Hypothyroidism

Thyroid deficiency in infants leads to cretinism and in older children it produces juvenile myxoedema. The most characteristic feature is delayed bone maturation and, in the infant, absence of the distal femoral and proximal tibial epiphyses. Distinctive radiographic findings are observed in older children (fragmented irregular epiphyseal contours, termed epiphyseal dysgenesis). Many of the musculoskeletal abnormalities associated with hypothyroidism are listed in Table 1.

Hypothyroidism, Table 1. Some musculoskeletal abnormalities noted in hypothyroidism.

In children, abnormalities of epiphyseal development are accompanied by alterations in development of synchondroses (e.g. between segments of sternum and sacrum) and sutures, and physeal growth plates and sutures may persist well beyond the age at which they normally should have disappeared.

In the skull, decreased growth of the spheno-occipital synchondrosis produces brachycephaly. Enlargement of the sella turcica, prominent sutures with accessory (wormian) bones, underdevelopment of the paranasal sinuses and mastoid air cells, and a prognathous lower jaw may also be present.

Affected epiphyses have multiple centres of ossification rather than a single site, leading to an irregular or fragmented appearance (epiphyseal dysgenesis). Epiphyseal dysgenesis is particularly frequent in the femoral and humeral heads. In the hip, coxa plana, coxa magna and coxa vara have been described.

Entrapment neuropathies such as the Carpal tunnel syndrome and muscle cramps and stiffness are common in hypothyroidism. Slipped capital femoral epiphysis may also occur in patients with decreased thyroid hormones.

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