Clinical Information. The Chagas Disease or American Trypanosomiasis. The ChagaSpace Group



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• Epidemiology
• Mortality
• Race, Sex and age
• Modes of Transmission
• Pathophysiology
• Clinical Information
• Diagnosis
• Other Medical Information

Progress of the Disease

Incubation.

• Incubation is asymptomatic and lasts 7-10 days in cases of vectorial contamination and 20-40 days in cases of transmission by blood transfusion.

• The latter, more prolonged incubation period is believed to be due to the weaker capacity of circulating blood trypomastigotes to invade cells, compared to the metacyclic trypomastogotes.

Acute Phase.

• The acute phase, defined by the detection of blood parasites using direct classic parasitological techniques (see workup), usually affects children and young adults and remains asymptomatic in other patients.

• Mortality in the acute phase, due to acute myocarditis and/or meningoencephalitis, occurs in fewer than 5% of children younger than 2 years.

• In most persons who are infected, the illness is not diagnosed because of the nonspecific nature of the signs and symptoms and because some people lack access to medical care.

• The manifestations of the acute disease resolve spontaneously within 3-8 week in approximately 90 % of individuals who are infected. The latter enter in the so-called Chronic latent or indeterminate asymptomatic phase of the disease.

• A direct progression from the acute phase to a defined (symptomatic) chronic form of chagas disease occurs in fewer than 5% of patients.

• Symptoms of the acute phase may include malaise, myalgia, headche, asthenia and annorexia.

Indeterminate Phase

• Infection in patients in the indeterminate phase can be recognized by positive serological test because subpatent parasitemia is no longer detectable by the parasitological ,methods.

• Approximately 50-70 % of patients in the indeterminate phase never develop chronic lesions and remain asymptomatic. The other 30-50% of patients develop cardiac and/ or digestive dysfunction 10-30 years after the acute infection.

Defined Clinical forms of Chronic Chagas Disease

Cardiac involvement is the most frequent and serious defined manifestation of chronic Chagas disease and typically leads to arrhytmias, cardiac failure, thromboembolic phenomena, and sudden death.

Symptoms of chronic chagasic cardiomyopathy are as follows:

• Palpitations, dizziness, syncope, and Adams-Stokes syndrome, ie, due, to arrhythmias.

• Atypical precordial chest pain without evidence of coronary artery disease.

• Dyspnea (in case of heart failure).

• Symptoms related to the clinical manifestations of thromboembolims, mainly in brain, lungs, and limbs.

The digestive forms of the disease lead to megaesophagus and/or megacolon. Symptoms are as follows:

• Dysphagia, mainly for dry, solid, and cold food.

• Severe constipation for a few days to 2-3 months and abdominal pain (frequently associated with episodes of bowel obstruction)

Physical:

Acute phase

• Fever: This is present and is often a suggestive sign.

• Lesion at the portal of entry of the parasite (vectorial transmission): The chagoma (furunculoid and pealing cutaneous lesion) occurs in cases of parasite entry through the skin. The Romaña sign occurs in cases of entry through the conjunctiva. The Romaña sign is a typical sign present in 20-50% of acute cases. It is a painless, periophthalmic, unilateral edema of both palpebra, frequently accompanied by conjunctivitis and local lymph node enlargement. It persists for 30-60 days.

• Liver and spleen enlargement: An enlarged liver and spleen are mainly observed in children, whereas generalized lymphadenopathy is observed in 60% of patients.

• Edema: Subcutaneous edema, either generalized or localized to the face and/or lower extremities, is observed in 30-50% of cases.

• Rash: Patients may develop a rash. No itching occurs, and the rash clears in several days.

• Heart rhythm: A persistent tachycardia may be observed in 30-80% of patients.

• Heart and meninges: Signs of acute myocarditis or meningoencephalitis develop in some cases of congenital infection or in patients with recrudescent T cruzi infection due to HIV (AIDS) co-infection.

• Lung: Bronchopneumonitis is sometimes observed in congenital cases.

Chronic chagasic cardiomyopathy

• Heart failure: Signs of isolated left heart failure may be present in the early stages of chronic chagasic cardiomyopathy. Biventricular heart failure with peripheral edema, hepatomegaly, and pulmonary congestion are more frequent in the later stages.

• Thromboemboli: Signs of thromboembolism are present, mainly in the brain, lungs, and limbs.

Chronic Chagasic megaesophagus.

• Pneumonitis related to regurgitation and aspiration of food (particularly during sleep).

• Irritative esophagitis

• Salivary gland hypertrophy

• Weight loss and cachexia (in severe cases)

• Signs of rupture of esophagus

• Increased incidence of cancer of the esophagus.

Chronic chagasic megacolon.

• Asymmetric distension of abdomen.

• Meteorism.

• Fecaloma.

• Signs of intestinal occlusion, sigmoid volvulus.

Causes.

Factors depending on parasites (eg, size, of rthe inoculum , repeated inoculations) and indicivualas, host differences, immunological or nutritional status) likely contribute to the diversity of clinical forms of chagas disease.

The occurrence of cardiopathy and digestive forms of Chagas disease has been associated with some HLA haplotypes.

Correlation has still not been established among the genetic polymorphims of the parasite, the degree of parasitemia or the level of antibodies, and the different clinical forms of the severity of lesions in humans.