Background: It is uncommon to have a hydatid cyst in the pulmonary artery. Typically, it results from an intracardiac cyst or a surgical cyst rupturing from a primary hepatic hydatid cyst. The objective of this meta-analysis is to quantitatively describe this rare disease.
Methods: The electronic databases "Google Scholar" and "PubMed" were searched exhaustively for all pertinent publications in the English language. To explain the clinical parameters, the collected data was assembled and computationally processed. Its epidemiology was also mapped.
Results: A total of 45 papers were initially found by the systematic search; however, only 16 studies that comprised 16 patients were included. Eight of the patients were male and eight were female. Hemoptysis, dyspnea, bloody sputum, vomiting, and shortness of breath were the clinically significant symptoms. Seventy-five percent of the patients had a history of hepatic hydatid disease, followed by three patients with primary lung cystic lesions and one patient with primary cardiac lesions. Severe pulmonary hypertension, septic shock, and massive hemoptysis all contributed to the death of three pulmonary echinococcosis patients.
Conclusion: Localization of hydatid cysts inside the pulmonary artery is an uncommon but life-threatening condition. Surgery may be the only choice for some patients. The surgery outcomes depend on the patient's current condition and the severity of their underlying diseases.
Echinococcosis; pulmonary artery; MRI, pulmonary resection
Hydatidosis is a parasitic infection caused by Echinococcus granulosus larvae. The parasite enters the human body via the gastrointestinal route, most frequently, the liver and lungs are affected . The disease can spread to any organ system via systemic vessels, and vital organs such as the heart and brain can occasionally be affected . Even though hydatid cysts in the pulmonary arteries are extremely uncommon, they might develop as a result of cardiac hydatid cyst embolizing through the pericardium, interventricular septum, and cardiac chamber walls or by the passage of the hydatid cyst from the liver into the inferior vena cava, right heart chambers, and into the pulmonary artery and/or from lung hydatic lesions . The various symptoms of this disease can include anything from cough, dyspnea, and chest pain to severe hemoptysis. The disease must be managed as soon as possible for patients, especially if they have severe hemoptysis or chest pain . High mortality is associated with the cyst's location inside the pulmonary artery due to secondary dissemination, embolization, and anaphylactic shock after cyst rupture . When pulmonary hypertension and cystic infiltrations of the lung occur in endemic regions, the presence of normal acute-phase reactants should trigger an echocardiogram and a serology test for hydatid disease . Ultimately, accurate evaluation of the unique radiologic signs of hydatid cyst embolization to the pulmonary arteries is essential for timely diagnosis and the implementation of suitable treatment . The objective of the current study is to present a meta-analysis of studies that have been published regarding the hydatid cyst inside the pulmonary artery.
According to the Preferred Reporting Items for Meta-analyses (PRISMA), this meta-analysis was completed.
The electronic databases "Google Scholar" and "PubMed” were searched exhaustively for all pertinent publications in the English language, using the key terms "Pulmonary artery hydatid,” "Pulmonary artery Echinococcus,” "Pulmonary artery echinococcosis”, “Pulmonary hydatid,” "Pulmonary arterial hydatid,” "Arterial echinococcosis,” "Vascular hydatid,” "Vascular echinococcosis” and "Pulmonary artery echinococcosis,". To supplement the data collection, the references mentioned in the included papers were checked as well.
The study's selection criteria concentrated on all articles that discussed hydatid cysts in the pulmonary artery, and life-threatening consequences associated with arterial hydatid disease.
The exclusion criteria included
(1) Articles removed due to abstracts and titles that were unrelated: (2) non-English articles: (3) Pre-print articles: (4) Published articles in fake journals, and (5) hydatid disease of the arteries other than pulmonary hydatid disease.
Initially, the duplicates were removed using Mendeley software. The demographic and clinical data were extracted from the included studies.
Data synthesis and statistical analysis
The extracted data were calculated and thoroughly re-evaluated. They have been displayed as proportions, mean values, and variance ranges.
The initial database searches turned up a total of 45 articles. The electronic database did not contain the full texts of 3 of them. Thirty-six non-duplicate studies remained after six duplicates were removed. The remaining articles were 32 after removing four non-English articles. Three articles were removed due to fake and preprint content. Six irrelevant studies were removed from the evaluation after the titles and abstracts were reviewed. The full-text screening process also resulted in the removal of about seven unrelated studies. Sixteen papers were selected for the final analysis. All of the studies were case reports. The PRISMA chart is detailed in Fig.1. Fig. 2 displays the epidemiological distribution of studies on hydatid cysts inside the pulmonary artery. The current meta-analysis included a total of 16 cases, eight cases (50%) were male and eight (50%) were female. The age ranged from 14 to 86 years, with an average of 42.62 years. The included cases reported various manifestations; 8 (50%) cases had hemoptysis, 9(56.2%) cases had dyspnea, 4 (25%) patients had bloody sputum, and 2 (12.5) cases had vomiting and shortness of breath (Table 1). In about 12 (75%) cases, the origin of the cysts were liver, 11 (68.7%) were pulmonary, and 6 (37.5%) were cardiac origin/. Nine (56.2%) patients had previously received surgical treatment, and 7 (43.7%) had received medication therapy. Hydatid cyst’s spread from the liver to the pulmonary arteries via the inferior vena cava was found in 12 (75%) patients. Hydatid cyst localization to the pulmonary artery from the lung parenchyma or cardiac chambers by tiny vessel wall breaks was observed in 3 (25%) reported cases. A primary cardiac lesion in one patient (6.25%) resulted in a hydatid cyst germinative membrane embolization to the pulmonary artery. Among the patients, 4(25%) had pulmonary hypertension. Seven patients were treated with medication therapy, while the remaining cases were treated surgically (Table 2).
The echinococcosis therapies used in the past may have contributed to hydatid cyst spread to the pulmonary artery. However, there was not a statistically significant association between them in this study (Table 3). Hemoptysis, a vascular involvement symptom, and a history of prior organ involvement are related, as shown in Table 4 and the relationship was non-significant.
Table1 Show the demographic, characteristics, history, and clinical presentation of the included studies.
|Author||Country||No. of cases||Published date||Gender||Age||Clinical manifestations|
|Tercan et al. ||Turkey||1||01/02/2005||Male||39||hemoptysis, dyspnea|
|Alper et al. ||Turkey||1||1995||Male||55||dyspnea|
|Sirmali et al. ||Turkey||1||11-Mar-06||Female||33||fatigue, dyspnea, pain, swelling in the leg|
|Attaran et al. ||Iran||1||25-Feb-19||Female||50||dyspnea, hemoptysis, fever|
|Karantanas et al. ||Greece||1||2000||Male||67||dyspnea, hemoptysis, bloody sputum|
|Çetin et al. ||Turkey||1||2017||Female||14||fatigue, dyspnea|
|Namn et al. ||USA||1||2003||Male||32||Chest pain, vomiting, hemoptysis|
|Yagüe et al. ||Spain||1||1998||Male||44||hemoptysis, vomiting|
|Tanju et al. ||Turkey||1||2005||Female||21||N/A|
|Koksal et al. ||Turkey||1||2006||Male||24||cough with bloody stained sputum|
|Bulman et al. ||Columbia||1||12-Apr-07||Male||37||dyspnea, hemoptysis|
|Bayraktaroglu et al. ||Turkey||1||2009||Female||28||dyspnea, hemoptysis|
|Demirpolat et al. ||Turkey||1||2014||Female||76||weight loss, cough with bloody sputum, loss of appetite,|
|Schuuring et al. ||Netherland||1||2016||Female||44||sudden thorathic pain, shortness of breath|
|Bakan et al. ||Turkey||1||2016||Male||32||dyspnea, hemoptysis, bloody sputum|
|Almutairi et al. ||Saudi Arabia||1||15-May-18||Female||86||productive cough, mild shortness of breath|
Table 2 Illustrates the organ involvement, the characteristics of pulmonary arterial hydatid cyst localization and intra-arterial hydatid cyst treatments.
|References||Hydatid cyst treatments||Lung hydatic lesion||Hepatic involvement||Cardiac involvement||Previous surgical cyst resection||Arterial cyst localization||Life threating complications|
|Tercan et al. ||Surgical cyst resection||Yes||Yes||Yes||Yes||Dissemination from liver||Sever pulmonary hypertension, heart failure and died|
|Alper et al. ||Surgical cyst resection||Yes||Yes||Yes||Yes||Dissemination via IVC then through cardiac chamber||Cyst rupture|
|Sirmali et al. ||Surgical cyst resection||No||Yes||No||Yes||Dissemination via IVC||No|
|Attaran et al. ||Surgical cyst resection||No||Yes||Yes||Yes||Dissemination via IVC cyst rupture in cardiac chamber||Cyst rupture and pulmonary hypertension, patient died|
|Karantanas et al. ||On medication||Yes||No||No||No||dissemination from lung parenchyma||No|
|Çetin et al. ||On medication||No||No||Yes||No||Germinative membrane embolization from cardiac||Pulmonary hypertension|
|Namn et al. ||On medication||No||Yes||No||No||Dissemination via IVC||No|
|Yagüe et al. ||Surgical cyst resection||No||Yes||No||Yes||Dissemination from liver||Anaphylactic reaction and cyst rupture|
|Tanju et al. ||Surgical cyst resection||Yes||No||No||Yes||Dissemination from lung||No|
|Koksal et al. ||Surgical cyst resection||Yes||Yes||No||Yes||Dissemination from liver||No|
|Bulman et al. ||Surgical cyst resection||Yes||Yes||No||No||Dissemination via IVC or cystotomy of lung hydatid cysts||hypertension and cyst rupture|
|Bayraktaroglu et al. ||On medication||Yes||Yes||Yes||Yes||Dissemination via IVC cyst rupture in cardiac chamber||No|
|Demirpolat et al. ||On medication||Yes||Yes||No||No||Dissemination via IVC||No|
|Schuuring et al. ||On medication||Yes||Yes||yes||No||Dissemination via IVC and lung parenchyma||No|
|Bakan et al. ||Surgical cyst resection||Yes||No||No||No||lung hydatid cyst dissemination||dissemination of cysts|
|Almutairi et al. ||On medication||Yes||Yes||No||Yes||dissemination by cystotomy of lung and hepatic hydatid cysts||Septic shock, hypertension and died|
Table 3 Hydatid cyst dissemination to the pulmonary artery and it’s related to previous echinococcosis treatment methods.
|The pulmonary arterial hydatid cyst and previous echinococcosis treatments||Dissemination of a hydatid cyst to the pulmonary artery from the infected organs|
|Liver||Lung and cardiac chamber||Liver and lung||Primary cardiac lesion||Total||P-value|
|Surgical cyst resection||6 (66.7%)||1 (11.1%)||2 (22.2%)||0 (0.0%)||9 (100.0%)||0.4|
|Treatment on medication||4 (57.1%)||2 (28.5%)||0 (0.0%)||1 (14.3%)||7 (100.0%)|
|Total||10 (62.5%)||3 (18.7%)||2 (12.5%)||1 (6.25%)||16 (100%)|
Table 4 Illustrates hydatid cyst dissemination to the pulmonary artery and it’s related to previous organ involvement in the disease and hemoptysis as a sign of vascular involvement.
|Hydatid cyst in the pulmonary artery||Dissemination of a hydatid cyst to the pulmonary artery from the infected organs|
|Liver||Lung and cardiac chamber||Liver and lung||Primary cardiac lesion||Total||P-value|
|Clinical sign of hemoptysis||6 75%||1 12.5%||1 (12.5%)||0 (0.0%)||8 100.0%||0.2|
|No indication of hemoptysis||4 50.0%||2 25.0%||1 (12.5%)||1 (12.5%)||8 (100.0%)|
|Total||10 (62.5%)||3 (18.7%)||2 (12.5%)||1 (6.3%)||16 (100%)|
Cystic echinococosis is a zoonosiscaused by the cestode Echinococcus granulosus larval stage. Carnivores, including dogs, are definitive hosts. However, sheep and other ruminants act as intermediate hosts. By consuming food or water that has been contaminated with dog feces that contain the parasite eggs, humans become infected. These embryos cross the intestinal wall to reach the hepatic portal system, where they encyst in the liver and other organs of the intermediate host . The lungs filter 15%–25% of the embryos, the liver filters 60%–70% of them, and 10%–15% are transported by systemic circulation to other organs .
The parasite and the host contribute to the hydatid cyst's wall structure. The fibrous tissue that makes up the pericyst, which is the outer layer, was created by the host in reaction to the infection. The protoscolices-containing inner germinal layer known as the endocyst and the acellular outer laminated membrane known as the ectocyst make up the actual wall of the hydatid cyst . Cyst rupture causes the protoscolices to spread, which can lead to the formation of secondary cysts in the infected tissues. Blood tests for hydatid infection can show anti-echinococcal antibodies and eosinophilia, but the latter is typically linked to cyst rupture .
There are few ideas explaining the highly rare occurrence of a hydatid cyst inside the pulmonary artery . The most common cause of localization is embolization from primary cardiac locations. Another possibility is that the embryos travel from the liver into the inferior vena cava and then travel to the pulmonary arteries via the right cardiac chambers . Cysts in the lung parenchyma will result in a tiny break in the arteries' walls, allowing the parasites to pass through . In the current analysis, hydatid cysts in 12 patients had either spread from the liver to the lung or had embolized through the inferior vena cava from the liver to the pulmonary arteries.
In 0.5% to 2% of all cases of hydatidosis, the heart is afflicted. The interventricular septum, right or left atrium, right ventricle, pericardium, and left or right ventricle may also be damaged, though the left ventricle is most usually afflicted (50–60%) . In the case described by Çetin et al., hydatid cyst in the bilateral pulmonary arteries was most likely caused by germinative membrane embolization with the spread of hydatid cysts from the right ventricle and the subsequent development of chronic thrombosis . According to the case reported by Tercan et al., no cysts were found in the right heart chambers or walls, although a hepatic hydatid cyst had previously undergone surgical excision. Since the liver's scolices ruptured into the hepatic veins during surgery, it was suspected that the cysts in the pulmonary arteries were scolices emboli . A total of 50% of pulmonary artery echinococcosis cases had a history of hepatic hydatid cysts being surgically removed in the present analysis.
Echinococcosis of the lungs might be asymptomatic or mimic thromboembolic disease. Common symptoms of pulmonary echinococcosis are chest pain, dyspnea, coughing up cyst contents, hemoptysis, and/or an anaphylactic reaction . Most intact lung cysts are found accidentally on chest radiography due to a primary infection in the lung parenchyma, which may go undetected for many years . Clinical classifications of hydatid pulmonary embolism include acute fatal, sub-acute with pulmonary hypertension and mortality within a year, and chronic pulmonary hypertension . The embryos located within an artery usually grow slowly, finally occluding it, and possibly asymptomatic at first. If the cysts continue to grow, symptoms may develop over time, and pulmonary perfusion may become inadequate when they compress a vital structure or obstruct blood flow, leading to anaphylactic shock . The patient in the case study by Bakan et al. lived symptom-free for three years after having a cystotomy capitonnage for right-sided pulmonary hydatid cysts. It may be explained by the cysts' slow development rate as this might continue long enough for collaterals to develop .
When the cyst material is discharged from the cyst owing to trauma or surgery, anaphylactic shock may result in death . Additionally, systemic cyst problems such as sepsis, respiratory failure as well as perioperative difficulties may be caused by spontaneous cyst rupture or by the dysfunction of the affected organ as a result of cyst growth . Increasingly, hemoptysis in patients who are prone to have hydatid cysts could be a warning sign of vascular involvement, which requires close vital sign monitoring and reanimation . In the current analysis, hemoptysis as a marker of vascular involvement and hydatid cyst dissemination to the pulmonary artery occurred in 50% of patients. And by this analysis, 4 patients have had pulmonary hypertension.
A computed tomography (CT) scan shows spherical, fluid-attenuating intravascular masses that are hydatid cysts in the pulmonary arteries. These cysts may lead to artery hypertrophy. There has also been evidence of calcification around the edges of the cysts . Furthermore, by exhibiting lesions that are cystic and highlighting homogenously hypointense lesions in T1 weighted images and hyperintense lesions in T2 weighted images, magnetic resonance imaging may help with diagnosis. The cyst walls have low signal margins that are visible on the T2-weighted images. Computed tomography and magnetic resonance imaging (MRI) are helpful in follow-up to investigate in recurrence and formation of pseudoaneurysm. Hydatid cysts are also confirmed by pathological examinations . Treatment for hydatid cysts is crucial and the fluid from a hydatid cyst is a highly potent anaphylactic agent. Because surgery has a high morbidity and mortality rate, it must be customized for each patient if can be complicated by artery or cyst rupture, disease propagation, anaphylactic shock, embolism, and the development of a pseudoaneurysm. As a result, this choice must be made with great care . While in the right circumstances, a cyst should be surgically removed and additional medicine employing benzimidazole substances, such as albendazole and mebendazole, should be used as a therapy of choice . The surgical methods used to treat hydatid disease of the lungs include enucleation of the lung, pericystectomy, cystotomy with or without capitonnage, and other surgical procedures . Hydatid disease pre- and post-operative medications are effective in eliminating spilled scolices in ruptured cysts. The surgical outcomes depend on the patient's previous diseases and the severity of their underlying diseases .
The findings of Namn and colleagues' investigation led to the advice of some prophylactic measures because they showed that surgical removal of hepatic echinococcal cysts proximal to hepatic venous structures also entails a risk of hydatid cyst embolization to the pulmonary arteries. These include clamping of the inferior vena cava, avoidance of traction on the liver, and cavocaval bypass if necessary . In a case presentation with concurrent hydatid cysts inside the pulmonary artery and the lung parenchyma, According to Koksal et al it is crucial to first remove the intra-arterial cyst followed by the care of the lung cyst with a parenchyma-saving procedure or lung resection is critical . According to Çetin et al., it is becoming increasingly evident, that it is not feasible to completely remove the cyst due to the bilateral pulmonary arterial involvement. Bilateral pulmonary hydatidosis is treated surgically like that of chronic thromboembolic pulmonary hypertension, which is treated by pulmonary artery endarterectomy. However, special care should first be given to first removing the hydatid vesicles attached to the vascular endothelium before beginning an endarterectomy .
In conclusion, hydatid disease of the pulmonary arteries is extremely unusual and may develop when cysts rupture into the hepatic veins, heart, or lung parenchyma either spontaneously or secondary to surgery. Within the pulmonary arteries, hydatid cysts have a particular appearance on both CT scan and MRI. For an early diagnosis and effective therapy, recognition of this illness is crucial.
Acknowledgments: None to be declared.
Funding: None to be declared.
Author contribution: AMS designed the study; FHK and DMH participated in preparing the manuscript; BAA, HMH, and SJH participated in data collection; BHA, DHB and SHT critically revised the manuscript; FHF and RKA performed the data analysis; GSA and HOA confirmed the authenticity of the data; all authors approved the final version of the manuscript
Ethical approval: Not Applicable
Patient consent (participation and publication): Not applicable
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