A 3-year-old girl has a two-day history of dyspnea with feeding, vomiting, and pallor. On
arrival, she is tachypneic, tachycardic, hypotensive, and febrile. Physical examination shows eyelid
puffiness, hepatomegaly, and generalized edema. Her mother reports that she recently had a runny
nose for a few days and a low-grade fever that self-resolved. The most likely pathogen responsible
for this patient’s condition is also known to be associated with which of the following?
- A) Renal insufficiency
- B) Hand-foot-mouth disease
- C) Herpangina
- D) Pulmonary hypertension
- D) Diabetes mellitus
0 voters
This patient has dilated cardiomyopathy caused by coxsackie B virus-induced myocarditis.
Myocarditis is a common cause of dilated cardiomyopathy.1 The majority of cases of myocarditis
are secondary to a viral infection, with the most common in children being coxsackie B virus.2, 3
The most likely pathophysiology is direct viral cytotoxicity to myocardium.4 This mechanism is
exceedingly HY on the USMLE because it contrasts with rheumatic fever due to Group A Strep,
which is a type II hypersensitivity.5
Dyspnea with feeding, vomiting, and pallor are frequently seen in infants with viral-induced
cardiomyopathy. Tachypnea, tachycardia, and fever are also common clinical signs. Hypotension
reflects a decompensation in cardiac function.6
In addition to dilated cardiomyopathy, coxsackie B virus is associated with the development
of diabetes mellitus type I.7
Mechanism
• Viral induction of autoimmunity is believed to be due to either T cell activation or molecular
mimicry. Coxsackie B4 virus is strongly associated with the development of diabetes mellitus
type I and shares sequence homology with the islet auto-antigen glutamic acid decarboxylase
(GAD).