Recalcitrant hypocalcaemia in autoimmune enteropathy

Case Report: Severe Hypocalcemic Episodes Due to Autoimmune Enteropathy

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) is a rare monogenic disorder, associated with endocrine deficiencies and non-endocrine involvement. Gastrointestinal (GI) manifestations appear in approximately 25% of patients and are the presenting symptom in about 10% of them. Limited awareness among pediatricians of autoimmune enteropathy (AIE) caused by destruction of the gut endocrine cells in APECED patients delays diagnosis and appropriate therapy. We describe an 18-year-old female presenting at the age of 6.10 years with hypoparathyroidism, oral candidiasis and vitiligo. The clinical diagnosis of APECED was confirmed by sequencing the autoimmune regulator-encoding (AIRE) gene. Several characteristics of the disease-Hashimoto's thyroiditis, Addison's disease, diabetes mellitus type 1 and primary ovarian insufficiency-developed over the years. She had recurrent episodes of severe intractable hypocalcemia. Extensive GI investigations for possible malabsorption, including laboratory analyses, imaging and endoscopy with biopsies were unremarkable. Revision of the biopsies and chromogranin A (CgA) immunostaining demonstrated complete loss of enteroendocrine cells in the duodenum and small intestine, confirming the diagnosis of AIE. Management of hypocalcemia was challenging. Only intravenous calcitriol maintained calcium in the normal range. Between hypocalcemic episodes, the proband maintained normal calcium levels, suggesting a fluctuating disease course. Repeated intestinal biopsy revealed positive intestinal CgA immunostaining. The attribution of severe hypocalcemic episodes to AIE emphasizes the need for increased awareness of this unique presentation of APECED. The fluctuating disease course and repeated intestinal biopsy showing positive CgA immunostaining support a reversible effect of GI involvement. CgA immunostaining is indicated in patients with APECED for whom all other investigations have failed to reveal an explanation for the malabsorption.

Presumptive Glucocorticoid-Induced Refractory Hypocalcemia in a Dog with Idiopathic Immune-Mediated Hypoparathyroidism, Thrombocytopenia, and Hemolytic Anemia

Clinically relevant hypocalcemia is a well-documented complication of glucocorticoid administration in people with hypoparathyroidism. The current report describes the phenomenon in a dog. A 7 yr old neutered male Pomeranian was diagnosed with immune-mediated thrombocytopenia, immune-mediated hemolytic anemia, and primary hypoparathyroidism. This dog required long-term parenteral calcium gluconate to prevent clinical hypocalcemia despite appropriate doses of oral calcitriol and calcium carbonate. This is the first description of clinically significant presumptive glucocorticoid induced hypocalcemia in a dog with primary hypoparathyroidism.

Autoimmune enteropathies

Autoimmune enteropathy (AIE) is a rare condition characterized by intractable diarrhea and immune-mediated injury of the intestinal mucosa. As the clinical and histopathologic manifestations of this disease are highly variable, its diagnosis is challenging for both clinicians and pathologists. In fact, the term autoimmune enteropathies is likely more appropriate since the clinicopathologic manifestations are observed in association with a heterogeneous group of disorders. The pathophysiology of AIE has not been fully elucidated. It appears to result from dysregulation of intestinal immunity and particularly in children, often presents in association with immunodeficiency. The overarching histopathologic changes seen in AIE include mucosal inflammation and epithelial injury, although this can manifest in the form of different patterns. Recognition of the clinical settings and of the various histologic patterns can aid the pathologist in establishing the correct diagnosis.

[Polyglandular autoimmune syndromes : An overview]

Polyglandular autoimmune syndromes (PGAS), also known as autoimmune polyendocrinopathy syndromes (APS), are a heterogeneous group of rare, genetically caused diseases of the immune system which lead to inflammatory damage of various endocrine glands resulting in malfunctions. In addition, autoimmune diseases of non-endocrine organs may also be found. Early diagnosis of PGAS is often overlooked because of heterogeneous symptoms and the progressive occurrence of the individual diseases. The two most important forms of PGAS are the juvenile and adult types. The juvenile type (PGAS type 1) is caused by mutations in the autoimmune regulator (AIRE) gene on chromosome 21, exhibits geographic variations in incidence and is defined by the combination of mucocutaneous candidiasis, Addison's disease and hypoparathyroidism. In addition, autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) syndrome and other autoimmune diseases can also occur. The adult form of PGAS (PGAS type 2) is a multigenetic disorder associated with some HLA haplotypes, is more common than the juvenile type, shows female predominance and exhibits the combination of type 1 diabetes, autoimmune thyroid disease, Addison's disease and other autoimmune disorders. The histological alterations in affected organs of PGAS patients are similar to findings in sporadically occurring autoimmune diseases of these organs but there are no pathognomic fine tissue findings. If patients exhibit autoimmune changes in two different endocrine glands or if there are indications of several autoimmune disorders from the patient history, it is important to consider PGAS and inform the clinicians of this suspicion.