Paragonimus

Background

• Parasitic lung fluke
• Infectious species found mainly in East/Southeast Asia, Africa, and Central/South America. Rare reports of infection acquired in the Midwest US
• Transmission via ingestion of undercooked crab or crayfish

Clinical Features

• Onset 2-15 days
• Diarrhea, abdominal pain
• Followed by fever, chest pain, fatigue
• Cough: sputum may be rusty or blood-tinged
• Symptoms similar to TB or chronic bronchitis
• CNS disease (found in 25% of hospitalized patients)
  • Meningitis, HA, seizure, visual disturbances
• May also invade liver, spleen, intestinal wall, peritoneum, abdominal lymph nodes

Differential Diagnosis

Helminth infections

Cestodes (Tapeworms)

• Taenia saginata
• Taenia solium (Cysticercosis)
• Diphyllobothrium latum
• Hymenolepis nana
• Echinococcus granulosus

Trematodes (Flukes)

• Fasciola hepatica
• Fasciolopsis buski
• Opistorchis viverrini
• Schistosoma spp
  • Schistosomiasis
• Chlonorchis sinensis
• Paragonimus spp.

Nematodes (Roundworms)

• Ascaris lumbricoides
• Enterobius vermicularis (Pinworm)
• Filarial worms
  • Loa Loa
  • Onchocerciasis
  • Lymphatic filariasis (Elephantiasis)
    • Wuchereria bancrofti
    • Brugia malayi
    • Brugia timori
• Hookworm
  • Necator americanus
  • Ancylostoma duodenale
  • Cutaneous larva migrans (Ancylostoma braziliense)
• Dracunculiasis
• Strongyloides stercoralis
• Trichuris trichiura (Whipworm)
• Anisakis
• Toxocara spp.
• Trichinosis

Evaluation

• Diagnosis made by sputum (though parasite is killed by acid-fast testing for TB)
• CBC: may have marked eosinophilia
• CXR: range of findings (lobar infiltrates, calcified nodules, coin lesions, pleural thickening) but characteristic finding is ring-shaped opacities of contiguous cavities that look like a bunch of grapes
• CT head: may also see "bunch of grapes" type cavities if CNS involvement

Management

• Praziquantel 25mg/kg q8h x 2 days
• Add short course of corticosteroids if CNS involvement to reduce inflammatory response to dying flukes