Emergency Department Care
Unless the parasite is detected (eg, presence of eggs, worm segments, cysts), definitive therapy in the ED is unlikely. Stabilization of any patient in the presence of a systemic disease such as seizure, anaphylaxis, or organ failure is essential.
Intestinal tapeworm infestation
Recent reviews summarize that most intestinal tapeworm infections can be effectively treated with praziquantel or niclosamide. [10, 11] These antihelminthic agents have effective rates of 85-98%. [12] Praziquantel was found to be 100% effective in the treatment of Taenia and H nana infection. [13]
Administer parenteral vitamin B-12 if evidence of vitamin B-12 deficiency occurs with Diphyllobothrium infections.
Cysticercosis
In neurocysticercosis, neurologic manifestations indicate the need for antihelminthic agents and antiepileptics. The recommended antihelminthic agent is albendazole. In a meta-analysis of comparative trials, albendazole provides better seizure control and resolution of cysts or granuloma as compared with praziquantel. [14, 15] In trials of nonviable lesions, seizure recurrence is substantially lower with albendazole. [16]
Antihelminthic treatment may provoke an inflammatory response in the central nervous system. Steroids affect this inflammatory response and may influence outcomes such as headache, but further research is needed to test this. [16]
Effectiveness of therapy can be monitored via radiographic imaging. The size of the active lesions should decrease within 3-6 months.
Neurosurgical interventions should be considered for patients with mass effect, cerebral spinal fluid obstruction, and fourth ventricular cysts. [17] Endoscopic approaches provide better outcomes than the traditional open approaches for intraventricular neurocysticercosis with hydrocephalus. [17] Among patients who had undergone surgical resection of a single intraventricular lesion, those who received postoperative antihelminthic therapy, most commonly albendazole, had significantly lower risk of developing delayed hydrocephalus. [18]
Echinococcosis
Echinococcosis is treated with albendazole and surgery or albendazole and PAIR (puncture, aspiration, injection, re-aspiration). Albendazole is recommended for 1-3 months before surgical intervention. [19]
Sparganosis and coenurosis treatment involves surgical excision for localized infections.
Consultations
An infectious diseases specialist can secure the tracking and reporting of important epidemiologic and epidemic patterns.
Most patients' symptoms hasten the physician to notify the gastroenterologist for evaluation of their source of symptoms. After treatment, the passage of segments and eggs may continue for several days. Treatment is reevaluated for success by examining the stool at intervals allowing regrowth of worms: 3 months for Taenia species and 1 month for Hymenolepis, Diphyllobothrium, and other species. The difficulty arises with H nana, which can result in reinfection through internal autoinfection, causing patients to appear as though treatment has failed. Fortunately, the medications will reduce the worm burden, and the infections in children are usually spontaneously resolved in adolescence.
In the presence of apparent cysts in the brain, meninges, or spinal cord, consultation with a neurologist may be indicated. Aspiration may be needed for diagnostic purposes and for relief of compression that may cause severe or discomforting symptoms.
Some cestode infections require surgery not only for diagnostic purposes but also for therapy. Patients with hydrocephalus due to cysticercosis require placement of a ventricular shunt. This is needed prior to any recommended drug therapies because drug therapies typically result in further increases in intracranial pressures. In patients with neurocysticercosis, the rate of shunt dysfunctions requiring frequent revisions is high. These patients high mortality rate (50% in 2 y) is directly related to the number of surgeries involving their shunt.
Symptomatic echinococcosis infections require surgical treatment with perioperative medical interventions. The surgical resections that are usually performed have an operative mortality rate that has dropped from about 7-23% before 1980 to 0-5% in more recent years. The recurrence rate is between 3% and 10% after open surgery for patients with hepatic hydatid cyst. Special laparoscopic surgery technique for liver hydatid cysts has been described, with a result of 0% recurrence rate. [20]
The puncture of cysts percutaneously, aspiration of fluid, introduction of protoscolicidal agent, and reaspiration method, also known as the PAIR method, has been described as an alternative treatment for hepatic cysts. Currently, however, the efficacy and safety of the PAIR method has not been confirmed. Therefore, the PAIR method cannot be regarded as an established alternative to surgery.
The only treatment of sparganosis and coenurosis is surgical excision of the localized infections.
-
Adult tapeworm of Dipylidium caninum. Image courtesy of the Centers for Disease Control and Prevention (CDC).
-
Ultrasonographic appearance of echinococcal cysts (Gharbi type I, World Health Organization [WHO] standardized classification CE1).
-
Diagram of the Echinococcus life cycle. Image courtesy of the Centers for Disease Control and Prevention.
Tables
Cestode |
Primary Host |
Intermediate Host |
T solium |
Humans |
Pigs, humans, dogs, cats, sheep |
T saginata |
Humans |
Cattle |
Diphyllobothrium |
Humans |
Fish |
Hymenolepis |
Humans |
Hymenolepis nana: None; Hymenolepis diminuta: Rodents |
D caninum |
Humans, dogs, cats |
Fleas on dogs/cats |
Echinococcus |
Dogs |
Humans, sheep, cattle, goats, horses, camel |
Spirometra |
Humans |
|
T multiceps |
|
Hares, rabbits, squirrels, humans (rarely) |
