Retinitis Pigmentosa.pptx an eye condition

patient with retinitis pigmentosa has problem with vision starting from the peripheral

1. Retinitis Pigmentosa Wednesday, May 18, 2022 1

2. Group of rare, genetic disorders that involve a breakdown and loss of cells in the retina. It is considered a rare disorder; estimated to affect roughly 1 in 4,000 people world wide. Retinitis Pigmentosa Wednesday, May 18, 2022 2

3. Decreased night vision (often night blindness) Loss of peripheral vision Decrease in central vision can occur early or late in the disease process. Colour vision is intact until late. Symptoms Wednesday, May 18, 2022 3

4. Critical: Classically, vitreous cells, clumps of pigment dispersed throughout the peripheral retina in a perivascular pattern. Bone spicule arrangement. Signs Wednesday, May 18, 2022 4

5. Critical Areas of depigmentation or atrophy of the RPE Narrowing of arterioles Later waxy optic disc pallor. Progressive visual field loss Usually ring scotoma which progresses to a small central field ERG usually moderately to markedly reduced. Signs Wednesday, May 18, 2022 5

6. Other Focal or sectoral pigment clumping CME Epiretinal membrane Posterior subcapsular cataract Signs Wednesday, May 18, 2022 6

7. RP Wednesday, May 18, 2022 7

8. Salt and pepper fundus Wednesday, May 18, 2022 8

9. RP in a child Wednesday, May 18, 2022 9

10. RP is an inherited disorder caused by harmful changes in any one of 50 genes These genes carry instructions for making proteins that are needed in photoreceptors Some mutations are so severe that the gene cannot make the required protein, limiting the cells function Other mutations produce a protein which is toxic to the photoreceptor Still other mutations lead to abnormal protein that does not function properly Causes Wednesday, May 18, 2022 10

11. Autosomal recessive (most common): It takes two copies of the mutant gene to give rise to the disorder. An individual with a recessive gene mutation is known as a carrier. When two carriers have a child, there is: 1 in 4 chance the child will have the disorder 1 in 2 chance the child will be a carrier 1 in 4 chance the child will neither have the disorder or be a carrier Inheritance patterns Wednesday, May 18, 2022 11

12. Autosomal recessive: Diminished vision (severe) and night blindness occur at an early age Inheritance Patterns Wednesday, May 18, 2022 12

13. Autosomal dominant (least severe): It takes just one copy of the gene with a disorder causing mutation to bring about the disease When a parent has a dominant gene mutation, there is a 1 in 2 chance that any child will inherit this mutation and the disorder. Inheritance Patterns Wednesday, May 18, 2022 13

14. Autosomal dominant: More gradual onset of RP, typically in adult life. Variable penetrance, late onset of cataract, visual loss less severe Inheritance Patterns Wednesday, May 18, 2022 14

15. X-linked Inheritance: Mothers carry the mutated gene on one of their X chromosomes and pass it to their sons. Because females have two X chromosomes, the effect of a mutation on one X chromosome is offset by the normal gene on the other chromosome 1 in 2 chance of having a son with the disorder 1 in 2 chance of having a daughter who is a carrier Inheritance Patterns Wednesday, May 18, 2022 15

16. Refsum Disease Hereditary Abetalipoproteinemia Kearns-Sayre Syndrome READ UP ON THESE Systemic Diseases Associated with RP Wednesday, May 18, 2022 16

17. Hereditary choroidal dystrophies Other causes of nyctalopia Differential Diagnosis Wednesday, May 18, 2022 17

18. Medical and ocular Hx Drug Hx Family Hx : for diagnostic and counseling purposes Ophthalmoscopic examination Visual field testing ERG which may distinguish stationary red-cone dysfunction from RP, and dark adaptation studies Work Up Wednesday, May 18, 2022 18

19. Fundus photographs FTA-ABS if diagnosis is uncertain FTA-ABS: fluorescent treponemal antibody absorption test If patient is male and type of inheritance is unknown, examine his mother and perform an ERG on her. Women carriers of X-linked disease often have abnormal pigmentation in mid-periphery and abnormal results on dark adapted-ERG Work Up Wednesday, May 18, 2022 19

20. If neurologic abnormalities such as ataxia, polyneuropathy, deafness, or anosmia are present, obtain a fasting (at least 14 hours) serum phytanic acid level to rule out Refsum disease Work Up Wednesday, May 18, 2022 20

21. If hereditary abetalipoproteinenmia is suspected, obtain serum cholesterol and triglyceride levels, (levels are low) Serum protein and lipoprotein electrophoresis and (lipoprotein deficiency is detected) Peripheral blood smears ( Acanthocytosis is seen) Work Up Wednesday, May 18, 2022 21

22. If Kearns-Sayre syndrome is suspected, the patient must be examined by a cardiologist with sequential ECGs; Patients can die of heart block. Work Up Wednesday, May 18, 2022 22

23. No definitive treatment for RP is currently known Vitamin A palmitate 15,000 IU has been shown to slow reduction of ERG Controversial treatment which showed no visual benefits Recommended only for non-pregnant patients >21 years of age. Treatment Wednesday, May 18, 2022 23