ANGIOID STREAKS

Dr. Asim wasim

Angiod Streaks

Irregular, Spoke like, curvilinear streaks that radiate outward from the peripapillary area in all directions

HISTORICAL PERSPECTIVE

First described by Dr. Robert W. Doyne, a British ophthalmologist, in 1889.

1892, Knapp thought that they resembled vessels and used the term angioid streaks

1917 that Kofler correctly stated that the main pathologic changes were at the level of Bruch's membrane.

This finding was confirmed histopathologically in the late 1930s.

CNVM

Important

Recognition is important because can be associated with

(CNVM) Macular degenerationPseudoxanthoma elasticum (PXE),Paget's disease and the

hemoglobinopathies

Clinical features:

Symptoms:– Usually

asymptomatic, but may affect vision over time due to progression of streaks towards the fovea

They lie beneath the retina and above the choroidal vasculature and thus can be distinguished from blood vessels.

These lesions are almost always bilateral.

Angioid streaks are within 2 disc diameters of the optic nerve in 27 percent of cases and are widespread in 73 percent of patients. 

They usually do not go past the equator. The streaks can be wide or narrow and can vary in number from one to many.

There is usually associated peripapillary chorioretinal changes.

Fluorescein angiographic findings:

Irregular hyperfluorescence of the streaks during early phases and late staining

Can be seen as hypofluorescence of the streaks outlined by hyperfluorescence margins, which stain in the late phases

Some clinically invisible streaks may be observed during fluorescein angiography

Cause of vision Loss

Macular degeneration or CNVM, or both

Unlike AMD, the exudative form is more common than atrophic form.

Macular degeneration is not always associated with angioid streak passing through the fovea

Subretinal Hemorrhage,

Minor trauma may cause subretinal hemorrhage, often with macular involvement.

Macular scarring after CNV

Most common systemic associations

Idiopathic 50%Pseudoxanthoma elasticum (PXE) 34%Paget's disease 10%Sickle cell disease 5%Ehler's- Danlos Syndrome 1-2%

Other systemic diseases

– Abetalipoproteinemia – Acromegaly – Dwarfism – Diabetes mellitus – Hemochromatosis – Facial angiomatosis – Idiopathic

thrombocytic purpura – Chronic familial

hyperphosphatemia

– Hypercalcinosis – Diffuse lipomatosis – Acquired hemolytic

anemia – Myopia – Neurofibromatosis – Epilepsy – Senile elastosis – Sturge-Weber

syndrome – Trauma – Tuberous sclerosis

Pseudoxanthoma Elasticum (PXE)

Systemic elastorrhexis that affects mainly the skin, eyes, gastrointestinal (GI) system, and heart.

Female: male= 2:1. Patients usually diagnosed in the

third to fourth decades of life. Inheritance is usually A/R but may be A/D.

Condition is caused by elastic fiber abnormalities with secondary calcification.

Recently, accumulation of polyanions in the dermis has been reported as an early finding.

The polyanions attract calcium, which causes mineralization. Thus, the basic defect in PXE may not be one of calcium or elastin metabolism but rather of glycosaminoglycans and glycoproteins.

These glycosylated molecules may attach to elastic fibers, mineralize, and cause abnormal collagen synthesis.

Clinical features

The characteristic skin change in PXE is a redundant waxy, yellow, papule-like lesion, which commonly affects the neck, face, abdomen, axillary areas, inguinal regions, periumbilical area, and oral mucosa

This skin lesion looks like a “plucked chicken.”

Other systemic findings

Cerebral ischemia, cerebrovascular accidents, intracranial aneurysms, claudication, hypertension, myocardial infarction, and GI hemorrhage with or without ulceration. The GI hemorrhage may be life-threatening, can occur in up to 15 percent of patients, and may occur before the skin or eye findings.

The peau d'orange changes represent a diffuse mottling of the RPE in the temporal midperiphery and consist of multiple yellowish RPE lesions that have the appearance of the skin of an orange (peau d'orange)

The salmon spot is a multiple focal, yellow, atrophic peripheral RPE lesion that appears “punched-out” like a histoplasmosis syndrome spot. Macular drusen and atypical drusen may be present in up to 75 percent of cases.

Optic disc drusen are commonly associated with PXE and angioid streaks.

Paget's Disease

Paget's disease or osteitis deformans is a chronic, progressive connective tissue disorder that involves the collagen matrix of bone.

The condition may be due to a slow virus related to measles or may be transmitted in an autosomal dominant manner. Males and females are equally affected.

Ocular Features

Occasionally patients with Paget's disease may have peau d'orange lesions and other RPE changes.  

Optic atrophy, sometimes secondary to bony compression, may also occur.

Systemic findings

Enlarged bone mass affecting the pelvis, skull, spine, humeri, and femora, extraskeletal calcifications of the skin and arteries, pain, secondary osteoarthritis, neurologic damage, cardiac disease, decreased hearing, hyperparathyroidism, and claudication.

Hemoglobinopathies that occasionally are associated

– Homozygous sickle cell disease (Hb-SS) – Sickle cell trait (Hb-AS) – Sickle cell thalassemia (Hb-thal) – Sickle cell hemoglobin (Hb-SC) – Hemoglobin H (Hb-H) – Homozygous B-thalassemia major – Intermedia – Minor and hereditary spherocytosis

Hemoglobinopathies

Complications, such as CNVM or macular degeneration, are uncommon.

The frequency of angioid streaks appears to be higher in elderly patients

PATHOPHYSIOLOGYThe pathogenesis of angioid streaks is

controversial, In PXE and Paget's disease, Bruch's

membrane may become calcified and brittle,

Cracks may occur in a brittle Bruch's membrane because of the ocular muscles pulling the eye around a fixed origin.

Calcification is observed in other parts of the body in both PXE and Paget's disease, and thus this mineralization may be a common mechanism.

The cause of angioid streaks in sickle cell disease is even more confusing. Calcification is not common in this disorder.

PATHOLOGIC FEATURES

It is believed that the pathology may be a combination of diffuse elastic degeneration of the Bruch membrane, iron deposition in elastic fibers from hemolysis with secondary mineralization, and impairment of nutrition because of sickling, stasis, and small vessel occlusion

Work up

Lab Studies: 50% of patients with angioid streaks have systemic association. General workup is important to diagnose and treat other aspects of the disease that may be life threatening, such as GI hemorrhage, heart disease, anemia, and pathological fractures.

Pagets disease

The diagnosis is made by finding an elevated serum alkaline phosphatase level, increased urinary total peptide hydroxyproline levels, and characteristic radiographic findings.

Imaging Studies:

Fluorescein angiographyIndocyanine green angiography Radiology studies: X-rays of head,

abdomen, and lower extremities are helpful to show bone involvement in Paget disease of the bone and premature calcification of arteries in PXE.

Other Tests:

GI studies: GI hemorrhage is common in patients with PXE.

Dermatologic: Skin biopsy may provide important diagnostic clues in cases of PXE with angioid streaks.

TREATMENT

Observation and patient counselingAsymptomatic Patients need to be

monitored closely– Amsler grids and FA.

Safety glasses should be considered for these patients with angioid streaks because trauma precipitates hemorrhage.

Should not engage in contact sports.

TREATMENT

in some cases genetic counseling should be considered.

Prophylactic treatment of angioid streaks should not be performed, as it may induce CNVM.

Laser photocoagulation

Argon laser for lesions that are located at least 100 mm from the center of foveal avascular zone (FAZ).

Many patients need multiple treatments because of persistent leakage and recurrence that occurs during the first 3 months. 77%

Careful setup of laser power and spot size is important to prevent further damage to the brittle and mineralized Bruch membrane.

Photodynamic therapy

PDT is used for treatment of subfoveal CNV.

It uses a light activated drug (eg, verteporfin [Visudyne]) and applying a nonthermal red light in the range of 689 nanometers. The total energy delivered is 50 J/cm2 over a period of 83 seconds. The power of laser output can be adjusted according to size of CNV and ophthalmic lens magnification.

Long-term effects of PDT are unknown. Patients with angioid streaks are at higher risk of recurrent CNV.

Submacular surgery

Patients with classic subfoveal CNVM are not candidates for laser photocoagulation therapy. In the past, they were left without treatment. However, recent advances in instrumentation and vitreoretinal surgical techniques made it possible to remove CNVM without significant damage to RPE and neurosensory retina.

Low-vision aids may be useful

D/DAge-related macular degeneration. Other disorders that are confused with the

angioid streaks includeChoroidal sclerosis,Myopia and lacquer cracks,Histoplasmosis, Toxoplasmosis, Retinal vasculitis Papilledema,Traumatic hemorrhage.Choroidal rupture and choroidal folds

CONCLUSIONS

Angioid streaks are distinctive fundus lesions that are associated with systemic disorders in 50 percent of cases. The most commonly associated diseases include PXE, Paget's disease, and the hemoglobinopathies.

Angioid streaks themselves are usually asymptomatic, but the occurrence of CNVM and macular degeneration can cause devastating visual loss. The streaks represent breaks in a calcified and thickened Bruch's membrane. Laser photocoagulation may be beneficial to treat CNVM associated with angioid streaks; however, the recurrence rate is high.

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