Anti-neutrophil cytoplasmic antibody for proteinase 3 in a child with polyarteritis nodosa

Metabolic myopathy presenting with polyarteritis nodosa: a case report

Introduction

To the best of our knowledge, we describe for the first time a patient in whom an unusual metabolic myopathy was identified after failure to respond to curative therapy for a systemic vasculitis, polyarteritis nodosa. We hope this report will heighten awareness of common metabolic myopathies that may present later in life. It also speculates on the potential relationship between metabolic myopathy and systemic vasculitis.

Case presentation

A 78-year-old African-American woman with a two-year history of progressive fatigue and exercise intolerance presented to our facility with new skin lesions and profound muscle weakness. Skin and muscle biopsies demonstrated a medium-sized artery vasculitis consistent with polyarteritis nodosa. Biochemical studies of the muscle revealed diminished cytochrome C oxidase activity (0.78 μmol/minute/g tissue; normal range 1.03 to 3.83 μmol/minute/g tissue), elevated acid maltase activity (23.39 μmol/minute/g tissue; normal range 1.74 to 9.98 μmol/minute/g tissue) and elevated neutral maltase activity (35.89 μmol/minute/g tissue; normal range 4.35 to 16.03 μmol/minute/g tissue). Treatment for polyarteritis nodosa with prednisone and cyclophosphamide resulted in minimal symptomatic improvement. Additional management with a diet low in complex carbohydrates and ubiquinone, creatine, carnitine, folic acid, α-lipoic acid and ribose resulted in dramatic clinical improvement.

Conclusions

Our patient's initial symptoms of fatigue, exercise intolerance and progressive weakness were likely related to her complex metabolic myopathy involving both the mitochondrial respiratory chain and glycogen storage pathways. Management of our patient required treatment of both the polyarteritis nodosa as well as metabolic myopathy. Metabolic myopathies are common and should be considered in any patient with exercise intolerance. Metabolic myopathies may complicate the management of various disease states.

A Case of Classical Polyarteritis Nodosa Complicated by Ulcerative Colitis

Classical polyarteritis nodosa (PAN) is a term that includes patients with necrotizing inflammation of medium-sized arteries and excludes those with microscopic vessel involvement. Although gastrointestinal manifestations are not unusual in patients with classical PAN, the association with ulcerative colitis has been reported only rarely. We describe a patient with classical PAN complicated by bilateral renal artery aneurysms with subsequent rapture and perirenal hemorrhages. He was successfully treated, and the bilateral renal aneurysms resolved with steroid therapy. Two years later, the patient presented with hematochezia. Colonoscopy revealed inflamed rectal mucosa with bleeding ulcers. Histologic findings of biopsy specimens showed severe mucosal inflammation and crypt abscess. The patient was diagnosed with ulcerative colitis, and the symptoms attenuated after meselazine therapy.