Myasthenia gravis, Hashimoto's thyroiditis, and pernicious anaemia

Severe Cobalamin Deficiency Disguised as Schistocytes: A Case Report

Patient: Male, 53

Final Diagnosis: Non immune intravascular hemolytic anemia

Symptoms: Dyspnea • fatigue

Medication: —

Clinical Procedure: —

Specialty: Hematology

Anti-parietal cell antibodies in patients with autoimmune thyroid diseases

BACKGROUND

Autoimmune thyroid disease (ATD) patients may have a higher prevalence of anti-parietal cell antibodies (APCA) than normal population.

OBJECTIVE

To study the prevalence of APCA in a cohort of ATD patients to know its association with patient's clinical profile and gastrointestinal complaints.

METHODS

APCA was sought for by indirect immunofluorescence test in 243 ATD patients: 136 (55.9%) with Graves' disease and 107 (44.0%) with Hashimoto's thyroiditis. A structured questionnaire for gastrointestinal symptoms, previous history of thrombosis, arthralgia and other autoimmune diseases in the patients and their families was applied. Positive and negative APCA individuals were compared. Positive patients were invited to perform upper gastrointestinal endoscopy and biopsy of duodenum segments. Sera from 100 healthy individuals from the same geographic area were used as controls.

RESULTS

APCA was present in 20.1% (49/243) of ATD patients: 21.3% (29/136) in the Graves' sample and 18.6% (20/107) in the Hashimoto's sample (p = 0.61). Patients with positive APCA had more anemia (p = 0.03; OR = 2.89; 95% CI = 1.03-8.07) and less heartburn (p = 0.01; OR = 0.4; 95% CI = 0.20-0.83). Among the group of 49 APCA-positive patients, 24 agreed with upper endoscopy and it was found that 54.1% had atrophic gastritis.

CONCLUSIONS

There is a high prevalence of positive APCA in ATD patients. APCA are more common in those with anemia and less common in those with complaints of heartburn. Almost half of positive APCA patients had atrophic gastritis.

Autoimmune atrophic gastritis--pathogenesis, pathology and management

Autoimmune gastritis is a chronic progressive inflammatory condition that results in the replacement of the parietal cell mass by atrophic and metaplastic mucosa. A complex interaction of autoantibodies against the parietal cell proton pump and sensitized T cells progressively destroy the parietal cells, inducing hypochlorhydria and then achlorhydria, while autoantibodies against the intrinsic factor impair the absorption of vitamin B₁₂. The resulting cobalamin deficiency manifests with megaloblastic anaemia and neurological and systemic signs and symptoms collectively known as pernicious anaemia. Previously believed to be predominantly a disease of elderly women of Northern European ancestry, autoimmune gastritis has now been recognized in all populations and ethnic groups, but because of the complexity of the diagnosis no reliable prevalence data are available. For similar reasons, as well as the frequent and often unknown overlap with Helicobacter pylori infection, the risk of gastric cancer has not been adequately assessed in these patients. This Review summarizes the epidemiology, pathogenesis and pathological aspects of autoimmune metaplastic atrophic gastritis. We also provide practical advice for the diagnosis and management of patients with this disease.

Prevalence of parietal cell antibodies in a large cohort of patients with autoimmune thyroiditis

BACKGROUND

Autoimmune thyroiditis (AIT) may be associated with other organ-specific autoimmune disorders, including autoimmune gastritis, but the prevalence of this association is not entirely quantified. The aim of this study was to investigate the prevalence of parietal cell antibodies (PCA) in a large cohort of consecutive patients with AIT.

METHODS

We retrospectively studied 2016 consecutive women and 258 men with AIT seen at our referral center in the period from 2004 to 2008. All patients were screened for the presence of PCA in the serum.

RESULTS

The prevalence of serum PCA in female patients was 29.7% and progressively increased from 13% in the first-second decade of life to peak at 42% in the ninth decade. During follow up, 21.1% of the PCA-positive patients converted to PCA-negative status. Mean (±standard deviation) basal PCA levels in this group were significantly lower (32 ± 28 U/mL) compared with those remaining PCA positive (129 ± 200 U/mL). A similar prevalence (29.8%) with a similar age-dependency was found in male patients.

CONCLUSIONS

In conclusion, our study demonstrates a high, age-dependent prevalence of PCA in an unselected large population of patients with AIT.

Thyroid function and autoimmunity in pernicious anemia before and during cyanocobalamin treatment

Out of 35 consecutive patients with decreased plasma-cobalamin 22 had newly diagnosed overt pernicious anemia (PA) six of which had a known history of thyroid disease. At referral, 5 of these 6 were thyroid peroxidase antibody (TPOAb)-positive and 2 were thyroglobulin antibody (TgAb)-positive, while none were thyroid stimulating antibody (TSAb)-positive (an overall autoantibody appearance of 83.3%). Fifty percent of the 22 patients had TPOAb and 13.6% had TgAb compared to 18.2% and 4.5%, respectively in sex and age matched healthy controls. Six PA-patients without a history of thyroid disease had thyroid autoantibodies and another patient seroconverted within the first year during treatment with cyanocobalamin. Measurements of serum concentrations of thyroid hormones and thyroid stimulating hormone were performed during the first year of treatment with cyanocobalamin. Two cases of subclinical myxoedema were found among PA-patients and another case was found among patients with latent PA. The female:male ratio of thyroid disease among PA-patients and among thyroid autoantibody-positive PA-patients was interestingly found to be 1:1. Treatment with cyanocobalamin did not have any systematic effect on thyroid function. Routine screening for thyroid function and thyroid autoantibodies in patients with latent or overt PA is recommended.

Myasthenia gravis: overlap with 'polyendocrine' autoimmunity

81 patients with spontaneously acquired myasthenia gravis (MG) were investigated for the presence of autoimmune (AI) diseases and their sera were tested for a range of organ-specific autoantibodies. 77 of the patients were HLA-phenotyped. Antibody titres to acetylcholine receptors (AChR) were higher in non-thymomatous patients who possessed HLA-B8 (p less than 0.05) and/or -DR3 (p less than 0.05) as compared to patients lacking these HLA antigens. 3 out of 20 (15%) patients with ocular MG, 7/23 (30%) with generalized MG of early onset, 11/23 (48%) generalized MG of late onset and 5/14 (35%) patients with thymoma had either overt AI diseases or significant titres of organ-specific autoantibodies suggesting subclinical AI disease. In ocular MG, low titres and an infrequent finding of antibodies to AChR (32%) as well as the low prevalence of associated autoantibodies and AI diseases indicate that this subgroup of MG consists of patients with restricted AI reactivity. HLA-B8 and -DR3 were present in all the patients with associated AI disorders in the young onset group but in none of the patients with old age of onset. In the young group, 6 out of 7 patients with associated AI conditions were women whereas the sex ratio was about equal in the older cases in both, patients with and without associated AI diseases or autoantibodies. We conclude from these observations that ageing provides conditions that allow the breakdown of self tolerance. The simultaneous presence of HLA B8, DR3 and female sex provide important additional factors for early expression of MG.

Myasthenia gravis with a monoclonal gammopathy--report of a case

An elderly man with relapsing myasthenia gravis was found to have hypergammaglobulinaemia, a monoclonal peak of gamma mobility and paraproteinaemia IgG, type K. Bence-Jones proteinuria, type K was present. This is the fourth report of myasthenia gravis associated with a monoclonal gammopathy. Myasthenia gravis is considered to be an autoimmune disease. Recent findings implicate a dysfunction of cellular immunity in the pathogenesis of both immunoproliferative and autoimmune disease. We suggest that the association of myasthenia gravis and monoclonal gammopathy in our patient might have stemmed from a disorder of T lymphocyte function.

Humoral and cellular immunity to intrinsic factor in myasthenia gravis

Myasthenia gravis (MG) is an autoimmune disease often associated with other autoimmune disorders. A case history of MG with a coexisting atypical megaloblastic anaemia with vitamin B12 deficiency and anti Intrinsic Factor (IF) antibodies, led to a study of humoral and cellular immunity to IF in 81 MG patients. Within this series, 3 other patients had a disturbed humoral and cellular immunity to IF. These 3 patients presented no other features of pernicious anaemia. The possible origins and significance of the anti IF antibodies in MG patients are discussed.

Polyradicular neuritis and Hashimoto's thyroiditis

The case of a patient with a pluripotential immuneproliferative syndrome is reported. She suffered from Hashimoto's thyroiditis with secondary cold agglutination disease and from polyradicular neuritis. Polyradicular neuritis with albumino-cytological dissociation in the CSF had developed chronically and improved only when corticosteroid therapy was begun. Based on this case report fundamental considerations concerning the pathogenesis and therapy of Landry-Guillain-Barre-tstrohl syndrome are discussed.

Anemia in thyroid diseases

Thyroid hormones generally stimulate erythropoiesis. These agents also increase erythrocyte 2,3-DPG concentrations, which serve to enhance the delivery of oxygen to tissues. In the absence of thyroid hormones, anemia frequently develops and may be normocytic, hypochromic-microcytic, or macrocytic. Anemia is an uncommon finding in hyperthyroidism but when present may be morphologically similar to that observed in hypothyroidism. Pernicious anemia has been strongly associated with hypothyroidism, hyperthyroidism, and thyroiditis. Complete correction of anemia often requires restoration of thyroid function as well as specific hematinic therapy. Continued attention to hematologic status is essential in the management of patients with thyroid diseases.

Episodic encephalopathy associated with thyroid disorders

Two patients with a thyroid disorder and an associated episodic encephalopathy are reported. The relationship between Hashimoto's thyroiditis, myxoedema, and neurological disease is considered, and the evidence for such disorders being due either to an underlying autoimmune process or that the encephalopathy is a direct result of the thyroid disorder is discussed.

Autoimmunity in myasthenia gravis: a family study

The prevalence of autoantibodies to muscle, epithelial cells of calf thymus, thyroid, gastric parietal cells and antinuclear and rheumatoid factors has been studied in the sera of thirty-two patients with myasthenia gravis and their relatives.

Previous reports of an increased prevalence of autoantibodies in the sera of patients with myasthenia gravis have been confirmed and it has been shown that concurrent reactivity to muscle and thymus is closely correlated with the severity of the myasthenia and the presence of a thymoma, whereas no such correlation occurred with the other antibodies studied. None of the sera from relatives or spouses showed concurrent reactivity with thymus and muscle, and with the exception of one patient with pernicious anaemia, sera from patients with a variety of other diseases were also negative.

A slight increase in the prevalence of autoantibodies to thyroid and gastric components and antinuclear factor was found in first degree relatives of patients with myasthenia gravis; this could be accounted for by their aggregation in a few families.