nw2005 ocular parasites
DESCRIPTION
ocular parasitic infectionTRANSCRIPT
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