Hypothyroidism - Reptiles

Galapagos Tortoises are a commonly affected species (Wikimedia Commons)

Introduction

Hypothyroidism can be seen in herbivorous reptiles that are fed a diet deficient in iodine. This is most commonly seen in species that evolved in an volcanic environment such as Galapagos tortoises, as plants that hold large quantities of halogens (such as iodine and bromine) are plentiful in these areas. Problems are often exacerbated by the feeding of plants that actually decrease thyroid gland function, such as cabbages.

Clinical Signs & Diagnosis

The reptile normally presents with large fibrous goitres. When combined with the history and signalment this should be diagnositic. Normal thyroid hormone values are not normally available for the affected species, therefore it is of little use to measure them.

Treatment & Prevention

Iodine supplementation should be given either orally or intravenously approximately once a week.

The condition can be prevented by supplementing the diet with kelp tablets, which are a non-toxic source of iodine.

Hypothyroidism - Reptiles Learning Resources
Flashcards Test your knowledge using flashcard type questions	Reptiles and Amphibians Q&A 17

References

Frye, FL & Williams, DL (1995) Self-Assessment Colour Review - Reptiles & Amphibians Manson

Norton, TM & Jacobson ER (1989) Medical Management of a Galapagos Tortoise with Hypothyroidism Journal of Zoo and Wildlife Medicine Vol. 20, No. 2, Jun. 1989