Treatment strategies for myasthenia gravis

The emerging role of tacrolimus in myasthenia gravis

OBJECTIVE

To describe and evaluate the available evidence assessing the role of tacrolimus in the management of patients with myasthenia gravis (MG).

DATA SOURCES

A literature search of MEDLINE (1946 to September 2014) and EMBASE (1947 to September 2014) was performed using the terms 'tacrolimus' and 'myasthenia gravis'. Citations of retrieved articles were examined for relevance.

STUDY SELECTION AND DATA EXTRACTION

The search was limited to prospective clinical trials focused on clinical outcomes in patients with generalized MG. Case reports, retrospective evaluations and non-English articles were excluded.

DATA SYNTHESIS

A total of 12 studies met inclusion criteria, of which seven articles evaluated tacrolimus in steroid-dependent patients and two examined the utility of tacrolimus in patients failing corticosteroids and cyclosporine. Other studies evaluated early initiation of tacrolimus after thymectomy, effectiveness of tacrolimus in de novo MG and the effectiveness of tacrolimus post-thymectomy in thymoma patients versus nonthymoma. A total of eight trials showed statistically significant improvements in quantitative MG score (QMGS) and postintervention status criteria - Myasthenia Gravis Foundation of America (PSC-MGFA). Of the trials examining steroid reduction with tacrolimus, two reported high rates of complete withdrawal; however, the most robust trial was unable to detect a difference in mean steroid dose. Long-term effects of tacrolimus (up to 5 years) were assessed in eight trials, which consistently showed positive effects on QMGS or reduction in adjunct therapies.

CONCLUSIONS

There is limited yet promising information to suggest a beneficial role for tacrolimus in reducing QMGS and corticosteroid burden in patients with refractory symptoms or new-onset MG. Long-term use appears to be safe in this population.

Perioperative management in myasthenia gravis: republication of a systematic review and a proposal by the guideline committee of the Japanese Association for Chest Surgery 2014

Thymectomy is regarded as a useful therapeutic option for myasthenia gravis (MG), though perioperative management in MG patients is largely empirical. While evidence-based medicine is limited in the perioperative management of MG patients, treatment guidelines are required as a benchmark. We selected issues faced by physicians in clinical practice in the perioperative management of extended thymectomy for MG, and examined them with a review of the literature. The present guidelines have reached the stage of consensus within the Japanese Association for Chest Surgery.

The role of methotrexate in resolving ocular inflammation after specific therapy for presumed latent syphilitic uveitis and presumed tuberculosis-related uveitis

PURPOSE

This study was designed to investigate whether the antiinflammatory and antiproliferative activity of oral and intravitreal methotrexate (MTX) suppresses intraocular inflammation in patients with presumed latent syphilitic uveitis and presumed tuberculosis-related uveitis.

METHODS

Interventional prospective study including three cases with presumed latent syphilitic uveitis treated with intravenous penicillin and oral MTX, and two cases with presumed tuberculosis-related uveitis treated with standard antituberculosis therapy and intravitreal MTX injections. Treatment efficacy of all cases was assessed by best-corrected visual acuity, fundus fluorescein angiography, and optical coherence tomography.

RESULTS

Four eyes of 3 patients with presumed latent syphilitic uveitis had improved best-corrected visual acuity, suppression of intraocular inflammation, and resolution of cystoid macular edema in 6 months with oral MTX therapy. No recurrence of intraocular inflammation was observed in 6 months to 18 months of follow-up period after cessation of MTX. Two eyes of two patients with presumed tuberculosis-related uveitis showed improved best-corrected visual acuity, suppression of intraocular inflammation, and resolution of cystoid macular edema after intravitreal injections of MTX. No recurrence of intraocular inflammation was observed in 6 months to 8 months of follow-up period after cessation of antituberculous therapy.

CONCLUSION

For the first time in the treatment of presumed latent syphilitic uveitis and presumed tuberculosis-related uveitis, we believe that MTX might have an adjunctive role to suppress intraocular inflammation, reduce uveitic macular edema, and prevent the recurrences of the diseases.

Evaluation of the New Classification and Surgical Strategy for Myasthenia Gravis

The aim of this study was to discuss the new methods of clinical classification and staging of patients with myasthenia gravis (MG) proposed by our group and to summarize the experiences of surgical treatment of MG with a novel incision by cutting the sternum cross-sectionally at the second intercostal level. A retrospective analysis was made for the clinical data from the patients with MG who underwent thymectomy from July 1988 to May 2009. The surgical procedures were designed into three groups, a group with Osserman classification and median incision of the sternum (Group 1), a group with MGFA typing (Myasthenia Gravis Foundation of America) and a small transverse sternal incision at the second intercostal level (Group 2), and a group with new typing and a smaller transverse sternal incision at the second intercostal level (Group 3). Observation of the clinical typing and staging was made in the patients with myasthenia crisis. The parameters such as procedure duration in Group 2 and 3 was significantly lower than those in Group 1 ( P < 0.05). The incidence of myasthenia crisis in Group 3 was significantly lower than that in Groups 2 and 3 ( P < 0.05). The procedure with a smaller transverse sternal incision at the second intercostal level (Group 3) is a safer method for patients with MG. The combination of this procedure with the new typing and staging methods proposed by our group could facilitate the selection of operation indications and opportunity, resulting in the lower incidence of myasthenia crisis and mortality. Our new procedure is well deserved to be a preferential selection by other hospitals.

Treatment of ocular myasthenia gravis

OPINION STATEMENT

Myasthenia gravis (MG) is an autoimmune disorder that is characterized by variable weakness and fatigability. Often, MG presents with only ocular symptoms such as ptosis and diplopia. Treatment of ocular MG is aimed at relieving the symptoms of ptosis and diplopia, as well as preventing the development of generalized MG symptoms. Immune suppression with steroids is often the main therapy. Steroid doses must be increased slowly because of a risk of precipitating myasthenic crisis. After achieving the highest target dose, steroids are then slowly tapered down to the lowest effective dose. Often, acetylcholinesterase inhibitors such as pyridostigmine and neostigmine are also employed to help control symptoms. When steroids are contraindicated, acetylcholinesterase inhibitors can be tried as the primary therapy. Steroid-sparing agents such as azathioprine and mycophenolate may also have a role in treating ocular MG. Other treatments for MG include plasmapheresis, intravenous immunoglobulin, and other immunosuppressive agents, but these are rarely required for ocular MG. Patients should also be evaluated for thymoma. Thymoma should be resected surgically. Ocular MG without thymoma is not usually treated with thymectomy. Topical agents may be useful as additional therapy for mild or moderate ptosis. Nonpharmacologic treatments include occlusive devices, prisms, eyelid supports, contact lenses, and (in long-standing, stable cases) strabismus surgery or eyelid elevation surgery.

Impact of screening with thyroid ultrasonography in myasthenia gravis patients

OBJECTIVES

This study was conducted to screen thyroid abnormality evaluated with ultrasonography (US) in patients with myasthenia gravis (MG) and investigate further when malignancy is suspected.

METHODS

Thyroid screening using US was conducted in 162 patients with MG. In cases where malignancy was suspected, further investigations were performed.

RESULTS

Abnormal US findings were detected in 125 of 162 patients with MG (72 patients with nodules, 74 patients with cysts, 27 patients with diffuse findings such as enlargement, atrophy, a hypoechoic pattern or a heterogenous echoic pattern, and 28 patients with calcification). From among these 125 subjects, 30 patients underwent further examinations such as needle aspiration cytology. As a result, six patients (3.7% of 162 cases) were positive for papillary carcinoma. The size of the carcinoma in three patients was <10 mm, yet the stage of thyroid carcinomas was high (stage III or IVa) in all six cases.

CONCLUSIONS

Our data suggest that the prevalence of thyroid carcinoma in cases of MG may be higher than that of the general population. Furthermore, in patients with MG, there is a possibility that the stage of the carcinoma is higher even when the carcinoma is of a very small size. Patients with MG, when diagnosed, should be advised to undergo US screening of the thyroid because most cases of thyroid carcinoma are highly curable.

Treatment of myasthenia gravis based on its immunopathogenesis

The prognosis of myasthenia gravis (MG) has improved dramatically due to advances in critical-care medicine and symptomatic treatments. Its immunopathogenesis is fundamentally a T-cell-dependent autoimmune process resulting from loss of tolerance toward self-antigens in the thymus. Thymectomy is based on this immunological background. For MG patients who are inadequately controlled with sufficient symptomatic treatment or fail to achieve remission after thymectomy, remission is usually achieved through the addition of other immunotherapies. These immunotherapies can be classified into two groups: rapid induction and long-term maintenance. Rapid induction therapy includes intravenous immunoglobulin (IVIg) and plasma exchange (PE). These produce improvement within a few days after initiation, and so are useful for acute exacerbation including myasthenic crisis or in the perioperative period. High-dose prednisone has been more universally preferred for remission induction, but it acts more slowly than IVIg and PE, commonly only after a delay of several weeks. Slow tapering of steroids after a high-dose pulse offers a method of maintaining the state of remission. However, because of significant side effects, other immunosuppressants (ISs) are frequently added as "steroid-sparing agents". The currently available ISs exert their immunosuppressive effects by three mechanisms: 1) blocking the synthesis of DNA and RNA, 2) inhibiting T-cell activation and 3) depleting the B-cell population. In addition, newer drugs including antisense molecule, tumor necrosis factor alpha receptor blocker and complement inhibitors are currently under investigation to confirm their effectiveness. Until now, the treatment of MG has been based primarily on experience rather than gold-standard evidence from randomized controlled trials. It is hoped that well-organized studies and newer experimental trials will lead to improved treatments.

Estimation of Cholinesterase Inhibitory and Antioxidant Effects of the Leaf Extracts of Anatolian Ficus carica var. domestica and their Total Phenol and Flavonoid Contents

Ficus carica var. domestica Tsch. & Rav. (common fig) is widely grown in Turkey and exported for its edible fruits. In this study, the n-hexane, chloroform, acetone, methanol, n-butanol, and water extracts of the leaves of F. carica var. domestica were screened for their cholinesterase inhibitory and antioxidant activities. Cholinesterase inhibition against acetyl- (AChE) and butyrylcholinesterase (BChE) was measured by the spectrophotometric method of Ellman at concentrations of 25, 50, and 100 μg/mL., while antioxidant activity was tested using three in vitro methods; 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, metal-chelation capacity, and ferric-reducing antioxidant power (FRAP). Total phenol and flavonoid contents of the extracts were determined spectrophotometrically. Our results revealed that the n-hexane and acetone extracts exerted a notable inhibition against both AChE (62.9±0.9% and 50.8±2.1%, respectively) and BChE (76.9±2.2% and 45.6±1.3%, respectively). However, they had low activity in the antioxidant tests. The chloroform extract was found to be the richest in total flavonoid content (252.5±1.1 mg/g quercetin equivalent), while the n-butanol extract had the highest total phenol amount (85.9±3.2 mg/g extract gallic acid equivalent).

Comparison of clinical manifestations between patients with ocular myasthenia gravis and generalized myasthenia gravis

Purpose

To compare the clinical manifestations between patients with ocular myasthenia gravis and those with generalized myasthenia gravis (MG).

Methods

The medical records of 71 patients diagnosed with MG between January 1995 and December 2007 were reviewed. Demographics, sensitivities of diagnostic methods, the presence of systemic autoimmune diseases, ophthalmic complications caused by MG, and treatments were evaluated and compared.

Results

Fourteen patients (20%) were diagnosed with ocular MG and 57 patients (80%) with generalized MG. Sensitivities of anti-acetylcholine receptor antibody and repetitive nerve stimulation tests were significantly higher in the generalized MG group (84%, 89%) compared to those in the ocular MG group (50%, 54%) (p = 0.011, p = 0.008). The sensitivity of the neostigmine test was the highest in both groups (98% of generalized MG, 79% of ocular MG), and the difference between the two groups was borderline significant (p = 0.058). The most common symptoms were ptosis and diplopia, and both groups presented with pain, blurred vision, and tearing. Systemic autoimmune disease was more prominent in the generalized MG group (21%) than in the ocular MG group (14%), and steroid therapy was used more frequently in the generalized MG group (82%) than in the ocular MG group (57%). Ophthalmic complications associated with long-term steroid treatment were more profound in the generalized MG (30%) compared to those of the ocular MG (21%).

Conclusions

The generalized MG group was associated with higher sensitivities to diagnostic tests, more systemic steroid use, higher ophthalmic complications caused by systemic autoimmune disease, and long-term steroid treatment compared to those of the ocular MG group.

Extracorporeal immunoglobulin elimination for the treatment of severe myasthenia gravis

Myasthenia gravis (MG) is a neuromuscular disorder leading to fluctuating muscle weakness and fatigue. Rarely, long-term stabilization is not possible through the use of thymectomy or any known drug therapy. We present our experience with extracorporeal immunoglobulin (Ig) elimination by immunoadsorption (adsorbers with human Ig antibodies). Acetylcholine receptor antibodies (AChRAs) were measured during long-term monitoring (4.7 +/- 2.9 years; range 1.1-8.0). A total of 474 samples (232 pairs) were analyzed, and a drop in AChRA levels was observed (P = .025). The clinical status of patients improved and stabilized. Roughly 6.8% of patients experienced clinically irrelevant side effects. The method of Ig elimination by extracorporeal immunoadsorption (IA) is a clinical application of the recent biotechnological advances. It offers an effective and safe therapy for severe MG even when the disease is resistant to standard therapy.