Not a cause of Gynaecomastia
. Ans. is 'a' i.e., Hypothyroidism Causes of Gynaecomastia Pubey During pubey, the serum oestradiol rises to adult levels before testosterone, causing transient gynaecomastia. This normally resolves within six months to two years. Cirrhosis Gynaecomastia occurs due to altered sex hormone metabolism, and an increase in the oestradiol; free testosterone ratio. Hypogonadism Primary hypogonadism causes a compensatory rise in LH, in turn causing increased peripheral aromatization of testosterone to oestradiol. Secondary hypogonadism, due to pituitary or hypothalamic disease (e.g. prolactin excess, Kallman's syndrome haemachromatosis), may also cause gynaecomastia despite LH deficiency, since the adrenal coex continues to produce oestrogen precursors, which are conveed to oestrogens in peripheral tissues. Tumours Testicular tumours: Germ cell tumours account for over 95% testicular tumours. Gynaecomatia occurs in 5% of patients, due to hCG secretion stimulating oestradol production by the testes. Leydig cell tumours cause gynaecomastia in 20 - 30% of cases. These tumours present with precocious pubey in boys, or poot libido and gynaecomastia in young males. Approximately 10% of these tumours are malignant. Seoli cell turnours cause gynaecomastia through excess aromatization of androgents to oestrogens. These turnours may occur in Peutz- Jeger 's syndrome. Adrenocoical turnours may cause gynaecomastia through overproduction of androgens such as androstenedione, which are conveed to oestrogens in peripheral tissues. Ectopic hCG-secreting tumours include lung, gastric, renal, and hepatocellular carcinomas. Hypogonadism from chemotherapy or radiotherapy may also cause gynaecomastia in patients with testicular tumours. Graves disease Gynaecomastia may occur due to increased sex hormone-binding globulin (SHBG), and decreased free testosterone levels. Chronic renal failure: Half of patients receiving haemodialysis develop gynaecomastia due to decreased leydig cell function. Gynaecomastia may also occur following kidney transplantation due to ciclosporin use. Androgen insensitivity syndrome : Complete androgen insensitivity, .formerly termed 'testicular feminization syndrome', causes a femalephynotype in patients who are genotype males. These patients are regarded as female, and therefore present with infeility and amenorrhoea rather gynaecomastia. Paial androgen receptor defects maycause gynaecomastia in phenotypic males. Drugs cause gvnaecomastia Anti-androgens Cyproterone acetate Finasteride/dutasteride Gastrointestinal drugs Cimetidine / ranitidine Cancer chemotherapy Alkylating agents/vinca alkaloids (due to testicular damage and hypogonadism) Imatinib (tyrosine kinase inhibitor used for chronic myeloid leukemia (CML) and gastrointestinal stromal tumour (GIST). Cardiovascular drugs Spironolactone (displaces oestrogen from SHBG, increasing free oestrogen: testosterone ratio) Digoxin Amiodarone Methyl-dopa Antimicrobial drugs Isoniazid Ketoconazole Metronodazole Anti-viral drugs Highly active anti-retroviral (HAA) therapy (especially protease inhibitors) Neurological drugs Phenothiazines Metoclopramide Tricyclic anti-depressants Opiates
Hypothyroidism
Kallman
obesity
Klinefelter syndrome