Outcomes and characteristics of myasthenia gravis: A 10-year retrospective cross-sectional study at King Fahad Medical City

Abdulrahman Ali; Daifallah Almalki; Mamdouh A. Kotb; Reem S. Alenazi

doi:10.17712/nsj.2022.4.20220038

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Table 1

- Demographic and clinical data of patients with myasthenia gravis. N=147

Characteristics	n (%)
Age in years Mean±SD	34.2±16.6
Disease duration in months Mean±SD	25.7±8.9
Gender
Male	40 (27.2)
Female	107 (72.8)
Clinical presentation
Ocular	84 (57.1)
Bulbar	40 (27.2)
Generalized	23 (15.6)
Anti AChR antibody
Positive	130 (88.4)
Anti-MuSK antibody
Positive	8 (5.4)
Double seronegative	11 (7.5)
RNS
Decremental response	65 (44.2)
Normal	24 (16.3)
Not done	58 (39.5)
Treatment
Pyridostigmine	14 (9.5)
Azathioprine	4 (2.7)
Pyridostigmine, prednisolone, with or without azathioprine	94 (63.9)
Pyridostigmine, prednisolone, with or without azathioprine, and one dose IVIg	10 (6.8)
Pyridostigmine, prednisolone, and mycophenolate	11 (7.5)
Pyridostigmine, prednisolone, with or without azathioprine, and monthly IVIg	14 (9.5)
Thymectomy
Done	92 (62.6)
Not done	55 (37.4)
Treatment response
Controlled	101 (68.7)
Not controlled	46 (31.3)
CT chest
Prominent thymus	30 (20.4)
Thymoma	17 (11.6)
Normal	100 (68.0)
Histopathology
Thymic hyperplasia	57 (38.8)
Thymoma	13 (8.8)
Normal	22 (15)
Clinical state at the end of follow up
Ocular	7 (4.8)
Bulbar	4 (2.7)
Generalized	136 (92.5)
Family history of MG
Positive	6 (4.1)
Negative	95 (64.6)
Not recorded	46 (31.3)

MG- Myasthenia gravis, AChR-acetylcholine receptors, RNS - repetitive nerve stimulation

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Table 2

- Demographic and clinical differences between the myasthenia gravis subgroups.

Characteristics	Ocular n=84	Bulbar n=40	Generalized n=23	P-value
Characteristics	n (%)			P-value
Age Mean ±SD	35.6±16.1	36.1±19.2	25.6±10.2	0.03^* 0.043^**
Gender
Male	25 (29.8)	11 (27.5)	4 (17.4)	0.497
Female	59 (70.2)	29 (72.5)	19 (82.6)
Anti AChR antibody
Positive	80 (95.2)	30 (75)	20 (87)	0.004
Anti-MuSK antibody
Positive	0 (0)	8 (20)	0 (0)	0.000
Double seronegative	4 (4.8)	4 (10)	3 (13)
NCS
Decremental response	33 (39.3)	20 (50)	12 (52.2)	0.002
Normal	11 (13.1)	4 (10)	9 (39.1)
Not done	40 (47.6)	16 (40)	2 (8.7)
Treatment
Pyridostigmine	7 (8.3)	2 (5)	5 (21.7)	0.000
Azathioprine	0 (0)	4 (10)	0 (0)
Pyridostigmine, prednisolone, with or without azathioprine	65 (77.4)	18 (45)	11 (47.8)
Pyridostigmine, prednisolone, with or without azathioprine, and one dose IVIg	2 (2.4)	8 (20)	0 (0)
Pyridostigmine, prednisolone, and mycophenolate	2 (2.4)	6 (15)	3 (13)
Pyridostigmine, prednisolone, with or without azathioprine, and monthly IVIg	8 (9.5)	2 (5)	4 (17.4)
Thymectomy
Done	55 (65.5)	18 (45)	19 (82.6)	0.009
Not done	29 (34.5)	22 (55)	4 (17.4)
Treatment response
Controlled	59 (70.2)	23 (57.5)	19 (82.6)	0.106
Not controlled	25 (29.8)	17 (42.5)	4 (17.4)
CT chest
Prominent thymus	19 (22.6)	11 (27.5)	0 (0)	0.003
Thymoma	9 (10.7)	8 (20)	0 (0)
Normal	56 (66.7)	21 (52.5)	23 (100)
Histopathology
Thymic hyperplasia	35 (41.7)	13 (32.5)	9 (39.1)	0.000
Thymoma	9 (10.7)	4 (10)	0 (0)
Normal	11 (13.1)	1 (2.5)	10 (43.5)
Clinical state at the end of follow up
Ocular	7 (8.3)	0 (0)	0 (0)	0.003
Bulbar	0 (0)	4 (10)	0 (0)
Generalized	77 (91.7)	36 (90)	23 (100)
Serology
Positive	82 (97.6)	38 (95)	20 (87)	0.104
Negative	2 (2.4)	2 (5)	3 (13)

AChR - acetylcholine receptor, MuSK - muscle-specific kinase, RNS - repetitive nerve stimulation, IVIg - intravenous immunoglobulin, CT - computed tomography,