Treatment of Myasthenia Gravis in Patients with Elderly Onset at Advanced Age

Hemogram parameters can predict in-hospital mortality of patients with Myasthenic crisis

BACKGROUND

Myasthenia gravis (MG) is an autoimmune disease involving the neuromuscular junction. Myasthenic crisis (MC), which is characterized by respiratory failure and the requirement of mechanical ventilation in patients with MG, is still a medical emergency despite the decrease in mortality with the advances in acute management. Hemogram is a cost-effective test for evaluating hematological complications and systemic inflammation, and hemogram data have been used to predict various clinical outcomes of several diseases. The relationship between hemogram and MG has been discussed, but the role of hemogram data in predicting the prognosis of MC patients has not been established.

METHODS

To identify whether hemogram data can predict in-hospital mortality in patients with MC, we retrospectively investigated 188 myasthenic crisis events from the Chang Gung Research Database between April 2001 and March 2019. Demographic and clinical characteristics were collected, as well as hemogram data before intubation and extubation. The endpoints were mortality during mechanical ventilation and mortality after extubation.

RESULTS

The overall in-hospital mortality rate was 22%. Multivariate logistic regression analysis for predicting mortality during mechanical ventilation showed that old age at MC onset (OR = 1.039, p = 0.022), moderate-to-severe anemia (OR = 5.851, p = 0.001), and extreme leukocytosis (OR = 5.659, p = 0.022) before intubation were strong predictors of mortality, while acute management with plasma exchange or double-filtration plasmapheresis (PE/DFPP) significantly decreased mortality (OR = 0.236, p = 0.012). For predicting mortality after extubation, moderate-to-severe anemia before extubation (OR = 8.452, p = 0.017) and non-treated with disease-modifying therapy before MC (OR = 5.459, p = 0.031) were crucial predictive factors.

CONCLUSION

This study demonstrated that both old age at MC onset and moderate-to-severe anemia are important predictors of in-hospital mortality in patients with MC, and extreme leukocytosis is another crucial predictor of mortality during mechanical ventilation. The suggested mechanism is that anemia-induced hypoxia may enhance the release of proinflammatory cytokines, exacerbate systemic inflammation, and lead to multiple organ dysfunction syndrome and, finally, mortality.

Outcome measures and treatment effectiveness in late onset myasthenia gravis

Background

Recently different subtypes of myasthenia gravis (MG) have been described. They differ for clinical features and pathogenesis but the prognosis and response to treatment is less clear. The aim of the study was to evaluate outcome and treatment effectiveness including side effects in late onset MG (LOMG) compared with early onset MG (EOMG).

Methods

We analysed retrospectively 208 MG patients. Clinical features were recorded as well as treatment and side effects. Outcome at the last follow-up was evaluated with MGSTI and MGPIS scales.

Results

The 208 patients included were classified as follow: 36 ocular MG, 40 EOMG, 72 LOMG, 25 thymoma-associated, 14 anti-MuSK and 21 double seronegative. Similar positive outcome was achieved in either early and late onset subgroup. We found pharmacological remission and minimal manifestations at the MGFA-PIS in the 95% and 94,4% of EOMG and LOMG respectively but in LOMG a lower dose of immunosuppressors (MGSTI< 2) was required compared to EOMG (p = 0,048). Severe side effects were present in a small percentage of patients in both group but diabetes was more frequent in LOMG vs EOMG (2,2% vs 5%, p = 0.017).

Conclusions

Despite LOMG has more comorbidities that might interfere with treatment and outcome, therapeutic management does not seem to differ between EOMG and LOMG. A similar positive outcome was seen in both subgroups but LOMG group seems to require lower doses of medication to control symptoms.

[Clinical effect of tacrolimus in the treatment of myasthenia gravis in children]

OBJECTIVE

To evaluate the efficacy and safety of tacrolimus in the treatment of children with myasthenia gravis (MG).

METHODS

A total of 28 children with MG were treated with tacrolimus. MG-Activities of Daily Living (MG-ADL) scale was used to assess clinical outcome and safety after 1, 3, 6, 9, and 12 months of treatment.

RESULTS

After tacrolimus treatment, the MG-ADL score at 1, 3, 6, 9 and 12 months was lower than that at baseline (P<0.05), and the MG-ADL score showed a gradually decreasing trend. The response rates to tacrolimus treatment at 1, 3, 6, 9, and 12 months were 59%, 81%, 84%, 88%, and 88% respectively. At 6, 9, 12, and 18 months of treatment, 4, 13, 14, and 15 children respectively were withdrawn from prednisone. No recurrence was observed during treatment. Major adverse reactions/events were asymptomatic reduction in blood magnesium in 5 children and positive urine occult blood in 1 child, which turned negative without special treatment, and tacrolimus was not stopped due to such adverse reactions/events. One child was withdrawn from tacrolimus due to recurrent vomiting. According to CYP3A5 genotypes, all of the patients were divided into two groups: slow metabolic type (n=19) and non-slow metabolic type (fast metabolic type + intermediate type; n=9). The non-slow metabolism group received a higher dose of tacrolimus, but had a lower trough concentration of tacrolimus than the slow metabolism group (P<0.05). The slow metabolism group had a higher response rates to tacrolimus treatment than the non-slow metabolism group (P<0.05).

CONCLUSIONS

Tacrolimus appears to be effective and safe in the treatment of children with MG and is thus an option for immunosuppressive therapy. CYP3A5 genotyping has a certain guiding significance for determining the dosage of tacrolimus.

A Practical Approach to Managing Patients With Myasthenia Gravis-Opinions and a Review of the Literature

When the diagnosis of myasthenia gravis (MG) has been secured, the aim of management should be prompt symptom control and the induction of remission or minimal manifestations. Symptom control, with acetylcholinesterase inhibitors such as pyridostigmine, is commonly employed. This may be sufficient in mild disease. There is no single universally accepted treatment regimen. Corticosteroids are the mainstay of immunosuppressive treatment in patients with more than mild MG to induce remission. Immunosuppressive therapies, such as azathioprine are prescribed in addition to but sometimes instead of corticosteroids when background comorbidities preclude or restrict the use of steroids. Rituximab has a role in refractory MG, while plasmapheresis and immunoglobulin therapy are commonly prescribed to treat MG crisis and in some cases of refractory MG. Data from the MGTX trial showed clear evidence that thymectomy is beneficial in patients with acetylcholine receptor (AChR) antibody positive generalized MG, up to the age of 65 years. Minimally invasive thymectomy surgery including robotic-assisted thymectomy surgery has further revolutionized thymectomy and the management of MG. Ocular MG is not life-threatening but can be significantly disabling when diplopia is persistent. There is evidence to support early treatment with corticosteroids when ocular motility is abnormal and fails to respond to symptomatic treatment. Treatment needs to be individualized in the older age-group depending on specific comorbidities. In the younger age-groups, particularly in women, consideration must be given to the potential teratogenicity of certain therapies. Novel therapies are being developed and trialed, including ones that inhibit complement-induced immunological pathways or interfere with antibody-recycling pathways. Fatigue is common in MG and should be duly identified from fatigable weakness and managed with a combination of physical therapy with or without psychological support. MG patients may also develop dysfunctional breathing and the necessary respiratory physiotherapy techniques need to be implemented to alleviate the patient's symptoms of dyspnoea. In this review, we discuss various facets of myasthenia management in adults with ocular and generalized disease, including some practical approaches and our personal opinions based on our experience.

Late-onset generalized myasthenia gravis: clinical features, treatment, and outcome

Late-onset myasthenia gravis (LOMG) is a unique MG subgroup. More information is needed on its subgroups such as non-thymomatous generalized LOMG. We evaluated the effect of demographic, clinical, and serological factors as well as different immunosuppressive modalities on outcome in generalized non-thymomatous LOMG with onset ≥ 50 years. Myasthenia Gravis Foundation of America (MGFA) Clinical Classification, MGFA postintervention score (MGFA PIS) and MG Composite scores were obtained to define the severity of disease and clinical outcome. In 95 patients with generalized non-thymomatous LOMG, 60 (63%) were men, 45 (47%) had mild disease, 80 (84%) were anti-AChR, and 56 (61%) were anti-titin positive. In those who received immunosuppressives and provided the clinical scores (84 patients), 50 (60%) had favorable outcome (MGFA PIS categories of complete stable remission, pharmacological remission and minimal manifestations) at the end of 3 years. Use of prednisone + azathioprine had significantly positive effect on outcome. The presence of anti-titin antibodies had no significant effect on severity and outcome. Five anti-MuSK-positive patients had favorable outcome. In conclusion, the presence of neither anti-titin nor anti-MuSK antibodies points to unfavorable outcome. Prednisone and azathioprine combination has beneficial effects in non-thymomatous generalized LOMG.

Autoimmune Attack of the Neuromuscular Junction in Myasthenia Gravis: Nicotinic Acetylcholine Receptors and Other Targets

The nicotinic acetylcholine receptor (nAChR) family, the archetype member of the pentameric ligand-gated ion channels, is ubiquitously distributed in the central and peripheral nervous systems, and its members are the targets for both genetic and acquired forms of neurological disorders. In the central nervous system, nAChRs contribute to the pathological mechanisms of neurodegenerative disorders, such as Alzheimer and Parkinson diseases. In the peripheral nerve-muscle synapse, the vertebrate neuromuscular junction, "classical" myasthenia gravis (MG) and other forms of neuromuscular transmission disorders are antibody-mediated autoimmune diseases. In MG, antibodies to the nAChR bind to the postsynaptic receptors and activate the classical complement pathway culminating in the formation of the membrane attack complex, with the subsequent destruction of the postsynaptic apparatus. Divalent nAChR-antibodies also cause internalization and loss of the nAChRs. Loss of receptors by either mechanism results in the muscle weakness and fatigability that typify the clinical manifestations of the disease. Other targets for antibodies, in a minority of patients, include muscle specific kinase (MuSK) and low-density lipoprotein related protein 4 (LRP4). This brief Review analyzes the current status of muscle-type nAChR in relation to the pathogenesis of autoimmune diseases affecting the peripheral cholinergic synapse.

Comparative study of computed tomography of normal and lymphoid follicular hyperplasia thymus in myasthenia gravis patients

The aim of the present study was to evaluate the thymuses of non-thymomatous myasthenia gravis (MG) patients by computed tomography (CT) for differentiating lymphoid follicular hyperplasia (LFH) thymus from normal/involuted thymus in order to assist surgeons in determining whether a non-thymomatous MG patient requires an operation. In the present retrospective review over 10 years, 80 patients who received CT scan and thymectomy at the Affiliated General Hospital of Tianjin Medial University (Tianjin, China) were included. According to the pathological records, 54 of the cases initially detected on CT were confirmed as LFH thymus. Thymic measurements, including anteroposterior and transverse dimensions, width (the longest axis of the lobe on a transverse scan) and thickness (the largest dimension perpendicular to the long axis of the lobe) and CT attenuation of the thymus region, adipose tissue and chest wall musculature in each CT slice were included to assess differences between the LFH group and the normal/involuted thymus group. Although a negative association between patient age and the CT attenuation of the thymus region was identified (r=-0.779, P<0.05, Pearson's correlation test), the LFH thymus group featured nodular changes on CT, while no such changes were observed in the normal/involuted thymus group. The mean age of disease onset in the LFH thymus group was significantly lower than that in the normal thymus group (40.2±17.3 vs. 59.2±9.3 years). Furthermore, significant differences in CT attenuation were identified between the LFH group and the normal/involuted thymus group [-41.21±54.42 vs. -108.23±8.72 Hounsfield units (HU) on unenhanced CT; -25.57±58.65 vs.-117.40±6.22 HU on contrast-enhanced CT]. In the LFH group, the difference in mean CT attenuation between the thymus region and adipose tissue was significant, while no significant difference was observed in the normal/involuted thymus group. In conclusion, CT may be used to distinguish LFH thymus from normal/involuted thymus in MG patients.