Continuing Education Activity

Acute esophageal necrosis is a life-threatening condition resulting in acute ischemia of the esophagus. It is associated with a local insult to the esophagus in medically co-morbid patients. Prompt diagnosis and aggressive supportive treatment are needed in the initial setting with early consideration of surgical intervention to prevent poor outcomes. This review evaluates the etiology and clinical presentation of acute esophageal necrosis and the key management steps required by the interprofessional team to treat this rare entity.

Objectives:

• Describe the etiology of developing acute esophageal necrosis concerning the two-hit hypothesis.
• Identify the risk factors associated with developing acute esophageal necrosis.
• Describe the relevant clinical anatomy of the esophagus.
• Summarise the principles of management by the interprofessional team and indications for surgical intervention.

Introduction

Acute esophageal necrosis (AEN), also known as the black esophagus, Gurvit syndrome, or acute necrotizing esophagitis, is a rare and life-threatening condition. It is characterized by either partial or total circumferential blackening of the esophagus that stops abruptly at the gastro-esophageal junction, as seen on an upper GI endoscopy. AEN was first documented in 1990 by Goldberg et al., and the exact cause remains unclear but tends to follow a pattern of acute ischemia in association with a topical insult to the esophagus.[1]

It is strongly associated with medical comorbidities and most commonly presents between the ages of 60 and 80 in the male population. The management of AEN is primarily medical but can include surgical intervention in the event of complications such as perforation and mediastinitis.  Overall mortality associated with AEN is approximately 30%; however, mortality specific to AEN is closer to 5%.

Etiology

The etiology of AEN remains unclear. The main developing theory is the two-hit hypothesis, the combination of a hemodynamic compromise in conjunction with an increase in metabolic requirement from local insult leading to necrosis.[2][3] 

The majority of AEN occurs in the distal esophagus (approximately 60% to 90% of cases).[4][5][6] The distal third of the esophagus derives its blood supply from the left gastric or inferior phrenic arteries and has the poorest blood supply with the poorest collateral support compared to the proximal two-thirds.[7][8] The distal third is closest to the stomach and most at risk from gastric acid reflux. Gastric acid increases esophageal mucosal blood flow and oxygen requirement in normal physiological conditions.[9] 

Significantly increased volumes of gastric acid, for example, as a result of gastric outlet obstruction, have been shown to cause AEN.[2][3] The cause appears to be the combined effect of pre-existing vasculopathy, an acute low flow state, and increased oxygen demand. Contrary to this, there have been cases of AEN in the absence of other medical conditions or a low flow state.[10][11] However, in all cases, at least two of the following are present; acute ischemia, chronic vascular disease, and significant topical injury.

Epidemiology

AEN is a rare but potentially underdiagnosed condition. In a review of published cases, only 88 patients existed over forty years.[2] In this series of published cases, just under 80% occurred in males (70 of 88), with only 20% occurring in females. In an autopsy series, the prevalence of blackening of the esophagus, a symptom of AEN, was 2%.[12] However, this may have occurred post-mortem as opposed to in vitro. In endoscopic studies, prevalence appears to be between 0.1 to 0.3%, with the average age of occurrence between 70 and 80 years. Overall, it is approximately four times more likely to occur in males.[12][13][14][15][16]

In a more recent literature review, the average age of occurrence was sixty-two, with 70% of patients being male [6].  Contrary to the above studies, one study from Japan found a prevalence of approximately 6% of patients on who they performed endoscopies; their other most common findings were a hiatus hernia and NSAID usage.[17] This implies that AEN may be more common and present transiently in patients with an upper GI bleed.[17]

Risk factors for AEN include:[2][3][4][5][6][14][16][18]

• Type two diabetes (approximately 40%)
• Hypertension (approximately 35%)
• Ischaemic heart disease (12%)
• Alcoholism (approximately 25%)
• Chronic kidney disease (approximately 15%)
• Chronic liver disease (approximately 15%)
• Solid-organ malignancy (approximately 10%)
• Peripheral vascular disease (approximately 10%)
• Chronic obstructive pulmonary disease (approximately 5%)
• Poor nutritional state

History and Physical

In most case studies, AEN cases initially present symptoms of an upper GI bleed, with haematemesis/melaena (70% to 85% of cases) and hemodynamic instability.[2][6] Patients are typically aged 60 to 80, male, and have numerous co-morbidities.[4] 

On examination, the patient may have epigastric tenderness, pallor, and peripheral hypoperfusion. Vital signs often show low-grade pyrexia, hypotension, tachycardia, and in more severe cases, hypoxia. As AEN often presents as a result of hemodynamic instability, whatever is causing this may well confound the clinical picture.[19][20][21] Cases of AEN have been seen as a result of sepsis, Cardiogenic shock, hemorrhage from either planned operation or trauma, or other medical conditions including DKA and diarrhea, and vomiting.[22][23][24][21]

Evaluation

Blood tests will likely show a raised white cell count, anemia, and lactic acidosis.[7] If upper GI bleeding is present and gastroscopy is performed, the typical presentation of AEN is a diffuse circumferential black discoloration of the esophageal mucosa that stops abruptly at the gastroesophageal junction.[7] 

As stated previously, it is most common in the distal third of the esophagus. However, it can extend proximally to involve the whole esophagus in 36% of cases in one literature review.[5] Other pathology may well also be present such as hiatus hernias, active bleeding, gastric ulceration, blood clots, or gastric outlet obstruction.[3] 

Tissue biopsy is not required for diagnosis however is often useful to exclude other causes of the black esophagus. Imaging is typically not performed in cases reviewed except in diagnostic uncertainty or concerns over an esophageal perforation, in which case CT scanning of the chest showed air in the mediastinum.[4][17]

Treatment / Management

In isolation, AEN has a poor prognosis. When AEN is observed as one of the multiple symptoms (it should be view as a poor prognostic factor), initial efforts should be made to treat the underlying cause. Treatment for AEN typically involves fluid resuscitation with accompanying blood transfusion if there is significant anemia.[4][25] In addition to this, patients should be placed NPO ("nil-per-os’ or nothing by mouth), and intravenous proton pump inhibitors should be given to reduce local insult to the vulnerable esophagus.[5][7][26] 

Sucralfate has also been used to further reduce local insult to the esophagus. Due to an often lengthy period of NPO, there has been some evidence for total-parenteral nutrition improving outcomes.[3][27] Nasogastric tubes should not be inserted due to the risk of esophageal perforation.[26] Antibiotics should be given in the presence of sepsis or evidence of esophageal perforation but are otherwise not required [3].

Acute complications include upper GI bleeding and esophageal perforation, which may be present at the time of presentation to healthcare or during the first few days in the hospital. Localized bleeding is controllable with an adrenaline injection during a gastroscopy or by metallic stent insertion.[28] The incidence of esophageal perforation as a result of AEN appears to be approximately 5%.[5][26][29][5]

If there is evidence of perforation, surgery is the primary treatment. Surgery occurred in approximately 4% of cases in one analysis.[5] This involves an initial emergency esophagectomy followed by elective esophageal reconstruction following recovery from the initial event.[30] In one case, stent insertion in the initial phase is effective but required subsequent intervention to correct stent migration.[31] One case used a combination of video-assisted thorascopic surgery (VATS) and drain placement which was reportedly successful.[32]

Differential Diagnosis

Differential diagnoses of AEN include:

• Malignant melanoma[33]
• Acanthosis nigricans[34]
• Coal dust deposition[35]
• Psuedomelanosis[36]
• Melanosis of the esophagus[37]
• Black dye ingestion[38]
• Direct caustic injury[1]

The majority of the above conditions follow a longer-term, more insidious course and are often found during elective gastroscopy rather than in an emergency scenario. The exceptions to this are dye ingestion or direct caustic injury, for which history will be key to determining the underlying cause of black esophagus. If there is doubt over the pathogenesis of a black esophagus, then histology can be performed following an upper GI endoscopy. If it is the result of AEN, then this will show mucosal and submucosal necrosis, necrotic debris, and localized inflammatory response.[14][39][40]

Prognosis

AEN itself is a poor prognostic factor that results from other conditions. The mortality rate in the most recent literature review stands at just under 30%.[6] This is similar to earlier reviews which put estimated mortality at 32%.[2][5] Due to AEN’s association with other conditions, it can be difficult to distinguish which condition is responsible for the death. Taking this into account, AEN-specific mortality has been noted to be as low as 5%.[2]

Complications

Acute complications, as listed above, include localized bleeding and esophageal perforation. Upper GI bleeding is commonly present in ~85% of cases [6]. The perforation rate is thought to be 5% to 7%.[2][5] Middle to long-term complications includes esophageal strictures and trachea-esophageal fistulas. There is a complication rate of approximately 12% in one literature review, with 70% of these patients developing strictures and the other 30% of patients developed fistulas.[6] 

These complications do not develop until at least 2 weeks after the initial event. Management of strictures is not well documented in the literature, but iterative balloon dilatation is an effective treatment.[41] The majority of patients who recover will do so without complication; however, a follow-up endoscopy is recommended at approximately 1 month to rule out other sequelae.[7]

Deterrence and Patient Education

As AEN is a multifactorial condition and primarily a prognostic marker rather than an isolated pathology, prevention should center on reducing comorbidities such as vascular disease, liver disease, and renal disease. Lifestyle factors would include the moderation of alcohol consumption, smoking cessation, regular exercise, and maintaining a healthy weight. Medical prevention for AEN has not been documented in the literature.

Enhancing Healthcare Team Outcomes

Acute esophageal necrosis is an uncommon condition that can present in a number of different ways include upper GI bleeding, signs of sepsis, or peripheral hypoperfusion. Medically co-morbid patients presenting with epigastric pain and hemodynamic compromise should raise concern for urgent investigation and treatment. Early recognition and subsequent resuscitation form the cornerstone of management for these patients, regardless of diagnostic uncertainty.

Upper gastrointestinal endoscopy is vital for diagnosis and should be performed as soon as possible. This may require liaising closely with the endoscopy department or even the operating theatre if the patient is not considered stable enough. Evidence of perforation will need surgical input, and long-term parental nutrition, guided by the dieticians, should be instigated early on. Nursing staff can coordinate and liaise activities between various clinicians, other professionals such as the dietician and the patient. Interprofessional care and communication with prolonged rehabilitation are clearly required in such cases to ensure a positive outcome.