Disseminated cysticercosis in China with complex and variable clinical manifestations: a case series

Cysticercosis is a parasitic infestation caused by the larval stage (cysticercus) of Taenia solium. Humans become infected by ingesting T. solium eggs liberated from gravid proglottids. The eggs subsequently develop into oncospheres that can hatch and penetrate the intestinal wall and circulate to the musculature. Although larvae can migrate to any human organ or tissue, the cysts can found in the central nervous system (CNS), eyes, muscles, heart, and subcutaneous soft tissues [1]. Cysticercosis is one of the most common neglected tropical diseases (NTD) in developing countries, and is endemic in most of Latin America, Sub-Saharan Africa, Southeast Asia, India, and China [2].

Disseminated cysticercosis (DCC) is an uncommon manifestation of the disease, in which the cysticerci spread to various tissues, organs or systems, such as the lesions in the CNS, eyes, muscles, and subcutaneous tissues at the same time. Although over 100 cases of DCC have been reported in the world, most of them originate from India and neighboring countries in South Asia [3‐5].

In the current study, we reported three DCC cases that were diagnosed and treated in Beijing Friendship Hospital in China. In addition, we have compared these cases to others that have been reported in the literature from Chinese journals.

The clinical and radiological presentations of our patients are summarized in Table 1.

The three DCC cases were all native cysticercosis in three different regions of China, including Beijing, Henan and Heilongjiang provinces. According to the data from the second report on the national survey of important human parasitic diseases in China (2004) [6], the prevalence of cysticercosis has increased from 0.011% in 1992 to 0.58% in 2004. The seroprevalence of cysticercosis was investigated in all provinces/areas of China and was detected in 31, except Beijing, Tianjin, Chongqing, Jiangsu, Zhejiang and Hunan Provinces, and. In this report, DCC cases from Beijing and Henan Province have been reported for the first time.

According to the literature, 13 DCC cases were reported from eight provinces in China from 1982 to 2011 (Table 2). These cases were from the Shanghai, Fujian, Guangxi, Sichuan, Hebei, Heilongjiang, Shandong and Yunnan Provinces of China [7‐16]. In the last 8 years, almost no DCC cases have been reported in the literature. However, we have found three cases of DCC from 2012 to 2016 in China that should be included in the current literature.

Two of our three DCC cases lived in a cysticercosis-endemic area (Henan and Heilongjiang Provinces), and one case was a tapeworm carrier. Notably, the first case was infected by direct ingestion of T. solium eggs for body weight control, and the laboratory tests indicated that the eggs purchased online were the ova of tapeworms rather than roundworms. Data from the second national survey showed that it is not unusual that so-called white-collar staffs, such as office workers and teachers, have a high prevalence of food-borne parasitosis like cysticercosis [6]. A previous study in China also found that among a random sample of 200 cases of cysticercosis from 2004 to 2006, almost a half came from urban areas, while most infected patients had an occupational history as a farmer [17]. For this reason, it is crucial to raise health awareness and knowledge by building a comprehensive public health outreach network in the community [18].

The clinical manifestation of cysticercosis varies between patients. DCC is the most unusual cysticercosis of all forms, as it involves the brain and can be fatal in some cases. In all of the literature from China and our reported cases [7‐16], all cases (16/16, 100%) were neurocysticercosis. Among them, 15 cases were associated with subcutaneous lesions, eight cases with ocular cysticercosis, five cases with pulmonary cysticercosis, and one case each associated with hepatic, splenic, and oral mucosal lesions. Among the three DCC cases in China, Case 1 presented with a very rare form of DCC. She had an active and disseminated parenchymal neurocysticercosis, ocular cysticercosis, soft tissue, and skeletal muscles cysticercosis.

Diagnostic criteria for cysticercosis was based on objective clinical, imaging, immunologic, and epidemiologic data [18]. From the 13 DCC cases, 6 cases (separately reported in 1988, 1991, 2002, 2003, 2011) were confirmed by characteristic lesions on the neuro-imaging and positive by IgG antibody positivity in serum. The rest were confirmed by subcutaneous nodule biopsy, or the eye cysts removed were confirmed as cysticercosis combined with imaging finding and positive serologic tests [7‐16]. In this article, one of the three DCC cases were diagnosed by flat mount preparation of the ocular cyst.

All DCC patients should undergo surgery prior to medical treatment to remove ocular and intraventricular cysticercosis [19], given that inflammation around the degenerating cysticerci in the eye, particularly in the setting of anti-parasitic therapy, can increase the risk of blindness. Subsequently, anti-parasitic therapy was active in treating active cysts, while reducing seizure risk and the likelihood of recurrent hydrocephalus [20]. The significant risk of anti-parasitic therapy was the worsening of neurologic symptoms due to inflammation around the degenerating cyst, particularly for patients with a large number of lesions or elevated intracranial pressure. However, anti-parasitic therapy generally reduced the number of parasites and reduced seizures in patients with seizures due to viable parenchymal cysts [20].

Previous studies have shown that conventional-dose albendazole therapy (15 mg/kg per day in two daily doses up to 800 mg/day, with food) had limited effectiveness in some cases [21], and adjunctive corticosteroids should be administered prior to and during anti-parasitic therapy [19]. Multiple high doses were considered (daily albendazole at a dose of 60 mg/kg of body weight up to 1200 mg/day in three divided doses) over a relatively long course (10 days per course). Albendazole can cross the blood-brain barrier and enter parasites for better pharmacological effects, and there are minimal adverse effects associated with the drug. The radiological outcomes of motile lesions are an important treatment response indicator. Motile lesions may be stable, chronic, or calcified in patients after treatment. Timely and effective treatment may eliminate chronic lesions in the body. Since clinical symptom may relieve after MRI manifestation, it is necessary to perform MRI follow-ups one to three times after the clinical symptoms show improvements. Our three patients were considered cured with the disappearance or calcification of the lesions, as confirmed by MRI and CT after several treatment courses.

In conclusion, cysticercosis is a severe food-borne parasitic disease, and DCC presents a threat to human health in both rural and urban areas in China. The clinical presentation of DCC is highly complex and variable, including CNS, ocular, and subcutaneous symptoms. The diagnostic criteria need to consider the epidemiologic data, as well as objective clinical findings, imaging data, immunologic studies, and biopsy information. High-dosage albendazole is an effective treatment for patients with DCC.