Ans. (c). i.e. N. meningitidis The patient here is under state of shock (hypotension, tachycardia) in conjunction with meningitis (headache fever)and rash. Meningococcal meningitis is the most common meningitis complicated by shock. CLINICAL MANIFESTATION OF MENINGOCOCCAL DISEASE Rash A nonblanching rash (petechial or purpuric) develops in >80% of cases of meningococcal disease. Rashesare initially blanching in nature but within hours become non-blanching. In severe cases large purpuriclesions (purpura fulminons) develops. Meningitis Commonly present as fever, vomiting, headache, irritability, petechial or purpuric rash occurs in 2/3 of cases. Headache is seen in adults usually. In upto 40% of cases there are some features of septicemia too. Septicemia Can be isolated or as a accomplication of meningitis. The condition may cause death within hours. Purpura fulminans is a specific feature. Chronic meningococcemia Present as repeated episodes of petechial rash associated with fever joint pain, ahritis and splenomegaly. The main differential diagnosis is acute rheumatic fever. This condition has been associated with complement deficiently and with inadequate sulfonamide therapy. If left untreated chances of progression to meningococcal septicemia are high. Postmeningococcal reactive disease In small propoion of patients, an immune complex disease develops 4-10 days after the onset of meningococcal disease with manifestations that include a maculopapular or vasculitic rash, ahritis, pericarditis and/or polyserosites associated with fever.