Anti-Muscle Specific Kinase (Anti-MuSK) Positive Myasthenia Gravis Overlapping With Parkinson's Disease: A Challenging Diagnosis

Coexistence of Parkinson's disease and myasthenia gravis: A case report and literature review

The coexistence of Parkinson's disease (PD) and myasthenia gravis (MG) is rare. When similar symptoms of both diseases overlap, it is challenging to make a concomitant diagnosis of PD and MG. The present study describes the case of a patient with concomitant PD and MG. In addition, a systematic literature review was conducted by searching PubMed and Embase for reports on all patients with concomitant PD and MG, which were then grouped and compared according to different preexisting diseases. Finally, a total of 47 cases of concomitant PD and MG (35 men; 12 women), including the present case, were analyzed. The median age of the patients at first diagnosis was 66.59±9.91 years. The interval between the two diseases varied from 2 months to 22 years. Based on the sequential occurrence of these two diseases, the patients were categorized into three groups: The prePD-MG (30 cases), preMG-PD (12 cases), and coPD-MG (5 cases) groups. In the prePD-MG group, the onset age of MG was older and head drop was more common. In the preMG-PD group, the patients were more likely to have comorbid immune diseases.

Myasthenia gravis concurrent with Parkinson's disease in a Spanish cohort. Causation or correlation?

BACKGROUND

Comorbidity between myasthenia gravis (MG) and other autoimmune diseases is well-documented. However, concurrent MG and Parkinson's disease (PD) have rarely been described. This concurrence has mostly been considered coincidental in cases reported to date.

MATERIAL/METHODS

We characterized patients with concurrent MG and PD within a cohort of 631 MG patients by gender, age, MGFA class, quantitative MG score at diagnosis, UPDRS score at diagnosis, and the DaTSCAN uptake pattern, to determine the frequency and the phenotype of individuals with these two concurrent entities. Meta-analysis of cases in the literature was used for comparison with our series.

RESULTS

Eighteen cases were identified in which the two diseases were concurrent. The major characteristics of the phenotype are male prevalence, late-onset MG, and frequent initial symptoms of dropped head and oculobulbar involvement. DAT confirmed reduced bilateral uptake in eleven patients and reduced unilateral uptake in the others.

CONCLUSIONS

To our knowledge, this is the largest reported series of concurrent MG and PD. This concurrence is more common than expected (2.85%). Either MG or PD may appear first. We found no iatrogenic relationship for the order of appearance. The overlapping of symptoms sometimes leads physicians to overlook the second disease, instead viewing it as a deterioration of the first. This study describes patients with well-documented diagnoses of both MG and PD, thus providing further indications of a shared etiology of these two diseases. Prospective studies including genetic, immunological, and environmental analysis are necessary to identify possible common pathogenic mechanisms.

Myasthenia Gravis crossing Parkinson's disease: a 20 year study from single Italian center

PURPOSE

The concomitant diagnosis of Parkinson's disease (PD) and Myasthenia Gravis (MG) is rare. The aim of the study was to report our experience of patients with both diagnoses.

MATERIAL AND METHODS

We performed a retrospective analysis of patients with MG and PD, seen at Neurology Department, Modena, Italy from 2000 to 2020. We encountered 12 patients with both diagnoses. All had late onset MG (LOMG) and low Myasthenia Gravis Foundation of America (MGFA) severity scores at baseline. In respect of PD assessement, clinical signs were followed and summarized with modified Hoehn and Yahr staging (mHY). Patients were ranked as progressive or non-progressive, according to any change in mHY staging. We compared characteristics and outcome of the patients with age matched myasthenic subjects without PD.

RESULTS

The male gender significantly prevailed (p < 0.01) as well as the presence of multiple comorbidities (p < 0.001) in patients with MG associated with PD. In respect of clinical course, MG was benign as most of cases remained stable (66.7%). Six cases showed worsening of mHY scores; only one subject became wheelchair bound by the end of follow up. This uneven progression, at least in our hands, might suggest that MG and PD can evolve independently.

CONCLUSION

Clinicians should be alert about the association of PD and MG since early diagnosis and treatment are essential.