Combining lamotrigine with sodium valproate increases the risk of SJS.Nonsteroidal anti-inflammatory drugs (NSAIDs) are a rare cause of SJS in adults; the risk is higher for older patients, women, and those initiating treatment. Typically, the symptoms of drug-induced SJS arise within a week of starting the medication. Similar to NSAIDs, paracetamol (acetaminophen) has also caused rare cases of SJS. People with systemic lupus erythematosus or HIV infections are more susceptible to drug-induced SJS. Infections
The second most common cause of SJS and TEN is infection, particularly in children. This includes upper respiratory infections, otitis media, pharyngitis, and Epstein–Barr virus, Mycoplasma pneumoniae and cytomegalovirus infections. The routine use of medicines such as antibiotics, antipyretics and analgesics to manage infections can make it difficult to identify if cases were caused by the infection or medicines taken.Viral diseases reported to cause SJS include: herpes simplex virus (possibly; is debated), AIDS, coxsackievirus, influenza, hepatitis, and mumps.In pediatric cases, Epstein–Barr virus and enteroviruses have been associated with SJS.Recent upper respiratory tract infections have been reported by more than half of patients with SJS.Bacterial infections linked to SJS include group A beta-hemolytic streptococci, diphtheria, brucellosis, lymphogranuloma venereum, mycobacteria, Mycoplasma pneumoniae, rickettsial infections, tularemia, and typhoid.Fungal infections with coccidioidomycosis, dermatophytosis and histoplasmosis are also considered possible causes. Malaria and trichomoniasis, protozoal infections, have also been reported as causes. Pathophysiology
SJS is a type IV hypersensitivity reaction in which a drug or its metabolite stimulates cytotoxic T cells (i.e. CD8+ T cells) and T helper cells (i.e.
Supernumerary phantom limb is a condition where the affected individual believes and receives sensory information from limbs of the body that do not actually exist, and never have existed, in contradistinction to phantom limbs, which appear after an individual has had a limb removed from the body and still receives input from it. An fMRI study of a subject with a supernumerary phantom left arm was done by Khateb et al. at the Laboratory of Experimental Neuropsychology at the University of Geneva. When the subject was told to touch her right cheek with the phantom limb, there was increased activity in the motor cortex of her brain in the area roughly corresponding to the left arm. When she announced that she had touched the phantom limb to her cheek, activity was monitored in the area of the somatosensory cortex that corresponded to the right cheek. At times during the experiment, the subject was asked to move the phantom limb to a location that was obstructed or otherwise unfeasible. In these instances, there was similar activation of the motor cortex but no such activity in the somatosensory cortex. Affected areas of the brain
Motor cortex
Somatosensory cortex
Tactile (touch) controlling areas

See also
Body integrity identity disorder (BIID)
Supernumerary body part – having an extra limb

References

McGeoch, P.D. et al. (2009). Apotemnophilia – the neurological basis of a ‘psychological’ disorder. Nature Precedings DOI: 10101/npre.2009.2954.1.