Polyneuropathy (poly- + neuro- + -pathy) is damage or disease affecting peripheral nerves (peripheral neuropathy) in roughly the same areas on both sides of the body, featuring weakness, numbness, and burning pain. It usually begins in the hands and feet and may progress to the arms and legs and sometimes to other parts of the body where it may affect the autonomic nervous system. It may be acute or chronic. A number of different disorders may cause polyneuropathy, including diabetes and some types of Guillain–Barré syndrome. Classification
Polyneuropathies may be classified in different ways, such as by cause, by presentation, or by classes of polyneuropathy, in terms of which part of the nerve cell is affected mainly: the axon, the myelin sheath, or the cell body. Distal axonopathy, is the result of interrupted function of the peripheral nerves. It is the most common response of neurons to metabolic or toxic disturbances, and may be caused by metabolic diseases such as diabetes, kidney failure, connective tissue disease, deficiency syndromes such as malnutrition and alcoholism, or the effects of toxins or drugs such as chemotherapy. They may be divided according to the type of axon affected (large-fiber, small-fiber, or both), the most distal portions of axons are usually the first to degenerate, and axonal atrophy advances slowly toward the nerves cell body. However, if the cause is removed, then regeneration is possible, although the prognosis depends on the duration and severity of the original stimulus.
Irukandji syndrome is a condition that results from envenomation by certain box jellyfish. In rare instances the sting may result in cardiac arrest and death. The most common jellyfish involved is the Carukia barnesi, a species of Irukandji jellyfish. Those stung may experience severe or even excruciating pain. The syndrome was given its name in 1952 by Hugo Flecker, after the Aboriginal Irukandji people who live in Palm Cove, north of Cairns, Queensland, Australia, where stings are common. Signs and symptoms
Most stings occur during the summer wet season in October–May in North Queensland, with different seasonal patterns elsewhere. Because the jellyfish are very small, the venom is only injected through the tips of the nematocysts (the cnidocysts) rather than the entire lengths; as a result the sting may barely be noticed at first. It has been described as feeling like little more than a mosquito bite. The symptoms, however, gradually become apparent and then more and more intense in the subsequent 5 to 120 minutes (30 minutes on average). Irukandji syndrome includes an array of systemic symptoms, including severe headache, backache, muscle pains, chest and abdominal pain, nausea and vomiting, sweating, anxiety, hypertension, tachycardia, and pulmonary edema. Symptoms generally improve in four to 30 hours, but may take up to two weeks to resolve completely. Toxicity
When properly treated, a single sting is almost never fatal; however, two people in Australia are believed to have died from Irukandji stings, which has greatly increased public awareness of Irukandji syndrome.