Young Man with Foreign-Body Sensation in the Right Eye
Article Outline
[Ann Emerg Med. 2010;55:578.]
A 25-year-old US-born man, formerly healthy, presented to the emergency department, complaining of foreign body sensation in his right eye for 1 day. Review of symptoms revealed 18 months of intermittent pruritic skin swellings. Travel history was extensive, mainly to Central and South America (including Peru recently), with one 12-day trip to Equatorial Guinea (Central Africa) 2 years before. Physical examination was notable for the findings above, and laboratory studies were notable for marked eosinophilia.
Diagnosis
Loaiasis (African eye worm). The Figure shows a motile filarial nematode, Loa loa, endemic to Central and West Africa. Transmission is by bite of the chrysops fly. Larvae deposited in the human bloodstream mature into worms, which migrate throughout the subcutaneous tissue and the subconjunctivae (pathognomonic for L loa). Infection with worms of both sexes allows mating and release of microfilariae, which migrate to the pulmonary circulation at night. The evanescent skin lesions reported are characteristic of Calabar swellings, thought to be hypersensitivity responses to subcutaneous worms.1, 2, 3
Figure.
Patient's eye. Photo by Martin Moran, PA.
Used with pemission.
The preferred treatment for loaisis is oral diethylcarbamazine. Before therapy, a midday blood sample must be examined for microfilariae because higher loads (more common in natives to endemic areas than visitors, who are often amicrofilaremic) are associated with posttreatment meningoencephalitis, likely a result of antigen release with microfilariae lysis.4 In the United States, diethylcarbamazine is available only from the Centers for Disease Control and Prevention, which released it for 10 cases in 2007 (E. D. Kennedy, personal communications, September 2008 and May 2009).
Our patient had an undetectable microfilarial load, was treated with DEC, and remained asymptomatic 6 months later.
References
- . Hunter's Tropical Medicine and Emerging Infectious Diseases. 8th ed.. Oxford, England: WB Saunders Co; 2000;
- . Loiasis: African eye worm. Trans R Soc Trop Med Hyg. 2008;102:983–989
- Loiasis in endemic and nonendemic populations: immunologically mediated differences in clinical presentation. J Infect Dis. 1991;163:1318–1325
- . Loiasis. Ann Trop Med Parasitol. 2006;100:715–731
For the diagnosis and teaching points, see page 583.
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PII: S0196-0644(09)01136-6
doi:10.1016/j.annemergmed.2009.06.505
© 2009 American College of Emergency Physicians. Published by Elsevier Inc. All rights reserved.
