Group A Strep (GAS) Infection Complications
Bacteremia refers to the presence of bacteria in the bloodstream. GAS bacteremia is believed to be responsible for 3.3% of cases of bacteremia in children and 0.6% of cases of bacteremia in adults. Risk factors for GAS bacteremia include burns, varicella virus infection, cancer, immunosuppression from corticosteroid use, immunocompromised status, intravenous drug use, HIV infection, post-influenza GAS pneumonia, surgery, trauma, diabetes, peripheral vascular disease, and cardiac disease. Despite the relatively low frequency, GAS nevertheless remains a serious infection whose mortality (death rate) for adults ranges from 25%-48% and for children, approximately 8%. The mortality for those patients who develop shock is higher, and this may be the most important predictor of mortality.
Scarlet fever is characterized by the development of a diffuse, fine rash coincident with acute GAS pharyngitis.
A form of kidney inflammation known as glomerulonephritis may be a complication of GAS infection. Glomerulonephritis that occurs secondary to GAS infection, likely mediated by the body's immunologic response to acute GAS infection, typically occurs one to two weeks following an initial infection.
Acute rheumatic fever (ARF), another potential complication of GAS infection, typically occurs two to four weeks following acute GAS tonsillopharyngitis. ARF is an inflammatory disease that may occur following inadequately treated GAS infection. Symptoms vary and can include fever, joint pain and swelling, small nodules beneath the skin, rash, heart murmur, and neurologic changes like abnormal body movements (chorea) or unusual behavior. ARF can cause permanent damage to the heart. Rheumatic heart disease, a spectrum of progressive valvular heart disease and carditis that occurs as a late sequel of acute rheumatic fever, typically occurs 10-20 years following the initial infectious process.
Treatment of potentially life-threatening complications of GAS infections includes not only eradication of the organism from normally sterile sites throughout the body but also management of secondary problems -- namely, hypotension, tachycardia, and end organ system failure, typical hepatic and renal, that occur in streptococcal toxic shock syndrome. The diagnosis of STSS is made by isolating the organism in a culture sent to the laboratory from a normally sterile site (skin, throat, vagina) and by the observation of hypotension along with two or more of the following: renal dysfunction; blood-clotting disturbances; liver dysfunction; acute respiratory distress syndrome; a diffuse, red, flat rash and/or soft-tissue necrosis. Other conditions that may cause similar symptoms must also be ruled out, such as staphylococcal toxic shock syndrome, typhoid fever, Rocky Mountain spotted fever, meningococcemia, infection with S. pneumonia, leptospirosis, and heat stroke.
Pediatric autoimmune neuropsychiatric disorder associated with group A streptococci (PANDAS) is a controversial entity observed in a small subset of pediatric patients. It is believed that GAS infection triggers a heightened immunologic response with subsequent central nervous system manifestations, including abrupt and episodic onset of obsessive-compulsive disorder (OCD) and/or tic disorder and other neurological abnormalities involving abnormal motor activity. Demonstration of a temporal relationship between an acute GAS infection and the development of neuropsychiatric symptoms is essential for the diagnosis of PANDAS.