This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
[{'content': "Rigidity of facial muscles 'Risus sardonicus' is associated with: \nSelect and explain. \nA. Tetany, B. Tetanus, C. Leprosy, D. Actinomycosis", 'role': 'user'}, {'content': "Answer: B \nExplanation: Generalized\xa0tetanus\xa0is\xa0characterized\xa0by lock-jaw or trismus due to spasm of masseter, which is the initial symptom\xa0and a dental surgeon is the first person often to be consulted. Dysphagia, stiffness or pain in the neck, shoulder or back muscles appear concurrently. Marked rigidity interferes with\xa0the\xa0movement\xa0of\xa0chest\xa0and\xa0impairs\xa0cough\xa0and\xa0swallowing reflexes. Laryngeal spasms may lead to asphyxia. The involvement\xa0of\xa0various\xa0muscles\xa0produces\xa0rigid\xa0abdomen and stiff proximal limb muscles. Hands and feet are relatively spared and sustained contraction of facial muscles results in a grimace or sneer called risus sardonicus. The contraction of muscles of the back produces an arched back called opisthotonus. The spasms\xa0occur\xa0repetitively\xa0or\xa0spontaneously or provoked\xa0by\xa0slight stimulation.\nTreatment\nAntitoxin\xa0is\xa0injected\xa0to\xa0neutralize\xa0circulating\xa0toxin\xa0and unbound toxin. Human tetanus immunoglobulin (TIG) 3000–6000 units\xa0IM individual doses. Though the optimum dose is not known, a 500 unit dose is as effective as higher doses.\xa0\nProphylaxis -\xa0Wound debridement and booster doses of TT.\xa0\nUnimmunized individuals -\xa0Anti-tetanus serum 1500 units or TIG 250 units should be given.\xa0\nRef: Shafer's textbook of oral pathology 7th edition page 328", 'role': 'assistant'}]