affect the interpretation of every one of the laboratory tests. 6. Nutritional status often impacts more on the interpretation of commonly performed laboratory tests than laboratory tests impact on the assessment of nutrition.

Thyroid function and endocrine abnormalities in elderly patients with severe chronic obstructive lung disease

Serum pituitary and thyroid hormones, testosterone, and the response of pituitary hormones to thyrotrophin releasing hormone were measured in 20 inpatients (mean age 68, range 42-81 years) with severe chronic obstructive lung disease and in 15 control convalescent inpatients (mean age 73, range 57-83 years) who had normal respiratory function. No significant differences were found in total and free thyroid hormone concentrations and basal concentrations of thyrotrophin, growth hormone, and prolactin; and their increments after injection of thyrotrophin releasing hormone were similar in patients with chronic obstructive lung disease, and control patients. Three patients with chronic obstructive lung disease, however, had no thyrotrophin responses to thyrotrophin releasing hormone. In men, low testosterone concentrations were found both in patients with chronic obstructive lung disease and in controls. Luteinising hormone concentrations were higher in men with chronic obstructive lung disease (p less than 0.02), whereas concentrations of follicle stimulating hormone in the two groups were not significantly different. There was no significant correlation between arterial blood gas tensions and these hormone measurements. General effects of age and illness may be more important than direct effects of hypoxia in determining hypothalamic-pituitary function in elderly patients with chronic obstructive lung disease.

Impaired growth hormone secretion in the adult population: relation to age and adiposity

Growth hormone (GH) release was studied in adults of normal stature, ages 21-86 yr. The subjects were 85-115% of ideal body weight, between the 5th and 95th percentiles in height, and free of active or progressive disease. 9 to 12 individuals in each decade from thirds to ninth were evaluated. The following criteria of GH status were measured: serum GH concentration, analyzed by radioimmunoassay at half-hour intervals for 4 h after onset of sleep, and at 1-h intervals from 8 a.m. to 4 p.m. in 52 subjects; daily retention of N, P, and K in response to 0.168 U human (h)GH/kg body wt3/4/day in 18 subjects; and plasma somatomedin C (SmC) level before and during exogenous hGH treatment in 18 subjects. All 10 individuals, 20-29 yr old, released substantial amounts of endogenous GH during both day and night (average peak serum GH obtained during day and night was 7.3 and 20.3 ng/ml, respectively); average plasma SmC was 1.43 U/ml (95% tolerance limits, 0.64-2.22 U/ml). There was no significant effect of exogenous hGH on elemental balances or on plasma SmC. In contrast, 6 of 12 individuals 60-79 yr old showed the following evidences of impaired GH release; peak waking and sleeping serum GH less than 4 ng/ml; plasma SmC less than 0.38 U/ml; a significant retention in N, P, and K; and a significant rise in plasma SmC, in response to exogenous hGH. Plasma SmC, serum GH during sleep, serum GH during the day, retentions of N, P, and K in response to exogenous hGH, and rise in plasma SmC in response to hGH were all intercorrelated (P less than 0.05). Plasma SmC less than 0.38 U/ml corresponded to peak nocturnal serum GH less than 4 ng/ml. The prevalence of plasma SmC less than 0.38 U/ml increased progressively from age 20 to 90: third decade, 0%; fourth, 11%; fifth, 20%; sixth, 22%; seventh, 42%; eight, 55%; and ninth, 55%. Within each decade, plasma SmC was inversely related to adiposity.