André Macedo Serafim da Silva

Clinical, histological and radiological responses to methylprednisolone in HIV-associated rod myopathy

Skeletal muscle involvement as a neurologic manifestation in individuals with HIV is rare, especially as rod myopathy. We describe a 41-year-old male with HIV infection who presented progressive proximal muscle weakness and limb-girdle atrophy. A muscle magnetic resonance image showed bilateral fatty infiltration and post-contrast enhancement in the arm and thigh muscles. The muscle biopsy revealed intracytoplasmic aggregates with appearance of nemaline rod bodies with Gomori trichrome staining and electron microscopy in most fibers. The patient underwent six cycles of intravenous methylprednisolone pulses, presenting clinical improvement. Post-treatment muscle biopsy showed fewer nemaline bodies and muscle magnetic resonance image depicted a pronounced reduction of muscular edema. These findings corroborate that deposition of nemaline bodies in these patients might be related to an immune response triggered by the virus.

Clinical variability of early-onset congenital myasthenic syndrome due to biallelic RAPSN mutations in Brazil

Mutations in RAPSN are an important cause of congenital myasthenic syndrome (CMS), leading to endplate acetylcholine receptor deficiency. We present three RAPSN early-onset CMS patients (from a Brazilian cohort of 61 CMS patients). Patient 1 and patient 2 harbor the mutation p.N88K in homozygosity, while patient 3 harbors p.N88K in compound heterozygosity with another pathogenic variant (p.V165M; c.493G ≥ A). At onset, patient 3 presented with more severe symptoms compared to the other two, showing generalized weakness and repeated episodes of respiratory failure in the first years of life. During adolescence, she became gradually less symptomatic and does not require medication anymore, presenting better long-term outcomes than patients 1 and 2. This case series illustrates the variability of RAPSN early-onset CMS, with patient 3, despite severe onset, revealing an almost complete reversal of myasthenic symptoms, not limited to apneic episodes. Moreover, it suggests that RAPSN CMS may be underdiagnosed in non-European countries.

Pearls & Oy-sters: A curable myopathy manifesting as exercise intolerance and respiratory failure

Few forms of severe genetic myopathies can successfully be treated, although multiple acyl-CoA dehydrogenase deficiency (MADD) is highly responsive to riboflavin supplementation.

Facial and bulbar muscle atrophy in acetylcholine receptor antibody-positive myasthenia gravis.

A 62-year-old man presented with seven years of progressive dysphagia, dysphonia and difficulty in closing both eyes. His examination showed weakness and atrophy of facial and bulbar muscles without ocular involvement (Figure A, B and C). Single-fiber electromyography revealed increased jitter (Figure D). To evaluate for concurrent myopathy, a muscle biopsy was performed and showed angulated atrophic type II fibers, a particular finding described in patients with myasthenia gravis1,2 (Figure E). Acetylcholine receptor antibody was positive (2.2 nmol/L). Pronounced facial and tongue atrophy is uncommon in myasthenia gravis and usually associated with the muscle-specific receptor tyrosine kinase antibody, which was negative in this patient3,4.

Nemaline myopathy related to HIV infection with a good response to immunosuppression

examination, sclerotic skin and multiple erythematous indurations were observed on chest and all limbs. Range of motion of all the fingers was limited. However, neurologic examination is otherwise normal. Laboratory tests revealed peripheral eosinophilia, hypergammaglobulinemia and polyclonal gammopathy. Antinuclear antibody was marginally elevated while extractable nuclear antibodies were negative. Serum creatine kinase, aldolase and parasitic markers were within normal limits. T1-enhanced magnetic resonance imaging of thigh showed a diffuse thickening and enhancement of fasciae overlying thigh muscles bilaterally. Histopathologic findings were normal in muscle, while marked lymphocytic infiltration was present in fascia. Oral prednisolone and methotrexate relieved his symptoms remarkably leaving no limitation in joint movements or fibrosis. Although EF in childhood has been occasionally reported juvenile EF is even more uncommon. This case shows that initial combined treatment is corticosteroid and methotrexate could lead to a favorable course without residual change even marked limb at a young age of onset.