Opisthorchiasis-associated biliary stones: light and scanning electron microscopic study

Aim: Biliary stones are frequently encountered in areas endemic for opisthorchiasis in Thailand. The present study was to describe the prevalence and pathogenesis of these stones. Methods: Gallstones and/or common bile duct stones and bile specimens from 113 consecutive cholecystectomies were included. Bile samples, including sludge and/or microcalculi, were examined for Opisthorchis viverrini eggs, calcium and bilirubin. The stones were also processed for scanning electron microscopic (SEM) study. Results: Of the 113 cases, 82 had pigment stones, while one had cholesterol stones. The other 30 cases had no stones. Most of the stone cases (76%, 63/83) had multiple stones, while the remainder had a single stone. Stones were more frequently observed in females. Bile examination was positive for O. viverrini eggs in 50% of the cases studied. Aggregates of calcium bilirubinate precipitates were observed in all cases with sludge. Deposition of calcium bilirubinate on the eggshell was visualized by special staining. A SEM study demonstrated the presence of the parasite eggs in the stones. Numerous crystals, morphologically consistent with calcium derivatives and cholesterol precipitates, were seen. Conclusion: Northeast Thailand has a high prevalence of pigment stones, as observed at the cholecystectomy, and liver fluke infestation seems involved in the pathogenesis of stone formation. Copyrigh

Human Angiostrongyliasis Outbreak in Dali, China

Angiostrongyliasis, caused by the rat lungworm Angiostrongylus cantonensis, is a potentially fatal food-borne disease. It is endemic in parts of Southeast Asia, the Pacific Islands, Australia, and the Caribbean. Outbreaks have become increasingly common in China due to the spread of efficient intermediate host snails, most notably Pomacea canaliculata. However, infections are difficult to detect since the disease has a rather long incubation period and few diagnostic clinical symptoms. Reliable diagnostic tests are not widely available. The described angiostrongyliasis epidemic in Dali, China lasted for eight months. Only 11 of a total of 33 suspected patients were clinically confirmed based on a set of diagnostic criteria. Our results demonstrate that the rapid and correct diagnosis of the index patient is crucial to adequately respond to an epidemic, and a set of standardized diagnostic procedures is needed to guide clinicians. Integrated control and management measures including health education, clinical guidelines and a hospital-based surveillance system, should be implemented in areas where snails are a popular food item

Histological analysis of gallbladder diseases in relation to opisthorchiasis in endemic areas of Thailand

Chronic gallbladder disease frequently accompanies infection with the liver fluke, Opisthorchis viverrini, in Northeast Thailand. However, the pathology and pathogenesis of the gallbladder disease have not been described. Accordingly, gallbladder specimens from 187 consecutive patients who had undergone cholecystectomy at a referral hospital in an endemic area in Thailand were histologically characterized in relation to O. viverrini infection. The infection was assessed by the presence of parasite eggs in the bile and/or antibody response to the liver fluke. The average level of parasite-specific IgG was significantly higher in patients with Opisthorchis eggs in the bile than those without (P < 0.001). The main histopathologic features of the gallbladder included inflammation, mucosal atrophy/or hyperplasia, goblet cell metaplasia, mucous gland hyperplasia, Rokitansky-Aschoff sinus formation, dysplasia and fibrosis. The fibrosis was strongly associated with elevated levels of Opisthorchis-specific antibody (P < 0.001) but not with the presence of parasite eggs. Other pathologic features did not vary in frequency or severity with parasitological status. Our results show that severe fibrosis of the gallbladder is a more common histologic feature of cholecystitis among those with O. viverrini infection compared to those without infection. The close relationship between parasite-specific IgG and severe fibrosis suggests that specific immune response to the parasite play an important role in the pathogenesis of the fibrotic change. (C) 2003 Elsevier B.V. All rights reserved

Macular sensitivity after half-dose verteporfin photodynamic therapy in central serous chorioretinopathy

Thuss Sanguansak, Prapapan Pitujaturont, Yosanan Yospaiboon, Suthasinee Sinawat, Tanapat Ratanapakorn, Chavakij Bhoomibunchoo Department of Ophthalmology, Faculty of Medicine, KKU Eye Center, Khon Kaen University, Khon Kaen, Thailand Objective: To study the macular sensitivity after half-dose verteporfin photodynamic therapy in patients with resolved central serous chorioretinopathy using the automated static perimeter.Methods: Prospective consecutive case study of 24 patients with resolved central serous chorioretinopathy was performed. The macular sensitivity was measured using a conventional automated static perimeter with the Swedish interactive threshold algorithm 10-2 and foveal threshold. Best corrected visual acuity, intraocular pressure, fundus examination, macular thickness, and volume were also examined. The mean macular sensitivities of the affected eyes and their normal fellow eyes were calculated and compared. P&lt;0.05 was considered statistically significant.Results: The mean macular sensitivities of the affected eyes were lower than the normal fellow eyes with a statistically significant difference in all areas of the study (P&lt;0.05). Best corrected visual acuity improved significantly from pretreatment (0.26&plusmn;0.3 logMAR) to posttreatment (0.075&plusmn;0.15 logMAR, P&lt;0.05). Macular thicknesses in affected eyes were 230.66&plusmn;67.34 &micro;m and in the normal eyes were 238.33&plusmn;92.26 &micro;m (P=0.68). Macular volumes in affected eyes were 8.77&plusmn;0.49 and in the normal eyes were 8.70&plusmn;0.50 (P=0.60). These findings were not statistically significant.Conclusion: Eyes with resolved central serous chorioretinopathy after half-dose verteporfin photodynamic therapy had lower macular sensitivity than normal fellow eyes. These findings agreed well with the previous microperimetric studies. The conventional automated static perimeter can also be used when a microperimeter is not available. Keywords: macular sensitivity, half-dose photodynamic therapy, automated static perimeter, central serous chorioretinopath