Answer 75 - Streptococcus pyogenes.
Strep. pyogenes
a. is the most common bacterial cause of tonsillitis
b. asymptomatic pharyngeal carriage occurs in about 10% of children
c. septicaemia carries a mortality similar to meningococcal septicaemia
d. pharyngitis may be complicated by suppurative cervical adenitis
e. causes scarlet fever
All true
a. Acute pharyngitis is usually caused by viral infections. Strep. pyogenes is the cause in up to 50% of children aged 4-13 years but in <30% of cases in other age groups. Other bacterial causes of pharyngitis include gonococcus, diphtheria and Arcanobacterium haemolyticum.
b. Asymptomatic carriage occurs in about 10% of children. Bacterial numbers are generally small. Risk of systemic spread and of acute rheumatic fever is generally very low in such cases.
c. Strep. pyogenes septicaemia has a mortality of about 50%. Severe Strep. pyogenes infections (bacteraemia, septic shock like syndrome and necrotising fasciitis) as a group are now more common than meningococcal septicaemia.
d. Complications of pharyngeal infection include: otitis media, suppurative cervical adenitis, quinsy, acute rheumatic fever and acute post infectious glomerulonephritis.
