Answer :USMLE step 2 Mcq 344:A 50 year old farmer complains of pain in his left arm



Correct Answer: B

Peripheral neuropathies are present in 50 to 70% of patients with Polyarteritis nodosa and despite increasing recognition of central nervous system (CNS) involvement, appear to be more common than CNS disease . Manifestations of peripheral neuropathies include mononeuritis multiplex, extensive mononeuritis, distal sensorimotor polyneuropathy, and sensory neuropathy. The onset of peripheral neuropathies is usually early in the course of the disease with equal distribution between the upper and lower extremities. In general, the lesions occur distally rather than proximally, and are a direct result of occlusion of vasa nervorum or nutrient arteries . With appropriate therapy, the prognosis for improvement and recovery of peripheral neuropathies is good Polyarteritis nodosa is probably mediated by deposition of immune complexes. The onset is gradual over weeks to months, and the initial symptoms are often nonspecific. The earliest clues that the patient has vasculitis come usually from the skin (where vasculitis may appear as palpable purpura, livedo reticularis, digital gangrnen, or tender nodules), or the peripheral nervous system (where infarction of one mixed motor and sensory nerve after another results in mononeuritis multiplex, one of the most specific clues that a patient has vasculitis). Mononeuritis multiplex (mononeuropathy multiplex) is a form of peripheral neuropathy (damage to nerves other than the nerves of the brain and spinal cord). It involves isolated damage to at least 2 separate nerve areas. Mononeuritis multiplex is a group of symptoms, not a distinct disease entity. The underlying disorder involves isolated nerves in multiple, random areas. As the disorder worsens, the damage appears less multifocal and more symmetric, resembling polyneuropathy. The damage to the nerves involves destruction of the axon (part of the nerve cell) which interferes with nerve conduction at the location of the damage. Common causes include a lack of oxygen from decreased blood flow or inflammation of blood vessels. About one-third of cases are without identifiable cause. Multiple specific disorders are associated with mononeuritis multiplex, including (but not limited to) blood vessel diseases such as polyarteritis nodosa and connective tissue diseases such as rheumatoid arthritis or systemic lupus erythematosus Connective tissue disease is the most common cause in children.Less common causes include Sjogren's syndrome Wegener's granulomatosis , hypersensitivity (allergic) reactions that cause inflammation of blood vessels, leprosy , sarcoidosis , amyloidosis , multifocal forms of diabetic neuropathy, and various disorders of the blood (such as hypereosinophilia, and cryoglobulinemia)


>>>> Post your Answer Here ????

Design by