Approach
Treatment varies depending on the clinical manifestations, and location, size, stage, and number of parasites and the host's response. Antiparasitic therapy is the mainstay of therapy in most patients; however, additional interventions including corticosteroids, anticonvulsants, and surgical intervention may be required in extra-intestinal disease. Patients with neurocysticercosis may present with elevated intracranial pressure, which is a medical emergency.[54]
Intestinal infection
When stool examination reveals evidence of tapeworm infection (e.g., Hymenolepis nana, Diphyllobothrium latum, Taeniaspecies), the treatment of choice is the broad-spectrum antiparasitic drug praziquantel. Praziquantel has excellent activity against all tapeworms. It is given as a single dose in both children and adults.[55] Infections with H nana require higher doses. Alternative antiparasitic drugs include albendazole and niclosamide. However, praziquantel has excellent efficacy and is well tolerated, so alternatives are not commonly used.
Praziquantel and albendazole should be used with caution in patients with suspected cysticercosis as there have been case reports of seizures in these patients when these drugs are used.[55]
Stools should be re-examined 1 and 3 months after treatment to ensure treatment is successful.[55]
Central nervous system (CNS) manifestations
CNS manifestations include disease with T solium (neurocysticercosis) or Echinococcus species. In patients with neurocysticercosis, specific treatment depends on the location of the cysts.
The focus of the initial management of neurocysticercosis is the control of seizures, intracranial hypertension, hydrocephalus, and oedema. Antiparasitic therapy may need to be deferred for certain presentations of neurocysticercosis.[56]
Increased intracranial pressure can be life threatening and should be managed immediately. Antiparasitic therapy is not recommended until intracranial pressure is stabilised. Use of antiparasitic therapy in patients with elevated intracranial pressure can lead to fatal adverse events (e.g., herniation).[43] Once the patient is stabilised, management depends on the type of neurocysticercosis.
Active parenchymal disease
Patients with untreated hydrocephalus or diffuse cerebral oedema (cysticercal encephalitis) require urgent management of elevated intracranial pressure with corticosteroids for diffuse cerebral oedema, or a surgical approach for hydrocephalus.[43]
Antiparasitic therapy (i.e., albendazole or praziquantel) is then started. The addition of corticosteroids is recommended to suppress the inflammatory effect of antiparasitic therapy, and may reduce the risk of generalised seizures in patients with active parenchymal cysts.[43][46][47]
Inactive parenchymal disease
Inactive parenchymal disease (with calcified lesions) does not usually require treatment with antiparasitic therapy as there are no viable cysts.
Calcified lesions can be associated with symptomatic perilesional oedema. Guidelines recommend against the routine use of corticosteroids in these patients, as there are a few case reports that suggest rebound perilesional oedema can occur when corticosteroids are tapered or stopped.[43]
Surgical removal of seizure foci can be considered in select patients.[43]
Intraventricular disease
Patients with active ventricular disease may present with obstructive hydrocephalus. Management of these patients is focused on relieving the intracranial hypertension with ventriculoperitoneal shunting.
Once intracranial pressure is stabilised, neuroendoscopic removal of cysticerci in the lateral and third ventricles is performed, while surgical removal of cysticerci in the fourth ventricle is recommended.[43] Patients with magnetic resonance imaging (MRI) findings of significant ependymal enhancement (secondary to adherence of lesions to the ependyma) may not be suitable for this surgery.[41]
Some experts do not recommend antiparasitic therapy before surgical removal as it may disrupt the integrity of the parasite and cause an inflammatory response that could prevent cyst removal and precipitate obstructive hydrocephalus.[43][56]
Corticosteroids are recommended in the perioperative period, or in combination with antiparasitic therapy after shunt placement.[43]
Subarachnoid disease
Evidence regarding treatment of subarachnoid disease is limited as the condition is relatively rare and prognosis is very poor. There have been no controlled trials of subarachnoid disease management; however, case series in which patients were treated with antiparasitic drugs, corticosteroids, and shunting for hydrocephalus demonstrated improved prognosis.[57]
It is recommended that raised intracranial pressure is initially treated with shunting, and prolonged antiparasitic therapy (i.e., several months to more than 1 year), with slow tapering of corticosteroids.[57] Methotrexate may also be used as a corticosteroid-sparing agent in order to reduce the adverse effects associated with long-term corticosteroid use.[57][58] Some patients may also benefit from surgical debulking.[43]
Spinal/ocular disease
Case-specific, individualised surgery is the mainstay of treatment for spinal cord disease. Antiparasitic therapy plus corticosteroids (especially in cases with spinal cord dysfunction) are also recommended.[43] Non-surgical management alone may be adequate in some patients, with surgery reserved for patients with progressive neurological decline.[59]
Intra-ocular cysticerci should be treated by surgical removal.[43]
General principles of treatment
Antiparasitic therapy: monotherapy with albendazole is generally recommended. However, patients with greater disease burden (i.e., >2 viable cysts) may benefit from combination antiparasitic therapy (i.e., albendazole plus praziquantel). This recommendation is derived from studies done in patients with parenchymal disease. Prolonged or repeated treatment courses may be required for extraparenchymal or extensive disease.[43][56]
A randomised, double-blind, placebo-controlled phase II trial found much greater cysticidal activity (cyst resolution 95% versus 30%; complete cyst clearance 75% versus 25%) of albendazole plus praziquantel compared with albendazole alone.[60]
These findings were confirmed in a phase III study (double-blind, placebo-controlled) that also found that patients with viable intraparenchymal neurocysticercosis have increased parasiticidal effect with combination therapy of albendazole plus praziquantel compared with albendazole alone. The benefit was largely driven by the sub-group of patients with three or more viable cysts. No increased risk of adverse effects were seen in the combination antiparasitic therapy arm.[61]
One systematic review and meta-analysis found that combination therapy with albendazole and praziquantel was more effective in achieving complete resolution of lesions at both 3 months and 6 months in children with neurocysticercosis, compared with albendazole monotherapy. However, calcification outcomes were more significant in the combination therapy group.[62]
One Cochrane review found that albendazole monotherapy reduced the risk of seizure recurrence in patients with a single cyst who presented with seizures compared with placebo or no antiparasitic therapy (moderate-certainty evidence). Evidence for albendazole in patients with more than one cyst is lacking but suggests potential harm (very low-certainty evidence).[63]
Anticonvulsants: seizures may be controlled with the use of an anticonvulsant, regardless of the type of neurocysticercosis. Anticonvulsants can be tapered and stopped after resolution of cysts on MRI and if the patient is seizure-free for a certain period of time (dependent on the location of cysts), provided they have no risk factors for seizure recurrence. Evidence for the optimal duration of anticonvulsant treatment in patients with neurocysticercosis is limited.[56][64] The World Health Organization (WHO) recommends considering discontinuation 6 months after the last seizure in patients with a single enhancing lesion and a low risk of seizure recurrence; treatment should be continued for at least 2 years in patients with calcified neurocysticercosis and epilepsy.[46] Choice of anticonvulsant is guided by availability, drug interactions, adverse effects, and cost. Many anticonvulsants should not be used in pregnant women due to their teratogenic effects.[43]
Corticosteroids: concomitant administration of corticosteroids is usually indicated to suppress the inflammatory response caused by the destruction of live cysticerci.[56] The optimal dose, duration, and formulation of adjunctive corticosteroid to administer with antiparasitic therapy have not been established. An open-label randomised trial compared conventional dexamethasone dosing with enhanced dexamethasone dosing in patients with viable parenchymal neurocysticercosis with recent (within 6 months) seizure activity. Although the study did not meet its primary end point of reducing seizure days or individuals with seizures, the study had two important findings. First, this study found that seizure activity was heightened during days 1 to 21 and decreased after day 21; second, that enhanced dexamethasone dosing reduced seizure activity from days 1 to 21. Adverse effects were not different between the two groups. These data suggest that patients with intraparenchymal viable neurocysticercosis at risk for seizure during the first 21 days of treatment may benefit from an enhanced corticosteroid regimen.[65] Corticosteroids are generally started prior to antiparasitic treatment.
Hepatic or thoracic manifestations
The clinical management of cystic echinococcosis depends on the location and stage of the cyst.[20] See Criteria.
Treatment options include antiparasitic therapy with albendazole, percutaneous treatment, or surgery. Albendazole may be recommended in combination with percutaneous or surgical treatments in certain patients.
Uncomplicated hepatic cyst types CE1 or CE3a and <5 cm
The WHO recommends treatment with albendazole, based on very-low certainty evidence.[20]
Treatment duration depends on the stage and size of the cyst and the clinical presentation. Continuous treatment for 3-6 months is typically recommended. If there is a lack of response to an initial course of albendazole after 3 months (defined as absence of cyst changes), a repeat course of albendazole may be considered.
Uncomplicated hepatic cyst types CE1 or CE3a and 5-10 cm
The WHO recommends treatment with albendazole plus PAIR (puncture, aspiration, injection, and reaspiration), based on very-low certainty evidence.[20]
Alternative treatments include: percutaneous drainage (S-CAT) without injection of a protoscolecidal agent with prolonged administration of albendazole for 6 months; surgery (open or laparoscopic approach) plus albendazole; or medical management.
Uncomplicated hepatic cyst types CE1 or CE3a and >10 cm
The WHO recommends treatment with albendazole plus percutaneous treatment, based on very-low certainty evidence and expert consensus. PAIR is preferred over S-CAT. PAIR is suggested rather than standard catheterisation or surgery.[20]
Alternative treatments include: percutaneous drainage (S-CAT) without injection of a protoscolecidal agent with prolonged administration of albendazole for 6 months; surgery (open or laparoscopic approach) plus albendazole; or medical management.
Uncomplicated hepatic cyst types CE2 or CE3b and ≤5 cm
The WHO recommends treatment with albendazole, based on expert consensus.[20]
Treatment duration depends on the stage and size of the cyst and the clinical presentation. Continuous treatment for 3-6 months is typically recommended. If there is a lack of response to an initial course of albendazole after 3 months (defined as absence of cyst changes), surgery (radical or non-radical approaches) should be offered alongside continued albendazole treatment.
Uncomplicated hepatic cyst types CE2 or CE3b and >5 cm
The WHO recommends treatment with albendazole plus surgery (open or laparoscopic approach), based on very-low certainty evidence and expert consensus.[20]
Alternative treatments include: albendazole alone; or modified catheterisation technique (Mo-CAT) plus albendazole.
Uncomplicated lung cysts ≤5 cm
The WHO recommends surgery, based on expert consensus. Albendazole should not be given before surgery due to the risk of rupture of lung cysts, but may be considered after surgery if cyst spillage is suspected or confirmed.[20]
Medical therapy with albendazole alone may be considered if surgery is contraindicated or not feasible. However, it is uncertain whether albendazole for 6 months is effective at treating small lung cysts.
Surgery should be as conservative as possible. Radical procedures may be required for extended parenchymal involvement, severe pulmonary suppuration, and complications.[53]
Complicated cysts
Open surgery is typically the treatment of choice for complicated hepatic cysts, based on expert opinion and medical practice. There is a lack of guidance on the management of complicated pulmonary cysts; however, lung cysts are usually managed surgically.[20]
Inactive cysts
Current practice is a watch and wait approach with follow-up imaging (ultrasound or magnetic resonance imaging [MRI]), based on expert consensus. Surgery should be avoided unless the inactive cyst is causing complications (e.g., portal hypertension).[20][53]
General principles of treatment
Albendazole is contraindicated in cysts at risk of rupture, and in the first trimester of pregnancy. It may be used in later stages of pregnancy if the benefits outweigh the risks. Contraceptive measures are recommended in women of child-bearing potential while on long-term treatment. Albendazole should be used with caution in patients with hepatic disease, and avoided in patients with bone marrow depression. Liver function tests and blood cell counts should be monitored during treatment.[20]
PAIR is a percutaneous procedure where the cyst is aspirated under computed tomography (CT) guidance, and a scolicidal agent is instilled into the cyst cavity. Fluid is then reaspirated.[66][67] PAIR is not recommended if biliary communication is present. Cysts >10 cm have a high risk of such fistulas and extra caution is recommended in these patients. Injection of a protoscolecidal agent after aspiration is not recommended if bile-stained cyst fluid is aspirated, or contrast is observed in the biliary tract during the procedure.[20]
Surgery is either through an open or laparoscopic approach, depending on factors such as cyst location, setting infrastructure, expertise of the surgical team, surgeon or patient preference, and general health of the patient. Typically, the laparoscopic approach is preferred for peripheral superficial cysts (especially paediatric cases), and open surgery is preferred for deep or complicated cysts.[20]
Albendazole is given for 1-7 days prior to percutaneous or surgical treatment of hepatic cysts (a shorter period is recommended for larger cysts to reduce the risk of perforation), and should be continued for 1-3 months after the procedure. An extended duration may be considered if appropriate. In cases of cyst fluid spillage, albendazole may be given for an extended duration of 6-12 months after the procedure. Albendazole should not be given prior to surgical treatment of lung cysts due to the risk of rupture, although it may be given for 1-3 months after the procedure if there is a concern for intraoperative spillage.[20]
A 2-week course of praziquantel may be considered in addition to albendazole after percutaneous or surgical procedures for hepatic or lung cysts if there is suspected or confirmed spillage of cyst contents. The duration can be increased to 4 weeks if considered clinically appropriate. Some clinicians use praziquantel in combination with albendazole for 2 weeks prior to the procedure; however, further evidence for this approach is needed.[20]
Patients should be closely monitored after percutaneous or surgical treatment for potential complications (e.g., infection, bleeding, anaphylaxis, prolonged air leak or bleeding after lung surgery).[20]
One Cochrane review found a lack of evidence comparing percutaneous and surgical interventions in patients with uncomplicated hepatic cystic echinococcosis.[68]
Standard catheterisation in combination with albendazole may lead to fewer cases of recurrence, more major complications, and similar complication rates compared to PAIR in combination with albendazole, based on very low-certainty evidence.
Laparoscopic surgery in combination with albendazole may result in fewer cases of recurrence and fewer major complications compared to open surgery in combination with albendazole, based on very low-certainty evidence.
However, due to the limited number of studies and small sample size, firm conclusions could not be established.
Follow-up imaging at 3-6 months, and then annually for a minimum of 5 consecutive years after inactivation, is recommended to evaluate treatment success and monitor for cyst recurrence. A lack of response is defined as the absence of cyst changes after 3 months of treatment. Complete response should not be evaluated earlier than 12 months after completion of treatment.[20]
Individualised management is recommended in patients with multiple cysts, multiple cyst stages, or multi-organ involvement.[20]
Hepatic and thoracic cysticercosis is extremely rare, with only a small number of cases reported in the literature. There is a lack of data evaluating any specific treatment approach, although surgery plus antiparasitic therapy (sometimes along with corticosteroids) has been used in practice. The management of hepatic and thoracic cysticercosis is beyond the scope of this topic.
Other manifestations
There is a lack of guidance on the management of other, less common, manifestations (e.g., bone, heart, disseminated disease). Surgery is typically recommended.[53] Cardiac cysts are usually resected regardless of their stage. Although approximately 50% of patients with cardiac cysts receive antiparasitic therapy, and its use seems reasonable, there is a lack of data available.[38] The management of these manifestations is beyond the scope of this topic.
Special patient groups
Pregnant women are treated in the same way as non-pregnant people, with the following considerations: antiparasitic therapy should generally be delayed until after delivery (although may be used after the first trimester if the benefits outweigh the risks); corticosteroids may be used safely when necessary; and teratogenic effects should be taken into account when deciding on a suitable anticonvulsant. Children are generally treated the same as adults.[43]
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