Bence-Jones protein-type myeloma with amyloid myopathy presenting as amyloidomas and extensive amyloid deposits in the muscularis propria: a rapidly fatal autopsy case

Secondary myopathy due to systemic diseases

Background

Some systemic diseases also affect the skeletal muscle to various degrees and with different manifestations. This review aimed at summarizing and discussing recent advances concerning the management of muscle disease in systemic diseases.

Method

Literature review by search of MEDLINE, and Current Contents with appropriate search terms.

Results

Secondary muscle disease occurs in infectious disease, endocrine disorders, metabolic disorders, immunological disease, vascular diseases, hematological disorders, and malignancies. Muscle manifestations in these categories include pathogen‐caused myositis, muscle infarction, rhabdomyolysis, myasthenia, immune‐mediated myositis, necrotising myopathy, or vasculitis‐associated myopathy. Muscle affection may concern only a single muscle, a group of muscles, or the entire musculature. Severity of muscle affection may be transient or permanent, may be a minor part of or may dominate the clinical picture, or may be mild or severe, requiring invasive measures including artificial ventilation if the respiratory muscles are additionally involved. Diagnostic work‐up is similar to that of primary myopathies by application of non‐invasive and invasive techniques. Treatment of muscle involvement in systemic diseases is based on elimination of the underlying cause and supportive measures. The prognosis is usually fair if the causative disorder is effectively treatable but can be fatal in single cases if the entire musculature including the respiratory muscles is involved, in case of infection, or in case of severe rhabdomyolysis.

Conclusion

Secondary muscle manifestations of systemic diseases must be addressed and appropriately managed. Prognosis of secondary muscle disease in systemic diseases is usually fair if the underlying condition is accessible to treatment.

Neuromuscular complications in cancer

Cancer is becoming a treatable and even often curable disease. The neuromuscular system can be affected by direct tumor invasion or metastasis, neuroendocrine, metabolic, dysimmune/inflammatory, infections and toxic as well as paraneoplastic conditions. Due to the nature of cancer treatment, which frequently is based on a DNA damaging mechanism, treatment related toxic side effects are frequent and the correct identification of the causative mechanism is necessary to initiate the proper treatment. The peripheral nervous system is conventionally divided into nerve roots, the proximal nerves and plexus, the peripheral nerves (mono- and polyneuropathies), the site of neuromuscular transmission and muscle. This review is based on the anatomic distribution of the peripheral nervous system, divided into cranial nerves (CN), motor neuron (MND), nerve roots, plexus, peripheral nerve, the neuromuscular junction and muscle. The various etiologies of neuromuscular complications - neoplastic, surgical and mechanic, toxic, metabolic, endocrine, and paraneoplastic/immune - are discussed separately for each part of the peripheral nervous system.

Clinical Neuropathology practice guide 3-2014: combined nerve and muscle biopsy in the diagnostic workup of neuropathy - the Bordeaux experience

Simultaneous combined superficial peroneal nerve and peroneous brevis muscle biopsy, via the same cutaneous incision, allows examination of several tissue specimens and significantly improves the diagnosis of systemic diseases with peripheral nerve involvement. Vasculitides are certainly the most frequently diagnosed on neuro-muscular biopsies, but this procedure is also well advised to asses a diagnosis of sarcoidosis or amyloidosis. More occasionally, combined nerve and muscle biopsy may reveal an unpredicted diagnosis of cholesterol embolism, intra-vascular lymphoma, or enables complementary diagnosis investigations on mitochondrial cytopathy or storage disease.