Myasthenia gravis (MG) is the most prevalent autoimmune disorder affecting the neuromuscular junction. While MG is largely treatable, it can lead to significant morbidity and mortality if not diagnosed and managed promptly. Early intervention can often prevent these adverse outcomes. The disease presents heterogeneously, both in terms of phenotype and underlying pathogenesis. Its symptom spectrum varies from a purely ocular form to severe weakness affecting the limbs, bulbar muscles, and respiratory system. The onset of MG can occur at any age, from childhood to late adulthood, with peak incidences observed in younger women and older men [1]. MG exemplifies an antibody-mediated autoimmune disorder, also representing a class II hypersensitivity reaction, where IgG autoantibodies target intra- or extracellular antigens, resulting in end-organ damage. The majority of MG patients have autoantibodies against acetylcholine receptors (AChRs) [2,3], while a smaller subset are seropositive for antibodies targeting muscle-specific kinase (MuSK) [4,5], low-density lipoprotein receptor-related protein 4 (Lrp4) [6,7], or agrin [8,9]. These antibodies are instrumental in categorizing different disease subgroups and distinguishing various phenotypic forms. Additionally, striational antibodies, including those against titin, ryanodine receptor, and the alpha subunit of the voltage-gated K+ channel (Kv1.4), have been identified in some MG patients. These antibodies primarily serve as markers of disease severity and are frequently found in patients with late-onset MG or thymoma, and may be associated with concomitant myositis and/or myocarditis [10,11].

We retrospectively enrolled patients who presented to the outpatient or inpatient departments of a tertiary care hospital in India. Inclusion criteria included a confirmed diagnosis of either ocular or generalized myasthenia gravis, based on patient history and clinical examination, supported by fatigability tests, ice pack test, neostigmine test, and repetitive nerve stimulation (RNS) test. High-resolution chest CT (HRCT) was performed on all participants to evaluate for the presence of thymoma. All patients underwent RNS testing and acetylcholine receptor (AchR) antibody assays, with MuSK antibody testing conducted in cases where AchR antibodies were negative. Patients were classified according to the Myasthenia Gravis Foundation of America (MGFA) clinical classification system as follows: Grade I—weakness restricted to ocular muscles; Grade II—mild weakness involving non-ocular muscles; Grade III—moderate weakness in non-ocular muscles; Grade IV—severe weakness affecting non-ocular muscles; and Grade V—requiring tracheal intubation with or without mechanical ventilation, excluding routine postoperative management. Treatment for ocular myasthenia gravis included symptomatic management with or without oral corticosteroids. Patients with generalized myasthenia gravis received symptomatic treatment with oral corticosteroids, with or without azathioprine. Intravenous immunoglobulin (IVIg) therapy was administered to those experiencing myasthenic crises. Statistical analysis was performed using SPSS version 22.0. Continuous variables were expressed as mean ± standard deviation (SD), and categorical variables as count (percentages). For analysis of variance, the chi-square test and the student's t-test were used.

The study included a total of 40 patients diagnosed with MG (Table 1). The cohort consisted of 15 females (37.50%) and 25 males (62.50%). The mean age of the participants was 43.5 years, with a standard deviation of ±8.4 years. The age of the patients ranged from 16 to 74 years.

Table 1. Demographic Characteristics of MG Patients

As shown in Table 2, ptosis was the most prevalent clinical feature, observed in 37 patients (92.50%), followed by restricted eye movements in 35 patients (87.50%). Generalized myasthenia was present in 30 patients (75.00%), while 27 patients (67.50%) exhibited nasal voice, and 23 patients (57.50%) reported dysphagia. Limb weakness was noted in 15 patients (37.50%), and both ocular myasthenia and dyspnea were seen in 10 patients (25.00%) each. Comorbid conditions included hypertension in 5 patients (12.50%), diabetes mellitus in 4 patients (10.00%), hypothyroidism in 3 patients (7.50%), and hyperthyroidism in 1 patient (2.50%).

Table 2 : Clinical characteristics of MG Patients

The majority of patients (60.80%) tested positive for acetylcholine receptor (AChR) antibodies, while 6.70% were positive for muscle-specific kinase (MuSK) antibodies.

Table 3: Antibody status of MG Patients

This study aimed to investigate the clinical characteristics of myasthenia gravis (MG) in patients from a tertiary care center in India. MG affects individuals of all ages and both sexes, with a higher prevalence in young women and older men. While global studies have reported MG as being predominantly female [12-15], our study found a male predominance. Similarly, one of the largest epidemiological studies from India also identified a male predominance, with a ratio of 2.7:1 [16]. A study from Singapore also showed male dominance in Indian MG patients (4:1) [17]. The mean age of onset in our study was 43.5 years. Specifically, the mean onset age for females was 34.5 years, while for males it was 47.07 years. Increased incidence in elderly males has been noted in previous studies [18,19]. Ocular MG was diagnosed in 25% of the patients, a finding consistent with other studies from Asia [20,21]. Intubation and mechanical ventilation were required in 15% of the cases, similar to findings reported by Ojha et al. [18]. However, other studies have reported a lower incidence of myasthenic crisis requiring intubation [16,21]. The association between MG and autoimmune thyroid disorders, particularly hyperthyroidism, has been documented [22]. In our cohort, 3 MG patients had hypothyroidism, and one had hyperthyroidism. Weakness and fatigability are key features of MG, and 70-90% of patients experience ocular involvement, such as ptosis or restricted extraocular movements [23,24]. In our study, 92.50% of patients presented with eyelid drooping or diplopia, and 87.50% had restricted eye movements. The ice pack test is a highly sensitive and specific diagnostic tool for ocular MG, even in cases where the neostigmine test is negative [25]. In our study, it was positive in 80% of the patients. Regarding electrophysiological testing, 55.89% of MG patients exhibited a decremental response in repetitive nerve stimulation (RNS) studies, although this test is relatively insensitive for ocular and mild generalized MG. Additionally, 60.80% of our patients were positive for acetylcholine receptor (AChR) antibodies, and 6.70% tested positive for muscle-specific kinase (MuSK) antibodies.

Early diagnosis of MG is vital for effective management. The condition demands long-term monitoring to assess treatment outcomes, as there is a significant risk of progression from ocular to generalized MG and myasthenic crises in the early years. Monitoring for adverse effects of treatment is essential. As a chronic disorder with periodic exacerbations, MG requires continuous emotional and psychological support to enhance patient well-being. During the COVID-19 pandemic and amidst emerging infections, MG patients must take extra precautions due to immunosuppression and increased disease susceptibility.

Conflicts of interest: none

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