Intraperitoneal vancomycin-induced immune thrombocytopenia.

Vancomycin is one of the drugs used in the peritonitis treatment regimen of peritoneal dialysis patients. Intraperitoneal route is generally preferred to provide rapid elimination of infective agents. Systemic toxicities of certain drugs after intraperitoneal administration are not very clear. The same also applies to vancomycin, although it has a considerable amount of systemic absorption after intraperitoneal administration. We herein report a case of severe thrombocytopenia, which was seen during the treatment of a peritonitis attack in a peritoneal dialysis patient. Culture studies revealed methicillin resistant staphylococci as the causative agent and the patient received intraperitoneal vancomycin per sensitivity analysis. Thrombocyte levels dropped abruptly to 3,900/µl after 10 days of vancomycin treatment. Clinical criteria pointed out to vancomycin-related immune thrombocytopenia. Platelet levels did not recover with initial dexamethasone treatment and platelet transfusions. In the meantime, the clinical course was also complicated with intracranial bleeding. Intravenous immunoglobulin treatment was applied and dexamethasone was switched to high-dose methylprednisolone. This latter treatment generated a response and platelet levels gradually increased to normal levels. The patient could be discharged without any sequelae. There have been two previous intraperitoneal vancomycin-related immune thrombocytopenia cases in the literature. Previous cases were reviewed, and the present case was given in comparison with the previous cases.

Effect of metformin on thyroid cancer risk in patients with acromegaly: A preliminary observational study.

PURPOSE: To evaluate the role of metformin on thyroid cancer risk in patients with acromegaly. METHODS: Medical charts of 534 patients with acromegaly that were followed-up between 1983 and 2019 were reviewed. Patients with follow-up duration at least 6 months were included. Cohort entry was defined as first visit date. The date of each case's thyroid cancer diagnosis was defined as index date. Patients were followed until the index date, death, or last visit date, whichever came first. Nested case-control study design was selected to evaluate the association between metformin and the thyroid cancer risk in patients with acromegaly. RESULTS: 291 patients with acromegaly were included into final analysis. The mean age at acromegaly diagnosis was 42.3 ± 1.3 years. The median follow-up duration was 76 [34-132] months. Among 291 patients, 13 patients (4.5%) had thyroid cancer. Thirty-one percent (n = 92) of the patients used metformin for 6 months or longer. One standard deviation (SD) increase in average growth hormone increased the odds of having thyroid cancer by 1.164 folds (p = 0.017). One SD increase of the average insulin-like growth factor 1 to upper limit of normal ratio increased the odds of having thyroid cancer by 1.201 folds (p = 0.004). If a patient used metformin for at least 6 months, the odds to have thyroid cancer was decreased, multiplied by 0.62 with a 95% confidence interval of [0.47, 0.83] (p = 0.0013). The risk of thyroid cancer decreased with increasing duration of metformin use. CONCLUSION: Metformin may decrease the thyroid cancer risk in patients with acromegaly.