Acute swelling of the limbs: magnetic resonance pictorial review of fascial and muscle signal changes.

OBJECTIVE: This pictorial review analyzes the magnetic resonance (MR) fascial/muscular changes in 69 patients referred as emergencies with acute swelling of the limbs (ASL) from various causes. METHODS AND MATERIAL: A prospective MR imaging (MRI) study of 69 patients referred as emergencies for ASL was performed. Our population consisted of 45 patients with skin and soft-tissue infections (cellulitis and necrotizing fasciitis, and pyomyositis), six patients with soft-tissue inflammatory diseases (dermatomyositis, graft-versus-host disease), 11 patients with acute deep venous thrombosis, three patients with rhabdomyolysis, one patient with acute denervation and three other patients with rare diseases. Hematomas, tumorous or infectious bone involvement and soft-tissue tumors were excluded. All studies included spin echo T1-weighted images and spin echo T2-weighted images. Gadolinium-enhanced spin echo T1-weighted images were obtained when an abscess was suspected on T2-weighted images. Selective fat-saturated T1- and T2-weighted sequences were also used. MRI analysis was performed to obtain a compartmentalized anatomical approach according to the location of signal abnormalities in subcutaneous fat, superficial and deep fascia and muscle. RESULTS: In all patients with ASL, MRI demonstrated soft-tissue abnormalities involving subcutaneous fat, superficial fascia, deep fascia, or muscle. Although MR findings were non-specific, MRI appears sensitive for detecting subtle fascial and muscle signal changes. CONCLUSIONS: In skin and soft-tissue infections, MRI can be helpful for therapeutic management by determining the depth of soft-tissue involvement, particularly within fasciae and muscles, which is partly related to the severity of cellulitis with severe systemic manifestations. MRI can also aid the surgeon in diagnosing abscesses. In inflammatory diseases, MRI can determine the best site for biopsy and also monitor therapeutic response.

Myoglobin as a polymerase chain reaction (PCR) inhibitor: a limitation for PCR from skeletal muscle tissue avoided by the use of Thermus thermophilus polymerase.

Skeletal muscle tissue contains polymerase chain reaction (PCR) inhibitors that are coextracted by conventional nucleic acid extraction procedures. Myoglobin, a heme-containing molecule, was shown to act as a potent Thermus aquaticus DNA polymerase inhibitor and is likely to be involved in muscle tissue-associated PCR inhibition. The use of Thermus thermophilus DNA polymerase avoids muscle tissue-associated PCR inhibition, and should be used in case of small amounts or instability of the targeted nucleic acid.

Cytokine expression in the muscle of HIV-infected patients: evidence for interleukin-1 alpha accumulation in mitochondria of AZT fibers.

To evaluate the possible role of cytokines in human immunodeficiency virus (HIV)-associated muscular disorders, we performed immunocytochemistry for interleukin-1 alpha, -1 beta, and -6 and tumor necrosis factor-alpha on frozen muscle biopsy specimens from HIV-infected patients with various myopathies (HIV polymyositis in 5, HIV-wasting syndrome in 5, zidovudine myopathy in 10) and from seronegative individuals (normal muscle in 2, mitochondrial cytopathies in 10). The HIV-infected patients showed positive reactivities in vessels (interleukin-1) and in inflammatory cells (mainly interleukin-1 and tumor necrosis factor-alpha), including perivascular hemosiderin-laden macrophages in 5 patients. In zidovudine myopathy, a majority of AZT fibers (i.e., ragged-red fibers with marked myofibrillar changes) showed mild to marked expression of interleukin-1. Expression of interleukin-1 in the other mitochondrial myopathies was much weaker. Interleukin-1 beta messenger RNA was demonstrated in muscle fibers by in situ hybridization, implying that interleukin-1 was produced in muscle cells. Immunoelectron microscopy showed that interleukin-1 alpha was mainly bound to mitochondrial membranes in AZT fibers. Proinflammatory and destructive effects of the studied cytokines might be responsible for several myopathological changes observed in HIV-infected patients, including inflammation and hemosiderin deposits in muscle tissue, and prominent myofibrillar breakdown in AZT fibers.

[Non-bacterial thrombotic endocarditis complicating metastatic melanoma]. / Endocardite thrombotique non bactérienne compliquant un mélanome métastasé.

INTRODUCTION: Non-bacterial thrombotic endocarditis is defined by the presence of cardiac aseptic valvular vegetations made of fibrin and platelets. We report a case diagnosed ante mortem that occurred in a patient with metastatic melanoma. CASE REPORT: M. S., presented with a metastatic melanoma associated with an acute neurological deficit. Cerebral computerized tomographies and nuclear magnetic resonance showed occipital ischaemic lesions in the territory of the posterior cerebral artery. Cardiac echography showed large vegetations of the mitral valve. Bacterial endocarditis was eliminated. The diagnosis of non-bacterial thrombotic endocarditis was made, confirmed by post mortem examination. DISCUSSION: Non-bacterial thrombotic endocarditis is the second cause of neurological manifestations in patients with cancer. The presentation of our case was unusual because of an audible heart murmur and vegetations visible on echography.