A case of polyarteritis nodosa limited to the right calf muscles, fascia, and skin: a case report

Abstract

IntroductionLimited polyarteritis nodosa is a rare benign disease that usually responds well to systemic corticosteroid treatment. We report a case limited to calf muscles, fascia, and skin treated with local corticosteroid therapy directed to the affected areas by ultrasound guidance.Case presentationA 36-year-old Caucasian woman presented with a 10-month history of progressive right calf pain and swelling, which were unresponsive to treatment with non-steroidal anti-inflammatory drugs and physiotherapy. An examination revealed a swollen tender right calf with indurated overlying skin. Laboratory investigations showed an erythrocyte sedimentation rate of 24 mm/hour and a C-reactive protein of 15 mg/dl. Full blood count, renal profile, and creatinine kinase level were normal. A full autoantibody screen and hepatitis B and C serology results were negative. A chest X-ray was unremarkable. Magnetic resonance imaging of the right leg revealed increased signal intensity in T2-weighted images and this was suggestive of extensive inflammatory changes of the gastrocnemius muscle and, to a lesser extent, the soleus muscle. There were marked inflammatory changes throughout the gastrocnemius muscle and the subcutaneous tissue circumferentially around the right lower leg. A biopsy of affected skin, muscle, and fascia showed histopathological features consistent with polyarteritis nodosa, including small-vessel vasculitis with fibrinoid changes in the vessel wall and intense perivascular and focal mural chronic inflammatory changes. Our patient declined treatment with oral steroids. She received a course of ultrasound-guided injections of steroid (Depo-Medrone, methylprednisolone) in the involved muscle area and commenced maintenance azathioprine with a good response.ConclusionsLimited polyarteritis nodosa is rare and affects middle-aged individuals. In most cases, treatment with moderate- to high-dose corticosteroids gives symptomatic relief within one week. Resistant cases require treatment with cytotoxics or intravenous immunoglobulins. This case demonstrates response to local targeted steroid therapy as an alternative to systemic steroids.

Leg muscle involvement in polyarteritis nodosa (limited form)—A rare case report

“…The MRI findings of isolated skeletal muscle involvement in PAN have been sparsely reported. Previously reported cases [4] , [5] , [6] , [7] , [8] , [9] , [10] , [11] , [12] showed either patchy or diffusely increased signal intensity of the involved muscles on T2-weighted or STIR images. The high signal on T2-weighted images is likely due to edema, probably due to an increase in intracellular or extracellular free water [ 9 , 13 ].…”

“…MRI findings of skeletal muscle involvement in PAN have been reported in several individual cases. Various studies have reported different patterns of muscle edema (as diffuse or patchy T2/short tau inversion recovery [STIR] sequence signals) and/or contrast enhancement [4] , [5] , [6] , [7] , [8] , [9] , [10] , [11] , [12] . One case series described MRI findings of 3 patients with vasculitis restricted to limbs, in which 2 cases were of PAN [9] .…”

Severe Disabling Myalgia as an Initial Presentation of Polyarteritis Nodosa

“…It was evident that there are reports that some patients had longer duration of muscle pains. Ahmed et al [18] have published a case of PAN which presented with progressive right calf pain and swelling over ten-month duration with overlying skin induration. Another report [19] published a case of 59-year-old Japanese who has presented with prolong pyrexia of undetermined origin and developed calf pain later.…”

Cutaneous arteritis with compartment syndrome: Case report and review of published works

“…We searched for case reports describing cases with both skin lesions and muscle disorders based on biopsy or medical imaging, and found five cases, including the case presented here (Table 1). [11][12][13][14] All cases had swelling, and we considered that the presence of swelling might be useful for differential diagnoses between CA with and without muscle disorders. Oral steroid therapy was not effective in two cases, including our case, and four cases, including our case, required immunosuppressants or intravenous methylprednisolone pulse therapy.…”