microbio 2125 unit 5 (part 6) Streptococcal Diseases – Long-term Complications / Sequelae

Rheumatic fever

follows overt or subclinical pharyngitis in children or scarlet fever, lasts 3 - 6 months, can lead to carditis with extensive valve damage possible, degree of damage not apparent until middle age

Acute glomerulonephritis

nephritis, increased blood pressure, occasionally heart failure; can become chronic leading to kidney failure

Etiological Agent:

Streptococcus pyogenes (post-infection immunological response)

Distinguishing characteristics of etiological agent:

• Usually arranged in chains or as diplococci

• Non-spore forming, non-motile

• Form capsules and slime layers

• β-hemolytic on blood agar

• Strict parasite

• Inhabits throat, nasopharynx, occasionally skin 

• Most serious streptococcal pathogen

Virulence Factor(s):

C-carbohydrates and M-protein

the others might show up maybe Hemolysins, C5a protease, Hyaluronic acid, & Erythrogenic toxin in some instances

Predisposing Factors:

• Untreated or recurrent strep throat infections

• Genetic susceptibility (rheumatic fever)

• Children ages 5–15 (most at risk)

Transmission:

Not directly transmissible — these are immune-mediated complications following infection) but…

• contact, droplets, food, fomites

Syndrome (signs + symptoms): Rheumatic fever

• can cause arthritis, chorea, fever and nodules under skin

migratory arthritis, carditis, chorea, subcutaneous nodules, erythema marginatum

Syndrome (signs + symptoms): Acute glomerulonephritis

hematuria (“cola-colored urine”), edema, hypertension, proteinuria

• can become chronic leading to kidney failure

Affected body region/system:

Heart, joints, kidneys, CNS

Treatment:

• No treatment for rheumatic fever and acute glomerulonephritis once developed, must treat preceding infections to avoid these conditions

  • Recommend long-term penicillin prophylaxis for people with history of rheumatic fever or recurrent strep throat

Prevention:

• Timely and complete antibiotic treatment of strep throat

• Long-term prophylaxis in rheumatic fever patients to prevent recurrence

Other notes:

• Rheumatic heart disease can lead to lifelong cardiac issues… rheumatic fever can lead to carditis with extensive valve damage possible, degree of damage not apparent until middle age

• Glomerulonephritis usually resolves but can lead to chronic kidney disease in rare cases

Sequelae

are long-term or delayed complications that occur after the resolution of an initial disease or infection.
for example Rheumatic fever is a sequela of untreated streptococcal pharyngitis.