1. Ocular Toxoplasmosis
Dr. Md. Mominul
Islam
Fellow (Vitreo-Retina)
Ispahani Islamia Eye
Institute And
Hospital Dhaka
Bangladesh

2. Introduction
 Common zoonosis
 Caused by Toxoplasma Gondii
 Life threatening disease (newborn and
immnosuprresed patients)
 Asymptomatic in immuno competent patient
 Congenital or Acquired
 Both eye may affected

3. Epidemiology
Represent with posterior uveitis
 50-85% in Brazil
 25% in USA
Prevalence: (not well determind)
 0.6-2% in USA
 10-17.7% in Brazil

4. Transmission
 Beef
 Undercooked lamb , pork, chicken
 Environment contaminated by feces of infected cats
family
 Organ transplantation
 Blood transfusion
 Water

5. Biology And Life Cycle
 Obligate , intracellular protozoan
 Both sexual and asexual reproduction
 Definitive host – Members of cat family
 Intermediate host- Hundreds of species including
mammals, birds
 Host tissue - Muscle
- Retina
- Nervous tissue
- Body fluid

6. Contd
Three forms
Oocyte
Trachyzoite
Bradyzoit
(tissue cyst)

7. Genetics
Type- I
• Very
virulent
• Postnatal
acquired
ocular
infection
Type-II
• Less
virulent
• Congenital
infection
and
toxoplasmic
encephalitis
Type-III
• Less
virulent

8. Pathogenesis
In immunocompetent patients is characterized
histologically by
 Foci of granulomatous chorioretinal inflammation
 Coagulative necrosis of the retina with sharply
demarcated borders
 Inflammatory changes can be widespread in the eye
and involve choroid, iris, and trabecular meshwork

9. Contd
In Immunosuppressed
 Have both tachyzoites and tissue cysts in areas of
retinal necrosis and within retinal pigment epithelial
cells.
 Parasites can occasionally be found in the iris, choroid,
vitreous, and optic nerve

11. Ocular presentation
Symptoms
 Floaters
 Blurring or loss of vision
Sign (The hallmarks)
 necrotizing
retinochoroiditis
 Satellite lesion adjacent
to old hyperpigmented
scars
 Vitreous inflammation
 Anterior uveitis
 Retinal vasculitis is also
present (occationally)

13. Contd
New or Acute lesion
• Intensely white
• Focal lesion overlying
vitreous inflammatory
haze (head light in the
fog)
• Acute anterior uveitis
Healed lesion
• Border become more
defined
• Hyperpigmented after
several months
• Large scar will have
atrophic center
(devoid of all choroidal
retinal elements)

15. Investigation
 Serological test
 PCR

16. Differential Diagnosis
Infectious:
 Rubella
 Cytomegalovirus
 Syphilis
 Herpes simplex
 Tuberculosis
 Toxocariasis

17. Contd
Non-infectious:
 Retinal and choroidal coloboma
 Retinoblastoma,
 Retinopathy of prematurity
 Gyrate atrophy
 Retinal vascular membrane
 Serpiginous choroidopathy

18. Outcome And Complication
 Central vision will be lost
 Permanent loss of vision
 Sudden loss of vision.

19. Treatment and Prevention
 Available drugs do not eliminate tissue cysts and
cannot prevent chronic infection
 No treatment has proven to be superior or even more
effective than no treatment
 Antitoxoplasmic agents and systemic steroids have
never been studied in large clinical trials

20. “Classic” therapy:
 The combination of pyrimethamine, sulfadiazine, and
corticosteroids
Pyrimethamine:
75–100 mg loading dose given over 24 hours, followed by 25–
50 mg daily for 4–6 weeks depending on clinical response
Sulfadizine:
2.0–4.0 g loading dose initially, followed by 1.0 g given 4
times daily for 4–6 weeks, depending or clinical response
Prednisone:
40–60 mg daily for 2 to many weeks depending on clinical
response; taper off before discontinuing
pyrimethamine/sulfadiazine
Folinic acid:
5.0 mg tablet, 2–3 times weekly during pyrimethamine
therapy

21. Contd
Other Drugs:
Trimethoprim and sulfamethoxazole.
Systemic or intraocular clindamycin
The duration of treatment depends on the individual
clinical picture
Steroid treatment is often administered systemically and
always associated with antitoxoplasmic drugs
 Local drops are used when anterior uveitis is present

22. Take Whom Massage
Wrong concepts in ocular toxoplasmosis
 All cases congenital
 Must present as a “retinochoroiditis”
 Vertical transmission (pregnancy) only once in life
 Cats and meat are the only source
 No treatment to avoid recurrences
 All patients need antitoxoplasmic drugs for 4–6
weeks
 Recurrences are related only to local factors

23. Thank you