Mineralocorticoid and glucocorticoid status in idiopathic haemochromatosis

Endocrine dysfunction in hereditary hemochromatosis

Hereditary hemochromatosis (HH) is a genetic disorder of iron overload and subsequent organ damage. Five types of HH are known, classified by age of onset, genetic cause, clinical manifestations and mode of inheritance. Except for the rare form of juvenile haemochromatosis, symptoms do not usually appear until after decades of progressive iron loading and may be triggered by environmental and lifestyle factors. Despite the last decades discovery of genetic and phenotype diversity of HH, early studies showed a frequent involvement of the endocrine glands where diabetes and hypogonadism are the most common encountered endocrinopathies. The pathogenesis of diabetes is still relatively unclear, but the main mechanisms include the loss of insulin secretory capacity and insulin resistance secondary to liver damage. The presence of obesity and/or genetic predisposition may represent addictive risk factor for the development of this metabolic disease. Although old cases of primary gonad involvement are described, hypogonadism is mainly secondary to selective deposition of iron on the gonadotropin-producing cells of the pituitary gland, leading to hormonal impaired secretion. Cases of hypopituitarism or selected tropin defects, and abnormalities of adrenal, thyroid and parathyroid glands, even if rare, are reported. The prevalence of individual gland dysfunction varies enormously within studies for several bias due to small numbers of and selected cases analyzed, mixed genotypes and missing data on medical history. Moreover, in the last few years early screening and awareness of the disease among physicians have allowed hemochromatosis to be diagnosed in most cases at early stages when patients have no symptoms. Therefore, the clinical presentation of this disease has changed significantly and the recognized common complications are encountered less frequently. This review summarizes the current knowledge on HH-associated endocrinopathies.

All that is hypogonadal in haemochromatosis is not due to iron deposition

BACKGROUND

Hereditary haemochromatosis (HH) is an autosomal recessive condition resulting in excessive gastrointestinal absorption of iron, which may be deposited in various organs. Apart from diabetes, hypogonadism is the most common endocrinopathy associated with HH and is usually secondary to excess iron deposition in the anterior pituitary gland.

AIMS AND METHODS

We present three patients with HH and hypogonadism.

RESULTS

Careful clinical and biochemical analysis revealed that the hypogonadism was due to causes other than iron deposition.

CONCLUSIONS

This series illustrates the importance of having a high degree of clinical suspicion, even when dealing with what may clinically appear to be a straight-forward clinical problem.

Endocrinopathy of HFE-related hemochromatosis

Hereditary hemochromatosis is a condition affecting many organs, as reflected by the fact that it is managed variably by hematologists, gastroenterologists, rheumatologists and endocrinologists, depending on local preferences. A potential pitfall of this approach is that certain aspects of diagnosis and management may be overlooked, particularly if they fall beyond the normal scope of practice of the specialist physician concerned. The purpose of this article is to review the nature of the endocrine complications of hereditary hemochromatosis, which have changed dramatically since the condition was first described over 100 years ago.

Thyroid function in haemochromatosis

BACKGROUND

In hereditary haemochromatosis (HH), the thyroid gland is the site of substantial iron deposition. However, there have been relatively few reported cases of thyroid dysfunction in HH.

AIM

To evaluate the prevalence of thyroid disorders in a large group of patients with HH.

METHODS

A variety of endocrine investigations were undertaken including thyroid function tests and thyroid antibody studies.

RESULTS

A total of 154 consecutive patients (123 male, 31 female) were studied. One case of primary hypothyroidism was identified, giving a prevalence of 0.6%. Subclinical hypothyroidism was identified in two females, giving a prevalence of 1.3%. Iatrogenic hypothyroidism was identified in two other cases. No case of hyperthyroidism was identified.

CONCLUSION

Thyroid dysfunction is an uncommon occurrence in patients with HH.

Mineralocorticoid status and endocrine dysfunction in severe hemochromatosis

Selective iron deposition in the zona glomerulosa of the adrenal cortex is observed in hemochromatosis. Hypoaldosteronism should be excluded before starting venesection, to avoid long-term volume depletion. We evaluated the aldosterone status in patients with hemochromatosis. As other endocrine organs can be affected by the disease as well, we simultaneously evaluated anterior pituitary, gonadal, thyroid and pancreatic beta-cell activity. Nine patients with hereditary or acquired hemochromatosis and highly increased plasma ferritin levels were investigated. In patients, liver cirrhosis had been confirmed histologically. Five patients complained of sexual dysfunction, and one had impaired glucose tolerance. Plasma aldosterone (PA) and renin activity (PRA) were measured after a period of normal (100 mmol/day) and low (10 mmol/day) sodium intake. A combined anterior pituitary function test and a glucagon stimulation test were undertaken to evaluate other endocrine functions. Both PA and PRA levels were decreased in one patient with liver cirrhosis, who also presented attenuated cortisol, prolactin and gonadotrophin secretion. No patients had signs of primary hypoaldosteronism with hyperreninemia. Hypogonadotropic hypogonadism was observed in 3 males and 1 female. Pituitary ACTH reserve was impaired in 2, GH and prolactin response in 1, and thyroid function in none of the patients. Glucagon-stimulated plasma C-peptide was impaired in one patient. In conclusion, primary aldosterone deficiency was not observed in patients with severe iron overload. Hyporeninemic hypoaldosteronism was found in one patient who also presented other endocrinopathies. Hypogonadotropic hypogonadism is the most frequent endocrine abnormality in hemochromatosis.