Thursday, March 27, 2014

What is stevens-johnson syndrome?


Causes and Symptoms


Stevens-Johnson syndrome begins with a nonspecific upper respiratory tract infection or after the consumption of a particular drug. The early symptoms last for one to fourteen days and consist of fever, sore throat, headache, cough, body aches, and sometimes vomiting and diarrhea. Subsequently, a flat, red rash (erythema multiforme) breaks out over the face and trunk that later spreads to the rest of the body. Painful blisters form in the center of the rash, and the skin around the blisters is quite loose and rubs off easily. Patients have a headache, fever, weakness (malaise), and a cough that produces thick, pus-filled material.



Blisters can form on the mucous membranes that line the mouth (preventing the patient from eating or drinking), throat, genitals, eyes, and anus. If the urinary tract is involved, then the patient will not be able to urinate. Eye involvement causes the eyes to swell and fill with pus so that they seal shut. Blisters on the surface of the eyes (corneas) can scar them. Lesions in the respiratory tract restrict breathing, and tissue sloughing can cause respiratory collapse. Sores in the digestive tract can cause diarrhea and narrowing of the esophagus. The open, skinless sores are also susceptible to infections.


Stevens-Johnson syndrome is classified according to the percentage of the skin affected. If 10 percent or less of the body surface area detaches, then the patient has Stevens-Johnson syndrome. If 10 to 30 percent of the skin detaches, then the patient has overlapping Stevens-Johnson syndrome/toxic epidermal necrolysis (TEN). If more than 30 percent of the skin is detached, then the patient has TEN.


Drug reactions cause most cases of Stevens-Johnson syndrome. The drugs that may trigger it include antibiotics, such as penicillin, ciprofloxacin, and sulfa drugs; anticonvulsant drugs, such as phenytoin, carbamazepine, and barbiturates; nonsteroidal anti-inflammatory drugs (NSAIDs); the antigout drug allopurinol; the narcolepsy treatment modafinil (Provigil); anti-Human immunodeficiency virus (HIV) drugs; diuretics; and topical ocular medications. Viral, bacterial, fungal, and protozoan infections can also cause the disease, as can various types of cancers. Between one-quarter and one-half of all cases of Stevens-Johnson syndrome are idiopathic, which means that there is no discernable cause. There is also a genetic basis for this disorder.


Diagnosis requires a skin biopsy, which shows extensive cell death, detachment of the upper layer of the skin (epidermis) from the middle layer of the skin (dermis), and infiltration of the skin with particular white blood cells called lymphocytes.


The large amount of skin loss in TEN is similar to a severe burn and is life threatening. Water and salts leak through the denuded areas and can produce organ failure. Infection at the damaged areas is also a major cause of death in TEN patients.




Treatment and Therapy

The most important therapeutic step is to discontinue all drugs suspected of triggering the disease. Management of symptoms is also essential. Mouthwashes can treat oral lesions and allow fluid intake, which, when coupled with the intravenous replacement of fluid and salts, can prevent dehydration and electrolyte imbalance. Skin lesions are treated as burns. Topical anesthetics can reduce pain, and denuded skin areas are covered with saline compresses. Any secondary infection that develops must be rapidly identified and treated.


There is no universally accepted drug treatment for Stevens-Johnson syndrome. Oral corticosteroids appear to help during the first few days, but not after that. In advanced cases of TEN, corticosteroids increase the incidence of complications. Intravenous delivery of antibodies (immunoglobulins) against the Fas ligand that mediates cell death has helped small groups of TEN patients, but this treatment has not been systematically evaluated. Also, drugs that down-regulate the immune system have been used, but too little data exists to evaluate their efficacy properly.




Perspective and Prospects

Stevens-Johnson syndrome was first described in 1922 by Albert Mason Stevens and Frank Chambliss Johnson. They encountered two young boys who showed inflammation of the mucous lining of the cheeks, pus-filled eyes, and the generalized skin blisters that are now commonly associated with the disease. Stevens and Johnson originally thought that the boys suffered from a type of unknown infectious disease. Bernard Thomas named the condition in 1950. The condition gained public attention in 2010 when it contributed to the death of former professional basketball player Manute Bol.


No treatment for Stevens-Johnson syndrome provides consistent benefits to patients in systematic studies. Nevertheless, several treatments have shown promise in small studies. For example, intravenous immunoglobulin treatments, skin grafts, the antitransplant rejection drug cyclosporine, and a blood filtration procedure called plasmapheresis have successfully treated small groups of patients with few complications and little mortality. However, until larger, double-blind, placebo-based studies establish the efficacy of these treatments, they will remain experimental.




Bibliography


Berman, Kevin, et al. "Erythema Multiforme." MedlinePlus, Nov. 20, 2012.



Boyer, Woodrow Allen. Understanding Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis. Raleigh, N.C.: Lulu Press, 2008.



Kellicker, Patricia, and Peter Lucas. "Erythema Multiforme." Health Library, Sept. 30, 2012.



Koh, Mark-Jean-Aan, and Kwang-Yong Tay. “An Update on Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis in Children.” Current Opinion in Pediatrics 21, no. 4 (August, 2009): 505–510.



Parrillo, Steven J. “Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis.” Current Allergy and Asthma Reports 7, no. 4 (July, 2007): 243–247.



"Stevens-Johnson Syndrome." Mayo Clinic, Apr. 9, 2011.



Warn, Dana, and Nancy Matharu. Stevens-Johnson Syndrome: A Booklet for Children and Their Families. Vancouver, B.C.: Provincial Health Services Authority, 2006.

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