Unilateral retinal venous beading

Abstract

Inherited retinal venous beading is a rare retinal vascular disorder that is characterised by tortuosity and beading of the retinal veins. This can potentially lead to vision-threatening complications such as vitreous haemorrhage, macular hard exudation and ischaemia. We report a case of sporadic unilateral retinal venous beading in an 18-year-old white man who was referred by his optician following a routine eye examination. This malformation was unilateral and did not involve any other ocular structure. He had no associated ocular or systemic disorders. When last seen, he did not have any visual complications due to this vascular anomaly.

Background

Although a rare condition, an ophthalmologist may encounter such a case in their lifetime. One must be aware of the potential visual complications this may cause. Patients may need to be educated about this condition if diagnosed and reassured regarding the relatively good prognosis and outcome.

Case presentation

An 18-year-old white man was referred to the retina clinic by his optometrist following a routine eye examination. The patient was asymptomatic with unaided Snellen visual acuity of 6/6 in both the right and left eyes. Intraocular pressure by applanation tonometry was normal in both eyes. Examination of the fundus in the right eye revealed abnormal beading of the retinal veins in all four quadrants (figure 1). The left fundus was normal on examination (figure 2). Optical coherence tomography (OCT) of the right and left eyes was normal (figure 3). Optical coherence tomography angiography showed beading of the second-order and third-order venous tributaries, but there was no evidence of vascular dropout or ischaemia of the retina (figure 4). The patient was not on any medication and denied any medical history of significance. Investigations included full blood count, kidney and liver function tests, and abdominal ultrasonography. An MRI scan of the brain was done to rule out any vascular anomaly of the brain. All the investigations were reported as normal. His siblings and parents were examined, and none of them had any evidence of vascular malformations in the retina.

Figure 1.

Fundus photo of the right eye showing retinal venous beading in all four quadrants.

Figure 2.

Fundus photo of the left eye showing normal retinal vasculature.

Figure 3.

Normal optical coherence tomography (OCT) scan of the right and left eyes.

Figure 4.

Optical coherence tomography (OCT) angiography of the right eye showing beading of the second- and third-order tributaries.

Based on the absence of any systemic disease, or ocular disorder, the clinical appearance suggested a diagnosis of unilateral sporadic inherited retinal venous beading. When seen at his last follow-up, there was no evidence of visual complications related to his vascular anomaly.

Investigations

1. Full blood count.

2. Kidney and liver function tests.

3. Abdominal ultrasonography.

4. MRI scan of the brain to rule out a vascular anomaly.

Differential diagnosis

1. Diabetic retinopathy.

2. Eales’ disease.

3. Sickle cell retinopathy.

4. von Hippel-Lindau disease.

5. Primary retinal telangiectasia (Coat’s disease).

Treatment

There were no complications related to the condition, and it did not require any treatment.

Outcome and follow-up

Outcome was good, and the patient is being followed up on a yearly basis.

Discussion

Inherited retinal venous beading was first described by Meredith in 1987.¹ He described a pedigree with retinal vascular abnormalities that was associated with hereditary nephritis in two of the family members. Two other members were deaf, and two had low serum neutrophil counts. None of the family members exhibited all of the findings. Meredith considered the possibility that these retinal vascular changes might have been a part of Alport’s syndrome or Fabry’s disease. However, due to the absence of kidney disease in two of the family members, he concluded that the inherited retinal venous beading seen in his pedigree probably represented a new disorder that is associated with systemic vascular abnormalities. Piguet et al ² reported a family where the healthy youngest member presented with a large superficial intraretinal haemorrhage temporal to the disc and involving the fovea. This was associated with serous detachment of the retina and intraretinal hard exudates. These findings were associated with marked venous beading. Both his father and grandmother were found to have areas of retinal venous beading. Investigation failed to reveal any systemic vascular association. Stewart and Gitter³ have described similar findings of retinal and conjunctival venous beading, leading to recurrent vitreous haemorrhage in a pedigree.

Piguet et al ² and Stewart and Gitter³ believed that the above cases represented an autosomal dominant mode of inheritance. Whereas Fonseca and Dantas⁴ and Keyser and Ferguson⁵ described isolated findings of retinal venous tortuosity in their patients with no other family members being affected. They termed their patients as having an idiopathic variety of retinal venous tortuosity.

Retinal vascular beading can be seen in several acquired disease, such as diabetic retinopathy,⁶ Eales’ syndrome⁷ or sickle cell retinopathy.⁸ It can also be part of vascular malformations as seen in von Hippel-Lindau disease⁹ or primary retinal telangiectasia also referred to as Coat’s disease.¹⁰

Our patient did not have any systemic abnormalities of note. His parents and grandparents were examined, and there was no evidence of any vascular abnormality in the retina, thus ruling out a familial inheritance. In the absence of any ocular or systemic vascular disease, this probably represents a sporadic, inherited defect. The possibility of a vascular hamartoma, particularly a forme fruste of retinal cavernous haemangioma, needs to be considered. Although it affects the venous system, it is usually located in one quadrant and generally does not involve the entire four retinal venous tributaries.

Whereas all the cases of retinal venous beading had mentioned bilateral disease, our patient had a unilateral disease. Fonseca and Dantas⁴ have not mentioned bilateral affliction in their patient, whereas Keyser and Ferguson⁵ had mentioned asymmetric venous tortuosity in their patient.

It would appear from the above cases that inherited retinal venous tortuosity could be either autosomal dominant or sporadic. The idiopathic variety mentioned by some authors probably represents a sporadic form of inheritance. The presentation could be unilateral, as seen in our case. And if bilateral, the condition may have features of an asymmetric disease.

Retinal venous beading can produce a wide range of clinical manifestations, which includes microaneurysms, hard exudates, capillary non-perfusion, venous occlusion, retinal neovascularisation, preretinal and vitreous haemorrhage. The alterations in the calibre of the vessel would lead to turbulence and stasis, predisposing to vascular occlusion. This may lead to ischaemia, with exudation of blood and lipids into the extravascular compartment due to raised intraluminal pressure. It remains to be seen if the vascular abnormality in our patient could lead to vision-threatening changes in the future. In summary, we report a case of a healthy, 18-year-old white male, who was found to have unilateral retinal venous beading with no other ocular or systemic disorders. To the best of our knowledge, this is probably the first reported case of unilateral retinal venous beading.

Learning points.

• Inherited retinal venous tortuosity is transmitted as an autosomal dominant condition but can also be sporadic and unilateral.

• The venous tortuosity can lead to intraretinal, preretinal and vitreous haemorrhage. It can also cause venous occlusion and ischaemia.

• The visual prognosis in the long term usually appears to be good.