[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [General pathology](https://durgical.com/en/general-pathology/) › [Peripheral nerve and skeletal muscle](https://durgical.com/en/general-pathology/areas/nerve-muscle/) › Vasculitic, paraneoplastic and paraprotein neuropathies # Vasculitic, paraneoplastic and paraprotein neuropathies - Lesion Inflamed vessels starve nerves one by one; cancers trigger antibodies against sensory neurons; abnormal plasma cells and amyloid damage nerves. Updated Nov 12, 2026 ## Key points - Vasculitic neuropathy: painful, asymmetric mononeuritis multiplex; biopsy shows fibrinoid necrosis of epineurial arteries and axonal loss. - Causes: polyarteritis nodosa, eosinophilic granulomatosis with polyangiitis, microscopic polyangiitis, cryoglobulinaemia (hepatitis C), RA. - Anti-Hu (ANNA-1): sensory neuronopathy with small cell lung cancer; antibody marks the immune attack by cytotoxic T cells. - POEMS: polyneuropathy, organomegaly, endocrinopathy, M protein (lambda), skin changes; VEGF very high; sclerotic myeloma. - Anti-MAG: IgM paraprotein, distal sensory demyelinating neuropathy with tremor, in older men. - AL and transthyretin amyloid: painful small-fibre and autonomic neuropathy, carpal tunnel syndrome. ## What it is Several systemic diseases injure nerves from outside the nerve itself. In vasculitis, inflammation of small epineurial arteries causes nerve infarcts in a patchy pattern, usually mononeuritis multiplex, in polyarteritis nodosa, ANCA vasculitides, cryoglobulinaemia and rheumatoid arthritis. Sjögren disease can attack dorsal root ganglia. Cancers cause neuropathy by direct infiltration or compression (Pancoast tumour, lymphoma), by paraneoplastic immunity, most often anti-Hu sensory neuronopathy with small cell lung carcinoma, and by plasma cell disorders: IgM anti-MAG neuropathy, POEMS syndrome and AL amyloid. Radiation can damage plexuses years later. ## Structure - Vasculitis: transmural inflammation and fibrinoid necrosis of small epineurial arteries, thrombosis and scarring; asymmetric loss of fascicles. - Paraneoplastic ganglionitis: lymphocytes and loss of dorsal root ganglion neurons with nodules of Nageotte. - Amyloid: Congo red-positive deposits with apple-green birefringence in vessel walls and endoneurium. - Anti-MAG: widened myelin lamellae on electron microscopy. ## Step by step - Immune complexes or ANCA-activated neutrophils inflame the small arteries of the vasa nervorum. - Arteries necrose and thrombose, and watershed regions of individual nerves infarct. - Axons in the infarcted segment degenerate; nerves are hit one after another. - In paraneoplastic disease, tumour neural antigens (HuD) provoke T cells that kill sensory neurons. - Paraproteins bind myelin (anti-MAG) or deposit as amyloid, and VEGF in POEMS makes vessels leaky. ## Clinical notes - Sudden foot drop then wrist drop in a patient with fever, weight loss and raised inflammatory markers: think of vasculitic neuropathy. - Subacute sensory ataxia and pain in a smoker: look for small cell lung cancer and anti-Hu. - An unexplained neuropathy deserves serum and urine protein electrophoresis with immunofixation. ## Memory aid Vessels make it patchy, Hu makes it sensory, M proteins make it monoclonal. ## Test yourself Think of the answer, then tap the question to see it. ## What pattern of neuropathy does vasculitis typically cause? Mononeuritis multiplex, painful and asymmetric. ## Which tumour is linked to anti-Hu sensory neuronopathy? Small cell lung carcinoma. ## What does POEMS stand for? Polyneuropathy, organomegaly, endocrinopathy, monoclonal protein and skin changes. ## Which stain shows amyloid in a nerve biopsy? Congo red, with apple-green birefringence under polarized light. [Add to my cards (4)](https://durgical.app/estudiar/?add=/en/general-pathology/vasculitic-paraneoplastic-and-paraprotein-neuropathies/) [More Pathology questions →](https://durgical.com/en/practice/?f=pathology) ## Elsewhere in DurgiPedia - [Type III hypersensitivity (immune complexes)](https://durgical.com/en/immunology/type-iii-hypersensitivity/) ## Connections ## Related 6 - [Paraneoplastic syndromes: the table to know](https://durgical.com/en/general-pathology/paraneoplastic-syndromes-the-table-to-know/) - [Medium-vessel vasculitis](https://durgical.com/en/general-pathology/medium-vessel-vasculitis/) - [ANCA-associated vasculitis](https://durgical.com/en/general-pathology/anca-associated-vasculitis/) - [Plasma cell disorders: MGUS to myeloma](https://durgical.com/en/general-pathology/plasma-cell-disorders-mgus-to-myeloma/) - [Lung carcinoma: spread and paraneoplastic syndromes](https://durgical.com/en/general-pathology/lung-carcinoma-spread-and-paraneoplastic-syndromes/) - [Brain metastases and paraneoplastic syndromes](https://durgical.com/en/general-pathology/brain-metastases-and-paraneoplastic-syndromes/) ## Related conditions 10 - [Polyarteritis nodosa](https://durgical.com/en/conditions/polyarteritis-nodosa/) - [Eosinophilic granulomatosis with polyangiitis (Churg–Strauss)](https://durgical.com/en/conditions/eosinophilic-granulomatosis-with-polyangiitis/) - [Sjögren disease](https://durgical.com/en/conditions/sjogren-disease/) - [Paraneoplastic syndromes](https://durgical.com/en/conditions/paraneoplastic-syndromes/) - [Lung cancer](https://durgical.com/en/conditions/lung-cancer/) - [Multiple myeloma](https://durgical.com/en/conditions/multiple-myeloma/) - [Amyloidosis](https://durgical.com/en/conditions/amyloidosis/) - [Microscopic polyangiitis](https://durgical.com/en/conditions/microscopic-polyangiitis/) - [Cryoglobulinemic vasculitis](https://durgical.com/en/conditions/cryoglobulinemic-vasculitis/) - [Granulomatosis with polyangiitis](https://durgical.com/en/conditions/granulomatosis-with-polyangiitis/) [← All of general pathology](https://durgical.com/en/general-pathology/) Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given. Sources: [Amyloidosis: MedlinePlus](https://medlineplus.gov/amyloidosis.html) (MedlinePlus, US National Library of Medicine, 2025); [Transthyretin amyloidosis: MedlinePlus Genetics](https://medlineplus.gov/genetics/condition/transthyretin-amyloidosis/) (MedlinePlus, US National Library of Medicine, 2025); [Small Cell Lung Cancer](https://www.ncbi.nlm.nih.gov/books/NBK482458/) (StatPearls (NCBI Bookshelf), 2025). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/general-pathology/vasculitic-paraneoplastic-and-paraprotein-neuropathies/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/general-pathology/vasculitic-paraneoplastic-and-paraprotein-neuropathies/