Diagnosis → Ophthalmology

Retinitis pigmentosa

Etiology

Causes [ycd]

• Multiple genetic mutations are associated with the condition

• The genetic diversity contributes to the variation in the severity of the disease

• Autosomal recessive: 5-20%

• Autosomal dominant: 15-25%

• X-linked recessive: 5-15%

• Sporadic mutation: 40-50%

Pathophysiology [ycd]

1. The affected genes are responsible for critical retinal functions:

   • Phototransduction, the visual cycle, ciliary transport, and photoreceptor structure

2. Genetic mutation --> Biochemical dysfunction affecting rod photoreceptors

3. Injury pathways: Apoptosis, light damage, and ciliary transport dysfunction

4. The result is death of the rod photoreceptors (responsible for low-light vision)

5. The loss of large numbers of rods --> toxic environment:

   • Retinal pigment epithelium destruction

   • Cone photoreceptor cell death

6. Clinical manifestation:

   • Visual disturbances

   • Nyctalopia: Loss of night vision

   • Gradual narrowing of the visual fields

   • Tunnel vision

   • Complete vision loss

   • Dyschromatopsia: Loss of accurate color discrimination

   • Loss of visual acuity

   • Photopsia

   • Visual hallucinations

Complications [ycd]

• Myopia

• Astigmatism

• Macular edema

• Retinal detachment

• Vitreous detachment

• Cataracts

• Glaucoma

• Keratoconus

• Mild hearing loss (Usher syndrome)

Epidemiology

Prevalence per 100.000 [ycd][fbh][ehc][9ur][wmk]

Default

Approach

• Ophthalmologic evaluation

  • Test visual acuity and contrast sensitivity

  • Visual field assessment

  • Dyschromatopsia: Assess color vision

  • Dust-like particles in the vitreous cavity

• Fundoscopic exam:

  • Bony spicule pigmentation

  • Vascular narrowing

  • Abnormal waxy pallor of the optic disc

  • Fundus autofluorescence

• Electroretinogram showing rod dysfunction

• Fluorescein angiography

• Optical coherence tomography angiography

• Adaptive optics scanning laser ophthalmoscopy

Treatment

1. There is currently no cure for RP [ycd]

2. Ongoing research shows promising potential:

   • Gene therapy

   • Stem cell therapy

   • Retinal implants show promise in restoring vision

3. Management involves to help individuals adapt to their changing vision:

   • Nutritional supplementation, especially with vitamin A

   • Low-vision aids

   • Sun glasses

   • Optimize refraction glasses

   • Orientation

   • Mobility training

4. Macular edema: topical or systemic carbonic anhydrase inhibitors

5. Cataracts: Intraocular lens

Differential diagnoses

Age-related macular degeneration, Cytomegalovirus, Drug side effects, Lyme disease, Measles, Retinal artery occlusion, Retinal detachment, Retinitis, Retinoblastoma, Retinopathy, Rubella, Sarcoidosis, Systemic lupus erythematosus, Toxoplasmosis, Trauma, Tuberculosis, Vitamin deficiency