E020 Pneumatosis intestinalis with spontaneous pneumoperitoneum in a patient with systemic sclerosis-myositis overlap syndrome: a case report and review of the literature
Authors: Lim Kian Wah , Knights Sally , Pauling John , Gotto James 
Published: April 2023

Abstract

Background/Aims
Pneumatosis intestinalis (PI) is a rare complication of systemic sclerosis (SSc), characterised by submucosal and/or subserosal collections of free gas, forming cystic lesions within the gastrointestinal (GI) tract.

Methods
A 67-year-old man with SSc-myositis overlap syndrome presented acutely unwell with worsening abdominal pain, bloating, bloody diarrhoea and vomiting for three weeks. He was afebrile and haemodynamically stable. His abdomen was distended with generalised tenderness but soft and regular bowel sounds were audible. There were no palpable organomegaly or signs of peritonism. He had raised CRP, serum amylase, serum lactate and pre-renal acute kidney injury. He tested positive for ANA Hep2 (speckled) and anti-Mi-2b. His contrast-enhanced CT abdomen and pelvis displayed extensive pneumatosis changes, moderately dilated small bowel loops and pneumoperitoneum without portal venous gas or acute thrombotic occlusion in the main-stem superior or inferior mesenteric arteries. He was managed conservatively with bowel rest, elemental diet, cycling antibiotics for small intestinal bacterial overgrowth (SIBO) and commenced on end-of-life care as surgical exploration was deemed too risky considering that he has exceedingly poor cardiac reserve. He made a surprisingly excellent recovery and his repeat CT scans at approximately 11 weeks showed a complete resolution of pneumatosis intestinalis and pneumoperitoneum.

Results
PI in SSc generally runs a benign course and is usually managed conservatively. The development of PI is multifactorial, involving a complex interplay between mechanical, biochemical, bacterial and drug factors. PI is usually asymptomatic but patients can present with GI and constitutional symptoms or peritonism. CT scan is the most preferred diagnostic modality for PI. Conservative management is preferable to surgical intervention after careful exclusion of acute surgical causes. The underlying cause of PI should be appropriately addressed and managed in all cases. The management of PI is based on the severity of symptoms and it includes bowel rest, elemental diet or parenteral nutrition, antibiotics, high concentration oxygen, hyperbaric oxygen therapy and/or octreotide. Our patient was managed conservatively as he did not exhibit clinical signs of peritonism or bowel ischaemia and surgical interventions were deemed too risky. He was treated with and has responded well to cycling oral antibiotics for SIBO which was thought to be contributory to his PI.

Conclusion
This case illustrates that PI with or without pneumoperitoneum could be a rare complication of SSc, and contrary to common belief, it is usually benign and managed conservatively with favourable outcome. An accurate interpretation of its clinical significance is crucial as acute presentations and ambiguous imaging findings can simulate acute surgical emergency leading to diagnostic dilemma and unnecessary or risky surgical interventions. However, emergency laparotomy should be considered in patients who exhibit signs of peritonism or bowel ischaemia and therefore timely involvement of surgeons and multidisciplinary team is essential.
Disclosure
K. Lim: None. S. Knights: None. J. Pauling: None. J. Gotto: None.