Investigating the pathways in primary practice leading to the diagnosis of central hypothyroidism

Clinical diagnosis of central hypothyroidism is not always obvious: patients may live for years with symptoms. Endocrinologists and biochemists have suggested that a first-line TSH strategy will lead to avoidable delays in diagnosis and treatment of patients with central hypothyroidism. In order to improve timely diagnosis, and thus decrease morbidity from a treatable disease, this study aimed to investigate the diagnostic journey of patients with central hypothyroidism in the Waikato region of New Zealand.

A retrospective convenience sample seeking note review and semi-structured interviews were carried out with 16 patients who had a diagnosis of central hypothyroidism that was not caused by pituitary surgery or radiotherapy to the pituitary or hypothalamus.

Seventy-five percent of participants had tests performed in general practice with results suggesting either pituitary disease or that further investigation would be required. In 38% (6/16) of participants diagnosis was made by the general practitioner. Time to diagnosis ranged from 3 months to more than 12 months. Seven participants identified having 3-6 visits to their general practitioner and five participants made 6 to 12 visits to their general practitioner prior to diagnosis. Lethargy was the most common symptom in 94% of participants. This was followed by changes in skin texture and body hair distribution and texture in 75% of participants and headaches in 63% of participants.

Due to the era during which these patients were diagnosed, we did not find that a delay in diagnosis was due to an absence of FT4 requests; which a first-line TSH strategy would imply. It is important to recognise that a normal TSH does not exclude central hypothyroidism. By raising awareness with general practitioners of pituitary disease, with potential for deficiency of other anterior pituitary hormones, would focus more specific questioning on related symptoms.