An 18-year-old young man complains of pain in his knee and elbow joints and body temperature up to 39.5°C. One week and a half earlier he developed a sore throat. On examination his body temperature is 38.5°C. Swelling of the knee and elbow joints is observed. Pulse is 106/min., rhythmic. Blood pressure is 90/60 mm Hg. Cardiac borders are unchanged, heart sounds are weakened, at the cardiac apex there is a soft systolic murmur. What factor would be the most indicative of the likely disease etiology?

Answer options

1. C-reactive protein
2. Rheumatoid factor
3. Seromucoid
4. Anti-streptolysin O
5. Creatine kinase

Explanation

An 18-year-old young man complains of pain in his knee and elbow joints and body temperature up to 39.5°C. One week and a half earlier he developed a sore throat. On examination his body temperature is 38.5°C. Swelling of the knee and elbow joints is observed. Pulse is 106/min., rhythmic. Blood pressure is 90/60 mm Hg. Cardiac borders are unchanged, heart sounds are weakened, at the cardiac apex there is a soft systolic murmur. What factor would be the most indicative of the likely disease etiology?Sore throats are usually Strep infections which could be indicated by Anti-streptolysin O Antistreptolysin O (ASO) titer is a blood test to measure antibodies against streptolysin O, a substance produced by group A streptococcus bacteria. Antibodies are proteins our bodies produce when they detect harmful substances, such as bacteria.