A case of eosinophilic polymyositis complicated by myasthenia gravis

Idiopathic Orbital Inflammation Appearing on the Affected Side of Preceding Myasthenia Gravis

The patient was a 70-year-old man with idiopathic orbital inflammation (IOI) that appeared on the severely affected side of preceding myasthenia gravis (MG). The patient was diagnosed with MG 5 years prior to the onset of IOI. When IOI was diagnosed, an edrophonium test was negative. IOI was considered because he complained of left orbital pain, eyelid swelling, and cerebral MRI exhibited the enhanced lesions along the left orbital periosteum. A biopsy specimen revealed pathological findings compatible with IOI. The administration of corticosteroids was effective for improving the ocular symptoms. IOI should be considered when ocular symptoms deteriorated with soft tissue swelling/pain in MG patients.

Severe Rhabdomyolysis without Systemic Involvement: A Rare Case of Idiopathic Eosinophilic Polymyositis

Introduction. Eosinophilic polymyositis (EPM) is a rare cause of rhabdomyolysis characterized by eosinophilic infiltrates in the muscle. We describe the case of a young patient with eosinophilic polymyositis causing isolated severe rhabdomyolysis without systemic involvement. Case Presentation. A 22-year-old Haitian female with no past medical history presented with progressive generalized muscle aches without precipitating factors. Examination of the extremities revealed diffuse muscle tenderness. Laboratory findings demonstrated peripheral eosinophilia and high creatinine phosphokinase (CPK) and transaminase levels. Workup for the common causes of rhabdomyolysis were negative. Her CPK continued to rise to greater than 100,000 units/L so a muscle biopsy was performed which showed widespread eosinophilic infiltrate consistent with eosinophilic polymyositis. She was started on high dose systemic corticosteroids with improvement of her symptoms, eosinophilia, and CPK level. Discussion. This case illustrates a systematic workup of rhabdomyolysis in the presence of peripheral eosinophilia. Many differential diagnoses must be considered before establishing a diagnosis of idiopathic eosinophilic polymyositis. To our knowledge, our case of eosinophilic polymyositis is unique as it presented with severe rhabdomyolysis without another organ involvement. Clinicians should maintain a high index of suspicion for this physically debilitating disease to aid in prompt diagnosis.

[Case of eosinophilic myositis in continuum from localized nodular myositis]

We report a 72-year-old man with eosinophilic myositis (EM). At age 71 he noticed a painful nodule in his left calf. A biopsy (first biopsy) showed marked infiltration of mononucleated cells and necrotic muscle fibers. Several phagocytosed fibers were also seen. He was diagnosed as having myositis. The painful nodule disappeared spontaneously. At age 72, he again had a painful nodule, but this time in his right calf; again, this disappeared spontaneously on the first admission. Just after discharge, he noted painful nodules in the left thigh and right anterior tibial muscles and was again admitted (second admission). Neurological examination revealed mild proximal-dominant weakness in all four extremities but no other abnormalities. Laboratory studies showed elevated creatine kinase (CK) level (38,803 U/l; normal 62-287) and positive Jo-1 antibody, but no eosinophilia. Needle electromyography of the limb muscles showed myogenic patterns. Magnetic resonance imaging of the lower limbs demonstrated several T2-high and gadolinium (Gd)-enhanced lesions. Muscle biopsy (second biopsy) from the left quadriceps femoris showed marked infiltration of eosinophils; he was diagnosed as having EM. Administration of prednisolone was initiated at 60 mg/day and then gradually tapered. After starting treatment with steroids, his muscle weakness gradually ameliorated, CK level dramatically decreased, and the nodules disappeared. Clinically, the patient had developed localized nodular myositis (LNM), but pathologically it was EM without peripheral blood eosinophilia and positive Jo-1 antibody that is occasionally found in polymyositis (PM). Thus, this patient demonstrated overlapping characteristics of EM, LNM, and possibly PM, suggesting that a common mechanism underlay these conditions. As discussed, the involvement of eosinophils in three inflammatory myopathies was indicated.

Eosinophilia, myositis, and myasthenia gravis associated with a thymoma

Hypereosinophilia has been associated with a wide variety of systemic disorders, including myositis. Myositis develops in a minority of patients with myasthenia gravis associated with a thymoma. We present a patient who developed a life-threatening myopathy in which testing demonstrated the concurrence of hypereosinophilia, myositis, and myasthenia gravis associated with thymoma. Thymoma-associated T-cell abnormalities may well have contributed to this rare association. This case underscores the need to reevaluate constantly the presumed cause of clinical complaints, as more than one cause may be present.

Eosinophilia and musculoskeletal disease

Eosinophilia is occasionally a feature of rheumatic disease. The differential diagnosis of eosinophilia includes parasitic infection, systemic vasculitides, eosinophilic arthritis, and myopathies, together with the idiopathic hypereosinophilic syndrome and malignancy. Careful evaluation of the patient should enable an accurate diagnosis to be made. Parasitic infection is the commonest cause of eosinophilia worldwide and can cause systemic disease, as illustrated by the report of Sarcocystis myositis in a group of military personnel in Malaysia. A persistent arthropathy associated with eosinophilia, but not with parasitic infection, has been reported from the far East. Drugs may also cause eosinophilia, and there has recently been much discussion of the relation between Churg-Strauss syndrome and the leukotriene antagonist zafirlukast. The present view is that reduction of steroid dose allows unmasking of previously undiagnosed Churg-Strauss syndrome. The idiopathic hypereosinophilic syndrome may represent a lymphoproliferative process; evidence for this comes from the demonstration that many patients have a clonally expanded population of aberrant T cells.