Proximal Lower Extremity Weakness Research Articles

Phenotypical statin‐associated immune‐mediated necrotizing myositis with histological features of inclusion body myositis

AbstractIntroductionStatin‐associated immune‐mediated necrotizing myositis (IMNM) is a rare but distinct idiopathic inflammatory myopathy (IIM) that requires early recognition and intervention to prevent irreversible muscle damage. It is typically characterized by active statin use, elevated creatinine kinase (CK) levels, proximal muscle weakness, and at times, a positive 3‐hydroxy‐3‐methyl‐glutaryl‐coenzyme A reductase (HMGCR) antibody. Treatment includes immediate discontinuation of the statin and may include corticosteroids, intravenous immunoglobulin (IVIG), and/or immunosuppressive therapy. Inclusion body myositis (IBM), another distinct IIM, also presents with elevated CK levels but with insidious onset of distal upper and proximal lower extremity weakness and is typically refractory to treatment.Case DescriptionA 64‐year‐old female patient presented with proximal muscle weakness, elevated CK levels, and a positive HMGCR antibody in the setting of statin use with muscle pathology suggestive of both statin‐associated IMNM and IBM. She responded to subcutaneous methotrexate and a slow prednisone taper over several months, however, will require close monitoring for symptoms associated with either disease.ConclusionIn conclusion, we report a case of muscle weakness with muscle pathology demonstrating both statin‐associated IMNM and IBM. This case highlights the importance of understanding the clinical and pathological features of statin‐associated IMNM and IBM.

Statin-Induced Immune-Mediated Necrotizing Myopathy with Anti-HMGCR Antibody

Anti-3-hydroxy-3-methylglutaryl coenzyme A reductase (anti-HMGCR) antibody related immune-mediated necrotizing myopathy (IMNM) are usually associated with statin use. The disease has features of persistent muscle weakness and creatine kinase (CK) elevation after statin discontinuation. This report describes a 65-year-old female taking atorvastatin, presenting with both proximal lower extremity weakness. IMNM feature were detected on muscle biopsy and high anti-HMGCR autoantibody titer on enzyme-linked immunosorbent assay (ELISA). This patient was treated with corticosteroid. Muscle weakness and CK are improved after immunosuppressive therapy.

Novel LMNA mutation presenting with cardiomyopathy, paraspinal muscle atrophy and proximal lower extremity weakness. (4389)

Novel LMNA mutation presenting with cardiomyopathy, paraspinal muscle atrophy and proximal lower extremity weakness. (4389)

Restrictive lung involvement in facioscapulohumeral muscular dystrophy

Few studies have evaluated the frequency or predisposing factors for respiratory involvement in facioscapulohumeral muscular dystrophy type 1 (FSHD1) and type 2 (FSHD2). We performed a prospective cross-sectional observational study of 61 genetically confirmed FSHD participants (53 FSHD1 and 8 FSHD2). Participants underwent bedside pulmonary function testing in sitting and supine positions, a standard clinical history and physical assessment, and manual muscle testing. Restrictive respiratory involvement was suggested in 9.8% (95% confidence interval 2.4-17.3): 7.5% FSHD1 and 25.0% FSHD2 (P = 0.17). Participants with testing suggestive of restrictive lung involvement (n = 6) were more severely affected (P = 0.005), had weaker hip flexion (P = 0.0007), and were more likely to use a wheelchair (P = 0.01). Restrictive respiratory involvement should be considered in all moderate to severely affected FSHD patients with proximal lower extremity weakness. The higher frequency of restrictive lung disease in FSHD2 seen here requires confirmation in a larger cohort of FSHD2 patients.

Lambert-Eaton Syndrome in Children

Investigators from Boston Children's Hospital; the Lahey Clinic, Burlington, MA; and Ohio State University, report 3 children presenting between ages 9 and 10 years with proximal lower extremity weakness with areflexia and low-amplitude compound muscle action potentials, and diagnosed with Lambert-Eaton myasthenic syndrome.

Frontal Plane Knee and Hip Kinematics During Sit-to-Stand and Proximal Lower Extremity Strength in Persons With Patellofemoral Osteoarthritis: A Pilot Study

Increased joint stress and malalignment are etiologic factors in osteoarthritis. Static tibiofemoral frontal plane malalignment is associated with patellofemoral osteoarthritis (PFOA). Patellofemoral joint stress is increased by activities such as sit-to-stand (STS); this stress may be even greater if dynamic frontal plane tibiofemoral malalignment occurs. If hip muscle or quadriceps weakness is present in persons with PFOA, aberrant tibiofemoral frontal plane movement may occur, with increased patellofemoral stress. No studies have investigated frontal plane tibiofemoral and hip kinematics during STS in persons with PFOA or the relationship of hip muscle and quadriceps strength to these motions. Eight PFOA and seven control subjects performed STS from a stool during three-dimensional motion capture. Hip muscle and quadriceps strength were measured as peak isometric force. The PFOA group demonstrated increased peak tibial abduction angles during STS, and decreased hip abductor, hip extensor, and quadriceps peak force versus controls. A moderate inverse relationship between peak tibial abduction angle and peak hip abductor force was present. No difference between groups was found for peak hip adduction angle or peak hip external rotator force. Dynamic tibiofemoral malalignment and proximal lower extremity weakness may cause increased patellofemoral stress and may contribute to PFOA incidence or progression.

Poster 75 The Importance of Electrodiagnostic Medicine in Diagnosing Compression Neuropathy of the Posterior Tibial Nerve Secondary to a Ganglion Cyst: A Case Report

treated with dilation and curettage. She had generalized weakness, which at the time contributed to dehydration and electrolyte imbalance. The patient was later readmitted for progressive generalized weakness and an inability to ambulate. Ultrasound revealed retained fetal products. Results of an initial physical examination revealed proximal lower extremity weakness and areflexia without sensory deficit. Setting: A tertiary hospital. Results: Initial nerve conduction studies revealed decreased motor amplitudes in the legs, with relatively preserved sensory responses. The motor and sensory studies in the arms were normal. Initial electromyography showed acute denervation and loss of motor units in proximal lower extremity muscles. Acute denervation was also seen in distal leg muscles. The upper extremities or lumbar paraspinals were electrically normal. Subsequent nerve conduction studies revealed a loss of motor and sensory responses in both arms and legs. Repeated electromyography reflected a similar denervation pattern in the upper extremities. She was diagnosed with acute motor and sensory axonal neuropathy subtype of Guillain-Barre syndrome (GBS). The patient had antecedent diarrheal illness but Campylobacter jejuni, antiganglioside GM1 antibodies, monoclonopathy, human immunodeficiency virus, West Nile serologies, and CSF studies were negative. Discussion: GBS is the most common cause of acute flaccid paralysis in the world. It is considered to be a postinfectious, immune-mediated disease targeting peripheral nerves though immune mimicry. There are several GBS subtypes: acute inflammatory demyelinating polyradiculoneuropathy, acute motor axonal neuropathy, and acute motor and sensory axonal neuropathy. The acute motor and sensory axonal neuropathy variant often presents with rapid and severe paralysis with delayed and poorer recovery. In several studies, C jejuni was the most commonly isolated pathogen associated with the axonal subtype. Conclusions: In the presence of multiple negative serologies, this would be the first case report that suggests a hyperimmune response to fetal demise and retained products as a potential etiology of GBS.

INCLUSION BODY MYOSITIS

Inclusion body myositis (IBM) was suspected on light microscopic grounds in 48 of 170 consecutive patients with inflammatory myopathies. One or more vacuoles containing membranous material, groups of atrophic fibres, and an autoaggressive endomysial inflammatory exudate occurred in 100, 96 and 92% of the muscle specimens. All three of these features were present in 88% of the specimens. Electron microscopy confirmed the presence of filamentous inclusions in 40 of 43 patients. The inclusions are typically near vacuoles and a minimum of three vacuolated fibres must be scrutinized to detect them with confidence. There is no electromyographic pattern that can reliably distinguish IBM from other inflammatory myopathies. The typical clinical features in the patients diagnosed by histological criteria as IBM were: insidious onset after age 50 yrs with painless, proximal lower extremity weakness; slow but relentless progression with selectively severe involvement of quadriceps, iliopsoas, tibialis anterior, biceps and triceps muscles; relatively early depression of the knee reflexes; and a normal or mildly elevated serum creatine kinase level. The male: female ratio was 3:1. Distal weakness occurred in about 50%, but only in 35% was it as great or greater than proximal weakness. Significant associated illnesses include other autoimmune disorders (15%), diabetes mellitus (20%), and diffuse peripheral neuropathy (18%). Prednisone treatment at dose levels frequently effective in polymyositis failed to prevent disease progression in those patients observed for 2 or more years. Our findings support the notion that IBM is a distinct entity in which a set of pathological features is associated with a constellation of clinical findings.