Exudative retinitis, also known as retinal telangiectasis or Coats disease, is a rare congenital disease affecting the eyes and is a cause of leukocoria.
It occurs predominantly in young males, with the onset of symptoms generally appearing in the first decade of life with a peak age of onset between 3-9 years of age 2. Although the condition is also recognized in adults, in which case it is usually less severe, the vast majority are diagnosed before the age of 20 years 3. There is well recognized male predominance (69-85%) 1,2.
Clinical presentation is usually with leukocoria or strabismus, although eventually, complete blindness may develop. The diagnosis is usually made with indirect ophthalmoscopy 2,3. The disease is unilateral in 80-90% of cases 2.
The exact etiology is unknown and the disease is a non-hereditary disorder. The disorder is primarily one of the weak capillaries of the retina, resulting in progressive retinal detachment due to an exudative sub-retinal collection.
These exudates contain cholesterol crystals, lipid-laden macrophages and a few red cells. However, hemosiderin is minimal 2.
Ultrasound is an excellent modality for the assessment of the globe, however, is hampered in advanced cases by limited specificity and difficulty in distinguishing Coats disease from non-calcified retinoblastoma 2.
Findings depend on the stage of the disease. Early on, the examination may be normal. Enhancement may be seen at the margins of the exudate and may have a V-shaped pattern similar to retinal detachment 1,2. In advanced cases the affected globe is hyperdense due to proteinaceous exudates and the vitreous space may be obliterated due to extensive retinal detachment. Calcification is uncommon but has been reported 2.
The affected eye in Coats disease is usually significantly smaller than the non-affected eye in older children and is thought to represent an impairment of growth rather than the reduction in the volume of a previously normal globe 2.
MRI appearances are similar to CT with better contrast resolution and the ability to visualize fainter enhancement, but reduced ability to visualize calcium. MRI is also able to visualize globe size.
- T1: high signal due to proteinaceous nature of the exudates
- T2: high signal due to proteinaceous nature of the exudates
T1 C+ (Gd)
- enhancement of the detached retina may be visible
- rarely an 'enhancing mass' may appear to be present in advanced cases 2
History and etymology
This disease is named after a Scottish ophthalmologist George Coats (1876-1915) who first described it in 1908 3.
Treatment remains controversial, and options include laser photocoagulation, cryotherapy and surgical repair of retinal detachment.
In general, patients who present at an earlier age will fare worse than older patients 3.
- 1. Kadom N, Sze RW. Radiological reasoning: leukocoria in a child. AJR Am J Roentgenol. 2008;191 (3): S40-4. doi:10.2214/AJR.07.7022 [pubmed citation]
- 2. Galluzzi P, Venturi C, Cerase A et-al. Coats disease: smaller volume of the affected globe. Radiology. 2001;221 (1): 64-9. doi:10.1148/radiol.2211010017 [pubmed citation]
- 3. Vitreoretinal Disease. Carl Regillo, Gary Brown, Harry Flynn. Thieme Medical Publishers ISBN:0865777616 (find it at amazon.com)
- 4. Edward DP, Mafee MF, Garcia-valenzuela E et-al. Coats' disease and persistent hyperplastic primary vitreous. Role of MR imaging and CT. Radiol. Clin. North Am. 1998;36 (6): 1119-31, x. - Pubmed citation