Sunny, Chi Lik Au

Department of Ophthalmology, Tung Wah Eastern Hospital, Hong Kong, China

ABSTRACT

KEYWORDS: Valsalva maneuver; Retinopathy; Vitreous hemorrhage; Retinal hemorrhage; General anesthesia

1. Introduction

Among the emergency department attendance with visual complaints, symptoms of floaters and signs of retinal hemorrhages are some of the common encounters to emergency physicians[1]. Down the bottom of the differential diagnosis list is Valsalva retinopathy, which is rare but occasionally visual threatening. Iatrogenic cause of Valsalva retinopathy is even rarer and potentially medico-legal. Here, we presented a case of bilateral Valsalva retinopathy after general anesthesia. Emergency practitioners may sometimes perform direct laryngoscopy and endotracheal intubation, which share some similarities to the causation mechanism of Valsalva retinopathy by general anesthesia.

2. Case report

Written informed consent was obtained from the patient. A 32-year-old lady attended the emergency department on 12th March 2019 for the bilateral blurring of vision and floaters. She had non-metastatic cervical cancer and was just discharged from the hospital one day after laparoscopic radical hysterectomy under general anesthesia. She enjoyed good past health, and a Mallampati Class 1 airway. The pre-operative assessment showed normal blood pressure, with normal baseline blood tests, including fasting glucose. In the operation theatre, she was intubated with an endotracheal tube without any difficulties, and the surgery was smoothly done in 2 h without significant blood loss. The anesthetic record revealed no complications.

Ophthalmology examinations found the best-corrected visual acuity of Snellen decimal 1.0 and 0.6 over right and left eye respectively, while the intraocular pressures were normal bilaterally of 13 and 15 mmHg. Anterior segment examinations were normal, but multilayered retinal hemorrhages and vitreous hemorrhages were seen on dilated fundus examination over both eyes (Figure 1). Without any cardiovascular risk factors of diabetic mellitus hypertension and hyperlipidemia, nor any evidence of background vascular retinopathy and maculopathy, the uncommon disease entity of Valsalva retinopathy was diagnosed. The patient was offered conservative observation treatment, and bilateral retinal hemorrhages were resolved after a 3-month follow-up . There was no more complaint of floaters but left residual metamorphopsia caused by the sequelae of inner retinal layers wrinkling (Figure 2). Visual acuity was Snellen decimal 1.0 and 0.7 over right and left eye respectively. Otherwise, there was no other complication for the eyes.

3. Discussion

Valsalva retinopathy is rarely seen within ophthalmology, not to say emergency medicine and daily practice. The post-operative cause is even rarer, no matter by the surgical procedures or general anesthesia itself[2]. From the literature search over MEDLINE, Pubmed, EMBASE, Google Scholar on 1st March 2020, there were only dozens of reported cases of Valsalva retinopathy after general anesthesia worldwide[2-4].

Valsalva retinopathy occurs from a sudden rise in venous pressure in the Valsalva maneuver. Valsalva maneuver refers to a forceful exhalation against a closed glottis which causes a sudden rise in intrathoracic pressure. It could occur after various types of Valsalva stress, for example, weight lifting, balloon blowing, retching, sexual intercourse[5] or birth labor[6]. As there are no venous system valves rostral to the heart, the pressure is transmitted right up to the retinal circulation. Valsalva retinopathy’s retinal hemorrhage is caused by the rupture of the retinal capillary with abrupt rises in intraocular venous pressure, spurting the blood anteriorly and posteriorly over different layers of the retina. According to the pressure gradient, retinal vasculature at the central retina adjacent to the disc is most commonly affected, thus the symptomatic calling for an investigation. Being a mechanical rupture of vessels, Valsalva retinopathy would not have any retinal exudate. Besides, micro-aneurysms formed by diabetic vascular pericytes loss[7] or retinal arteriole sclerosis from hypertension would be absent in Valsalva retinopathy. These characteristics contrasted the Valsalva retinopathy of traumatic etiology from those chronic systemic microvascular causes of retinopathy.

Figure 1. Fundus photographs of both eyes showing vitreous and multilayered retinal haemorrhages. Subretinal and vitreous haemorrhages are indicated by the white arrow and arrowheads, respectively, whereas retinal haemorrhages over the left eye are seen around the optic disc, and at the fovea with wrinkling of the internal limiting membrane (the innermost layer of the retina).

Figure 2. Bilateral fundus photographs 3 months after. Multi-layered haemorrhages were resolved, with left eye residual inner retina wrinkling over the macula, causing metamorphopsia.

Among the different layers of retinal hemorrhages caused by Valsalva retinopathy, macular subhyaloid hemorrhage[8] which is absent in our case, is the most alarming but forgiving. Evidenced by the fluid level, the pocket of blood at the subhyaloid space could be drained by neodymium-doped yttrium aluminium garnet laser membranotomy at inferior, with the help of gravity, to restore vision immediately. However, most patients with Valsalva retinopathy are less dramatic and would resolve with conservative treatment, yet permanent visual impairment could sometimes occur from secondary complications such as epiretinal membrane formation as in our case[9].

General anesthesia can cause Valsalva retinopathy in a few ways: intubation, iatrogenic induced cough, patient positioning, and post-operative coughing or vomiting[2,3]. The mechanism of intra-operative Valsalva maneuver for hemostasis checking was not discussed before. Despite the patient is intubated and could not exhale against a closed glottis, the intra-operative Valsalva maneuver is simulated by increasing the intrathoracic pressure through the endotracheal tube. Being used in both open and laparoscopic surgeries, iatrogenic Valsalva maneuver is commonly employed for surgical site hemostasis checking before the closure of surface wound[10].

Laparoscopic surgery is commoner and more prevalent nowadays, given its nature of faster recovery. The patient may be discharged shortly after surgery, and emergency practitioners might encounter their re-attendance with different complaints occasionally. The abdominal cavity is inflated with gas, usually carbon dioxide, during laparoscopic operations to expand the visualized area and working space for the surgeons. The intraabdominal inflation pressure, ～40 mmHg, is higher than capillary and venules’ pressures, yet lower than arterial pressure. Therefore, arterial bleeding would easily be detected in the pressurized intraabdominal cavity, but not for venous or capillary bleeding. Minor venous bleeding is usually subtle and will be missed. Thus, a Valsalva maneuver is necessary to raise the intrathoracic pressure, decreasing venous return to build up abdominal vessels’ venous pressure to above the inflation pressure, for minor bleeding to be visualized. Hemostasis checking towards the end of laparoscopic surgery is particularly important because a large volume of intraabdominal bleeding could be asymptomatic until physiological compensation sets in with apparent increasing heart rate, or later drop in blood pressure. Besides, significant intra-abdominal bleeding requiring second surgery would hinder patient’s postoperative recovery.

We reported a case of bilateral Valsalva retinopathy after general anesthesia. Bilateral involvement in our case is less common than unilateral[2], and thus intra-operative lateral posturing cause becomes less likely. Without significant peri-anesthesia coughing or retching throughout the smooth surgery, we propose the culprit is the iatrogenic Valsalva maneuver for hemostasis checking, a novel mechanism of such causation.

Working in the emergency medicine field, practitioners may sometimes encounter Valsalva retinopathy. The clinical history of the Valsalva maneuver is important in combination with signs of multi-layered hemorrhage on fundoscopy to arrive at the diagnosis. Besides, direct laryngoscopy for fish or chicken bone ingestion cases and airway intubation for critically ill patients are sometimes performed in daily practice. The induced gagging reflex and cough during these procedures are possible to cause Valsalva retinopathy, which shares some similarities in the causative mechanisms as in general anesthesia. Given the potentially medicolegal issue, emergency practitioners are reminded of this rare potential complication.

Conflict of interest statement

The author reports no conflict of interest.

Authors’ contribution

S.C.L.A. contributed to concept and design, acquisition of data, and drafting of manuscript.