The role of non-invasive dynamic tests in the diagnosis of Cushing's syndrome.

OBJECTIVE: To evaluate the role of non-invasive dynamic tests in the diagnosis and differential diagnosis of Cushing's syndrome (CS). METHODS: We studied laboratory features of 74 patients with endogenous CS, subdivided as follows: 46 (62.1%) with Cushing's disease (CD), 21 (28.3%) with an adrenal tumor, and 7 (9.5%) with ectopic ACTH syndrome (EAS). RESULTS: In 100% of cases of CS we found serum cortisol levels greater than 1.8 microg/dl after low-dose dexamethasone suppression tests (LDDST), as well as elevation of midnight serum or salivary cortisol. However, urinary free cortisol was normal in 11.5% of patients. ACTH levels were suppressed in patients with adrenal tumors, normal or high in CD and invariably increased in EAS. After the 8-mg overnight dexamethasone suppression test (HDDST), serum cortisol suppression >50% was observed in 79.5% of cases of CD and in 28.6% of subjects with EAS, whereas cortisol suppression >80% was only found in CD. After stimulation with CRH or desmopressin an ACTH rise > or =35% occurred in 86.5% of individuals with CD and 14.3% of those with EAS, whereas an ACTH rise > or =50 achieved 100% specificity. Moreover, the combination of serum cortisol suppression >50% after HDDST and an ACTH increase > or =35% after the administration of CRH or desmopressin only occurred in CD. CONCLUSION: Our findings demonstrate that LDDST had 100% sensitivity for the diagnosis of CS and that HDDST and stimulation tests with CRH or desmopressin may be very useful for confirmation of CS etiology when analyzed together or when more stringent cut-offs are used.

Clinical and laboratory features greatly overlap in patients with macroprolactinemia or monomeric hyperprolactinemia.

AIM: The aim of this study was to evaluate the clinical and laboratory features of 64 patients with macroprolactinemia and to compare them to those of individuals with monomeric hyperprolactinemia. METHODS: The study included 64 patients (54 women and 10 men) with macroprolactinemia and 96 patients (70 women and 26 men) with monomeric hyperprolactinemia (32 with prolactinomas). RESULTS: Symptoms related to prolactin (PRL) excess were found in about 44% of individuals from the macroprolactinemia group and in 88.5% of patients with monomeric hyperprolactinemia (P<0.0001). However, the frequency of menstrual disturbances (oligomenorrhea or amenorrhea), galactorrhea and erectile dysfunction did not differ in both groups. In contrast, the association of galactorrhea and menstrual disturbances was significantly more prevalent in women with monomeric hyperprolactinemia. Although mean PRL levels were higher in patients with monomeric hyperprolactinemia (565.9+/-2726.4 vs 113.3+/-94.5 ng/mL, P<0.001), there was a great overlap between both groups. Among macroprolactinemic patients, pituitary magnetic resonance imaging revealed an image suggestive of a microadenoma in 7 (10.9%) and a macroadenoma in 1 (1.6%). Normalization of PRL levels during therapy with dopamine agonists was significantly more frequent in patients with monomeric hyperprolactinemia than in subjects with macroprolactinemia (78.6% vs 32%, P=0.0006). CONCLUSION: Our data show that symptoms related to PRL excess are frequently found in subjects with macroprolactinemia. Moreover, no clinical or laboratory features could reliably differentiate macroprolactinemic patients from those with monomeric hyperprolactinemia. Therefore, the screening for macroprolactin should not be restricted to asymptomatic patients.

Breeding population fluctuations in some raptors.

We investigated differences in annual breeding population stability and its relationship to diversity in food habits for several species of raptors. Chi-square tests showed no significant differences between observed and expected (based on logistic growth equation) breeding population sizes for Peregrine Falcons (Falco peregrinus) during recovery from pesticide induced declines in 4 Alaskan populations. This indicates that no major Peregrine Falcon population fluctuations occurred aside from the recovery itself. On the Colville River, Alaska, Rough-legged Hawk (Buteo lagopus) and Gyrfalcon (F. rusticolus) breeding populations experienced several declines and increases during the Peregrine Falcon recovery. Serial correlation analysis does not indicate consistent regularity in fluctuation for either the Rough-legged Hawk or Gyrfalcon on the Colville River during 1967-1985. Possible occurrence of regular fluctuations in sub-populations or over shorter time periods, however, could not be investigated. Population fluctuations for the Rough-legged Hawk and Gyrfalcon are significantly correlated during 1971-1985, with largest declines for both occurring synchronously. This correlation is consistent with the possibility that shared environmental stresses, among other factors, are responsible for population limitation. Regularity, with a 3 year interval, is indicated, however, for extremely small fluctuations in an Idaho, USA population of the Red-tailed Hawk (Buteo jamaicensis), suggesting that investigations of raptor population fluctuation and regelarity should not be limited to arctic or subarctic environments. Low diversity in food habits is not a good predictor of degree of annual population fluctuation in the study groups, while greater diversity in food habits is associated with relatively stable annual populations. An association was found in the Rought-legged Hawk between reduced annual population variability and reduced climatic severity. Neither food habits diversity nor annual population variability is constant across species ranges. Food habits diversity was also variable between years in local populations of Peregrine Falcon, Rough-legged Hawk and Gyrfalcon.

Pharmacological study of the internal and sphincter in patients with chronic anal fissure.

A pharmacological study of the internal anal sphincter (IAS) was undertaken in patients with chronic and fissure. The sensitivity of the IAS to the contractile effect of phenylephrine and potassium chloride and to relaxation by isoproterenol was evaluated. Supersensitivity of the IAS to relaxation by isoproterenol was noted. Further research is necessary to determine the pharmacological basis of such a disturbance.