PURTSCHER-LIKE RETINOPATHY ASSOCIATED WITH ATYPICAL HEMOLYTIC UREMIC SYNDROME: CASE REPORT AND REVIEW OF OUTCOMES

Purtscher's and Purtscher-like retinopathy etiology, features, management, and outcomes: A summative systematic review of 168 cases

BACKGROUND

To describe Purtscher's and Purtscher-like retinopathy clinical features, etiologies, management options, and visual outcomes.

METHODS

Our protocol was registered on PROSPERO [registration number: CRD42023406843]. Seven online databases were searched: PubMed, Scopus, Medline, ScienceDirect, CENTRAL, clinicaltrials.gov, and Google Scholar. Original articles were included if they reported at least one subject diagnosed with Purtscher's or Purtscher-like retinopathy. The primary outcome is to describe the clinical features of Purtscher and Purtscher-like retinopathies, including etiologies, results of related investigations, management lines, and visual outcomes. All analyses were conducted with the use of Statistical Package for Social Sciences (SPSS) version 27 (IBM SPSS Corp, SPSS Statistics ver. 26, USA) and Cochrane's RevMan software. The methodological quality of included studies was assessed using the NIH quality assessment tools.

RESULTS

A total of 114 articles were included, describing 168 cases of Purtscher's and Purtscher-like retinopathy. Patients were evenly distributed between males (50.89%) and females (49.11%). Average age of patients was 34.62 years old. Trauma was the leading cause of retinopathy, being reported in 39.88% of our patients, followed by systemic lupus erythematosus (SLE) (13.1%) and acute pancreatitis (11.9%). Bilateral symptoms were reported in 57.7% of patients with centrally blurred vision being the most complained symptom (OS: 34.32% and OD: 18%). 75% of patients elicited bilateral retinal findings. Cotton-wool spots were of highest prevalence (58%). Purtscher flecken was seen in 53% of patients. Macular edema was seen in 13% of patients. Overall, patients had a favorable prognosis (53%).

CONCLUSION

Purtscher's and Purtscher-like retinopathies are rare sight-threatening retinopathies that develop most commonly following trauma or other systemic diseases as SLE and acute pancreatitis. Little data is available regarding these conditions, and available data is of low quality. Patients develop bilateral disease in approximately 50% of cases, and several retinal findings are observed, with no specific tendency. Most observed signs are cotton-wool spots in around 55% of patients and Purtscher flecken in 51% of patients. Patients spontaneously recovered, although data is not conclusive. No clear prognostic value of etiological factors is identified, and further research is required in this regard.

Bilateral Combined Central Retinal Artery and Vein Occlusion in a Child with Purtscher Retinopathy: A Case Report and Review of the Literature

Purtscher retinopathy is a hemorrhagic and vaso-occlusive vasculopathy that results from head trauma. Typically, patients present with sudden onset of painless reduction in visual acuity and a group of retinal findings including retinal hemorrhages, retinal whitening, and optic disc edema. The objectives of the study were to describe the rare occurrence of combined central retinal artery and central vein occlusion in a child with Purtscher retinopathy and to illustrate the course of visual recovery and anatomical changes over 6 months of follow-up. The data were collected from the patient file including circumstances of presentation, visual acuity, anterior segment examination, fundus photography, fundus fluorescein angiography (FFA), B scan ultrasonography (B scan), and optical coherence tomography (OCT). Follow-ups over a 6-month period with repeated imaging were documented. A 6-year-old boy presented with a complaint of bilateral vision loss which occurred 2 days after falling out of high bed. On examination, visual acuity was hand motion bilaterally. External and anterior segments exhibited regular examination, apart from traumatic iritis in both eyes. Posterior segment examination showed intraretinal hemorrhages, retinal whitening bilaterally, and exudative retinal detachment, which was confirmed by OCT and B-scan. FFA of both the eyes showed delayed arterial and venous filling with macular hypoperfusion. Comprehensive systemic workup including brain imaging, hematology, immunology, and uveitis screening was negative. The patient was treated with a high-dose oral steroid. Six months later, his vision improved to 20/40 OD and 20/28 OS. Fundus examination and OCT showed peripheral retinal atrophy but preserved subfoveal outer retinal layers, which explained the visual improvement. Treatment with corticosteroids seems to be effective in reducing retinal edema and hastened visual recovery in patients with Purtscher retinopathy. Cilioretinal artery sparing can preserve the central vision in cases with combined artery and vein occlusion.

Rare variants in complement system genes associate with endothelial damage after pediatric allogeneic hematopoietic stem cell transplantation

Introduction

Complement system has a postulated role in endothelial problems after hematopoietic stem cell transplantation (HSCT). In this retrospective, singlecenter study we studied genetic complement system variants in patients with documented endotheliopathy. In our previous study among pediatric patients with an allogeneic HSCT (2001-2013) at the Helsinki University Children´s Hospital, Finland, we identified a total of 19/122 (15.6%) patients with vascular complications, fulfilling the criteria of capillary leak syndrome (CLS), venoocclusive disease/sinusoidal obstruction syndrome (VOD/SOS) or thrombotic microangiopathy (TMA).

Methods

We performed whole exome sequencing (WES) on 109 patients having an adequate pre-transplantation DNA for the analysis to define possible variations and mutations potentially predisposing to functional abnormalities of the complement system. In our data analysis, we focused on 41 genes coding for complement components.

Results

50 patients (45.9%) had one or several, nonsynonymous, rare germline variants in complement genes. 21/66 (31.8%) of the variants were in the terminal pathway. Patients with endotheliopathy had variants in different complement genes: in the terminal pathway (C6 and C9), lectin pathway (MASP1) and receptor ITGAM (CD11b, part of CR3). Four had the same rare missense variant (rs183125896; Thr279Ala) in the C9 gene. Two of these patients were diagnosed with endotheliopathy and one with capillary leak syndrome-like problems. The C9 variant Thr279Ala has no previously known disease associations and is classified by the ACMG guidelines as a variant of uncertain significance (VUS). We conducted a gene burden test with gnomAD Finnish (fin) as the reference population. Complement gene variants seen in our patient population were investigated and Total Frequency Testing (TFT) was used for execution of burden tests. The gene variants seen in our patients with endotheliopathy were all significantly (FDR < 0.05) enriched compared to gnomAD. Overall, 14/25 genes coding for components of the complement system had an increased burden of missense variants among the patients when compared to the gnomAD Finnish population (N=10 816).

Discussion

Injury to the vascular endothelium is relatively common after HSCT with different phenotypic appearances suggesting yet unidentified underlying mechanisms. Variants in complement components may be related to endotheliopathy and poor prognosis in these patients.

Retinal findings in glomerulonephritis

The complement system is part of the innate immune system activated by three distinct pathways: classical, lectin and alternative. It is also involved in retinal development and homoeostasis. Dense deposit disease is a rare renal disease associated with mutations in Complement factor H and overactivity of the alternative complement pathway. As well as glomerulonephritis, many affected individuals have retinal drusen and may be at risk of vision loss due to macular atrophy or choroidal neovascularisation. We discuss the reclassification of dense deposit disease as a type of C3 glomerulonephropathy, and hypothesise on the mechanisms of retinal abnormalities. Drusen have also been described in individuals with other types of glomerulonephritis involving abnormalities of the classical (membranoproliferative glomerulonephritis type 1) or lectin (IgA nephropathy, lupus nephritis) complement pathways. Although drusen are found in abnormalities of all three complement pathways, the age at onset, aetiology, and the threat to vision differs. This review describes drusen and other retinal abnormalities associated with the glomerulonephritides due to abnormal activation in each of the three complement activation pathways, and provides the first report of drusen occurring in a patient with the recently reclassified C3 glomerulonephritis with homozygous variant V62I in complement factor H. Optometric management of young patients presenting with retinal drusen is discussed, and complement-based therapies for visual loss are reviewed.