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. [1,2,3]
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. [2,3,4]
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. [1,2,3]
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. [1,2,5]
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. [2,4,5]
Skin nodules Patients with subcutaneous paragonimiasis can present with swelling which are migratory and subcutaneous nodules. [1,3,4]
Limb weakness This may be due to hemi/ paraplegia caused by cerebral of spinal cord invasion of the parasite. [1,2,5]
Visual disturbances This is due to the cerebral disease or direct invasion of the eyes. [1,2,3]
Abdominal distension Chronic granuloma formation in the abdomen results in peritoneal abscesses which sometimes become large enough to cause significant abdominal distension. [2,5]
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. [2,3,4]
References
  1. SINGH TS, SUGIYAMA H, RANGSIRUJI A. Paragonimus & paragonimiasis in India. Indian J Med Res [online] 2012 Aug, 136(2):192-204 [viewed 17 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/22960885
  2. CENTERS FOR DISEASE CONTROL AND PREVENTION (CDC). Human paragonimiasis after eating raw or undercooked crayfish --- Missouri, July 2006-September 2010. MMWR Morb Mortal Wkly Rep [online] 2010 Dec 10, 59(48):1573-6 [viewed 17 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/21150864
  3. DIAZ JH. Paragonimiasis acquired in the United States: native and nonnative species. Clin Microbiol Rev [online] 2013 Jul, 26(3):493-504 [viewed 17 August 2014] Available from: doi:10.1128/CMR.00103-12
  4. LALL M, SAHNI AK, RAJPUT AK. Pleuropulmonary paragonimiasis: mimicker of tuberculosis. Pathog Glob Health [online] 2013 Jan, 107(1):40-2 [viewed 17 August 2014] Available from: doi:10.1179/2047773212Y.0000000067
  5. XU HZ, TANG LF, ZHENG XP, CHEN ZM. Paragonimiasis in chinese children: 58 cases analysis. Iran J Pediatr [online] 2012 Dec, 22(4):505-11 [viewed 17 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/23430310

Examination

Fact Explanation
Fever Low grade fever is rare finding and may indicate the migration of the parasite. [1,2]
Clubbing Clubbing of the fingers occasionally occur as a result of chronic lung involvement. [1,2,3]
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. [2,3,4]
Neurological sings Neurological features such as paresis, nerve palsies are very rare. Vision / visual acuity may be affected in some instances. [1,3,4]
Abdominal mass Palpable masses in the abdomen may indicate peritoneal abscesses. [1,2,4]
Subcutaneous nodules Firm, mobile and tender nodules can be found in the lower abdominal and inguinal region in subcutaneous paragonimiasis. [2,3,4]
References
  1. CENTERS FOR DISEASE CONTROL AND PREVENTION (CDC). Human paragonimiasis after eating raw or undercooked crayfish --- Missouri, July 2006-September 2010. MMWR Morb Mortal Wkly Rep [online] 2010 Dec 10, 59(48):1573-6 [viewed 17 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/21150864
  2. LALL M, SAHNI AK, RAJPUT AK. Pleuropulmonary paragonimiasis: mimicker of tuberculosis. Pathog Glob Health [online] 2013 Jan, 107(1):40-2 [viewed 17 August 2014] Available from: doi:10.1179/2047773212Y.0000000067
  3. DIAZ JH. Paragonimiasis acquired in the United States: native and nonnative species. Clin Microbiol Rev [online] 2013 Jul, 26(3):493-504 [viewed 17 August 2014] Available from: doi:10.1128/CMR.00103-12
  4. SINGH TS, SUGIYAMA H, RANGSIRUJI A. Paragonimus & paragonimiasis in India. Indian J Med Res [online] 2012 Aug, 136(2):192-204 [viewed 17 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/22960885

Differential Diagnoses

Fact Explanation
Ascariasis Ascariasis is caused by Ascaris lumbricoides (large roundworm of humans) It is extremely common infection worldwide and associated with poor sanitation (lack of latrines) in slum areas and estate line rooms. Ascariasis affects more in children than in adults. Mild infection of adult worms does not show symptoms or signs. Increasing worm loads result in worsening of chronic malnutrition especially in children with a poor diet, poor weight gain and stunting. Symptoms may include shortness of breath and fever in the beginning of the disease. These may be followed by symptoms of abdominal swelling, abdominal pain and diarrhea. [1]
Tuberculosis An infectious disease caused by the bacterium Mycobacterium tuberculosis. Low grade nocturnal fever with long standing chronic cough lasting more than 3 weeks. Cough is productive with blood stained sputum. Loss of appetite, night sweats and loss of weight are systemic features. There might be a past history or contact history of tuberculosis. [2]
Fascioliasis Fasciola hepatica or the sheep liver fluke is a common parasite of sheep and cattle kept on damp pastures in many parts of the world, but is only occasionally found in men. Most cases have been reported from from sheep rearing countries such as South America, Europe and North America. The major symptoms includes fever, abdominal pain, gastrointestinal disturbances such as loss of appetite, flatulence, nausea, diarrhea and urticaria. [3]
Pneumonia Pneumonia is an inflammation of lung tissues with accumulation of cells and secretions in alveolar spaces usually following an infection. The infection can be either bacterial, viral, fungal, and mycobacterial in origin. The causative organism depends on the age of person, exposure history, risk factors for unusual pathogens, and the immunization. Fever is one of the most common symptom after 5 years of age whose pneumonia is most probably due to bacterial infections (Streptococcus pneumonia is the common bacterial etiology). This fever is acute in onset, and usually high grade with chills and rigors. The fever pattern in continuous. Below the age of 5 years and specially in the infants, fever is not a prominent symptom except in those rare cases of severe bacterial pneumonia (Group B streptococcus, E coli, Klebsiella, Listeria, Streptococcus pneumonia,Staphylococcus aureus, Chlamydia). They may have low-grade fever or may be afebrile. This is basically due to the viral origin of the pneumonia or sometimes due to atypical etiologies such as mycoplasma. Respiratory Syncytial Virus and Parainfluenza are the commonest etiologies. Hypothermia is not a rare finding in infants. Fever usually follow non specific prominent prodromal features such as malaise, body weakness, arthralgia and myalgia. [4]
Asthma Asthma is a recurrent chronic inflammatory disease of the airways characterized by shortness of breath, wheezing and cough. The symptoms usually occurs at night and the cough is usually non productive despite of mucus obstruction of the airway. [5]
References
  1. WANG J, PAN YL, XIE Y, WU KC, GUO XG. Biliary ascariasis in a bile duct stones-removed female patient. World J Gastroenterol [online] 2013 Sep 28, 19(36):6122-4 [viewed 27 July 2014] Available from: doi:10.3748/wjg.v19.i36.6122
  2. ANDERSON ST, KAFOROU M, BRENT AJ, WRIGHT VJ, BANWELL CM, CHAGALUKA G, CRAMPIN AC, DOCKRELL HM, FRENCH N, HAMILTON MS, HIBBERD ML, KERN F, LANGFORD PR, LING L, MLOTHA R, OTTENHOFF TH, PIENAAR S, PILLAY V, SCOTT JA, TWAHIR H, WILKINSON RJ, COIN LJ, HEYDERMAN RS, LEVIN M, ELEY B, ILULU CONSORTIUM, KIDS TB STUDY GROUP. Diagnosis of childhood tuberculosis and host RNA expression in Africa. N Engl J Med [online] 2014 May 1, 370(18):1712-23 [viewed 23 July 2014] Available from: doi:10.1056/NEJMoa1303657
  3. ARADAğ-ÖNCEL E, OZSüREKçI Y, OZKAYA-PARLAKAY A, CELIK M, CENGIZ AB, HALILOğLU M, CEYHAN M, KARA A. Fasciola hepatica infection: clinical and radiological findings in pediatric patients. Turk J Pediatr [online] 2012 Jul-Aug, 54(4):362-7 [viewed 27 July 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/23692716
  4. HARRIS M., CLARK J., COOTE N., FLETCHER P., HARNDEN A., MCKEAN M., THOMSON A.. British Thoracic Society guidelines for the management of community acquired pneumonia in children: update 2011. Thorax [online] December, 66(Suppl 2):ii1-ii23 [viewed 23 July 2014] Available from: doi:10.1136/thoraxjnl-2011-200598
  5. CHEN ZH, WANG PL, SHEN HH. Asthma research in China: a five-year review. Respirology [online] 2013 Nov:10-9 [viewed 23 July 2014] Available from: doi:10.1111/resp.12196

Investigations - for 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. [1,2,3]
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. [2,3,4]
CT scan “Soap bubble appearance” in brain scans represents cystic lesions and calcifications. [1,3,4]
ELISA This is the serological investigation of choice due to its high sensitivity and specificity. [1,3,4]
References
  1. SINGH TS, SUGIYAMA H, RANGSIRUJI A. Paragonimus & paragonimiasis in India. Indian J Med Res [online] 2012 Aug, 136(2):192-204 [viewed 17 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/22960885
  2. CENTERS FOR DISEASE CONTROL AND PREVENTION (CDC). Human paragonimiasis after eating raw or undercooked crayfish --- Missouri, July 2006-September 2010. MMWR Morb Mortal Wkly Rep [online] 2010 Dec 10, 59(48):1573-6 [viewed 17 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/21150864
  3. DIAZ JH. Paragonimiasis acquired in the United States: native and nonnative species. Clin Microbiol Rev [online] 2013 Jul, 26(3):493-504 [viewed 17 August 2014] Available from: doi:10.1128/CMR.00103-12
  4. LALL M, SAHNI AK, RAJPUT AK. Pleuropulmonary paragonimiasis: mimicker of tuberculosis. Pathog Glob Health [online] 2013 Jan, 107(1):40-2 [viewed 17 August 2014] Available from: doi:10.1179/2047773212Y.0000000067

Management - General Measures

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. [1,2]
References
  1. LALL M, SAHNI AK, RAJPUT AK. Pleuropulmonary paragonimiasis: mimicker of tuberculosis. Pathog Glob Health [online] 2013 Jan, 107(1):40-2 [viewed 17 August 2014] Available from: doi:10.1179/2047773212Y.0000000067
  2. DIAZ JH. Paragonimiasis acquired in the United States: native and nonnative species. Clin Microbiol Rev [online] 2013 Jul, 26(3):493-504 [viewed 17 August 2014] Available from: doi:10.1128/CMR.00103-12

Management - Specific Treatments

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. [1,2,3]
Surgery Extrapulmonary lesions such as abscesses should be surgically excised. [1,2]
References
  1. DIAZ JH. Paragonimiasis acquired in the United States: native and nonnative species. Clin Microbiol Rev [online] 2013 Jul, 26(3):493-504 [viewed 17 August 2014] Available from: doi:10.1128/CMR.00103-12
  2. CENTERS FOR DISEASE CONTROL AND PREVENTION (CDC). Human paragonimiasis after eating raw or undercooked crayfish --- Missouri, July 2006-September 2010. MMWR Morb Mortal Wkly Rep [online] 2010 Dec 10, 59(48):1573-6 [viewed 17 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/21150864
  3. XU HZ, TANG LF, ZHENG XP, CHEN ZM. Paragonimiasis in chinese children: 58 cases analysis. Iran J Pediatr [online] 2012 Dec, 22(4):505-11 [viewed 17 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/23430310