Pentastomiasis: Diagnostics and Treatment

Transmission

Diagnostic Techniques

The presence of Pentastomiasis has mainly been in post-mortem findings. However, as the rare person will have symptoms, it is important to be able to make the accurate diagnosis of pentastomiasis.

1. X-Ray or Explorative Laparoscopy (the latter not recommended.) Over half of lesions are found in the liver, but can also be found in the intestinal wall, mesentery, peritoneum, and lung. Because pentastomid lesions are not found in muscle tissue, we can rule out cysticercosis. The types of lesions to identify are:

  • Necrotic pentastomida granuloma. These have a C-shaped outline, and the pentastomid hooks are usually well preserved. They arise from dead, calcified larvae, 4-8 m m in diameter. Their shapes have also been referred to as a rod, circular, crescent-shaped, “broken ring," “comma,” “cashew nut,” or “horseshoe.”
  • Recent viable larva. These are also C-shaped. These parasites are still alive, and can cause a very slight localized response: they become surrounded by hyalinized scar, absent of eosinophils. (Yet they can sometimes get out and migrate.) The surrounding host cells are normal, if a bit compressed. (Prathap)
  • Cuticle granuloma. These are remnants of a molted, excysted, and now migrating larva.

 

 

Calcified nymphs discovered in X-ray. (8)

Porocephalius in mesentery. (7)

 

 

2. Identification of live nymphs. Live nymphs can be found in nasal secretions, saliva, or vomit in the case of L. serrata.

3. There are no conclusive laboratory tests that signify pentastomiasis, but the patient may present with mild nonspecific eosinophilia.

4. Serologic test for Armillifer. Developed in France, this test utilizes gel immunodiffusion and indirect immunofluorescence. However, it requires very top-notch antigens.

 

Treatment:

Free or encrusted larvae in symptomatic patients should be removed surgically.

In the case of L. serrata infection, careful observation of the airway is recommended. Severe edema that leads to airway obstruction may necessitate tracheotomy.

Herzog, Martz, and Zak used Thiabendazole to treat a woman with acute abdominal infestation with pentastomiasis. The treatment was said to be successful, but the patient relapsed. (9)

Armillifer larva (1)