In Reply: Drs Kashyap and Kashyap are correct in highlighting the association between PPH and thyroid disease and in recommending that all patients with PPH be screened for hypothyroidism.1 Thyroid disease, either hypothyroidism or indeed hyperthyroidism,2 can occur at any stage in the course of PPH and should be considered whenever there is an abrupt change in clinical status, such as new tachycardia, unexplained weight loss, worsening right heart failure, or new pericardial effusion. While autoimmune features are occasionally seen in PPH, the majority of patients do not have Raynaud phenomenon or the presence of autoantibodies. The recent discovery that heterozygous mutations within the bone morphogenetic protein type II receptor gene of the transforming growth factor β cell–signaling superfamily have been identified in familial and sporadic cases of PPH argues against autoimmunity as the cause of PPH.3,4 However, as understanding of the pathobiology of PPH advances rapidly, a clearer explanation for the observed association between PPH and thyroid disease will no doubt become apparent.
Gaine S. Thyroid Disease and Primary Pulmonary Hypertension—Reply. JAMA. 2001;285(22):2853-2854. doi:10.1001/jama.285.22.2853