Peripapillary Pachychoroid Syndrome

Article initiated by:

Marianna Kavalaraki MD, Msc

All authors and contributors:

Marianna Kavalaraki MD, Msc, Neelakshi Bhagat, MD, FACS

Assigned editor:

Neelakshi Bhagat, MD, FACS

Review:

Assigned status Up to Date

 by Neelakshi Bhagat, MD, FACS on April 12, 2023.

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Contributing Editors:	add

Peripapillary Pachychoroid Syndrome (PPS) is a distinct PDS variant, in which peripapillary choroidal thickening is associated with nasal macular intraretinal and/or subretinal fluid and occasional disk edema. Recognition of PPS is important to distinguish it from disorders with overlapping features such as posterior uveitis and neuro-ophthalmologic conditions.

Disease

Peripapillary Pachychoroid Syndrome (PPS) has been recently identified as a distinct Pachychoroid Disease Spectrum (PDS) variant, in which pachychoroid features surround the optic nerve and are associated with the accumulation of intraretinal and/or subretinal fluid in the nasal macular region rather than the fovea, extending from the temporal margin of the optic disk , as well as with occasional optic nerve head edema in some eyes. Associated clinical findings include peripapillary choroidal thickening choroidal thickening associated with Haller vessel dilation (pachyvessels) and overlying inner choroidal thinning., serous pigment epithelial detachment and choroidal hyperpermeability, all of which are indicative of a pachychoroid-driven entity, rather than a variant of uveal effusion syndrome (UES) as was suggested in a single-case report. Most of the eyes have hyperopic refraction and short axial lengths Other common features present in patients with PPS are choroidal folds (77%), short axial lengths (39% less than 23 mm), and hyperopic refractive error (86%), older age, and a small cup-to-disc ratio. This entity is seen more commonly in males and is usually bilateral. Govetto et al described a sporadic association of PPS with pulmonary arterial hypertension published a case study, in which choroidal ischemia is thought to have been caused by hemodynamic disturbances due to increased central venous pressure

Etiology

The etiology is unknown. Some theorize arteriosclerosis and increased persistent sympathetic to dilation of choroidals vessels and hyperpermeability.

Pathophysiology

The pachychoroid disease spectrum (PDS) refers to a group of retinochoroidal disorders, which share distinctive choroidal findings identified with multimodal retinal imaging, which include focal or diffuse choroidal thickening associated with reduced fundus tessellation, dilated Haller layer vessels (termed “pachyvessels”) with thinning of the overlying inner choroid, and choroidal hyperpermeability demonstrated with indocyanine green angiography (ICGA). The PDS includes pachychoroid pigment epitheliopathy, focal choroidal excavation, central serous chorioretinopathy (CSC) , pachychoroid neovasculopathy, polypoidal choroidal vasculopathy, and recently described peripapillary pachychoroid syndrome.

Diagnosis

PDS was described initially by Phasukkijwatana et al in 2018 as presence of thick and hyperpermeable choroid in the peripapillary area and nasal macula. The peripapillary choroidal congestion leads to intra-retinal and subretinal fluid in the peripapillary area leading to compression of the optic nerve causing crowded disc appearance with choroidal folds and in some cases optic disc edema. Slowly overlying RPE atrophy ensues. It is often associated with hyperopia with short axial length, and can be sometimes confused with uveal effusion syndrome. Choroidal detachment is absent in PDS.

Clinical diagnosis

PPS shares many common imaging features with chronic central serous chorioretinopathy , such as RPE alterations, as well as similar ICGA findings, and, in some cases, the presence of serous pigment epithelial detachment, gravitational tracks, evidence of serous retinal detachment outside the peripapillary region with fundus autofluorescence, and outer retinal atrophy. However, the increased choroidal thickness in PPS is significantly different from typical CSC in that the nasal macular choroid can be particularly thick, with thickness sharply decreasing towards the temporal side.

Diagnostic procedures

Fluorescein Angiography (FA): Late-phase FA illustrates speckled hyperfluorescent window defects and staining surrounding the optic disk and intense staining of PPA in both eyes. There is no distinct leakage. Early-phase ICGA illustrates peripapillary dilated large choroidal vessels (pachyvessels)

Indocyanine green angiography (ICG): Early-phase ICGA shows dilated large choroidal vessels or pachyvessels predominantly in the nasal macula and peripapillary region in both eyes. Mid- to late-phase ICGA usually shows multifocal peripapillary choroidal hyperpermeability in areas corresponding to the pachyvessels.

OCT through the optic disks can show intraretinal fluid in both the nasal and temporal regions adjacent to the optic disks with associated choroidal hypertransmission and atrophy of the RPE, ellipsoid zone, and ELM. Peripapillary pachyvessels are more prominently seen in the nasal versus the temporal areas.

Enhanced depth imaging OCT will show intraretinal fluid with cysts in the nasal macula extending to the temporal optic disk margin with associated focal RPE, ellipsoid zone, and ELM atrophy in both eyes. Presence of RPE atrophy with corresponding choroidal signal hypertransmission in the peripapillary area is usually obvious.

Fundus autofluorescence illustrates hypoautofluorescent peripapillary atrophy (PPA) and large areas of peripapillary mottled autofluorescence of the RPE in the peripapillary region, as well as gravitational tracks in the peripapillary area.

Differential diagnosis

• Chronic central serous chorioretinopathy (CSC)

• Posterior uveitis
• Neuro-ophthalmological conditions with similar presentation

Management

General treatment

CSC- Spontaneous resolution of the disease occurs in 90% of the cases. However, recurrence occurs in around 50% of the cases after resolution of subretinal fluid.

In patients with exogenous steroid intake, the steroids should be stopped or tapered as needed.

Treatment is required in cases with duration greater than 3 months (chronic), highly symptomatic patients, or patient with poor vision in the fellow eye.

The treatment type is governed by the phase of disease and the site of leakage on FA.

Laser photocoagulation is considered for the treatment of extrafoveal leakage points in acute cases. Focal thermal coagulation seals the RPE defects and prevents further accumulation of subretinal fluid. However, focal laser photocoagulation causes permanent damage to the RPE and overlying photoreceptors and also carries the risk of iatrogenic CNV formation especially if the laser spot size is less than 100micron. To overcome these shortcomings of conventional laser system, sub-threshold micropulse (STM) laser was introduced. STM laser does not cause thermal damage to the RPE. Instead, it stimulates the proliferation of RPE cells. Since it is not destructive and does not produce visible burns/scars, STM laser may be used for even juxtafoveal leaks. Yellow wavelength (577nm) is often used for STM laser in CSC. The limitation of STM laser is reduced efficacy in chronic cases with diffuse retinal pigment epitheliopathy. This is because STM acts at the level of RPE and does not alter the dysfunctional hyperpermeable choroidal vasculature.

Verteporfin photodynamic therapy (PDT) is the preferred treatment for chronic cases. PDT targets the choroidal hyperpermeability, reduces the dilated choroidal vasculature, reduces the CT, and leads to resolution of subretinal fluid. PDT significantly decreases the thickness of Haller’s layer without alteration of the choriocapillaris and Sattler’s layer, thereby restores the normal choroidal morphology. Conventional full dose and full laser fluence PDT may have certain adverse effects such as transient visual disturbances, unexplained visual loss, diffuse RPE atrophy, CNV formation, and choroidal ischemia. To improve the safety, half dose and/ or half fluence PDT have been advocated, but the efficacy remains questionable. However, half dose PDT has shown promise in attaining better final visual acuity and lesser recurrence than conventional PDT in a few studies. Since aberrant steroid metabolism is thought to the underlying cause for CSCR, numerous systemic drugs have been tried with equivocal results. Mineralocorticoid receptors in the choroidal vasculature increase the congestion upon stimulation, therefore antagonists such as spironolactone and eplerenone may have a role in treatment. Rifampicin, a mineralocorticoid antagonist, potentiates the catabolism of endogenous steroids and has been reported to accelerate the resolution of subretinal fluid. However, the majorities of the studies reporting the benefits of systemic therapy in chronic CSC lacks a control group or have small sample size. There is no level 1 evidence to support the use of anti-VEGF agents in the treatment of persistent fluid in chronic CSC cases in the absence of underlying CNV.