Basal serum cortisol levels predict a normal response to the Synacthen stimulation test in hospitalised patients.

BACKGROUND: The short Synacthen test (SST) is widely used to assess the hypothalamus-pituitary-adrenal axis in the outpatient setting. However, in the inpatient setting, technical difficulties to adhere to the protocol may pose a challenge for using this test. AIMS: To find the most suitable basal serum cortisol (BSC) cut-off for predicting an adequate response to the SST in non-critically inpatients without conducting the actual test. METHODS: Information was retrieved retrospectively from medical files of 197 patients who had had a 250 µg SST between the years 2000 and 2016 at the Shaare Zedek Medical Center. BSC, electrolytes, creatinine, thyroid-stimulating hormone, blood counts and blood pressure values were evaluated for a correlation with the results of the SST. RESULTS: A BSC cut-off of 280 nmol/L provides a negative predictive value of 94% for adrenal insufficiency (AI). Using a cut-off of 380 nmol/L increases the sensitivity to 96% and yields a negative predictive value of 95.8%. CONCLUSIONS: In this study, we found two suitable BSC cut-offs for predicting an adequate response to the SST in hospitalised patients. We suggest using the lower cut-off (280 nmol/L) for patients with a low level of suspicion for AI and using the higher cut-off (380 nmol/L) for patients with a higher level of suspicion. A BSC above this cut-off makes the diagnosis of AI very unlikely and precludes the need for a Synacthen test.

Prosthetic valve endocarditis due to Streptococcus pneumoniae.

INTRODUCTION: In the pre-antibiotic era up 10% of cases of infective endocarditis were due to Streptococcus pneumoniae, but this association is currently exceedingly rare. CASE DESCRIPTION: Since 1997 we have diagnosed three patients, all aged >70, with endocarditis due to S. pneumoniae. One of these three cases involved a prosthetic valve, another a prosthetic ring. All three patients completely recovered with antibiotic treatment only. DISCUSSION AND EVALUATION: During the same period there were 1694 cases of pneumococcal bacteremia, of whom 395 (23%) after age 70. Therefore, after age 70 the prevalence of endocarditis out of all cases of pneumococcal bacteremia was 0.7%. A literature review detected another 16 cases of pneumococcal PVE. The mean age of these 17 patients was 64±14; 10 were female and 7 male. In most instances, symptom duration was short, < 6 days. Valve surgery was performed in 5 cases (29%) and 13 patients (76%) survived. CONCLUSIONS: Endocarditis due to S. pneumoniae is rare in the antibiotic era; even in patients with prosthetic valves its course is evidently not more virulent than with other low-virulent organisms.