Subcutaneous emphysema due to rectal perforation: A case report

Abstract

BACKGROUND

Rectal perforation leading to subcutaneous emphysema is relatively rare. This presentation is most frequently reported as a complication of endoscopic procedures. Consequently, its occurrence in spontaneous or non-endoscopic settings, particularly in elderly patients with subtle symptoms, represents a notable diagnostic dilemma.

CASE SUMMARY

This report describes a 94-year-old female patient who was admitted to hospital with lower abdominal pain. On physical examination, palpable subcutaneous emphysema was detected in the mandibular facial area, neck, chest, and abdomen. A computed tomography scan suggested the possibility of rectal perforation, along with multiple subcutaneous gas collections in the neck, chest, back, sacrococcygeal region, as well as around the esophageal vessels, mediastinum, and abdominal wall. An emergency exploratory laparotomy was decided upon. During the operation, a perforation in the middle segment of the rectum and pneumatosis retroperitonealis was found. The perforated segment of the rectum was resected surgically, and an end-sigmoid colostomy was fashioned in the left iliac fossa. Five months post-operation, the patient remained in a stable condition.

CONCLUSION

Subcutaneous emphysema in the elderly should prompt evaluation for colorectal perforation.

Key Words: Subcutaneous emphysema; Intestinal perforation; Rectal perforation; Atypical presentations; Case report

Core Tip: This case describes extensive subcutaneous emphysema as the primary sign of rectal perforation in an elderly patient. A literature review identified only eight similar non-endoscopic studies. The report underscores that in elderly patients, colorectal perforation may lack typical symptoms, and subcutaneous emphysema can be the leading clue, necessitating timely imaging and surgical evaluation.

INTRODUCTION

Subcutaneous emphysema is a clinical sign with a broad differential diagnosis, ranging from benign causes to life-threatening conditions. While commonly associated with thoracic trauma or infections, its occurrence due to gastrointestinal perforation, particularly rectal perforation, is exceedingly rare[1]. Such presentations are frequently documented as complications of endoscopic procedures. Spontaneous or non-iatrogenic rectal perforation leading to widespread subcutaneous emphysema is poorly characterized in the literature, with very few cases reported[2], especially in elderly patients who may not exhibit classic peritonitis symptoms.

We here describe a rare and instructive case of an elderly patient with extensive subcutaneous emphysema as the leading sign of rectal perforation, review the sparse existing literature on similar non-endoscopic cases, and emphasize the critical importance of including gastrointestinal perforation in the diagnostic workup of unexplained subcutaneous emphysema.

CASE PRESENTATION

Chief complaints

A 94-year-old female patient presented to the Emergency Department of the Second Affiliated Hospital of Zhejiang University School of Medicine on April 7, 2024, due to “lower abdominal pain for 1 week”.

History of present illness

The patient developed lower abdominal pain without obvious cause one week previously, which gradually worsened, accompanied by nausea and vomiting.

History of past illness

The patient had a body mass index of 24.22 kg/m², a history of hypertension, chronic constipation, and over 30 years of alcohol consumption, and had previously undergone cholecystectomy and ectopic pregnancy surgery. She had no history of non-steroidal anti-inflammatory drugs (NSAID), anticoagulant or corticosteroid use.

Personal and family history

The patient had no family history of colorectal diverticula, colorectal cancer, inflammatory bowel disease (IBD), or other gastrointestinal-related diseases. Additionally, no obvious genetic disease history was noted in immediate family members (parents, siblings, or children).

Physical examination

The body temperature was 36.2 °C, SpO₂ was 97%, respiratory rate was 15 breaths/minute, blood pressure was 133/56 mmHg, and pulse rate was 94/minute. Physical examination revealed lower abdominal tenderness, particularly in the left lower abdomen, with no obvious rebound tenderness or muscle guarding, suspicious crepitus in the abdomen, and obvious subcutaneous crepitus palpable in the bilateral neck, bilateral clavicles, and right shoulder.

Laboratory examinations

Laboratory tests showed a white blood cell count of 26.4 × 10⁹/L, neutrophils of 24.8 × 10⁹/L, whole blood C-reactive protein of 332.9 mg/L, procalcitonin of 6.13 × 10 ng/mL, lactate of 1.4 mmol/L, creatinine of 128.2 μmol/L, sodium of 137 mmol/L, potassium of 2.9 mmol/L, and hemoglobin of 132 g/L, and blood culture showed no growth of aerobic or anaerobic bacteria after 5 days of incubation.

Imaging examinations

Emergency abdominal computed tomography (CT) suggested possible extraperitoneal rectal perforation with fecal leakage, a small amount of exudate and effusion in the abdominal cavity and pelvis, multiple diverticula in the rectum and colon, and multiple gas accumulations in the subcutaneous soft tissues of the mediastinum, bilateral abdominal walls, back, and sacrococcygeal region (Figure 1), while chest CT indicated extensive gas accumulations in the subcutaneous tissues of the neck and chest, mediastinum, and periesophageal vessels, with no evidence of pneumothorax (Figure 2).

Figure 1 Abdominal computed tomography scan image. A: Multiple free gas shadows are seen within and around the rectal wall (arrow); B: Scattered bubbly gas-density shadows are observed in the extraperitoneal space of the pelvis and adjacent subcutaneous soft tissues (arrow).

Figure 2 Chest computed tomography scan image. A: Extensive gas shadows are visible in the subcutaneous soft tissues of the neck and mediastinum (arrow); B: Scattered gas-density shadows are observed in the subcutaneous soft tissues of the chest and periesophageal vessels (arrow).

FINAL DIAGNOSIS

Rectal perforation with subcutaneous emphysema and retroperitoneal pneumatosis; multiple diverticula of rectum and colon.

TREATMENT

The patient underwent emergency laparotomy on April 7, 2024. The patient's preoperative physical status was classified as American Society of Anesthesiologists grade II. Intraoperatively, bubbles were detected in the transverse mesocolon, likely due to retroperitoneal perforation (Figure 3A). A 3-cm rupture was found in the mid-rectum approximately 2 cm below the peritoneal reflection, with fecal masses protruding, accompanied by a large amount of fecal fluid in the retrorectal space, extensive mesenteric edema, severe retroperitoneal contamination, and hard fecal masses in the intestine (Figure 3B). Considering the perforation resulted from rectal diverticulum rupture, a combined procedure of partial rectal resection, end-sigmoid colostomy, and open fecalith removal was performed. Postoperative pathology: An 11-cm intestinal segment from the rectal perforation site showed mucosal erosion, local vascular hyperplasia, acute and chronic inflammatory cell infiltration in the serosa and adipose tissues, and fibrous tissue hyperplasia.

Figure 3 Intraoperative findings. A: Air accumulation in the transverse mesentery; B: Mid-rectal perforation 3-cm in diameter, showing fecal mass extruding through the perforation.

Postoperatively, the patient was transferred to the intensive care unit. In terms of the use of antibacterial agents: The antimicrobial regimen included imipenem-cilastatin sodium + ornidazole from April 7 to April 11, 2024. Ornidazole was then discontinued, and imipenem-cilastatin sodium was administered alone until April 14, 2024, after which it was switched to piperacillin sodium-sulbactam sodium until April 17, 2024.

The patient was transferred to a general ward on April 10. The postoperative course was uneventful, and no significant complications occurred. Diet started from postoperative day 5. The colostomy functioned normally throughout the recovery period. The patient was discharged on April 23, 2024, and had no subsequent readmissions.

OUTCOME AND FOLLOW-UP

Postoperative chest and abdominal CT scans showed that the pneumoperitoneum had basically resolved, with a small amount of fluid in the abdominal and pelvic cavities. The ostomy bag showed flatus and defecation. Regular blood tests revealed a gradual decline in inflammatory markers to normal levels. At the 5-month follow-up, the patient was well, with a functioning colostomy and had returned to her baseline functional status.

DISCUSSION

Subcutaneous air collection (subcutaneous emphysema) may arise from multiple etiologies. The most frequent causes include pneumothorax, esophageal perforation, and infectious processes such as gas gangrene[1]. The manifestation of subcutaneous gas accumulation caused by rectal perforation is extremely rare. In this case, the patient was admitted to the hospital due to abdominal pain. Interestingly, no obvious signs of peritonitis were found during the physical examination performed on admission. Subcutaneous emphysema lacks specificity as a sign of intestinal perforation, a limitation that often complicates diagnostic accuracy in such cases. The preferred diagnostic modalities for such cases typically include chest/abdominal CT and physical examination. When CT reveals subcutaneous, mediastinal, or intra-abdominal air-particularly in elderly patients with subtle abdominal signs-intestinal perforation should still be considered. However, laparotomy is often required to definitively identify the cause of subcutaneous air accumulation[2]. Notably, novel interventional approaches to rare gastrointestinal fistulas, such as gastro-bronchial fistulas, have recently been explored to minimize morbidity and improve outcomes in selected cases[3].

Among the various causes of subcutaneous emphysema, rectal perforation stands out as a critical yet often under-diagnosed factor. To fully comprehend its role, it is essential to first explore the underlying causes of rectal perforation. With respect to the etiology of rectal perforation, the majority of reported cases are either iatrogenic or associated with rectal prolapse[4]. Additionally, other potential causes include malignant tumors, diverticular disease, fecalitic ulcers, trauma, and ulcerative colitis (UC). In the present case, the possible causes of perforation are as follows.

Fecalitic perforation

Chronic constipation in elderly patients may result in the accumulation of hardened fecal masses, leading to compression and subsequent ischemia of the intestinal wall. This process can ultimately cause tissue necrosis and perforation, resulting in fecalitic ulcers. In the present case, hard fecal masses were found at the perforation site intraoperatively. In the present case, given the patient’s history of chronic constipation, the hard fecal mass found during surgery may be one of the contributing factors to the perforation.

Diverticular perforation

Colonic diverticula are predominantly located in the sigmoid colon and small intestine. Rectal diverticula, in contrast, are exceedingly rare, with only sporadic cases reported since 1911[5]. According to current literature, rectal diverticular disease constitutes approximately 0.1% of all colonic diverticular disease cases. Most patients with rectal diverticula are diagnosed incidentally, and symptomatic presentations are uncommon[6,7]. The primary complication of diverticular disease is diverticulitis, which may progress to intestinal wall perforation. Clinical manifestations often mimic those of acute abdomen, characterized by severe abdominal pain, constipation, a positive Blumberg sign, and muscular rigidity[2]. Additionally, recent studies have highlighted the role of NSAID-induced colonic injury, such as diaphragmatic disease, as a potentially under-recognized cause of colonic perforation, especially in elderly patients[8]. A CT scan of the patient in this case revealed multiple diverticula in the rectum, raising suspicion for the possibility of diverticular perforation.

IBD

IBD can also lead to intestinal perforation, which requires a surgical emergency. The incidence of colonic perforation in patients with IBD is highest in UC, particularly in the setting of toxic megacolon[9,10]. Diagnosis relies on a combination of clinical assessment and radiographic evidence. While diffuse peritonitis may be present on physical examination, its absence does not exclude perforation, especially in immunosuppressed patients. Abdominal X-rays or CT scans can detect free intraperitoneal perforation with pneumoperitoneum visible on both modalities, with free fluid specifically identified on CT. Management requires immediate exploratory laparotomy with control of sepsis. In UC, a perforated colon necessitates total abdominal colectomy and end ileostomy[9,11,12]. In our case, although the patient had no known history of IBD, the possibility of IBD-related perforation was considered given the atypical presentation and extensive subcutaneous emphysema.

How does subcutaneous emphysema develop following rectal perforation? Unraveling this intricate process necessitates a meticulous exploration of relevant anatomical structures and physiological pathways. Colorectal perforation gas dissemination depends on anatomical location. In extraperitoneal rectal perforations (below the peritoneal reflection), due to the loose connective tissues in the retroperitoneum, gas enters the retroperitoneal space and spreads cranially through pelvic and abdominal fascial planes, reaching the mediastinum via periesophageal and peritracheal tissues, then the neck and head. Some gas may also reach the medial thigh. For intraperitoneal rectal perforations (above the reflection), gas first causes pneumoperitoneum, then may infiltrate the retroperitoneum or thorax through diaphragmatic hiatuses, eventually spreading to the neck and head. Rectal perforations can also rapidly spread gas to the perineum and along the lower limb superficial fascia.

We reviewed PubMed database spanning from database inception to February 2026, restricting the search to English-language articles and utilizing the following keywords: “Colonic perforation” and/or “Intestinal perforation” combined with “Subcutaneous emphysema” and/or “Pneumoperitoneum”. Case reports or case series on subcutaneous emphysema secondary to intestinal perforation were included; and reviews and non-English articles were excluded. This search yielded 24 references, from which relevant articles were manually retrieved. Based on this search, we found that endoscopic procedures (such as endoscopic mucosal resection) constitute a considerable proportion of iatrogenic subcutaneous emphysema cases; and relevant literature has also reported cases of scrotal emphysema secondary to gastrointestinal perforation[9,13-16]. After excluding cases related to endoscopic procedures, we identified 8 studies of subcutaneous emphysema secondary to intestinal perforation caused by non-endoscopic causes, as summarized in Tables 1 and 2[2,17-23]. Notably, in these cases, subcutaneous emphysema often served as the sole sign of gastrointestinal perforation in the later stage, and most of the signs of peritonitis were atypical. For example, Janczak et al[2] described the case of a patient admitted due to dysuria. During the physical examination upon admission, no signs of peritonitis were detected, but subcutaneous emphysema was palpable in the neck, chest, and abdomen. During the operation, a retroperitoneal perforation of a sigmoid diverticulum was found. Subsequently, a segment of the sigmoid colon was resected, and a stoma was formed.

Table 1 Clinical characteristics of patients with subcutaneous emphysema due to intestinal perforation.

Ref.	Age/sex	Location	Causes	Signs of peritonitis	Treatment/surgery
Setoguchi et al[17]	66, M	Sigmoid	Colonic diverticular	No	Sigmoid colostomy
Turco and Trivedi[18]	71, F	Rectum	HAL-RAR	No	Sigmoid colostomy
Kurti et al[19]	55, F	Rectum	Rectal diverticulosis	Inapparent	Segmental intestinal resection and anastomosis
Gupta et al[20]	83, F	Rectum	Fecal-associated perforation	No	Sigmoid colostomy
Janczak et al[2]	76, F	Sigmoid	Colonic diverticular	No	Colostomy
Lee et al[21]	62, F	Rectum	Rectal prolapse	No	Diverting sigmoid loop colostomy
Morita et al[22]	73, M	Rectum	Rectal cancer	NR	Colostomy
Fox et al[23]	46, M	Rectum-sigmoid	Rectal cancer	No	Right transverse colostomy
	72, M	Rectum-sigmoid	Colonic diverticular	No	Right transverse colostomy

F: Female; M: Male; HAL-RAR: Hemorrhoidal artery ligation and recto anal repair; NR: No report.

Table 2 Imaging findings in patients with subcutaneous emphysema due to intestinal perforation.

Ref.	Age/sex	Imaging findings
Setoguchi et al[17]	66, M	CT imaging demonstrated subcutaneous (neck), mediastinal, and retroperitoneal emphysema, with no evidence of free air
Turco and Trivedi[18]	71, F	CT of the abdomen and pelvis demonstrated extensive extraluminal gas distribution throughout the neck, torso, and upper limbs. The gas was detected in various regions, including the retroperitoneal and intraperitoneal spaces, the mediastinum, the anterior and posterior chest walls, the superficial and deep cervical layers, the right lower abdominal wall, and the bilateral inguinal canals
Kurti et al[19]	55, F	CT imaging showed the presence of air bubbles in both perirenal areas. These air bubbles propagated to the mediastinum and spread laterally into the subcutaneous tissues. Notably, they were mainly present in the left subaxillary and supraclavicular spaces and ultimately reached the structures of the neck
Gupta et al[20]	83, F	CT of the abdomen and pelvis disclosed a fecaloma accompanied by pneumatosis. The abnormal gas was identified in the mediastinum, abdomen, and the subcutaneous tissues covering the chest and abdomen
Janczak et al[2]	76, F	CT examination revealed massive left-sided intra-abdominal and subcutaneous emphysema, as well as right-sided intramuscular emphysema of the chest. The gas predominantly accumulated in the right iliac fossa, and a large gas sac, measuring 6 cm × 8 cm, was situated to the right of the midline
Lee et al[21]	62, F	CT findings indicated a thickened rectosigmoid colon surrounded by a substantial amount of free air. Extensive surgical emphysema was observed, extending to the chest wall and groin regions. Additionally, large quantities of free air were present within the retroperitoneal space and around the aorta
Morita et al[22]	73, M	CT imaging demonstrated emphysema around the buttock, lower abdominal wall, and both lower extremities
Fox et al[23]	46, M	Roentgenograms of the abdomen and left lower extremity showed the presence of air within the soft tissues along the fascial planes
	72, M	Abdominal roentgenograms revealed soft-tissue gas in the left hip area

F: Female; M: Male; CT: Computed tomography.

These cases highlight that non-endoscopy-related intestinal perforations often occur insidiously, with subcutaneous emphysema as a key diagnostic clue in the absence of peritoneal signs. The atypical clinical manifestations observed in these patients underscore the importance of maintaining a high index of suspicion for intestinal perforation in elderly individuals presenting with unexplained subcutaneous emphysema, even in the absence of classic symptoms such as abdominal pain or peritonitis. Therefore, long-term follow-up studies of this rare condition are recommended to facilitate earlier recognition and improve clinical outcomes through timely surgical intervention.

CONCLUSION

When elderly patients present with subcutaneous emphysema, the possibility of gastrointestinal perforation should be considered to enable timely diagnosis and treatment.