Bhaskar Srinivasan
Dr. Bhaskar Srinivasan finished his graduation from Topiwala National Medical College, Mumbai, in 1997 and his masters in Ophthalmology (MS Ophthalmology) from Armed Forces Medical College, Pune, in 2002. He did his fellowship in cornea and external eye disease at Sankara Nethralaya, Chennai, following which he joined the same as faculty and is currently Senior Consultant Cornea and Refractive Services. His special interest is in managing various ocular surface diseases especially treating chemical injuries and Stevens–Johnson syndrome. He has experience with different kinds of keratoprosthesis and is a part of the ocular surface clinic at Sankara Nethralaya, a one of its kind in the world dealing with both ocular surface stem cell and various keratoprosthesis-based treatments. He is well versed in various kinds of corneal transplants (PK/DSEK/DALK), refractive surgery, and management of ocular surface tumors. He has 30 publications in peer-reviewed literature and has served as a faculty in various national and international conferences.
Shweta Agarwal
Dr. Shweta Agarwal, D.O, a gold medalist from Pune university, completed her cornea fellowship from Sankara Nethralaya Chennai in 2009. She was awarded the Dr. D.S.Sardesai ophthalmology award from Pune university. She has quite a few publications in national and international journals and also a chapter on dry eyes in post graduate textbook of ophthalmology. She has been a primary investigator in two studies and a co-investigator in many studies related to cornea and ocular surface disorders funded by national agencies. She has been invited as a faculty in several national and international conferences. She was awarded the Best Cornea Free Paper in AIOC 2012. Her areas of interest are corneal diseases, ocular surface disorders, stem cells, and keratoprosthesis.
Geetha Iyer
Dr. Geetha Iyer, FRCS (Glasgow), completed her basic medical training in 1999. She did her postgraduate training in Ophthalmology and fellowship in cornea and external disease from Sankara Nethralaya, Chennai, India. She was awarded the best postgraduate student following completion of her ophthalmology training at Sankara Nethralaya and has been adjudged twice as the Best Associate Consultant during the early years of her tenure. She has been the recipient of awards for the Best Cornea Paper at both regional and national conferences. She has done a short-term observership in Ocular Surface Disorders with Dr. Scheffer C G Tseng, Miami, USA, in October 2006 and in Boston Type 1 keratoprosthesis with Dr. Claes H Dohlman in November 2006. She was trained and is being guided by Prof. Giancarlo Falcinelli in performing the MOOKP procedure. She has so far done more than 100 keratoprosthesis surgeries (MOOKP, Boston Type 1 and 2 Kpro).Dr. Geetha Iyer has to her credit publications in peer-reviewed journals and has conducted courses and presented papers in national and international meetings. She is actively involved in the management of ocular surface disorders and is currently working as Senior Consultant at the Ocular Surface Clinic and the Cornea Services, Sankara Nethralaya. Her areas of interest include pediatric penetrating keratoplasty, ocular surface tumors, ocular surface disorders including chemical injuries, stem cell transplants, keratoprosthesis, and in particular Stevens–Johnson Syndrome.
Introduction
Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are acute blistering diseases affecting the skin and mucous membrane including the ocular surface. The underlying aetiology of both are similar, and they differ only with respect to the amount of body surface area of desquamated epithelium with SJS being at the less severe end of the spectrum and TEN at the worse. Erythema multiforme major (EMM) which was a term interchangeably used for SJS is now known to be different and has infection as the etiology with predominantly an acral distribution of skin lesions, whereas both SJS and TEN are primarily due to adverse drug reaction and have more of a truncal and facial distribution of lesions. Ophthalmic manifestations are more common in both SJS and TEN and occur in 43–81 % patients in the acute phase [1, 2].
Aetiopathogenesis
Adverse idiosyncratic reaction to drugs is the commonest cause of SJS and TEN. Infections such as mycoplasma pneumonia and herpes are also known triggering factors. The most common medications causing these reactions are anticonvulsants, antimicrobials and nonsteroidal anti-inflammatory drugs (NSAID). The medications that cause SJS/TEN are listed in Table 26.1.
Table 26.1
Commonly implicated drugs causing SJS/TEN
Drugs causing SJS | ||
|---|---|---|
Antimicrobials | Anticonvulsants | Nonsteroidal anti-inflammatory drugs |
Sulphonamides | Hydantoin derivatives (phenytoin) | Salicylates |
Penicillins | Carbamazepine | Ibuprofen |
Cephalosporins | Barbiturates | Pyrazolone derivatives |
Ciprofloxacin | ||
Rifampicin | ||
Isoniazid | ||
Chloroquine | ||
SJS occurs in individuals with lowered ability to detoxify reactive metabolites of drugs or due to an alteration of detoxifying enzymes due to a genetic basis or an acquired decrease in detoxifying enzymes as in acquired immune deficiency syndrome (AIDS). The incidence of SJS in AIDS is significantly more than the general population. The altered metabolite or drug act as haptens which bind to keratocytes and initiate a T cell immune reaction leading to keratocyte apoptosis. There is an increased incidence of HLA-B12, HLA-Aw33 and DRw5 in patients with the ocular lesions of Stevens-Johnson syndrome [1].
Clinical Features
The typical interval between taking a drug and disease manifestation is between 1 and 3 weeks with a rapid recurrence when the patient is re-exposed to the same medication. The prodromal clinical features include fever, malaise, myalgia, upper respiratory tract infection, prostration and arthralgias that precede the skin and mucous membrane lesions.
Skin Lesions
The cutaneous lesion consists of flat-topped erythematous macules which can form vesicles and bullae with epidermal necrosis having an atypical target lesion configuration. Skin lesion heals with residual hyperpigmentation and scarring. Nikolsky’s sign (separation of apparently normal epithelium with minimal friction) is positive in patients with TEN.
The differences between SJS, TEN and EMM are mentioned in Table 26.2.
Table 26.2
Differences between SJS/SJS-TEN overlap/TEN/EMM
SJS | SJS-TEN overlap | TEN | EMM | |
|---|---|---|---|---|
Type of lesion | Widespread macule or flat atypical target lesion | Widespread macule or flat atypical target lesion | Widespread macule or flat atypical target lesion | Localised typical target or raised atypical target lesion |
Distribution of lesion | Trunk and head | Trunk and head | Trunk and head | Acral (extremities) |
Extent of epithelial detachment (BSA) | <10 % | 10–30 % | >30 % | <10 % |
Aetiology | Cutaneous adverse drug reaction | Cutaneous adverse drug reaction | Cutaneous adverse drug reaction | Infective aetiology? Viral |
Histopathology | Necrotic reaction. Predominant dendritic cells and macrophages and TNF alpha | Necrotic reaction | Necrotic reaction
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