The types and timing of the degenerative changes seen in the cysts during and after benzimidazole treatment of cystic echinococcosis

Abstract

In a large-scale Bulgarian study, 122 patients with abdominal and/or lung echinococcosis were randomly selected for treatment with albendazole or mebendazole. The main aims were to evaluate the effect of each drug on the hydatid cysts, to follow the changes in cyst morphology during and after treatment, and to determine how quickly each drug produced the first, detectable, degenerative changes in the cysts. Follow-up was based on periodic ultrasonography, chest radiography and computed tomography. The abdominal cysts were categorised as small (<5 cm in diameter) or large. As albendazole treatment had effects that were almost identical to those of mebendazole treatment, the results for the two drugs were combined. In the lungs and, particularly, in the abdomen, the size of the cysts being treated influenced the character and timing of the degenerative changes seen in them. The initial change seen in each abdominal cyst was detachment of the endocyst, which occurred 1-3 months (small cysts) or 2-5 months (large cysts) after the initiation of treatment (P<0.05). The abdominal cysts then developed a hyper-echoic/hyper-dense appearance, became smaller, and finally disappeared 3.3-9.3 months (small cysts) or 5.6-13.9 months (large cysts) after treatment began (P<0.05). The first degenerative change noted in the lung cysts was cyst rupture, which occurred as early as day 10 of therapy but was generally observed 1 or 2 months after treatment began. After their complete evacuation, the ruptured lung cysts shrank and became deformed, some disappearing within 5-9 months of the initiation of treatment. The degenerative changes recorded, which began significantly earlier in the lung cysts than in abdominal cysts, indicate serious damage to the cysts and the parasiticidal, curative effect of each of the two benzimidazoles employed.

Evaluation of Oxfendazole, Praziquantel and Albendazole against Cystic Echinococcosis: A Randomized Clinical Trial in Naturally Infected Sheep

“…Although that difference might not be clinically relevant (approximately 10 mm in diameter for hepatic cysts), cyst reduction is one of the indicators of successful treatment as evidenced in chemotherapy studies in humans. For instance, a study evaluating the timing and degenerative changes in the cysts after patients received benzimidazole treatment demonstrated that abdominal cysts (<5 cm diameter) became smaller after 3.3–9.3 months [37]. We furthermore showed that the decreased cyst diameter can be observed in a relatively short period of time (4–8 weeks).…”

Disseminated Abdominal Hydatidosis: A Rare Presentation of Common Infectious Disease

“…Todorov and his colleagues evaluated the degenerative changes seen in the cyst with benzimidazole therapy in 122 patients and they found that the initial change to be seen in abdominal cysts is detachment of the endocyst followed by hyperdense appearance and shrinking of the cyst until it finally disappears [14]. This process may take up to one year of treatment and it is indicative of the parasiticidal effect of benzimidazoles on the cysts [14].…”

“…This process may take up to one year of treatment and it is indicative of the parasiticidal effect of benzimidazoles on the cysts [14]. …”

Long-Term Evaluation of Patients with Hydatidosis Treated with Albendazole and Praziquantel

“…(9,11,(16)(17)(18). According to Todorov et al (18) the first degenerative changes occurred 1-3 months (small cysts <5 em) or 2-5 months (large cysts) after initiation of treatment, and then cysts became smaller, and finally disappeared 3.3-9.3 months (small cysts) or 5.6-13.9 months (large cysts) after treatment began.…”