Hypothyroid cardiomyopathy due to hypopituitarism: a diagnostic dilemma

Central hypothyroidism and its role for cardiovascular risk factors in hypopituitary patients

Hypothyroidism is characterized by hypometabolism, and may be seen as a part of secondary failure due to pituitary insufficiency or tertiary due to hypothalamic disease. Secondary and tertiary failures are also referred to as central hypothyroidism. Whereas overt primary hypothyroidism has a well-known affection on the heart and cardiovascular system, and may result in cardiac failure, cardiovascular affection is less well recognized in central hypothyroidism. Studies on central hypothyroidism and cardiovascular outcome are few and given the rarity of the diseases often small. Further, there are several limitations given vast difficulties in diagnosing the condition correctly biochemically, and difficulties monitoring the treatment because normal thyroid-pituitary feedback interrelationships are disrupted. The present review summarizes available studies of central adult hypothyroidism and its possible influence on the cardiovascular system, describe differences from primary thyroid failure and seek evidence for performing guidelines for clinical management of this particular thyroid and hypothalamo-pituitary disorder.

Panhypopituitarism presenting as life-threatening heart failure caused by an inherited microdeletion in 1q25 including LHX4

Clinical presentation of hypopituitarism in the neonate may be variable, ranging from absent to severe nonspecific symptoms and may be life-threatening in patients with adrenocorticotropic hormone deficiency. The LIM homeobox gene 4 (LHX4) transcription factor regulates early embryonic development of the anterior pituitary gland. Autosomal dominant mutations in LHX4 cause congenital hypopituitarism with variable combined pituitary hormone deficiency (CPHD). We report on a neonate with unexplained heart failure and minor physical anomalies, suggesting a midline defect. She was diagnosed with complete CPHD. Cardiac function was rescued by replacement with hydrocortisone and thyroxine; hypoglycaemia stopped under growth hormone therapy. Magnetic resonance imaging revealed a dysgenetic pituitary gland suggesting an early developmental defect. Array comparative genomic hybridization showed a maternally inherited 1.5-megabase microdeletion in 1q25.2q25.3, including the LHX4 gene. Haploinsufficiency of LHX4 likely explains the predominant pituitary phenotype in the proposita and we suggest variable intrafamilial penetrance of the inherited microdeletion. To the best of our knowledge, we are the first to report on heart failure as a rare nonspecific symptom of treatable CPHD in the newborn. Variably penetrant pituitary insufficiency, including this severe and atypical presentation, can be correlated with LHX4 insufficiency and highlights the role of LHX4 for pituitary development.

Sheehan syndrome with reversible dilated cardiomyopathy

Cardiac abnormalities in patients with Sheehan syndrome are uncommon. A case of Sheehan syndrome with dilated cardiomyopathy is presented in whom hormone replacement with levothyroxine and prednisolone resulted in complete recovery of cardiomyopathy. A 25-year-old woman presented with lactation failure, secondary amenorrhea, features of hypothyroidism and a hypocortisol state following severe postpartum hemorrhage after her last child birth. She also had smear positive pulmonary tuberculosis. After starting antitubercular treatment, she developed shock, suggestive of hypocortisol crisis. Hormonal investigations revealed evidence of panhypopitutarism and magnetic resonance imaging revealed partial empty sella. Meanwhile echocardiography revealed evidence of dilated cardiomyopathy (DCM). The patient was given replacement therapy in the form of glucocorticoids and levothyroxine in addition to antitubercular treatment. She improved and on follow-up over a period of 7 months, the DCM completely reversed. To our knowledge this is the first report of reversible DCM in a patient with Sheehan syndrome.