Chagas Disease: Creeping into Family Practice in the United States
Although accreditation for this CE/CME activity has expired, and the posttest is no longer available, you can still read the full article.
Expires October 31, 2017
Chagas disease, a parasitic infection, is increasingly being detected in the United States, most likely due to immigration from endemic countries in South and Central America. Approximately 300,000 persons in the US have chronic Chagas disease, and up to 30% of them will develop clinically evident cardiovascular and/or gastrointestinal disease. Here’s practical guidance to help you recognize the features of symptomatic Chagas disease and follow up with appropriate evaluation and management.
PHYSICAL EXAMINATION: A CRUCIAL STEP
The physical examination of a patient with suspected Chagas disease can be crucial to the diagnosis. As noted, there are often few specific symptoms or physical exam findings during the acute phase. However, in some patients, swelling and inflammation may be evident at the site of inoculation, often on the face or extremities. This finding is called a chagoma. The Romaña sign, characterized by painless unilateral swelling of the upper and lower eyelid, can also be seen if the infection occurred through the conjunctiva.5 A nonpruritic morbilliform rash, called schizotrypanides, may be a presenting symptom in patients with acute disease.13 Children younger than 2 years of age are at increased risk for a severe acute infection, with signs and symptoms of pericardial effusion, myocarditis, and meningoencephalitis. Children can also develop generalized edema and lymphadenopathy. Those children who develop severe manifestations during acute infection have an increased risk for mortality.5
Chronic chagasic cardiomyopathy may present with signs of left-sided heart failure (pulmonary edema, dyspnea at rest or exertion), biventricular heart failure (hepatomegaly, peripheral edema, jugular venous distention), or thromboembolic events to the brain, lower extremities, and lungs.13 Chronic chagasic megaesophagus may lead to weight loss, esophageal dysmotility, pneumonitis due to aspiration of food trapped in the esophagus and stomach, salivary gland enlargement, and erosive esophagitis, which increases the risk for esophageal cancer. Chronic chagasic megacolon can present as an intestinal obstruction, volvulus, abdominal distention, or fecaloma.13
Clinicians should be alert to the possibility of congenital T cruzi infection in children born to women who emigrated from an endemic area or who visited an area with a high prevalence of Chagas disease. Most newborns with T cruzi infection are asymptomatic, but in some cases a thorough neonatal exam can lead to the diagnosis. Manifestations of symptomatic congenital infection include hepatosplenomegaly, low birth weight, premature birth, and low Apgar scores.5 Lab tests may reveal thrombocytopenia and anemia. Neonates with severe disease may also have respiratory distress, meningoencephalitis, and gastrointestinal problems.5
,LABORATORY WORK-UP
Laboratory work-up for Chagas disease depends on the provider’s awareness of the disease and its symptoms. All patients should undergo routine blood work, including complete blood count (CBC) with differential, comprehensive metabolic panel (CMP), and liver function tests to rule out other etiologies that manifest with similar symptoms. If the patient presents during the acute phase, microscopy of blood smears with Giemsa stain should be done to visualize the parasites. In the patient who presents during the chronic phase with cardiac symptoms, measurement of B-type natriuretic peptide, troponin, C-reactive protein, and the erythrocyte sedimentation rate can be used to rule out other differential diagnoses. Electrocardiogram (ECG) may show a right bundle-branch block or left anterior fascicular block.5 Echocardiogram may show left ventricular wall motion abnormalities and/or cardiomyopathy with congestive heart failure.5,10 A work-up for digestive Chagas disease may include a barium swallow, kidney-ureter-bladder x-ray, or MRI/CT of the abdomen.14
