Paragonimiasis is an endemic parasitic disease caused by lung flukes infecting the human lungs. It is contracted by consuming undercooked crabs or crayfish containing metacercariae. Cough, chest pain, and rust-colored sputum are the most common symptoms. The parasites and their eggs can also cause ectopic infections in the brain, liver, intestines, abdominal cavity, eyes, and subcutaneous tissues.

bubble_chart Clinical Manifestations

According to the location of Chinese Taxillus Herb, it is divided into the following types.

1. Pulmonary type: The onset is mostly slow, with systemic symptoms such as fever, lack of strength, weight loss, night sweating, etc. At the same time, there may be cough, chest tightness, chest pain, and rust-colored sputum or blood-streaked sputum. Sometimes it may be accompanied by pleural effusion.
2. Cerebral type: More common in children. Manifestations include headache, vomiting, impaired consciousness, epileptic seizures, and paralysis, etc. Depending on the main site of damage in the brain, it is divided into epileptic type, brain tumor type, meningitis type, cerebral thrombosis type, and hysteria type. Cerebrospinal fluid often shows abnormal changes.
3. Abdominal type: Mainly characterized by abdominal pain, abdominal wall tension, and localized tenderness. If the worm cyst invades the intestinal wall, diarrhea and mucopurulent bloody stools may occur.
4. Subcutaneous nodules vary in size (approximately 0.5–4 cm in diameter), located deep under the skin, most commonly on the abdominal wall, and can migrate and move to various locations.

bubble_chart Auxiliary Examination

1. The total white blood cell count in peripheral blood is slightly increased, approximately between 10–15×10⁹/L. In the early stage, eosinophils are significantly elevated, potentially exceeding 50%.
2. Sputum examination: Blood-tinged sputum, rusty sputum, and gelatinous sputum can be observed macroscopically. Microscopic examination of sputum may reveal red blood cells, white blood cells, eosinophils, phagocytes, Charcot-Leyden crystals, and parasite eggs.
3. Stool examination: The use of concentration methods to detect eggs can improve the positive rate.
4. Gastric fluid examination: For young children from whom sputum specimens are difficult to collect, gastric lavage fluid can be aspirated to check for parasite eggs.
5. Cerebrospinal fluid: Increased pressure, colorless and transparent or pale yellow in appearance, with a slight increase in white blood cell count, primarily eosinophils. Protein levels are elevated, glucose is normal or increased, and chloride levels are normal. Parasite eggs may sometimes be found.
6. Subcutaneous nodules can undergo biopsy to detect adult worms, larvae, or eggs.
7. Intradermal antigen tests and complement fixation tests are positive. Enzyme-linked immunosorbent assay (ELISA) demonstrates high sensitivity (positive rate up to 100%) and specificity for the diagnosis of paragonimiasis.

bubble_chart Diagnosis

Epidemiological history includes residing in an endemic area and having a history of consuming raw crabs, crayfish, or drinking untreated water.

bubble_chart Treatment Measures

﹝Treatment﹞

(1) General Treatment Strengthen nutrition and ensure bed rest. Hemoptysis can be treated with hemostatic medication. Epilepsy requires antiepileptic drugs. When there is a large amount of pleural or pericardial effusion with compressive symptoms, repeated fluid drainage is necessary. Increased intracranial pressure requires measures to reduce it. (2) Pathogen Treatment 1. Praziquantel: The dose is 45–50mg/(kg·d), divided into three doses, for a course of 2 days. 2. Bithionol: This is the drug of choice, with a dose of 50mg/(kg·d), divided into three oral doses, taken continuously for 10–15 days or every other day for 20–30 days as one course. For cerebral cases, 2–3 courses are required, with intervals of 1–2 weeks between courses. The cure rate can reach 80–100%. (3) Surgical Treatment For cerebral cases with localized compressive symptoms or other types with localized lesions, cysts, nodules, or adhesions can be excised or separated. Preoperative control of pulmonary lesions is essential. If the lesions are scattered or atrophic but pulmonary lesions are not yet controlled, surgical intervention should be carefully considered.

bubble_chart Prevention

(1) Thoroughly treat patients. (2) Strengthen health education. Change poor dietary habits by avoiding raw crabs, drunken crabs, and raw crayfish, and refrain from drinking untreated water. (3) Properly dispose of patient excreta such as feces and sputum, protect water sources, and prevent contamination. (4) Investigate and manage animal pestilence sources.