S2545 Hypothyroidism Heralding Hereditary Hemochromatosis (HH): An Unusual Initial Manifestation

Abstract

INTRODUCTION: HH is an autoimmune inherited disorder of iron metabolism causing unregulated iron absorption resulting in organ damage via iron overload. However, despite the iron excess, thyroid dysfunction is rarely seen. Instead, HH has strong association with autoimmune (AI) thyroiditis and is usually after diagnosis of HH in men. We describe a case of hypothyroidism in female caused by iron overload heralding manifestation of HH which is yet to be reported. CASE DESCRIPTION/METHODS: 30-year-old female, with history significant for hypothyroidism diagnosed 2 years prior, presented with progressively worsening abdominal distension for 1 week. She took laxatives without relief. She denied fever, chills , diarrhea, use of alcohol, smoking, Tylenol, or any illicit drug. Physical examination revealed scleral icterus, distended abdomen with shifting dullness. Lab work revealed elevated transaminases, bilirubin, & INR. Abdominal ultrasound showed ascites, micronodular cirrhosis with signs of portal hypertension (Figure 1). Patient underwent paracentesis which revealed transudative effusion. Cirrhosis investigation revealed homozygous for HFE C282Y gene mutation, consistent with type 1 HH. Due to Hemochromatosis, hypothyroidism secondary to iron deposition was suspected. Records revealed normal-high ferritin, iron saturation 50%, decreased T4, elevated TSH, normal TRH, & negative anti-TPO antibodies. FNAC showed lymphocytic infiltration. Additionally, excessive hemosiderin deposits were also visible (Figure 2). She responded to diuretics and fluid restriction. Hematology follow-up was planned for phlebotomy to prevent further iron overload and patient did well on 6-month follow up. DISCUSSION: HH associated with Autoimmune thyroid disease is well studied, followed by hypothyroidism due to iron deposition in anterior pituitary (seen with decreased TRH). However, no cases have been reported of hypothyroidism due to direct deposition of iron in thyroid gland. Secondly, hypothyroidism in HH occurs classically in men at a late/end stage after development of liver cirrhosis and/or other endocrinopathies. Women are less likely to develop iron overload related diseases due to iron loss through menstruation. Our case is unique because the patient was a young female who developed hypothyroidism prior to other manifestations of HH. Our case highlights the possible benefit of testing for deposition related diseases, particularly hemochromatosis, in case of unknown etiology for hypothyroidism.Figure 1.: Ultrasound abdomen demonstrating coarse echogenic liver, secondary to micronodular cirrhosis.Figure 2.: Fine Needle Aspiration cytology showing dense lymphocytic infiltrate with effacement of thyroid architecture. Hemosiderin deposits also visible (red arrow).