Exudative Retinal Detachment

Background

Anytime subretinal fluid accumulates in the space between the neurosensory retina and the underlying retinal pigment epithelium (RPE), a retinal detachment occurs. Depending on the mechanism of subretinal fluid accumulation, retinal detachments traditionally have been classified into rhegmatogenous, tractional, and exudative.

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Pathophysiology

Under normal conditions, water flows from the vitreous cavity to the choroid. The direction of flow is influenced by the relative hyperosmolarity of the choroid with respect to the vitreous and the RPE that actively pumps ions and water from the vitreous into the choroid. When there is an increase in the inflow of fluid or a decrease in the outflow of fluid from the vitreous cavity that overwhelms the normal compensatory mechanisms, fluid accumulates in the subretinal space leading to an exudative retinal detachment.

The composition of the choroidal interstitial fluid plays a fundamental role in the pathogenesis of an exudative retinal detachment. The composition of the choroidal interstitial fluid in turn is influenced by the degree of choroidal vascular permeability. Any pathological process that affects choroidal vascular permeability can potentially cause an exudative retinal detachment. Alternatively, damage to the RPE prevents the pumping action of fluid and can lead to fluid accumulation in the subretinal space. Several inflammatory, infectious, vascular, degenerative, malignant, or genetically determined pathological conditions have been recognized to cause exudative retinal detachments.

In preeclampsia, there is intense vasoconstriction of the choroidal arterioles, which leads to choroidal ischemia and RPE infarction. The outer blood-retinal barrier is broken down and causes increased vascular permeability.

Eyes with Coats disease exhibit vascular endothelial growth factor (VEGF) and VEGF receptors. Nine enucleated eyes with Coats disease were analyzed, and immunoreactivity for VEGF and vascular endothelial growth factor receptor 2 (VEGFR-2) was detected in macrophages and endothelia of abnormal vessels.^[1]

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Epidemiology

Frequency

United States

Given the diverse nature of the underlying causes of exudative retinal detachments, no reports are available on the frequency of this condition.

Mortality/Morbidity

Mortality and morbidity depend on the underlying cause. For instance, a patient with an exudative retinal detachment from scleritis secondary to rheumatoid arthritis has a severe condition. Compare this to a healthy patient who underwent scleral buckling surgery with an exudative retinal detachment. The outlooks are very different in each case.

Exudative retinal detachment secondary to preeclampsia usually resolves without long-term complications. After delivery, the subretinal fluid is absorbed by the RPE pump and the visual acuity returns to pre-detachment levels in a few weeks. However, patients with severe eclampsia may experience permanent visual loss secondary to extensive RPE necrosis even when the retinal detachment resolves.

Race

Racial predilection depends on the underlying cause, to include the following:

• Vogt-Koyanagi-Harada syndrome appears to be more common in Asians and Hispanics than in Caucasians.
• Choroidal melanoma is more common in Caucasians than in other races.
• Exudative age-related macular degeneration is more common in Caucasians than in other races.

Sex

Sex predilection depends on the underlying cause, to include the following:

• Coats disease is more common in males than in females.
• The uveal effusion syndrome is more common in males than in females.
• Idiopathic central serous chorioretinopathy occurs more commonly in men than in women.

Age

Age predilection depends on the underlying cause, to include the following:

• Coats disease is more common in children and young adults.
• Exudative age-related macular degeneration is a condition of elderly persons.
• Idiopathic central serous retinopathy occurs most often in middle-aged people.

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History

Patients may complain of a red eye (eg, uveitic pathologies).

Patients may notice a decrease in vision or visual field defect.

Pain may be present (eg, scleritis).

Parents may notice a white pupil (leukocoria).

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Physical

Bullous retinal detachment with shifting subretinal fluid: Depending on the position of the patient, the fluid accumulates in its most dependent position.

The retina is characterized by a smooth surface that lacks folds as seen in a rhegmatogenous retinal detachment (RRD).

The anterior segment may show signs of inflammation (eg, episcleral injection, iridocyclitis) or even rubeosis depending on the underlying cause.

In chronic cases, deposition of hard exudates may be seen.

Dilated telangiectatic vessels may be seen.

The images below show exudative retinal detachment in a patient with Coats disease.

View Image

An 8-year-old boy with Coats disease. Notice the macular exudation.

View Image

An 8-year-old boy with Coats disease. Notice the peripheral vascular dilatations. This patient underwent cryotherapy months before, and the exudative ....

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Causes

An extensive list of conditions that cause exudative retinal detachments exists. The conditions have been classified according to similar pathogenic mechanisms.

• Idiopathic

  • Coats disease
  • Central serous chorioretinopathy
  • Uveal effusion syndrome

   

  

   
• Inflammatory

  • Vogt-Koyanagi-Harada syndrome
  • Orbital pseudotumor
  • Lymphomatoid granulomatosis
  • Scleritis
  • Sympathetic ophthalmia
  • Collagen vascular diseases
  • Wegener's granulomatosis
  • Sarcoidosis
  • Inflammatory bowel disease

   

  

   
• Infectious

  • Syphilis
  • Toxoplasmosis
  • Cytomegalovirus [CMV] retinitis
  • Dengue fever
  • Tuberculosis^[2]
  • Lyme disease
  • Catscratch disease

   

  

   
• Congenital

  • Nanophthalmos
  • Colobomas of the optic nerve
  • Familial exudative vitreoretinopathy

   

  

   
• Tumors

  • Choroidal melanoma
  • Choroidal metastases
  • Choroidal nevus
  • Choroidal hemangioma
  • Retinoblastoma
  • Primary intraocular lymphoma
  • Choroidal osteoma^[3]

   

  

   
• Renal diseases

  • Lupus nephritis
  • Crescentic membranous nephropathy
  • Goodpasture syndrome
  • Patients on hemodialysis
  • IgA nephropathy
  • Type II membrane proliferative glomerulonephritis
  • Chronic renal failure

   

  

   
• Iatrogenic

  • Excessive panphotocoagulation^[4]
  • Scleral buckling

   

  

   
• Systemic disorders that induce an occlusive vascular choroidal disorder

  • Pregnancy-induced hypertension (eclampsia/preeclampsia)
  • Malignant hypertension
  • Collagen vascular diseases
  • Disseminated intravascular coagulopathy

   

  

   

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Laboratory Studies

Although the diagnosis of an exudative retinal detachment can usually be made clinically, the underlying etiology may be difficult to elucidate. Laboratory examinations under these circumstances are warranted, as follows:

• Venereal Disease Research Laboratory (VDRL) test and fluorescein treponema antibody (FTA) test
• Antineutrophil cytoplasmic antibodies
• Erythrocyte sedimentation rate
• Rheumatoid factor

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Imaging Studies

Ultrasound is a useful adjunct when the media is hazy. It can detect choroidal thickness, the presence or absence of choroidal masses, the size and location of choroidal masses, and scleral thickness. Peripheral annular choroidal detachments are seen in nanophthalmos and uveal effusion syndrome.

Fluorescein angiography is a useful adjunct to identify areas of leakage in central serous chorioretinopathy, Vogt-Koyanagi-Harada syndrome, and Coats disease.^[5] Ultra–wide-field fluorescein angiography is used to identify areas of peripheral retinal nonperfusion, allowing guidance of treatment.^[6]

Optical coherence tomography (OCT) can be used for quantitative examination.

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Histologic Findings

The histopathologic findings are similar to those of a RRD with loss of photoreceptor outer segments acutely and chronic changes exemplified by retinoschisis, cysts, and RPE proliferation. Other findings include massive leakage into the retina and subretinal space.

In the acute uveitic phase of Vogt-Koyanagi-Harada syndrome, an eosinophilic exudate containing proteinaceous material is found in the subretinal space that is not usually present in the convalescent and chronic recurrent phases of the disease.^[7]

Biochemical analysis of subretinal fluid in Coats disease reveals high levels of protein, albumin, and cholesterol in combination with nearly normal levels of other biochemical components suggesting entrapment of larger molecules in the subretinal space with equilibrium of smaller molecules, probably by active transport of the RPE.

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Medical Care

The medical and surgical treatments of exudative retinal detachments have to be tailored to the underlying condition.

Inflammatory conditions, such as scleritis and Vogt-Koyanagi-Harada syndrome, should be treated with anti-inflammatory agents.^[8]

Tumors need to be treated accordingly. External beam radiation therapy or brachytherapy with a plaque may be used for choroidal melanoma. Metastatic lesions respond to chemotherapy or localized radiation therapy. Choroidal hemangiomas may respond to laser photocoagulation or plaque brachytherapy. Retinoblastomas may be shrunk with chemotherapy and then treated locally with heat, laser, or cryotherapy.

Infectious etiologies may respond to antibiotics.

Reports exist of patients with exudative retinal detachments secondary to chronic renal failure that have spontaneous retinal reattachment following renal transplant or renal dialysis.^[9]

Anti-VEGF agents may play a role in the management of Coats disease.^{[1, 10, 11]}

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Surgical Care

The medical and surgical treatments of exudative retinal detachments have to be tailored to the underlying condition.

Conditions with vascular anomalies, such as Coats disease, should be treated with laser or cryotherapy to obliterate the vascular abnormalities. If an exudative retinal detachment is present, surgical techniques such as drainage with or without vitrectomy have been recommended.^[12] A retrospective case review of 8 eyes in 8 children with total or subtotal retinal detachment due to Coats disease demonstrated that transscleral drainage of subretinal fluid accompanied by anti-VEGF injection and laser photocoagulation appears to be successful in halting progression of advanced Coats disease with exudative detachment and is less invasive than conventional management.^[13]

In nanophthalmos where the sclera is abnormally thick, vortex vein decompression with scleral windows and suprachoroidal fluid drainage is indicated.

Congenital anomalies, such as optic pits or colobomas, may respond to vitrectomy and endolaser techniques.

Central serous chorioretinopathy may respond to mild laser treatment of the focal areas that leak on fluorescein angiogram. Photodynamic therapy and micropulse laser have been used in cases of central serous chorioretinopathy that involve the fovea.^[14]

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Consultations

Consult a vitreoretinal specialist early in the disease process. If immunosuppressive therapy is being considered, consultation with an immunologist or rheumatologist is highly recommended.

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Further Inpatient Care

Most ophthalmic care is rendered in an outpatient facility. For the most part, even surgical cases are treated in an ambulatory setting.

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Complications

See the list below:

• Neovascular glaucoma
• Phthisis bulbi

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Prognosis

Prognosis depends on the underlying condition.

In a series of 43 patients with Coats disease, 75% of treated patients had an improvement or stabilization of vision from baseline. Only 30% of untreated patients had a stable visual acuity.^[15]

The long-term prognosis in optic pits is probably poor because of secondary cystoid macular changes.^[16]

Idiopathic central serous chorioretinopathy is not as benign as previously thought. As many as 15% of patients may end up with a visual acuity of 20/200 or worse.^[17]

Exudative retinal detachments secondary to preeclampsia or eclampsia usually resolve without sequelae.

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