Chapter 45: Acute Rheumatic Fever

Patient Story

An 11-year-old girl was referred for evaluation of a heart murmur. She has right knee pain and swelling that was preceded by right ankle pain and swelling. Three weeks prior to the presentation, she had a fever and sore throat. On exam, she has swelling and tenderness of her right knee, a hyperdynamic precordium with a pansystolic murmur heard best at the apex. She has an elevated Anti-streptolysin O (ASO) titer. Her echocardiogram confirms severe mitral regurgitation (Figure 45-1). She was diagnosed with acute rheumatic fever and admitted to the hospital. She was treated with penicillin, aspirin, and bed rest with significant clinical improvement. She was discharged from the hospital within a week and over the course of the next few months, her mitral regurgitation improved.

Introduction

Acute rheumatic fever (ARF) is an inflammatory disease that affects susceptible children and adolescents, (most commonly aged 3 to 19 years). It is mediated by humoral and cellular autoimmune responses that occur as delayed sequelae of Streptococcus pyogenes (group A) (GAS) pharyngitis. The manifestations of ARF usually manifest 2 to 4 weeks after the initial infection.

Synonyms

• Sydenham’s chorea is also called St. Vitus’ dance. It is only one manifestation of ARF and is addressed in the following section.

Epidemiology

• Rheumatic heart disease has a prevalence of at least 15.6 million cases, with 282,000 new cases and 233,000 deaths each year.¹

• The disease today mostly occurs in developing countries.

• There has been a dramatic decline in the incidence of ARF in the US over the past few decades. Although the reasons for this decline are not entirely clear, a shift in the prevalence from circulating rheumatologic to nonrheumatologic strains of GAS likely has played an important role.²

• Nevertheless, outbreaks of acute ARF have continued to occur in the US over the past three decades.^3,4

Etiology and Pathophysiology

• Mimicry between group A streptococci and host antigens has been proposed as a mechanism for the development of the manifestations observed in ARF.

• GAS possess antigens and superantigens, which stimulate B and T cells to respond to self.

Risk Factors

Risk factors for RF can be categorized as being:

• Socioeconomic factors such as poverty, crowding, lack of education, and poor access to health care.

• Biological factors such as failure to diagnose the infection and genetic susceptibility.

• Lifestyle factors, such as poor nutrition.

Diagnosis

Clinical Features