Methods

Blood investigation was done and revealed Hemoglobin 9.65 gm% [Normal: 12-16 gm%], Neutrophil 41% [Normal: 40-60%], Lymphocyte 43% [Normal: 20-40%], Platelet 4,45,6000 cells/cum [Normal: 150,000-450,000 cells/cumm]. Her PT count was 32.8 second [Normal: 11-13.5 seconds], and INR was 2.5 [Normal: 0.8-1.2]. Her biochemical profile revealed Blood Urea Nitrogen to be 11 mg/dl [Normal: 7-20 mg/dl], Creatinine 0.7 mg/dl [Normal: 0.6-1.2 mg/dl], Sodium 137 mmol/L [Normal: 135-145 mmol/L] and potassium 3.7 mmol/L [Normal: 3.5-5.0 mmol/L]. Blood culture and urine culture were sterile. However, Hematology and serology tests suggested increased ESR and positive CRP Latex. The Renal function test was also normal. Further, Urinalysis was done and was found to be normal. (Table 1) Based on the history, examination, and investigations, serum sickness, hepatitis, and viral illness, including dengue, acute rheumatic fever, and subacute bacterial endocarditis, were considered for differential diagnosis. For further confirmation and to rule out other conditions, Hepatitis B antigen serology, antinuclear antibody, ELISA, Direct Coombs, Rheumatic factor, Anti CCP, and LDH tests were done to rule out other conditions and came negative. The absence of fever, thrombocytopenia, malaise, and weakness ruled out another differential diagnosis except for serum sickness and infective endocarditis. Having temporal association with streptokinase, absence of infective endocarditis symptoms (petechiae, Osler node, Janeway node, splinter haemorrhage, sign of sepsis), sterile blood culture, normal cardiac examination (including inspection, palpation, percussion and auscultation) , Serum sickness as a diagnosis was made. Further Rheumatological consultation was done, and a clinical diagnosis of serum sickness secondary to streptokinase therapy was made, considering the clinical history and laboratory investigation.