Abstract
This is a short report describing the clinical presentation, investigations, treatment and outcome of a patient living in the Jamaican countryside who was diagnosed with a live, motile subfoveal helminth identified as Angiostrongylus cantonensis on optical coherence tomography at the University Hospital of the West Indies Eye Clinic. This is the second documented case in Jamaica. Early recognition of angiostrongyliasis is important as it may manifest as eosinophilic meningitis which can be fatal without prompt treatment.
Short report
A 50-year-old male, German patient, living in rural Jamaica, presented with a one week history of sudden painless blurred vision in his right eye. He had no nausea, vomiting, fever, headache or neck stiffness. He was referred to our hospital with a diagnosis of a live subfoveal worm in his right eye (Figure 1(a) to (c)). Visual acuity was count fingers and 20/20 vision in his right and left eye, respectively. His anterior segment was normal. Fundus examination of the right eye revealed that the ∼13 mm motile subretinal worm had migrated from the fovea to the inferior temporal arcade. No vitritis was present.
(a to c) Optical coherence tomogram fundus photographs of the right eye depicting motility of helminth.
Optical coherence tomography (OCT) done earlier that day, prior to the hospital referral, revealed a subretinal motile worm in the fovea, between the retinal pigment epithelium (RPE) and photoreceptors (Figure 2(a)). There was an associated neurosensory detachment with ‘shaggy photoreceptors’ and mild cystoid macular oedema in the right eye.
Serial OCTs and coloured fundus photographs of the right eye. (a) Day 1, OCT (B scan) through the fovea shows 2 circular areas indicating the cross section of the coiled subfoveal helminth present in the outer retinal layer. The overlying nerve fibre layer is intact. (b) Day 2, OCT shows resolution of the subfoveal fluid. Laser reaction around the worm along the inferior temporal arcade (fundal photograph). (c) Day 30, OCT shows macular atrophy of outer retinal layers. Partially disintegrated worm along the inferior temporal arcade (fundal photograph).
His haemoglobin and white cell count were normal: Hb 158g/l, WBC 10.31 × 109/L with no peripheral eosinophilia. A sputum culture isolated no pathogens. A chest radiograph showed vague interstitial changes to the lung bases; however, lung fields were clear and his stool was negative for cysts or parasites.
The nematode was identified as Angiostrongylus cantonensis. A 577 µm Iridex IQ pattern scanning yellow laser was used to ablate the worm and barricade it at the inferior temporal arcade. The patient was treated with systemic albendazole and prednisone. His macular oedema resolved with resulting atrophy and the subretinal worm partially disintegrated (Figure 2(b) and (c)). His visual acuity improved from counting fingers to 20/200, one month after treatment.
Discussion
A. cantonensis infection, also known as the ‘rat lungworm’, was first diagnosed in humans in 1935, China. 1 Angiostrongylus is present in rats, snails, slugs, land crabs, freshwater shrimps, predatory planarians, amphibians and reptiles. 1 Accidental ingestion of third-stage larvae in infected snails or slugs in contaminated vegetables is thought to be the route of infection in Jamaica. 1 Angiostrongyliasis can be prevented through proper washing of produce before consumption and avoiding ingestion of raw crustaceans.
A. cantonensis is the most common cause of eosinophilic meningitis worldwide. 1 In 2000, the first case of human angiostrongyliasis infection in Jamaica was confirmed after autopsy of a 14 month old boy. 1 There have been 23 documented cases of eosinophilic meningitis secondary to A. cantonensis in the island. 1
Ocular involvement occurs in 0.8%–1.1% of cases of human angiostrongyliasis.2,3 It is mainly found in Asia and can present with optic neuritis. 4 Sporadic cases of ocular angiostrongyliasis have been reported in the Caribbean, North and South America.2,5,6
Ocular angiostrongyliasis presents most commonly in the vitreous cavity, but subfoveal worms are rare.2,4 Patients with optic neuritis secondary to A. cantonensis may have subretinal worms that may leave tracks.4,6 Diode laser has been successfully used to ablate the worm as well as surgical removal.4,6 This patient developed atrophy of the foveal outer retinal layers, secondary to RPE damage caused by the motile worm when it was subfoveal. To conclude, this is the first documented case of subretinal angiostrongyliasis in Jamaica. The early recognition of angiostrongyliasis infection is important as this disease may manifest as eosinophilic meningitis which can be fatal without prompt treatment.
Footnotes
Declaration of conflicting interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) received no financial support for the research, authorship, and/or publication of this article.