What are the causes of retinal phlebitis?

Causes of Retinal Phlebitis

Retinal phlebitis is primarily caused by infectious agents (viral, bacterial, fungal, and parasitic) and systemic inflammatory/autoimmune conditions, with viral infections being the most common infectious etiology and sarcoidosis representing a major noninfectious cause. 1

Infectious Etiologies

Viral Causes (Most Common Infectious Category)

• Herpes simplex virus (HSV) types 1 and 2 produce retinal vasculitis with immunologically mediated infiltrates and are among the leading causes of necrotizing retinitis 1, 2, 3
• Varicella-zoster virus (VZV) causes retinal vascular inflammation and necrotizing retinitis, particularly in immunocompromised patients 1, 2, 3
• Cytomegalovirus (CMV) represents an important cause of infectious retinitis and retinal vasculitis, especially in immunocompromised individuals and AIDS patients 1, 4, 3
• Epstein-Barr virus may produce retinal vasculitis, though with lower frequency 1, 4

Bacterial Causes

• Mycobacterium tuberculosis is an important bacterial cause of retinal inflammation and vasculitis 1
• Treponema pallidum (syphilis) causes infectious retinal vasculitis 1

Parasitic Causes

• Toxoplasma gondii is the most common parasitic cause of retinal vasculitis, producing retinochoroiditis and representing the most common infectious cause of retinitis overall 1, 5
• Onchocerca volvulus (nematode) may cause retinal vascular inflammation 1
• Toxocara species and Echinococcus species can involve the retina in cases of trauma or severe immunosuppression 1

Fungal Causes

• Candida species can cause endogenous endophthalmitis through hematogenous spread during candidemia, with retinal involvement 6, 7, 8

Noninfectious/Autoimmune Etiologies

Systemic Vasculitides

• Granulomatosis with polyangiitis produces retinal vasculitis as part of systemic manifestations 1
• Polyarteritis nodosa may cause inflammatory retinal vessel involvement 1
• Eosinophilic granulomatosis with polyangiitis (Churg-Strauss syndrome) is associated with retinal vasculitis 1
• Microscopic polyangiitis can manifest with retinal vascular inflammation 1
• Kawasaki disease (primarily affecting children) may involve retinal vessels 1

Systemic Autoimmune Conditions

• Systemic lupus erythematosus is a well-established cause of retinal vasculitis and should be considered in the differential diagnosis 1
• Sarcoidosis represents a major systemic inflammatory condition associated with retinal vasculitis 1
• Rheumatoid arthritis can be associated with retinal vascular inflammation 1
• Relapsing polychondritis may produce retinal vasculitis 1

HLA-B27-Associated Conditions

• Ankylosing spondylitis, psoriatic arthritis, and inflammatory bowel disease are associated with uveitis and can involve retinal vasculitis 6

Drug-Induced Causes

• Methamphetamine, intravenous immunoglobulins, opioids, hydralazine, antifibrotics, antibiotics, and leukotrienes can all cause drug-induced vasculitis affecting retinal vessels 1

Association with Retinal Vein Occlusion

Retinal phlebitis may be associated with branch retinal vein occlusion (BRVO), representing a local inflammatory process that can contribute to venous occlusive disease 5

Special Clinical Contexts

Pregnancy-Associated

• Retinal phlebitis has been reported in association with pregnancy, though this remains a rare presentation 9

Immunocompromised States

• Patients with AIDS, prolonged hospitalization, indwelling catheters, and systemic immunosuppression are at higher risk for infectious retinal vasculitis, particularly from CMV and Candida species 7, 4, 3

Critical Clinical Distinction

Giant cell arteritis (GCA) must be excluded promptly in appropriate clinical contexts (patients over 50 with new-onset visual symptoms, jaw claudication, temporal headache, or elevated inflammatory markers), as it represents an ophthalmologic emergency that can cause central retinal artery occlusion with retinal vascular inflammation 1

Key Diagnostic Features

Infectious retinal vasculitis typically exhibits ischemic areas, arterial or venous sheathing or occlusion, and is usually associated with retinal or choroidal involvement, whereas noninfectious retinal vasculitis is predominantly associated with capillary vasculitis 8