CASE PRESENTATION
We report a 38-year-old female patient, previously healthy, presented
with high fever, adynamia, diffuse myalgia, and polyarthralgia of hands,
wrists, elbows, and knees. She sought medical attention and was
diagnosed with CHIKV infection, confirmed by a positive IgM
Enzyme-Linked Immunosorbent Assay (ELISA) serological study in two
samples. Joint pain and myalgia persisted, and after two months, she
presented progressive complaints of fatigue, difficulty combing her
hair, walking, and getting out of bed. She had frequent falls, dysphagia
for solids, dysphonia, dyspnea on mild exertion, and was bedridden. She
was then admitted to the hospital for investigation.
On physical examination, she presented decreased proximal limb muscle
strength, grade 2 in lower limbs and grade 3 in upper limbs, according
to Medical Research Council (MRC) scale. Pulmonary auscultation
presented fine bilateral basilar crackles. Manual muscle test (MMT) of
64 out of 150 points. Locomotor examination showed arthritis in knees
and ankles bilaterally.
Complementary examinations revealed elevated creatine phosphokinase
(CPK: 25150 U/L [VR: 0 A 170 U/L]) and increased transaminases (TGO:
377 U/L and TGP: 264 U/L [VR: 0 A 31 U/L]). Anti-Jo-1 antibody was
reagent (141 U/mL [VR: reagent > 10 U/mL]). Antinuclear
antibody (ANA) with a mixed pattern of 1/80 fine dotted nuclear type and
1/160 dotted cytoplasmic type. Electroneuromyography of four limbs
confirmed a pattern of myopathy, affecting mostly proximal muscles.
Magnetic resonance imaging (MRI) of thighs showed diffuse edema of
muscles, without areas of liposubstitution, suggesting an acute
inflammatory process (Figures 1 and 2). Chest computed tomography (CT)
scan showed ground-glass opacities in bases up to the middle third of
lungs, compatible with nonspecific interstitial pneumopathy (NSIP).
The diagnosis of Antisynthetase Syndrome, an immune-mediated
inflammatory myopathy, post-Chikungunya infection, was then established.
The patient presented with a compatible clinical, with proximal muscle
weakness in all four limbs, MRI of thighs showing a muscular
inflammatory process, electroneuromyography with a myopathic pattern,
interstitial pneumopathy, and a positive Anti-Jo1 antibody, in addition
to joint involvement.
Other etiological causes were investigated and ruled out, such as viral
infections by hepatitis virus, cytomegalovirus, HIV, syphilis, and
COVID-19, metabolic disorders, use of previous medications, and
screening for neoplasms, confirming chikungunya as the trigger for
myopathy.
Pulse therapy was started with methylprednisolone for 3 days and human
immunoglobulin for 6 monthly cycles. The patient had clinical recovery
and a gradual decrease in muscle enzymes, reaching 257 U/L (VR: 0 to 170
U/L) after 6 months. She was also given monthly intravenous
cyclophosphamide for a period of 6 months due to pulmonary involvement.
The patient maintained motor and respiratory physical therapy, evolving
with grade V muscle strength in the four limbs, with no complaints of
fatigue, dysphagia, or dysphonia.
Figure 1: A) Coronal T1 (hip and thigh images): absence of
muscle liposubstitution. B) Coronal T2 with fat saturation (SPAIR
technique): Diffuse muscular edema affecting the pelvic girdles and
thighs.