Exogenous Cushing’s Syndrome, Hypogonadism and Diabetes Secondary to Megestrol Acetate

Abstract

Introduction: Megestrol acetate (MA) is a synthetic progestin that is often prescribed for anorexic patients with HIV due to its effects on weight gain and appetite stimulation. It can cause several endocrine/metabolic abnormalities. Chronic use of MA can cause exogenous Cushing’s Syndrome (ECS) and iatrogenic adrenal insufficiency (AI) due to its stronger affinity for the glucocorticoid receptor (GR). It can also cause gonadotropin suppression, diabetes and hyperprolactinemia. We present a case of a young woman with perinatal HIV/AIDS that developed ECS secondary to MA treatment in the setting of fatigue, rapid weight gain and irregular menses. Case: A 19 year old female with perinatal HIV/AIDS (CD4<200) was treated with MA (200mg/day for 5 months) for anorexia and weight loss. On exam she was pre-hypertensive (BP 138/62), obese (BMI 43.07, SDS +2.25; weight 114kg, SDS +2.34) with increased fat deposition over upper back and abdominal striae, excessive weight gain (21.5 kg in 5 months) suggestive of ECS. She had menarche at 13 years of age and had regular menses until starting MA, upon which she developed oligomenorrhea. A random serum cortisol level was <0.5ug/dl at 1pm with a low ACTH <1.5pg/ml and DHEAS of 13.4ug/dl. Her FSH was 3.4 mIU/L and LH 0.82 mIU/L, estradiol was <2pg/dl and total testosterone <2.5ng/dl consistent with secondary hypogonadism. Liver/kidney function, prolactin and lipid profile were normal. HbA1c increased from 5.3 to 6.4% in 8 months so she was started on metformin. ECS with AI, central hypogonadism and diabetes were all attributed to MA therapy. MA was discontinued gradually over two weeks. Stress dosing of glucocorticoids were advised as needed. Results: Gradual recovery of HPA axis was noted after discontinuation of MA. Two months after taper, serum ACTH level rose to 2.5pg/ml but AM cortisol level remained low at <0.5ug.dl. Her HPA axis showed partial recovery by 5 months with ACTH level of 53.2pg/ml and AM cortisol level of 5.5ug/dl. By 8 months after discontinuing MA therapy, AM cortisol was 9.3ug/dl, suggesting complete HPA axis recovery. Her HPG axis also normalized by 8 months with FSH 6.6 mIU/L and LH of 14.6 mIU/L, estradiol 32pg/dl with regular menses. Metformin was discontinued at 4 months due to hypoglycemia and HbA1C of 5.7%. Subsequently, euglycemia was achieved (HbA1C of 5.4%) within 9 months. BMI was stable (BMI 43.07, SDS +2.25; weight 114kg, SDS +2.34). Conclusion: Multiple endocrine abnormalities may occur due to MA therapy due to its affinity to bind with glucocorticoid and progesterone/androgen receptors. ECS and AI are known to occur with various forms of glucocorticoid use, but rarely can be seen with MA therapy. HPA axis, HPG axis and metabolic parameters should be evaluated and monitored carefully during MA therapy.