Paragonimiasis - Clinicals, Diagnosis, and Management

Infectious diseases

Clinicals - History

Fact Explanation
Diarrhea Paragonimiasis is caused by a trematod called Paragonimus westermani (Lung fluke). The infection is acquired by eating undercooked/raw freshwater crabs/crayfish, where the cercarias reside encysted. The young fluke is developed in the human
intestine and it burrows through the intestinal wall. Most infections are asymptomatic. But in heavy infections this migratory phase (acute stage) results in various symptoms owing to the local and systemic allergic and inflammatory reaction triggered by the migration. The resultant diarrhea onsets acutely. It is mild and watery in nature, and mostly self-limiting. Diarrhea may be accompanied with mild fever abdominal pain and malaise.
Diarrhea
Paragonimiasis is caused by a trematod called Paragonimus westermani (Lung fluke). The infection is acquired by eating undercooked/raw freshwater crabs/crayfish, where the cercarias reside encysted. The young fluke is developed in the human
intestine and it burrows through the intestinal wall. Most infections are asymptomatic. But in heavy infections this migratory phase (acute stage) results in various symptoms owing to the local and systemic allergic and inflammatory reaction triggered by the migration. The resultant diarrhea onsets acutely. It is mild and watery in nature, and mostly self-limiting. Diarrhea may be accompanied with mild fever abdominal pain and malaise.
Cough The fluke which departed from the intestine further burrows through the diaphragm and enters various extra pulmonary sites. This stage of the disease is called establishment or chronic phase. The commonest site is the lung. Adult fluke develops in the lung and lives for many years. It causes chronic inflammatory reactions and the first effects are usually dry cough which may transform in to a productive cough with purulent sputum or hemoptysis before long. And it is accompanied with chest pain, dyspnea and rarely low grade fever mimicking pulmonary tuberculosis. Productive cough with purulent sputum in a febrile patient may be due to pneumonia that occur as a complication.
Hacking cough that persists for 5 days or more with clear, yellow, white, or green phlegm, absence of fever/ low grade fever may indicate bronchitis, another complication of the disease.
Cough
The fluke which departed from the intestine further burrows through the diaphragm and enters various extra pulmonary sites. This stage of the disease is called establishment or chronic phase. The commonest site is the lung. Adult fluke develops in the lung and lives for many years. It causes chronic inflammatory reactions and the first effects are usually dry cough which may transform in to a productive cough with purulent sputum or hemoptysis before long. And it is accompanied with chest pain, dyspnea and rarely low grade fever mimicking pulmonary tuberculosis. Productive cough with purulent sputum in a febrile patient may be due to pneumonia that occur as a complication.
Hacking cough that persists for 5 days or more with clear, yellow, white, or green phlegm, absence of fever/ low grade fever may indicate bronchitis, another complication of the disease.
Difficulty in breathing This is due to primary infestation of the parasites that causes a chronic inflammatory reaction or due to pleural effusion and pneumonia occur as complications. Difficulty in breathing
This is due to primary infestation of the parasites that causes a chronic inflammatory reaction or due to pleural effusion and pneumonia occur as complications.
Drooling of saliva Rarely the cerebral invasion may cause facial nerve palsy. This may result in facial muscle weakness, drooling of saliva, with other symptoms including loss of taste. Drooling of saliva
Rarely the cerebral invasion may cause facial nerve palsy. This may result in facial muscle weakness, drooling of saliva, with other symptoms including loss of taste.
Fits Rarely, adult worms may also migrate to the brain causing cerebral abscess. These patients may present with newly onset fits, vomiting, headaches, and sometimes, visual disturbances. Fits
Rarely, adult worms may also migrate to the brain causing cerebral abscess. These patients may present with newly onset fits, vomiting, headaches, and sometimes, visual disturbances.
Skin nodules Patients with subcutaneous paragonimiasis can present with swelling which are migratory and subcutaneous nodules. Skin nodules
Patients with subcutaneous paragonimiasis can present with swelling which are migratory and subcutaneous nodules.
Limb weakness This may be due to hemi/ paraplegia caused by cerebral of spinal cord invasion of the parasite. Limb weakness
This may be due to hemi/ paraplegia caused by cerebral of spinal cord invasion of the parasite.
Visual disturbances This is due to the cerebral disease or direct invasion of the eyes. Visual disturbances
This is due to the cerebral disease or direct invasion of the eyes.
Abdominal distension Chronic granuloma formation in the abdomen results in peritoneal abscesses which sometimes become large enough to cause significant abdominal distension. Abdominal distension
Chronic granuloma formation in the abdomen results in peritoneal abscesses which sometimes become large enough to cause significant abdominal distension.
At risk population Paragonimiasis is most common in countries like China, Korea, Japan, Taiwan, South and Central America and Africa. Infection acquired by eating undercooked/raw freshwater crabs/crayfish. People who eats crabs soaked in salt/vinegar/wine and those communities using crab juice as a medicinal ingredient are at a higher risk. At risk population
Paragonimiasis is most common in countries like China, Korea, Japan, Taiwan, South and Central America and Africa. Infection acquired by eating undercooked/raw freshwater crabs/crayfish. People who eats crabs soaked in salt/vinegar/wine and those communities using crab juice as a medicinal ingredient are at a higher risk.

Clinicals - Examination

Fact Explanation
Fever Low grade fever is rare finding and may indicate the migration of the parasite. Fever
Low grade fever is rare finding and may indicate the migration of the parasite.
Clubbing Clubbing of the fingers occasionally occur as a result of chronic lung involvement. Clubbing
Clubbing of the fingers occasionally occur as a result of chronic lung involvement.
Lung examination This is usually normal except in complications like pleural effusion or pneumonia where the dullness can be demonstrated during the percussion over the affected area. Lung examination
This is usually normal except in complications like pleural effusion or pneumonia where the dullness can be demonstrated during the percussion over the affected area.
Neurological sings Neurological features such as paresis, nerve palsies are very rare. Vision / visual acuity may be affected in some instances. Neurological sings
Neurological features such as paresis, nerve palsies are very rare. Vision / visual acuity may be affected in some instances.
Abdominal mass Palpable masses in the abdomen may indicate peritoneal abscesses. Abdominal mass
Palpable masses in the abdomen may indicate peritoneal abscesses.
Subcutaneous nodules Firm, mobile and tender nodules can be found in the lower abdominal and inguinal region in subcutaneous paragonimiasis. Subcutaneous nodules
Firm, mobile and tender nodules can be found in the lower abdominal and inguinal region in subcutaneous paragonimiasis.

Investigations - Diagnosis

Fact Explanation
Parasitological diagnosis Demonstration of eggs in sputum or stools samples prepared in direct smear or aspirated material from abscesses, pleural fluids or CSF is the definitive way of diagnosis. Concentration techniques may be needed in light infections. The average egg size is 85 µm by 53 µm. It is yellow- brown in color and ovoidal or elongated in shape. Eggs have a thick shell. Operculum is clearly visible. The opposite end is thickened. Parasitological diagnosis
Demonstration of eggs in sputum or stools samples prepared in direct smear or aspirated material from abscesses, pleural fluids or CSF is the definitive way of diagnosis. Concentration techniques may be needed in light infections. The average egg size is 85 µm by 53 µm. It is yellow- brown in color and ovoidal or elongated in shape. Eggs have a thick shell. Operculum is clearly visible. The opposite end is thickened.
Chest radiographs Chest x-ray may reveal ring-shadowed opacities (bunch of grapes). This indicates the cavitating lesions , fibrosis, nodules or linear infiltrates. Pleural effusiona or pneumothorax are rare findings. Chest radiographs
Chest x-ray may reveal ring-shadowed opacities (bunch of grapes). This indicates the cavitating lesions , fibrosis, nodules or linear infiltrates. Pleural effusiona or pneumothorax are rare findings.
CT scan “Soap bubble appearance” in brain scans represents cystic lesions and calcifications. CT scan
“Soap bubble appearance” in brain scans represents cystic lesions and calcifications.
ELISA This is the serological investigation of choice due to its high sensitivity and specificity. ELISA
This is the serological investigation of choice due to its high sensitivity and specificity.

Management - Supportive

Fact Explanation
Prevention Eating raw/undercooked crustaceans/crayfish should be avoided without heating at 55 Celsius degrees for 5 min or roasting. Health education should be given for those who travel in the endemic countries. Prevention
Eating raw/undercooked crustaceans/crayfish should be avoided without heating at 55 Celsius degrees for 5 min or roasting. Health education should be given for those who travel in the endemic countries.

Management - Specific

Fact Explanation
Praziquantel Praziquantel as a single dose (25 mg/kg or less) is the current treatment of choice. Frequently occurring side effects are dizziness, headache, and malaise. Approximately 90% of all patients have abdominal pain or cramps with or without nausea and vomiting. Other drugs used to treat infestation include triclabendazole, bithionol, albendazole, levamisole and mebendazole. Praziquantel
Praziquantel as a single dose (25 mg/kg or less) is the current treatment of choice. Frequently occurring side effects are dizziness, headache, and malaise. Approximately 90% of all patients have abdominal pain or cramps with or without nausea and vomiting. Other drugs used to treat infestation include triclabendazole, bithionol, albendazole, levamisole and mebendazole.
Surgery Extrapulmonary lesions such as abscesses should be surgically excised. Surgery
Extrapulmonary lesions such as abscesses should be surgically excised.

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