Pulmonary paragonimiasis mimicking lung cancer in a tertiary referral centre in Korea

Paragonimiasis Misdiagnosed as Pulmonary Tuberculosis: A Case Report

Paragonimiasis is a zoonosis caused by the ingestion of raw or undercooked crustaceans parasitized with metacercaria of Paragonimus spp. In Peru, Cajamarca is considered an endemic region for paragonimiasis. A 29-year-old man from the department of San Martín, Peru presented with a three-year history of cough, chest pain, fever, and hemoptysis. Treatment for tuberculosis (TB) was initiated even with negative results for sputum acid-fast bacillus (AFB), due to the patient's clinical characteristics and the high prevalence of the condition in the region. After eight months, due to the lack of any clinical improvement, he was referred to a regional hospital, where Paragonimus eggs were evidenced in direct sputum cytology. The patient received treatment with triclabendazole and showed clinical and radiological improvement. It is important to consider eating habits, even in non-endemic areas, for diagnosing paragonimiasis in patients with TB symptoms who do not respond to a specific treatment.

What Findings on Chest CTs Can Delay Diagnosis of Pleuropulmonary Paragonimiasis?

Purpose: The purpose of this study was to investigate which findings were delayed in diagnosis with respect to chest CT findings of paragonimiasis. Methods: This retrospective, informed questionnaire study was conducted to evaluate chest CT scans of 103 patients (58 men and 45 women; mean age 46.1 ± 14.6 years). The patients were diagnosed with paragonimiasis from 2003 to 2008 in four tertiary hospitals. Statistical analysis was performed using the chi-square test to identify differences between an initially correct diagnosis and an incorrect one of paragonimiasis on chest CT scans, for which we evaluated such variables as the location of lesion, type of parenchymal lesions, and worm migration track. Results: Nodular opacities on chest CT scans were the most common findings (53/94, 56.4%). The sign of worm migration tracks was only present in 18.1% of cases (17/94). Although statistically insignificant, the form of consolidation (18/25, 72%) and mass (6/8, 75%) on CT was common in correct diagnostics, and the form of the worm migration track (12/17, 70.6%) was high in correct diagnostics. Conclusion: A delayed diagnosis of paragonimiasis may often be made in patients with non-nodular, parenchymal lesions who are negative for worm migration track on chest CT scans.

[Pulmonary larval paragonimiasis mimicking lung cancer]

Larval paragonimiasis is a parasitic disease caused by lung fluke larvae. Unlike the classic form of paragonimiasis, the larval form occurs with a large number of clinical manifestations. However, this fact only complicates the diagnosis of larval paragonimiasis, for the abundance of clinical manifestations results in the misdiagnosis of other diseases. Another feature of this form of paragonimiasis is the tendency to generalize and mimic the clinical presentation of malignant neoplasms. The performed diagnostic measures failed to give an accurate view of the nature of the disease, therefore diagnostic thoracoscopy was carried out and biopsy specimens were taken from the subpleural region of dissemination, followed by urgent histologic examination suggestive of glandular cancer. This circumstance became the reason for atypical resection of the affected portion, which was done; however, the patient died from pulmonary thromboembolism on postoperative day 2. The main diagnosis of chronic pulmonary generalized paragonimiasis (cystic and pneumosclerotic phases) with neoplastic syndrome was posthumously made.

Paragonimiasis

Paragonimiasis is a zoonotic disease caused by lung flukes of the genus Paragonimus. Humans usually become infected by eating freshwater crabs or crayfish containing encysted metacercariae of these worms. However, an alternative route of infection exists: ingestion of raw meat from a mammalian paratenic host. Adult worms normally occur in pairs in cysts in the lungs from which they void their eggs via air passages. The pulmonary form is typical in cases of human infection due to P. westermani, P. heterotremus, and a few other species (Table 5.1). Worms may occupy other sites in the body, notably the brain, but lung flukes have made their presence felt in almost every organ. Ectopic paragonimiasis is particularly common when infection is due to members of the P. skrjabini complex (Table 5.1). Human paragonimiasis occurs primarily in the tropics and subtropics of Asia, Africa, and the Americas, with different species being responsible in different areas (Table 5.1).

Demographic characteristic and analysis of pulmonary paragonimiasis in patients attending RIMS, Manipur

Background:

Human infection by the lung fluke Paragonimus westermani is widely distributed in Africa, Asia, and South America. Transmission of the parasite to humans primarily occurs through the consumption of raw or undercooked crabs. Clinical features of recently diagnosed pulmonary Paragonimiasis show that patients present with a variety of clinical and radiological findings, frequently mimics tuberculosis and lung cancer.

Methods:

Here in this study, we report a cross-sectional study of pulmonary paragonimiasis in our institute over a period of two year.

Results:

it was observed that out of eleven cases, prevalence of paragonimiasis was almost equal among both the genders, with a mean age of 38.1 ± 16.96, affecting people from hills. Three patients were erroneously treated with antitubercular drugs without any relief. The association with eosinophilia in the peripheral blood and tissue[16] was seen in all the study subjects and majority patients had pleural fluid eosinophilia. Patients were diagnosed by serological test, Paragonimus ova in Sputum smear and Pleural fluid. All study subjects had excellent clinical responses to praziquantel given at dose of 25 mg/kg given orally 3 times daily for 3 consecutive days.

Conclusions:

There is a need to generate awareness among the clinicians and public regarding Paragonimiasis and to consider it in differential diagnosis of TB and carcinoma lung. Physicians should consider the possibility of paragonimiasis among patients who present with chest complaints with eosinophilia from the endemic regions.

Pleural fluid characteristics of pleuropulmonary paragonimiasis masquerading as pleural tuberculosis

BACKGROUND/AIMS

Pleuropulmonary paragonimiasis produces no specific symptoms or radiologic findings, allowing for the possibility of misdiagnosis. We evaluated the specific clinical and pleural fluid features of pleuropulmonary paragonimiasis masquerading as pleural tuberculosis.

METHODS

We retrospectively analyzed the clinical and radiologic characteristics of 20 patients diagnosed with pleuropulmonary paragonimiasis between 2001 and 2011.

RESULTS

In total, 17 patients presented with respiratory symptoms, including dyspnea (30%), hemoptysis (20%), cough (20%), and pleuritic chest pain (15%). Chest radiographs revealed intrapulmonary parenchymal lesions, including air-space consolidation (30%), nodular opacities (20%), cystic lesions (15%), ground-glass opacities (10%), and pneumothorax (5%). A pleural fluid examination revealed eosinophilia, low glucose levels, and high lactate dehydrogenase (LDH) levels in 87%, 76%, and 88% of the patients, respectively. These traits helped to distinguish pleuropulmonary paragonimiasis from other pleural diseases such as parapneumonic effusion, malignancy, and pleural tuberculosis.

CONCLUSIONS

Pleuropulmonary paragonimiasis is often initially misdiagnosed as other pleural diseases. Therefore, it is important to establish the correct diagnosis. In patients with unexplained pleural effusion living in paragonimiasis-endemic areas, pleural fluid obtained by thoracentesis should be examined to distinguish pleuropulmonary paragonimiasis. When marked eosinophilia, high LDH levels, and low glucose levels are identified in pleural fluid, physicians could consider a diagnosis of pleuropulmonary paragonimiasis.

A Case of Delayed Diagnosis of Pulmonary Paragonimiasis due to Improvement after Anti-tuberculosis Therapy

Here, we report a case of pulmonary paragonimiasis that was improved with initial anti-tuberculosis (TB) therapy but confused with reactivated pulmonary TB. A 53-year-old Chinese female presented with a persistent productive cough with foul smelling phlegm and blood streaked sputum. Radiologic findings showed subpleural cavitary consolidation in the right upper lobe (RUL). Bronchoscopic and cytological examination showed no remarkable medical feature. She was diagnosed with smear-negative TB, and her radiologic findings improved after receiving a 6-month anti-TB therapy. The chest CT scans, however, obtained at 4 months after completion of anti-TB therapy showed a newly developed subpleural consolidation in the RUL. She refused pathologic confirmation and was re-treated with anti-TB medication. Nevertheless, her chest CT scans revealed newly developed cavitary nodules at 5 months after re-treatment. She underwent thoracoscopic wedge resection; the pathological examination reported that granuloma caused by Paragonimus westermani. Paragonimiasis should also be considered in patients assessed with smear-negative pulmonary TB.

A case of pleural paragonimiasis confused with tuberculous pleurisy

Here, we report a case of pleural paragonimiasis that was confused with tuberculous pleurisy. A 38-year-old man complained of a mild febrile sensation and pleuritic chest pain. Radiologic findings showed right pleural effusion with pleural thickening and subpleural consolidation. Adenosine deaminase (ADA) activity in the pleural effusion was elevated (85.3 IU/L), whereas other examinations for tuberculosis were negative. At this time, the patient started empirical anti-tuberculous treatment. Despite 2 months of treatment, the pleural effusion persisted, and video-assisted thoracoscopic surgery was performed. Finally, the patient was diagnosed with pleural paragonimiasis based on the pathologic findings of chronic granulomatous inflammation containing Paragonimus eggs. This case suggested that pleural paragonimiasis should be considered when pleural effusion and elevated ADA levels are observed.

Paragonimiasis

Paragonimiasis is a zoonotic disease caused by lung flukes of the genus Paragonimus. Humans usually become infected by eating freshwater crabs or crayfish containing encysted metacercariae of these worms. However, an alternative route of infection exists: ingestion of raw meat from a mammalian paratenic host. Adult worms normally occur in pairs in cysts in the lungs from which they void their eggs via air passages. The pulmonary form is typical in cases of human infection due to P. westermani, P. heterotremus, and a few other species (Table 5.1). Worms may occupy other sites in the body, notably the brain, but lung flukes have made their presence felt in almost every organ. Ectopic paragonimiasis is particularly common when infection is due to members of the P. skrjabini complex (Table 5.1). Human paragonimiasis occurs primarily in the tropics and subtropics of Asia, Africa, and the Americas, with different species being responsible in different areas (Table 5.1).