Ocular parasite

• Introduction• Organisms• Clinical presentations• Clinical findings• Complications• Treatment

Ocular parasite

Introduction

• Ocular inflammation as a result of infection with a helminthic parasite.

• The three most common are Toxocara canis, Cysticercus cellulosae, and microfilariae of Onchocerca volvulus.

Toxocariasis

• Organism : Toxocara canis• Common round worm of

Dogs• Easily infected, by ingest

the eggs, especially who exposed to puppies, lactating bitches or who have a history of ingesting contaminated soil.

Toxocariasis

• The eggs hatch in the small intestine and the larvar enter the bloodstream, and migrate in to the tissue.

Toxocariasis

Ocular manifestration

• Form of a dense white granuloma in the posterior pole or retinal periphery, which occurs when the organism enters the eye and encysts.

Toxocariasis

• Typical toxocara granuloma located over the optic nerve. Note how the surrounding retina is drawn toward the lesion.

Toxocariasis

• Vision may markedly decrease if the granuloma affects the optic nerve or posterior pole

• May develop RRD if the holes occur

• May cause endophthalmitis

Toxocariasis

• Another presentation consists of the identification of living, mobile larvae within the eye.

• In the subritinal space or lens.

• More unusual presentations include optic neuritis and neuroretinitis.

Toxocariasis

Diagnosis

• The classic presentation of a whitish granuloma and surrounding vitreoretinal traction

• Confirm by ELISA

Toxocariasis

Treatment

• Systemic or periocular corticosteroids

• Thiabendazole

• Vitrectomy

Toxocariasis

Prognosis

• A poor outcome associated with

a large fold in the macular region

• Destroy the larvae with minimal inflammatory reaction is important

GNATHOSTOMIASIS

Organism: Gnathostoma spinigerum

GNATHOSTOMIASIS

Life cycle

• Definite Host : Cat ,Dog ,Tiger ,Leopard

• First Intermediate Host : Cyclops (water)

• Second Intermediate Host : Reptile, Birds, Mammals, Fish, Amphibians

• Accidental Host : Human

GNATHOSTOMIASIS

Epidemiology

• Widely found in far east• Most cases occur in

Thailand and Japan

GNATHOSTOMIASIS

Pathogenesis and Pathology

• Third-stage lavare and sexually immature worms migrate through tissues

• Cause local necrosis, acute inflammation and hemorrhage

GNATHOSTOMIASIS

Clinical Manifestation

• Dark spot in field of vision

• Decreased vision• Redness• Pain in the eye• Photophobia

• Hypopyon• Uveitis• Chorioretinal

hemorrhage• Secondary glaucoma

GNATHOSTOMIASIS

Diagnosis

• History

• Clinical manifestations

• Discovery of the organism

GNATHOSTOMIASIS

Treatment

• No specific treatment• Supportive care : analgesics,

systemic corticosteriods• Medical therapy : Mebendazole ,

Albendazole• Surgical removal is the treatment

of choice

GNATHOSTOMIASIS

Prognosis

• Mortality 10-15% by CNS Gnathostomiasis

• 2/3 of survivors recover fully , the remainder have permanent or long-term sequelae

OCULAR CYSTICERCOSIS

Cysticercosis

SITE OF INFECTION

• EXTRAOCULAR MUSCLE• EYE LIDS • SUBCONJUNCTIVA• OPTIC NERVE • INTRAOCULAR

ANTERIOR CHAMBERVITREOUS CAVITYSUBRETINA SPACE

Cysticercosis

SYMPTOM AND SIGN

• EYES PAIN• PROPTOSIS• EYE LIDS SWELLING• CONJUNCTIVAL

INJECTION• CHEMOSIS• DIPLOPIA• OPTHALMOPARESIS

Cysticercosis

• EXTRAOCULAR MUSCLE– OCULAR PAIN– DIPLOPIA

• ANTERIOR CHAMBER– OCULAR PAIN – CATARACT– IMPAIR VISUAL

ACUITY

Cysticercosis

PATHOPHYSIOLOGY

• HEMATOGENOUS - POSTERIOR CILIARY ARTERY

• SUBRETINAL SPACE• VITREOUS CAVITY• ANTERIOR CHAMBER

• CYSTICERCOSIS LARVAE ENCYST WITH IN 2 MONTH

• ORGANISM DEAD – INFLAMATION – UVEITIS– IRITIS– RETINITIS– ENDOPHTHALMITIS– PANOPHTHALMITIS

• IMPAIR VISUAL ACUITY

Cysticercosis

Diagnosis

• CLINICAL • IMAGING• SEROLOGY

Cysticercosis

Cysticercosis

• CLINICAL

Suspected in patient who diagnosis cysticercosis

Cysticercosis

• IMAGING – Ultrasound– CT non enhance oval cystic lesion

with hyperdense rim– MRI

INTRAOCULAR CYSTICERCOSIS

Suspected by slit lamp biomicroscopy

and indirect ophthalmoscopy

Cysticercosis

• SEROLOGY – cysticercosis antibody

– ELISA– IMMUNOFLUORESCENCE– HEMAGGLUTINATION– ASSAY ENZYME LIKED

IMMUNOELECTROTRANSFER BLOT

Cysticercosis

TREATMENT– MEDICAL

• PRAZIQUANTEL• ALBENDAZOLE

– COMPLICATION = CEREBRAL EDEMA / INFLAMATION FROM DEAD CYST

– SURGICAL• TOTAL SURGICAL EXCISION WHEN POSSIBLE• AVOID TO ASPIRATION OR OPEN OF CYST

HISTOPLASMOSIS

- Airborne spores of the fungus inhaled into the lungs

- Spread from the lungs to the eyes by lodging in the choroid caused ocular histoplasmosis syndrome

Mechanism

- Fragile,abnormal blood vessels grow underneath the retina choroidal neovascularization (CNV) untreated scar tissue replace the normal retinal tissue in the macula.

HISTOPLASMOSIS

Symptom & Sign

- Early stage : intial OHS infection subsides with out treatment tiny scars called “histo spots” associated with the growth of the abnormal blood vessels

- Later stage : abnormal vessels cause vision change Ex ; straight lines crooked, wavy, blind spot

HISTOPLASMOSIS

Diagnosis

• The presence of histo spot.

• Swelling of the retina ,which signals the growth of new,abnormal blood vessels.

Diagnostic procedure“ Fluorescein agiography”

HISTOPLASMOSIS

HISTOPLASMOSIS

“ Histo spots ”

Treatment

-LASER surgery “photocoagulation”

HISTOPLASMOSIS

Paragonimiasis

Paragonimiasis