It is suggested that severe hypothyroidism could result in respiratory failure in some cases.3 4
The respiratory muscle strength is reportedly weakened in hypothyroidism and the weakness seems to be proportional to the degree of thyroid dysfunction.5
However, this is not the case in our patient as the plasma levels of thyroid hormones were within normal ranges with hormone substitution when he was diagnosed as respiratory failure. On the other hand, it is also reported that adult patients with GH deficiency showed moderate impairment of ventilatory function6
and that GH replacement therapy reversed that function.7
While it has been postulated that respiratory dysfunction in patients with GH deficiency might be due to weakened respiratory muscle strength and a reduction of lung volumes,7
there are no reports, to our knowledge, showing that GH deficiency resulted in severe respiratory failure as in our case. In treating patients with hypopituitarism, it is common practice to substitute hydrocortisone or testosterone, if necessary, before starting GH replacement. However, in our case, the patient refused replacement of hydrocortisone or testosterone at first and we substituted GH first. This resulted in an improvement of respiratory function, suggesting that a GH deficiency caused the respiratory dysfunction. As the ratio of PEmax
, which reflects the respiratory muscle strength,7
increased after the hormone therapy, it is possible that the improvement in respiratory function was due to increases in respiratory muscle strength. It is unclear whether deficits of glucocorticoids and androgens could affect respiratory function.3
In our case, the addition of hydrocortisone and testosterone had no apparent effects on respiratory function, although we cannot exclude the possibility that replacement of these hormones contributed to the maintenance of improved muscle strength. While patients with hypopituitarism may not often have respiratory dysfunction, our case report suggests that we should examine pituitary hormones, including GH, when the cause of chronic respiratory dysfunction is not clear.
- GH deficiency could cause severe respiratory failure.
- Substitution of GH could reverse respiratory function.
- It is important to check the levels of pituitary hormones when the cause of respiratory dysfunction is not clear.