Signs and symptoms include fever, malaise, headache, and enlargement of the liver, spleen, and lymph nodes. Sometimes, people develop a swollen nodule at the site of infection, which is called "Romañas sign" if it is on the eyelid, or a "chagoma" if it is elsewhere on the skin. In rare cases (less than 1–5%), infected individuals develop severe acute disease, which can involve inflammation of the heart muscle, fluid accumulation around the heart, and inflammation of the brain and surrounding tissues, and may be life-threatening. The acute phase typically lasts four to eight weeks and resolves without treatment.Unless treated with antiparasitic drugs, individuals remain infected with T. cruzi after recovering from the acute phase. Most chronic infections are asymptomatic, which is referred to as indeterminate chronic Chagas disease. However, over decades with the disease, approximately 30–40% of people develop organ dysfunction (determinate chronic Chagas disease), which most often affects the heart or digestive system.The most common long-term manifestation is heart disease, which occurs in 14–45% of people with chronic Chagas disease. People with Chagas heart disease often experience heart palpitations, and sometimes fainting, due to irregular heart function. By electrocardiogram, people with Chagas heart disease most frequently have arrhythmias. As the disease progresses, the hearts ventricles become enlarged (dilated cardiomyopathy), which reduces its ability to pump blood. In many cases the first sign of Chagas heart disease is heart failure, thromboembolism, or chest pain associated with abnormalities in the microvasculature.Also common in chronic Chagas disease is damage to the digestive system, which affects 10–21% of people.
Foscarnet (phosphonomethanoic acid), known by its brand name Foscavir, is an antiviral medication which is primarily used to treat viral infections involving the Herpesviridae family. It is classified as a pyrophosphate analog DNA polymerase inhibitor. Foscarnet is the conjugate base of a chemical compound with the formula HO2CPO3H2 (Trisodium phosphonoformate).Foscarnet was approved for medical use in 1991. Medical use
This phosphonic acid derivative (marketed by Clinigen as foscarnet sodium under the trade name Foscavir) is an antiviral medication used to treat herpes viruses, including drug-resistant cytomegalovirus (CMV) and herpes simplex viruses types 1 and 2 (HSV-1 and HSV-2). It is particularly used to treat CMV retinitis. Foscarnet can be used to treat highly treatment-experienced patients with HIV as part of salvage therapy. Mechanism of action
Foscarnet is a structural mimic of the anion pyrophosphate that selectively inhibits the pyrophosphate binding site on viral DNA polymerases at concentrations that do not affect human DNA polymerases.In individuals treated with the DNA polymerase inhibitors acyclovir or ganciclovir, HSV or CMV particles can develop mutant protein kinases (thymidine kinase or UL97 protein kinase, respectively) that make them resistant to these antiviral drugs. However, unlike acyclovir and ganciclovir, foscarnet is not activated by viral protein kinases, making it useful in acyclovir- or ganciclovir-resistant HSV and CMV infections.However, acyclovir- or ganciclovir-resistant mutants with alterations in viral DNA polymerase may also be resistant to foscarnet. Administration
Foscarnet is administered by intravenous infusion or intravitreous injection. Side effects
Nephrotoxicity — increase in serum creatinine levels and renal injury can occur in patients receiving foscarnet.