BASICS

DESCRIPTION

• Localized area of superficial retinal whitening

• Generally smaller than 1/2 disc area

• Primary importance is as a marker of underlying disease, usually systemic.

EPIDEMIOLOGY

Unknown.

RISK FACTORS

• Diabetes

• Systemic hypertension

• Atherosclerotic peripheral vascular disease

• Collagen vascular disease

• Other systemic abnormalities (see Differential Diagnosis)

PATHOPHYSIOLOGY

Occlusion of precapillary retinal arterioles.

ETIOLOGY

Damming of axoplasmic flow caused by small vessel obstruction.

COMMONLY ASSOCIATED CONDITIONS

• Diabetes

• Systemic hypertension

• Atherosclerotic peripheral vascular disease

DIAGNOSIS

HISTORY

• Cotton wool spots alone rarely cause symptoms unless very close to center of macula.

• Vision loss if associated with other features of retinal vascular disease such as macular edema or bleeding

PHYSICAL EXAM

• Discrete area of superficial retinal whitening

• Retinal hemorrhages, edema, exudation, neovascularization are often associated

DIAGNOSTIC TESTS & INTERPRETATION

Lab

Initial lab tests

• CBC with differential

• Fasting blood sugar

• Hemoglobin A1C

• Lipid panel

• Sedimentation rate

• C-reactive protein

Follow-up & special considerations

• If initial work-up is negative, additional testing is essential given that nearly all patients end up with some underlying systemic abnormality identified.

– Further blood work to include infectious causes, with guidance based on history and review of systems (RPR, FTA, Lyme, HIV, Leptospirosis, Rocky Mountain spotted fever, Onchocerciasis), inflammatory/autoimmune, hematologic, protein electrophoresis, pancreatic enzymes, and blood cultures.

Imaging

Initial approach

Intravenous fluorescein angiography – will confirm diagnosis and possibly identify additional aspects of retinal vascular disease such as vasculitis or microaneurysms.

Follow-up & special considerations

Consider cardiac ultrasound, chest x-ray, and carotid ultrasound.

Diagnostic Procedures/Other

In elderly patients, temporal artery biopsy.

Pathological Findings

• Cytoid bodies – nerve fiber layer, eosinophilic cellular appearing structures with “pseudonuclei” (1,[C]).

– On electron microscopy – accumulation of axoplasm with mitochondria and neurofilaments. The “pseudonuclei” is likely accumulation of lipid.

DIFFERENTIAL DIAGNOSIS

• Myelinated nerve fiber layer

• Central or branch retinal artery obstruction

• Retinal hamartoma

• Nematode

Differential for Underlying Illness: (2[B])

• Systemic hypertension

• Diabetes mellitus

• Collagen vascular diseases

– Systemic lupus erythematosus

– Dermatomyositis

– Scleroderma

– Giant cell arteritis

• Cardiac valvular disease

– Mitral valve prolapse

– Rheumatic heart disease

– Endocarditis

• AIDS

• Leukemia

• Trauma (Purtscher’s retinopathy)

• Radiation retinopathy

• Central/branch retinal vein occlusion

• Systemic malignancy

• Leptospirosis

• Rocky Mountain spotted fever

• Altitude retinopathy

• Severe anemia

• Acute blood loss

• Ocular ischemic syndrome (carotid disease)

• Dysproteinemias

• Septicemia

• Aortic arch syndrome

• Intravenous drug abuse

• Acute pancreatitis

• Onchocerciasis

• Interferon toxicity

TREATMENT

ADDITIONAL TREATMENT

General Measures

Treat underlying systemic disease.

ONGOING CARE

FOLLOW-UP RECOMMENDATIONS

Ensure follow up with primary physician until underlying diagnosis achieved.

Patient Monitoring

• Reexamine 1–2 months to ensure resolution or development of other findings

• Patient to monitor vision and report changes if they occur

PROGNOSIS

• Visual prognosis generally good

• Prognosis systemically dependent on underlying cause

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