Pancreatitis with infected pseudocyst presenting as a prevertebral abscess with spontaneous rupture into the oesophagus

Abstract

The development of a prevertebral abscess due to an infected pancreatic pseudocyst and its spontaneous rupture into the oesophagus is a rare complication. We report a man who presented with odynophagia, dyspnoea and abdominal pain. Contrast-enhanced CT showed evidence of pancreatitis and a prevertebral space abscess communicating with the pancreas through the oesophageal hiatus. The patient was diagnosed to have a prevertebral abscess with chronic pancreatitis. Surgical drainage was planned, but the patient died of spontaneous drainage of the prevertebral abscess into the oesophagus and aspiration of the collection into the lungs.

Background

Deep neck infections (DNIs) refer to infections originating in potential spaces in and around the neck, usually in subjects with predisposing immunosuppressive causes such as diabetes mellitus. DNIs have the propensity to cause life-threatening complications such as airway obstruction, mediastinitis, adult respiratory distress syndrome and jugular vein thrombosis.¹ Prevertebral space infections constitute less than 1% of all DNIs and can be secondary to odontogenic infections, Pott’s spine or trauma.^{2 3} Pancreatitis with a pseudocyst causing a prevertebral space abscess is very rare. There has been only one previous case report of an infected pseudocyst of the pancreas presenting as a prevertebral abscess.⁴ The dagnosis of a prevertebral abscess can be challenging due to the vague presenting features and rarity of neurological deficits.³ Imaging studies and biochemical evaluation of the abscess are helpful for definitive diagnosis. Treatment includes emergency surgical drainage of the abscess. We report a case of a prevertebral abscess occurring secondary to an infected pseudocyst which ruptured spontaneously into the oesophagus.

Case presentation

A man in his 30s presented to the emergency department with acute-onset pricking chest pain and breathlessness, which had worsened over 3 days. He had intermittent episodes of fever with chills, painful swallowing and upper abdominal pain in the preceding 3 weeks. He was a known alcoholic for the past 10 years and his last episode of heavy drinking was 3 weeks previously, just before the onset of symptoms. The patient was taken to another hospital for these complaints and was referred to our hospital for further management.

He had a history of previous hospitalisation episodes for abdominal pain and vomiting following heavy alcohol drinking, with each episode being conservatively managed. The patient had undergone an abdominal ultrasound 1 year previously in an outside hospital. He was diagnosed with a pancreatic pseudocyst and was advised to abstain from alcohol and was managed conservatively with analgesics. There was no history of jaundice or weight loss during this period.

On presentation he was anxious and breathless. His blood pressure was 70/40 mmHg which improved to 100/60 mmHg with inotropic support, his pulse rate was 118 beats/min, respiratory rate 40/min and saturation was 96% at room air. There was no pallor, icterus, cyanosis, clubbing, lymphadenopathy or oedema. There were no chest wall abnormalities and bilateral air entry was equal in the lungs. Abdominal examination revealed tenderness in the epigastrium without guarding or rigidity. A digital rectal examination showed normal stool staining. The systemic examination was unremarkable.

Investigation

A chest X-ray showed a widened mediastinum with no significant parenchymal changes in the lung, while an X-ray of the neck (lateral view) showed increased shadowing of the prevertebral space (figure 1). Ultrasonography of the abdomen showed an atrophic pancreas with a dilated main pancreatic duct of 5 mm and subhepatic free fluid of 3.4 cm × 1.2 cm.

Figure 1.

(A) X-ray of the neck (lateral view) showing increased prevertebral shadowing and (B) X-ray of the chest (posteroanterior view) showing widened mediastinum.

A CT scan with oral and intravenous contrast was carried out, which showed acute on chronic pancreatitis with peripancreatic fat stranding and collection with air foci tracking into the mediastinum via oesophageal hiatus (figure 2). The collection was seen extending into the middle mediastinum along the right lower paratracheal region and prevertebral space from T2 to T11 levels. A thick pericardial effusion and enlarged mediastinal nodes were noted. There was no evidence of pneumoperitoneum or pneumomediastinum. The vertebra was normal without evidence of Pott’s spine or any other abnormality. Oral contrast helped in ruling out oesophageal perforation. The diagrams in figure 3 and figure 4 help to illustrate the changes shown in the CT scans.

Figure 2.

CT scan of the abdomen showing peripancreatic inflammation (yellow arrow) and a dilated main pancreatic duct (blue arrow).

Figure 3.

CT scan of the chest (axial view) showing (A) prevertebral space collection with air foci (yellow arrow) and bilateral pleural effusion (blue arrows) and (B) no evidence of oesophageal perforation (oral contrast marked with yellow arrow). (C) Diagram of the thorax and abdomen (sagittal view): prevertebral space collection (blue arrow) with air foci (yellow arrow), T1 vertebra (yellow asterisk), pancreas (brown arrow) with probable direction of the spread and rupture of the pseudocyst (long yellow arrow) and duodenum (green arrow). (Diagram drawn by author OHS).

Figure 4.

(A) CT scan of the chest (coronal view) showing prevertebral space collection with air foci (yellow arrows). (B) Diagram of the thorax and abdomen (coronal view): prevertebral space collection (blue arrow) with air foci (yellow arrow), T1 vertebra (red arrow), T10 vertebra (brown arrow) and spleen (green arrow). (Diagram drawn by author OHS).

Blood investigations showed haemoglobin of 83 g/L and total leucocyte count of 31.2×10⁹ /L, platelet count of 183×10⁹/ L, with normal electrolytes and renal function tests. Serum amylase at admission was 1015 U/L. Pus was aspirated from the nasogastric tube and Klebsiella pneumoniae sensitive to piperacillin and meropenem was found growing in the endotracheal tube.

Treatment

The patient was transferred to the intensive care unit (ICU) for monitoring, kept nil orally, and started on empirical piperacillin-tazobactam, metronidazole, opioid analgesics, non-invasive ventilation, Ryle’s tube placement and intravenous hydration. Attempts at ultrasound-guided aspiration of the collection in the peripancreatic region failed. As the patient was severely tachypnoeic, CT-guided drainage of the prevertebral abscess was not possible. Surgical drainage of the prevertebral abscess was planned. The patient had progressive tachypnoea with an increased pulse rate and a further fall in blood pressure. There was a fall in saturation even with non-invasive ventilation.

As the initial diagnosis was not clear and the acute abdomen was considered as one of the differential diagnoses, a Ryle’s tube was placed for gastric decompression. Once the diagnosis of severe acute pancreatitis was confirmed, we planned to use a Ryle’s tube for enteral feeding. Before starting enteral feeds, the Ryle’s tube, which was initially draining bilious content, started draining purulent fluid (300 mL) which was found to have an amylase level of 316 840 U/L. He was intubated because of desaturation. We also found pus in the throat and vallecula during the intubation. After suctioning, the patient was intubated and endotracheal suctioning revealed the same purulent material as that seen in the Ryle’s tube. This endotracheal tube aspirate was also sent for biochemical analysis, showing an amylase level of 18 023 U/L. The patient was suspected to have spontaneous rupture of the prevertebral abscess into the oesophagus, and the patient had aspirated.

Outcome and follow-up

Following intubation, the patient had persistently high peak ventilatory pressures. The patient developed multiple organ failure as a result of sepsis. He suffered a cardiac arrest and intensive resuscitation was not successful.

Discussion

The prevertebral space is lined by prevertebral fascia which covers the vertebral column and muscles from the base of the skull to the coccyx.⁵ Infections in this space are relatively uncommon, accounting for 1–4% of all DNI. Possible causes are an extension from the cervical spine (as in Pott’s spine), local instrumentation of the oesophagus or trachea and haematogenous spread.^{6 7} Since the prevertebral space lies throughout the neck and thorax, symptoms due to infections in this space are non-specific and include neck pain, back pain or shoulder pain, difficulty swallowing, restriction of movements of the neck or nerve root pain. Odynophagia and fever should alert the treating physician to the possibility of a prevertebral abscess, which needs further evaluation. Our patient had developed odynophagia, chest pain and breathlessness, with a history of pancreatitis and a pseudocyst diagnosed previously.

Poor hygiene, substance abuse, multidrug resistance and conditions predisposing to immunosuppression such as diabetes mellitus, chemotherapy, renal failure and steroid intake are important predisposing factors for developing DNI and its life-threatening complications. Pancreatitis is one of the rarest causes of prevertebral abscess. Various types of fluid collections occur as a complication of acute pancreatitis (table 1). Although pancreatic pseudocysts extending into the mediastinum via diaphragmatic openings have been documented in case reports,^{8 9} there is only one reported instance of an infected pseudocyst causing a prevertebral abscess.⁴ However, rupture of the prevertebral collection into the oesophagus has never previously been reported in the literature. Activation of pancreatic enzymes and vulnerability of an infected pseudocyst to rupture into surrounding structures are believed to be possible mechanisms for the development of this complication. The same mechanism would probably have resulted in the spontaneous rupture of the prevertebral collection into the oesophagus.

Table 1.

Types of fluid collections occurring in acute pancreatitis showing time phase, characteristics, methods of diagnosis and appearance of the collections

Name of collection	Time phase of collection	Characteristic of collection	Method for diagnosis of collection	Appearance of collection on imaging
Acute fluid collection	Less than 4 weeks	Collection does not have a definable wall and does not contain any solid necrotic debris	Contrast-enhanced CT	Density of the fluid is homogenous without any definable wall and confined in the peripancreatic region
Pseudocyst	More than 4 weeks	Collection has a definable wall and does not contain any solid necrotic debris	Contrast-enhanced CT	Density of the fluid is homogenous with well-defined wall, completely encapsulated, and usually lies in the peripancreatic region
Acute necrotic collection	Less than 4 weeks	Collection does not have a definable wall and does contain solid necrotic debris	Contrast-enhanced CT	Fluid is heterogeneous and has non-liquid density. It does not have a definable wall and can be intrapancreatic and/or extrapancreatic
Walled-off necrosis	More than 4 weeks	Collection has a definable wall and does contain solid necrotic debris	Contrast-enhanced CT	Fluid is heterogeneous and has non-liquid density. It has a well-defined wall and is completely encapsulated. It can be intrapancreatic and/or extrapancreatic

DNIs are commonly polymicrobial, with Streptococcus species being the single most isolated organisms while, in the presence of immunocompromise, Klebsiella species can also be commonly isolated.^{10 11} The cultures of our patient’s endotracheal tube and Ryle’s tube aspirate grew Klebsiella pneumoniae. Physical examination alone can misdiagnose the location of infection and the number of cervical spaces involved, so imaging studies are vital in establishing the site of the DNI. A plain neck X-ray can indicate a prevertebral space collection if the soft tissue shadow is >22 mm at the C6 level.¹² Plain X-rays also rule out the presence of a foreign body and subcutaneous air. Additionally, a chest X-ray may rule out mediastinitis, pneumomediastinum or empyema in cases with high suspicion.⁵

Contrast-enhanced CT is the modality of choice for its high sensitivity and specificity.2 6 10 13 CT localises the collection, indicates the source and aids in planning surgical drainage. Smith et al found a 75% correlation between CT findings and surgical drainage in adult and paediatric populations.¹⁴ The specificity of CT can further be improved if lesions are >3.5 cm and by taking delayed post-contrast images after several minutes of injection, which can reliably differentiate between cellulitis changes and abscesses.¹⁵ In our patient, CT showed the prevertebral abscess extending from T2 to T11, with a collection extending into the middle mediastinum and features of pancreatitis. MRI is an alternative to CT but is more time-consuming and is used only in special situations. It is helpful to rule out epidural space involvement by prevertebral or paravertebral space collections and to accurately image the involvement of the skull base by these infections.¹⁵

Serum amylase levels are usually raised in patients with acute pancreatitis. The diagnosis can be confirmed by measuring amylase levels in the drained abscess. High amylase levels in aspirated material from the pseudocyst have been used to confirm the diagnosis in the previously reported literature.^{8 9} In our patient the serum amylase level was 1015 IU/L, the amylase level of pus from the endotracheal tube was 18 023 U/L and that of the Ryle’s tube aspirate was 316 840 U/L, which confirmed the diagnosis.

The role of enteral nutrition in severe acute pancreatitis has been well established in previous studies.¹⁶ Enteral nutrition stimulates and maintains gut function, gut integrity, gut-associated lymphoid tissue and gut microbiota composition. Enteral nutrition reduces bacterial, endotoxin and pancreatic enzyme translocation, which may attenuate systemic inflammation, multiorgan failure, infection and disease severity in acute pancreatitis.¹⁶ Many studies have shown that early enteral nutrition within 48 hours of admission is beneficial. Oral diet is better than tube feeding, which can be used later if the patient does not tolerate an oral diet.¹⁶ Our patient was diagnosed with acute severe pancreatitis with rupture of an infected pseudocyst in the prevertebral space and tube feeding was planned. However, the timing of tube feeding in patients with such complications of pancreatitis is uncertain and no clear guidelines are available. Early tube feeding may be beneficial, as in acute necrotising pancreatitis. Further studies are required to formulate clear guidelines. Before we started tube feeding our patient had deteriorated and purulent material was draining from the Ryle’s tube, so we did not start tube feeds.

Management of prevertebral abscess includes pharmacotherapy, surgical drainage and management of predisposing conditions. Initial treatment with broad-spectrum antibiotics, with modification to sensitive antibiotics when a culture report is available, is a prudent approach.^{6 10} The current recommendation for antibiotic therapy for prevertebral infections includes uncomplicated prevertebral space infections without evidence of discitis or osteomyelitis.¹⁷ Surgical drainage is almost always required in patients with prevertebral abscesses. It has been seen in previous studies that patients managed only conservatively usually have higher morbidity and mortality and eventually need surgical drainage.¹⁷ Emergency surgical intervention is usually done as soon as a diagnosis of complicated or severe deep neck space infection is made. The complications include airway compromise, critical condition of the patient, septicaemia, descending infections, no clinical improvement after 48 hours of initiation of the antibiotics, abscess >3 cm in diameter that involve prevertebral abscess and anterior visceral or carotid spaces.¹⁸ Surgical management includes airway evaluation, and management in the form of endotracheal intubation or tracheostomy is essential before draining the abscess.¹⁴ Transoral or transthoracic drainage of a prevertebral abscess can be carried out. However, the former runs the risk of fistula formation, which can be prevented using nasogastric tube drainage.⁴

In patients with pancreatitis, international guidelines recommend postponing catheter drainage until the stage of ‘walled-off necrosis’ has been reached, which typically takes 4 weeks after the onset of acute pancreatitis. This recommendation stems from the era of primary surgical necrosectomy.¹⁹ However, a patient with pancreatitis developing a prevertebral abscess may need emergency surgical intervention for drainage, as the patient may develop airway compromise and other complications such as DNIs. These can be prevented by early aggressive treatment with the above-mentioned multimodal management steps. Drainage of the abscess by thoracotomy was planned but the patient died as a result of septic shock and multiorgan dysfunction.

Guardian’s perspective.

We arrived in the emergency department with my brother suffering from breathlessness and abdominal pain. The doctors examined him and advised some investigations. After routine blood investigations and imaging studies, the doctors informed us about his condition and the need for intubation, surgery and ICU care. However, before any intervention was done, he deteriorated quickly and had a cardiac arrest. We thank the doctors for their timely help.

Learning points.

• Prevertebral abscess with spontaneous rupture into the oesophagus secondary to pancreatitis with a pseudocyst has not previously been reported in the literature. Clinicians should be aware of such a rare presentation of pancreatitis and plan early drainage of the abscess.

• A patient with known pancreatitis diagnosed previously who presents with dysphagia and odynophagia should raise a high degree of clinical suspicion for this rare complication and should undergo good quality cross-sectional imaging, which is essential to the diagnosis.

• Although a CT scan of the thorax is not routinely done in a patient suspected of having acute pancreatitis, the presence of a widened mediastinum prompted this investigation for further evaluation of the patient, which helped us to arrive at the diagnosis of prevertebral abscess.

• Treatment of such conditions should include airway management, early initiation of broad-spectrum antibiotics and early abscess drainage. These measures help to reduce the mortality associated with such conditions.

• In patients with necrotising pancreatitis, necrosectomy should be delayed for 4 weeks after the onset of acute pancreatitis. Patients with prevertebral abscess usually require emergency surgical drainage of the abscess. Although there are no clear guidelines for the timing of surgical drainage in a patient with a prevertebral abscess secondary to pancreatitis, these patients may need emergency surgical drainage of the collection as they may develop compromise of the airway and other complications as of DNI.

Ethics statements

Patient consent for publication

Consent obtained from the patient's guardian.