La tunisie Medicale - 2019 ; Vol 97 ( n°02 ) : 391-393
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Article


Introduction:
Hemochromatosis is a disorder caused by an excess of iron deposition in the parenchymal cells that leads to organ dysfunction. It may be divided into primary hemochromatosis and secondary hemochromatosis. The latter can arise in many disorders such as thalassemia or myelodisplastic syndrome, especially if patients have received a multiple blood transfusions [1]. In these patients, the absence of an effective chelation therapy leads to iron overload and gradually accumulation in various tissues, rising morbidity and mortality. Major organs affected by this surplus iron include the heart, lung, liver, and endocrine glands [2].
The prevalence of endocrine dysfunctions varies enormously within studies but they seem to be common in transfusion-associated hemochromatosis [3].
Herein we report the case of a patient with β-thalassemia major who developed diabetes mellitus, hypopituitarism and primary hypoparathyroidism due to secondary hemochromatosis.

OBSERVATION:
A 27-year-old male patient was diagnosed at the age of four years with hemochromatosis secondary to multiple transfusions for β-thalassemia major. He was very poorly compliant with his iron chelation therapy.
At the age of 19 years, he developed diabetes mellitus and hypopituitarism with hypogonadotropic hypogonadism [Total testosterone level =0.62 nmo/l (normal ranges:  7.87-35.74) Follicle-stimulating hormone (FSH) level= 0.10 mIU/ml (normal ranges: 1.37-21.63), Luteinizing hormone (LH) <0.09 mIU/ml (normal ranges:  1.14-8.75) with a normal prolactin level] and corticotropin deficiency [Basal cortisol level= 60 nmol/l (normal ranges: 101.2-535.7) with a suppressed level of adrenocorticotropic hormone (ACTH) <10 pg/ml].  Magnetic resonance imaging (MRI) scan showed hemosiderin deposits in anterior pituitary gland. 
The patient received insulin, hydrocortisone and testosterone enanthate. One year later, he was diagnosed as having iron-overload cardiomyopathy and hepatic cirrhosis.

At the age of 27 years, the patient presented with weakness and recurrent hypoglycemia secondary to the interruption of hydrocortisone replacement therapy. No hypocalcemia symptoms were reported.
On physical examination, he had a body weight of 56 kg, a body height of 1.80 m, a body mass index of 17.2 kg/m2, a blood pressure of 90/60 mmHg  and a pulse rate of 75/mn. Trousseau and Chvostek signs were negative. The abdomen was enlarged with presence of hepatomegaly.
Routine laboratory tests indicated hypocalcemia (corrected calcemia of 2.05 mmol/l; normal ranges: 2.2-2.6 mmol/l) with hyperphosphatemia (1.91 mmol/l; normal ranges: 0.8-1.45 mmol/l).  Parathormone (PTH) level was under the normal range (13.3 pg/ml, normal ranges: 26.5-96.5) consisting with the diagnosis of hypoparathyroidism.
Further hormone investigations revealed central hypothyroidism with a thyroid stimulating hormone (TSH) level of 3.94 µIU/ml (nr: 0.35-4.94 µIU/ml) and Free thyroxine (FT4) level of 0.66 ng/dl (nr: 0.7-1.48 ng/dl). 
MRI scan showed hypoplastic anterior pituitary lobe with significant decreased signal intensity on T1 and T2 weighted images [Figure 1]. The bone mineral density showed osteoporosis.
The patient was treated with levothyroxine and 1 α hydroxyvitamin D3.

COMMENTARIES
Patients with secondary hemochromatosis due to repeated transfusions may develop multiple endocrine failures among which diabetes mellitus is the most frequent encountered complication. Its main mechanisms include the loss of insulin secretory capacity and insulin resistance secondary to liver damage.
Hypogonadotropic hypogonadism represents also a frequent endocrine abnormality in hemochromatosis which is mainly secondary to selective deposition of iron on the gonadotropin-producing cells. The detection of pituitary iron overload on GRE T2*-weighted images is consistent with the hypothesis of hypogonadotropic pituitary insufficiency due to iron-induced cellular damage [4]. Insufficiencies of the other pituitary hormones are infrequent [5]. Moreover, iron overload can also cause functional failures in the adrenal, parathyroid, and thyroid glands. These dysfunctions are less common than diabetes or gonadotropin deficiency [6].
In patients with multiple endocrine dysfunctions, the diagnosis of hemochromatosis should be considered as a differential diagnosis of autoimmune polyglandular syndrome.

Although therapeutic phlebotomy is the only broadly accepted treatment for hemochromatosis, some studies have demonstrated the usefulness of aggressive iron-chelation therapy in long-term reversing and preventing clinical glandular dysfunctions [7]. Still, this recovery is most likely restricted to patients who have glandular iron without concomitant apoptosis and volume loss [7].
Endocrine dysfunctions are associated with a high morbidity and mortality especially in patients with hepatic and cardiac complications. Therefore, a regular use of chelation therapy and a follow up with repeated screening examinations are necessary in patients with multiple transfusions.

Figure 1: Pituitary MRI scan showed hypoplastic anterior pituitary lobe with markedly decreased signal intensity on T1 and T2 weighted images.

Références
  1. Beutler E, Hoffbrand AV, Cook JD. Iron deficiency and overload. Hematology Am Soc Hematol Educ Program 2003: 40-61.
  2. Rotaru I, Gaman A, Gaman G. Secondary haemochromatosis in a patient with thalassemia intermedia. Curr Health Sci J 2014; 40: 67-70.
  3. Kim MK, Lee JW, Baek KH, Song KH, Kwon HS, Oh KW et al. Endocrinopathies in transfusion-associated iron overload. Clin Endocrinol (Oxf) 2013;78(2 suppl):271-7.
  4. Sparacia G, Midiri M, D'Angelo P, Lagalla R. Magnetic resonance imaging of the pituitary gland in patients with secondary hypogonadism due to transfusional hemochromatosis. MAGMA 1999;8(2 suppl):87-90.
  5. Pedersen-Bjergaard U, Thorsteinsson B, Kirkegaard BC. Pituitary function in hemochromatosis. Ugeskr Laeger 1996; 158: 1818-22.
  6. Himoto Y, Kanzaki S, Nomura H, Araki T, Takahashi Y, Seino Y. Hypothyroidism and hypoparathyroidism in an 11 year old boy with hemochromatosis secondary to aplastic anemia. Acta Paediatr Jpn 1995; 37: 534-6.
  7. Farmaki K, Tzoumari I, Pappa C, Chouliaras G, Berdoukas V. Normalisation of total body iron load with very intensive combined chelation reverses cardiac and endocrine complications of thalassaemia major. Br J Haematol 2010;148:466–75
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