Description
A 34-year-old man presented with gradual onset facial puffiness and lethargy for 6 months. There was no history of headache, visual disturbance, seizures or sexual dysfunction. On examination, he had mild facial puffiness and pallor. There was no goitre by neck palpation. Systemic examination showed no significant findings except sluggish reflexes with delayed relaxation. Myoedema was observed during clinical examination (video 1) by flicking the biceps belly indicating hypothyroid myopathy. Laboratory studies showed free thyroxine level of 0.36 ng/dL (normal range, 0.8–1.8) and thyrotropin of 1.2 µU/mL (normal range, 0.5–4.9 suggestive of secondary hypothyroidism. Other anterior pituitary hormones were also low suggesting hypopituitarism. MRI of the head revealed pituitary adenoma measuring 1.2 cm that was non-functional. After rendering him euthyroid and eucortisolemic with thyroxine and hydrocortisone, he underwent transsphenoidal resection of pituitary adenoma. Two weeks after thyroxine supplementation, the myoedema disappeared. Myoedema is a local, non-tender, firm ridge in the muscle elicited by tapping or flicking the muscle belly. This is due to local calcium release and delayed reuptake in to the sarcoplasmic reticulum.1 2 Low thyroxine levels also contribute further by switching the muscle fibres from fast twitching type II to slow type I fibres, glycosaminoglycan deposition and reduced adenosine triphosphate (ATP) availability locally. Although myoedema is commonly elicited in primary hypothyroidism, it is rarely reported in secondary hypothyroidism.3 Rarely, myoedema is described in hypoalbuminaemia, renal failure, hyponatraemia, rabies and cachexia.
Video 1.
Learning points.
Myoedema is a classic sign of hypothyroid myopathy and is more common in primary than secondary hypothyroidism.
This clinical sign is more often missed since it is not being looked for.
Myoedema resolves within few weeks of thyroxine supplementation.
Acknowledgments
We thank the patient and his family for consenting to use his details in this publication.
Footnotes
Contributors: ARA drafted and edited the manuscript. KB had helped in editing the video images. SB helped in managing patient and editing the manuscript. SM was involved in clinical management of the patient and critical review of the manuscript.
Funding: The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests: None declared.
Patient consent for publication: Obtained.
Provenance and peer review: Not commissioned; externally peer reviewed.
References
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