Ophthalmopathy associated with primary hypothyroidism

Rituximab therapy in steroid-resistant severe hypothyroid Grave's ophthalmopathy

Association of Grave's ophthalmopathy with hyperthyroidism is well known, and it has also been reported in euthyroid or hypothyroid autoimmune thyroiditis, which rarely requires treatment. Here, we report a case of bilaterally symmetrical severe corticosteroid-resistant hypothyroid Grave's ophthalmopathy successfully treated with rituximab.

Hyperthyroid vs hypothyroid eye disease: the same severity and activity

PURPOSE

To compare demographics, severity, and activity of thyroid eye disease (TED) in patients with hyperthyroidism (Hr-TED) vs primary hypothyroidism (Ho-TED).

PATIENTS AND METHODS

In a cross-sectional study, demographics, complete eye examination, severity score (NOSPECS, total hundred eye score), clinical activity score, and Rundle grading were recorded for patients with TED and different thyroid disorders referred from an endocrinology clinic from 2003 to 2006.

RESULTS

TED was clinically found in 303 patients (303/851, 35.6%). The majority of them (280/303, 92.4%) had Graves' hyperthyroidism and 23 (23/303, 7.5%) had primary hypothyroidism. Mean age, gender, mean severity score, mean activity score, Rundle grade, unilateral presentation of TED, smoking habit, mean duration of eye disease, and mean interval time of thyroid to TED were not significantly different between the two groups (0.06<P<0.9). Mean duration of thyroid disease was significantly (P=0.02) longer in the Hr-TED group (49.6 months) than in the Ho-TED group (22.7 months). Most of the patients in both groups (63.2% of Hr-TED and 73.9% of Ho-TED) developed the eye disease within 18 months before or after the thyroid disease.

CONCLUSION

The same demographics, clinical characteristics, and severity and activity scores for Hr-TED and Ho-TED imply that both groups present the same category of eye disease.

Eye and eyelid abnormalities are common in patients with Hashimoto's thyroiditis

BACKGROUND

Overt ophthalmopathy is presumed to be uncommon in patients with Hashimoto's thyroiditis compared to Graves' disease, where significant eye changes are found in approximately 40% of patients. On the other hand, when observing, more subtle eye changes, particularly upper eyelid retraction (UER) and mild inflammatory signs, may be common in patients with Hashimoto's thyroiditis.

METHODS

We have determined the prevalence and characteristics of eye signs in recently diagnosed patients with Hashimoto's thyroiditis studied prospectively since 2004 till date in Sydney (Australia). We measured serum orbital antibodies in 20 of the patients in enzyme-linked immunosorbent assay.

RESULTS

The overall prevalence of eye signs in patients with Hashimoto's thyroiditis was 34%, of whom about a quarter had chronic UER, determined as a margin-reflex distance of >5 mm, as the main sign. There was no correlation between eye signs and cigarette smoking. Overall, there was only a modest correlation between eye signs and positive antibody tests, and 40% of patients with no eye signs at the time of study were antibody positive.

CONCLUSION

Eye changes, in particular UER, are common in patients with Hashimoto's thyroiditis. Since thyroid stimulating hormone-receptor antibodies are not usually associated with Hashimoto's thyroiditis, autoimmune mediated damage of the levator palpebrae superioris (eyelid) muscle cannot be due to these antibodies. Although eyelid abnormalities may be a minor problem for most patients, for some there are major cosmetic implications requiring surgical management.

The course of endocrine ophthalmopathy during antithyroid therapy in a prospective study

In a prospective study the ocular manifestations of 105 thyrotoxic patients were carefully observed and registered during a 24-month antithyroid drug therapy. The treatment was supervised very closely and every effort was made to avoid iatrogenic hypothyroidism. None of the patients required any ocular surgery and in none did the ophthalmopathy become significantly worse. This favourable experience may indicate that a careful antithyroid regimen as outlined is not likely to be accompanied by worsening of the endocrine ophthalmopathy.

The incidence of Graves' ophthalmopathy in Olmsted County, Minnesota

PURPOSE

To determine the incidence of Graves' ophthalmopathy.

METHODS

A population-based cohort of all Olmsted County, Minnesota, residents who had ophthalmopathy associated with autoimmune thyroid disease between Jan. 1, 1976, and Dec. 31, 1990, was identified through the medical diagnostic index of the Mayo Clinic and the Rochester Epidemiology Project.

RESULTS

One hundred twenty incident patients were identified, of whom 103 (85.8%) were women (P = .00001; normal relative deviate test). The overall age-adjusted incidence rate for women was 16.0 cases per 100,000 population per year, whereas the rate for men was 2.9 cases per 100,000 population per year (standardized rate ratio, 5.5; 95% confidence interval, 3.3 to 9.3). The distribution of incidence rates by five-year age groups included peak incidence rates in the age groups 40 to 44 years and 60 to 64 years in women, and 45 to 49 years and 65 to 69 years in men.

CONCLUSIONS

Incidence rates for Graves' ophthalmopathy exhibited an apparent bimodal peak for both men and women, although the peaks for men occurred approximately five years after those for women. No explanation for these trends was apparent from the data collected.

Improvement of infiltrative ophthalmopathy in parallel with decrease of thyroid-stimulating antibody (TSAb) activity in two patients with hypothyroid Graves' disease

Two patients with primary hypothyroidism associated with infiltrative ophthalmopathy without previous history of hyperthyroidism are presented. Anti-TSH receptor antibodies (TRAb) were detected by radioreceptor assay (TBII), and unexpectedly their biological activity was not of a blocking (TSBAb), but of a thyroid-stimulating type (TSAb). After the initiation of levothyroxine therapy, the TBII and TSAb activities both decreased gradually with normalization of the elevated TSH level. The inflammatory eye signs improved strikingly in parallel with decrease of these antibody activities. These data indicate that (1) TRAb in primary hypothyroidism do not always show TSAb activity, (2) the decrease in TRAb following levothyroxine therapy in these patients appeared to correlate with suppression of TSH, (3) changes in infiltrative ophthalmopathy were associated with that of TSAb even in primary hypothyroidism, and (4) the hypothyroidism in these patients is justifiably diagnosed as "hypothyroid Graves' disease". TSAb might be somewhat related to the pathogenesis of ophthalmopathy in autoimmune thyroid diseases.

Temporal relationship between onset of Graves' ophthalmopathy and onset of thyroidal Graves' disease

The temporal relationship between the onset of Graves' ophthalmopathy and the onset of thyroidal Graves' disease was evaluated in 125 consecutive patients with Graves' ophthalmopathy. Thyroidal Graves' disease--past or present--was clinically evident in 99 patients (79%): hyperthyroidism in 3 cases. Thyroid disease preceded the eye disease in 37 patients, it occurred simultaneously with the eye disease in 39 patients, and it developed after the eye disease in 23 patients (in 16 cases within one yr after the onset of eye disease). The age at the onset of thyroid disease (38.7 +/- 12.9 yr) was lower than the age at the onset of ophthalmopathy (41.8 +/- 12.5 yr; p less than 0.001). Among the 26 clinically euthyroid patients (21%) laboratory evidence of thyroidal Graves' disease was found in 14 cases (11%): abnormal TRH test, n = 9; normal TRH test but abnormal T3-suppression test, n = 4; normal TRH and T3-suppression tests but positive thyroid stimulating antibodies, n = 1). We conclude that Graves' ophthalmopathy as a rule develops at a time when thyroid autoimmunity also exists. This strongly suggests a common factor in the pathogenesis of thyroidal and ocular expressions of Graves' disease.

Autoimmunity and hypothyroidism

Hypothyroidism can be induced by various diseases. An autoimmune cause accounts for approximately 90% of adult hypothyroidism, mostly due to Hashimoto's disease. The majority of Hashimoto patients are women aged between 20 and 60 years old and nearly 10% show overt hypothyroidism. With time euthyroid patients progress to hypothyroidism and thus the prevalence of hypothyroidism is higher in elderly patients. Especially at 3 to 8 months postpartum, the prevalence of hypothyroidism is very high, up to 2-4%, but more than 90% of these cases are transient. Autoimmune destructive mechanisms, such as antibody dependent cytotoxicity, K and NK cell cytotoxicity, T lymphocyte cytotoxicity and lymphokine cytotoxicity, have been studied in vitro, but the most important factor in vivo is still unknown. A recent finding is that thyroid stimulation blocking antibody (TSBAb) may induce primary atrophic hypothyroidism. This antibody not only blocks TSH-induced cAMP production but also blocks TSH-induced DNA synthesis and iodine uptake in cultured thyroid cells. The prevalence of TSBAb in patients with primary atrophic hypothyroidism varies in different studies, from 0 to 47%. Reports on the relationship between TSBAb and TSH-binding inhibitory immunoglobulin (TBII) detected by radioreceptor assay are conflicting. The prevalence of TSBAb in patients with goitrous hypothyroidism is also controversial, varying from 0 to 20%. Transient hypothyroidism is observed frequently in the postpartum period and in the post-thyrotoxic phase of pregnancy-unrelated silent thyroiditis. Maternal TSBAb causes transient neonatal hypothyroidism when the activity is more than 1500 i.u./litre. The blocking and stimulatory types of anti-TSH receptor antibodies may both react with the same epitope(s) of TSH-receptor related antigens but the exact mechanisms that lead to the different effects are unknown. In some patients, including those with Graves' disease, stimulating and blocking antibodies co-exist and thyroid function may change from hyperthyroidism to hypothyroidism, or vice-versa, depending on the balance of stimulatory and blocking activities. Hypothyroidism in Graves' disease after treatment is thought to be induced in two ways: autoimmune thyroid destruction and the predominant appearance of TSBAb. Dietary iodine restriction is helpful in allowing recovery from hypothyroidism in more than half of the patients with spontaneously occurring primary hypothyroidism in Japan. Submaximal doses of T3 may be useful in differentiating transient from persistent hypothyroidism, since spontaneous recovery is detected by an increase of serum T4.(ABSTRACT TRUNCATED AT 400 WORDS)

Major histocompatibility complex (MHC) factors predisposing to and protecting against Graves' eye disease

We investigated the influence of gene mapping within the major histocompatibility complex on the susceptibility to Graves' eye disease. We studied 133 randomly selected patients with Graves' disease, many of whom had eye disease. HLA B8 and DR3 carried the greatest risk for disease but the difference between the two patient groups was not statistically significant. An earlier finding that Hungarian patients with a subset of B8, (B8 + DR7 +) had a greatly enhanced risk for eye disease was confirmed in Newfoundland patients. HLA B8 and DR7 are probably carried on different homologous chromosomes and their interaction enhances eye disease. HLA-DR4 was negatively correlated with eye disease. In particular, a subset of DR4 (B35 + DR4 +) appears to protect against eye disease. We have also derived the haplotypes of 22 probands, half of whom had eye disease. The haplotype data emphasized the high frequency of HLA A1 B8 DR3 C4A*QO and C4B*1 in both patient groups, 15% of the haplotypes in the group with eye disease and 25% in that without eye disease. Forty-one percent of haplotypes in the eye disease group and 32% in the no eye disease group were either C4A*QO or C4B*QO. In one proband with eye disease B8 and DR7 were carried on separate chromosomes. The phenotype DR4, C4A*3 C4B*1 was found in 3/20 haplotypes of patients without eye disease but in 0/20 of patients with eye disease. This finding is in keeping with the increased frequency of the DR4 C4A*3 C4B*1 in the patient group with no eye disease when 94 patients were phenotyped.(ABSTRACT TRUNCATED AT 250 WORDS)

Spontaneous hypothyroidism after antithyroid treatment of hyperthyroid Graves' disease

Out of 54 patients with hyperthyroid Graves' disease 35 remained euthyroid after treatment with antithyroid agents and have been continuously followed from 1 to 9 yr (4.85 +/- 2.55 yr, mean +/- SD). In 4 patients an exaggerated TSH response to TRH developed from 30 to 111 months after interrupting the treatment and one of them became hypothyroid 50 months (5.0 yr) thereafter. The annual incidence of subclinical hypothyroidism (exaggerated response to TRH) as calculated from the total number of observation yr was 2.5% and that of overt hypothyroidism was 0.6%. These figures are similar to those reported recently in 2 retrospective studies.