Endocrine Abstracts

Male hypogonadism is usually considered in the presence of classical symptoms like reduced libido, erectile dysfunction and reduced bone mineral density.

We present the case history of a 43-year-old man with learning difficulties who presented with long-standing lethargy. Clinical examination revealed bilateral ptosis, muscle weakness and slow relaxation of handgrip. He had abdominal obesity, pseudo-gynaecomastia, frontal balding, reduced facial, chest, axillary and pubic hair. Testes measured 15mls bilaterally. Investigations revealed hypergonadotrophic hypogonadism ((testosterone 3.0 nmol/l (nr 10–32); FSH 11.3 IU/l (nr 1.0–12.0), LH 11.1 IU/l (nr 1.0–11.0)). Other biochemical investigations: estradiol 193 (<172 pmol/l), 0900 h cortisol 640 nmol/l. Thyroid function tests, prolactin and IGF1 were normal.

Genetic test confirmed the presence of CTG repeat expansion of dystrophia myotonica protein kinase (DMPK) gene consistent with myotonic dystrophy type 1. Electromyography (EMG) revealed frequent myotonic discharges in the distal and proximal limb muscles, consistent with myotonic dystrophy.

Our case report highlights the importance of excluding hypogonadism in the presence of myopathy and specific phenotypic features of congenital muscle disease.