No wound is small: Delayed presentation of penetrating abdominal trauma by an iron nail

INTRODUCTION

Penetrating injuries to the abdomen can be easily underestimated, particularly when caused by small objects such as nails, sharp wires, or wooden splinters. While high-velocity trauma is well known for causing significant intra-abdominal injury, low-energy penetrations may be overlooked. Injuries from nail guns most commonly affect the extremities, especially the nondominant hand, but reports exist of nail gun trauma affecting nearly every part of the body.^1-3 Although abdominal nail gun injuries are far less frequent than stab or firearm wounds, they pose unique diagnostic and management challenges, as the small entry site can mask substantial high-velocity damage to vital intra-abdominal organs.⁴ Early symptoms may be minimal or absent, delaying recognition and increasing the risk of complications such as infection, adhesions, or contained perforations. We present a rare case of delayed bowel obstruction secondary to a sealed perforation caused by an iron nail, highlighting that even apparently minor wounds can conceal serious internal injury.

CASE REPORT

A 29-year-old previously healthy man presented to the surgical outpatient department with abdominal pain and purulent discharge from a small puncture wound over the left lower anterior abdominal wall. Ten days prior, while working, he had sustained an accidental penetrating injury after falling onto an exposed iron nail approximately 5–6 cm in length, which entered the left lower abdomen. The nail was removed immediately at the site by a co-worker, and the patient subsequently sought care at a local hospital, where the wound was irrigated and dressed, tetanus prophylaxis was administered, and oral antibiotics were prescribed. The wound appeared to heal, and the patient remained asymptomatic for approximately one week, with no fever, abdominal pain, or gastrointestinal complaints during this period. He then developed abdominal pain, which got aggravated after food intake. He was afebrile but had localized tenderness around the wound with purulent discharge [Figure 1].

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Figure 1:

Penetrating wound with pus discharge (red arrow)

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Abdominal examination revealed mild distension and increased bowel sounds. Laboratory investigations showed leukocytosis (white blood cell count: 14,900/mm³) and elevated C-Reactive protein. Contrast-enhanced computed tomography (CECT) of the abdomen [Figures 2a and 2b] demonstrated a tract extending from the anterior abdominal wall defect into the peritoneal cavity, associated with a pelvic collection measuring approximately 300–400 ml. Dilated small bowel loops with collapse of the large bowel were noted, without a discrete transition point, but likely extrinsic compression. No extraluminal air was noted. These imaging findings correlated with the clinical presentation and were consistent with dynamic intestinal obstruction.

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Figure 2:

(a) CT Abdomen- Pelvic collection (red circle). (b) CT abdomen- Dilated loop with abdominal wall defect (red arrow). CT: Computed tomography.

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Image-guided drainage of the pelvic collection was considered but deferred due to the close proximity of adjacent bowel loops, which precluded a safe percutaneous access route. Given the presence of bowel dilatation, radiologic suspicion of dense adhesions, and concern for a possible occult bowel injury, a diagnostic laparoscopy (DL) was preferred as it allowed comprehensive assessment with the option of definitive intervention. Accordingly, laparoscopy was performed but required conversion to an exploratory laparotomy due to extensive intra-abdominal adhesions [Figures 3a and 3b]. Intraoperatively, approximately 200-300 ml of purulent fluid was aspirated from the pelvic cavity. Multiple loops of small bowel were found to be densely adherent to each other, and the sigmoid colon was firmly adherent to the parietal abdominal wall along the presumed injury tract. Meticulous adhesiolysis was performed. A sealed sigmoid colonic perforation was suspected at the site of dense adhesions and localized pus collection; however, careful inspection of the entire bowel revealed no overt perforation. The sigmoid colon showed no active leak, induration, contamination, or demonstrable defect; therefore, no formal repair was performed. Thorough peritoneal lavage was carried out, subhepatic and pelvic drains were placed, the injury tract was excised and laid open.

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Figure 3:

(a) Inter-bowel adhesions on laparoscopy. (b) Adhesions of the sigmoid colon (yellow arrow) to the parietal wall at the wound site (arrow head).

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The postoperative course was uneventful. Empirical intravenous antibiotics were initiated and subsequently de-escalated based on culture sensitivity results and continued until postoperative day (POD) 7. The subhepatic drain, which had serous output, was removed on POD 3 after drainage decreased to <30 mL over two consecutive days. The pelvic drain initially yielded seropurulent output and was removed on POD 5 after ultrasonography confirmed the absence of residual intra-abdominal collection. The injury tract site was managed with regular dressings and underwent delayed closure after 2 weeks. Oral intake was initiated on POD 3 and advanced as tolerated. The patient was discharged in stable condition on POD 7 with a total hospital duration of 8 days. On follow-up after 4 weeks, the patient remained asymptomatic.

DISCUSSION

The severity of penetrating trauma depends on several factors, including the type of weapon, its speed, the anatomical site affected, and the tissues involved. Low-velocity projectiles typically damage only the structures directly in their path. Injuries may manifest immediately or appear later and can lead to complications such as shock or infection.⁵ A detailed patient history—covering the nature of the weapon and the timing of any physiological decline—helps guide clinical management. The spleen is the most frequently injured solid organ in penetrating abdominal trauma, followed by the liver.⁶ Damage to the mesentery and bowel is seen in up to 17% of cases.⁷, with injuries to the distal colon generally carrying a poorer prognosis.⁸

Penetrating injuries to the abdomen are often dramatic in presentation, but smaller puncture wounds may be easily overlooked, particularly if there are no immediate symptoms. When missed, such injuries contribute to significant morbidity due to complications such as localized or generalized intra-abdominal sepsis, abscess formation, and sealed hollow viscus perforation, which may progress to enteric fistulae or bowel obstruction. Solid organ involvement can result in subcapsular or intraparenchymal abscesses, while retroperitoneal injuries may manifest as pancreatitis, duodenal leak, or retroperitoneal sepsis. Retained foreign bodies may further contribute to chronic inflammation, migration, or persistent sinus formation, and delayed recognition increases the risk of septic shock, multiorgan dysfunction, and prolonged hospitalization. Premature removal of penetrating objects, particularly outside a medical setting, may further obscure the depth and trajectory of injury, thereby increasing the likelihood of missed visceral damage and contributing to delayed diagnosis and definitive management.

Mandatory exploratory laparotomy was historically performed for all penetrating abdominal injuries. In contemporary practice, diagnostic laparoscopy has emerged as a valuable minimally invasive alternative for the evaluation of penetrating abdominal trauma in hemodynamically stable patients, especially with inconclusive clinical or imaging findings. It is safe and effective in carefully selected patients without peritonitis or evisceration, although meticulous technique is essential to avoid missed injuries.⁹ Conversion to open laparotomy should be undertaken if significant hollow viscus, major vascular, or complex solid organ injuries are identified, if visualization is inadequate, or if the patient becomes hemodynamically unstable. Currently, abdominopelvic computed tomography is recommended in selected patients undergoing initial nonoperative management to aid early management decisions.¹⁰

This case illustrates several key points. First, no penetrating wound should be considered trivial. The nail likely caused a small perforation that sealed off over time, aided by adjacent bowel loops and omentum, preventing overt peritonitis. However, this led to localized abscess formation and bowel obstruction due to adhesions. Delayed presentation and subtle signs such as wound discharge, mild distension, or localized tenderness may be the only clues to deeper pathology.

Second, meticulous serial clinical assessment is essential, particularly during the first 24–48 hours following injury. Patients who are initially hemodynamically stable should undergo close observation with repeated abdominal examinations, supplemented by early CECT, with or without oral and rectal contrast. A randomized controlled trial in hemodynamically stable patients with low-velocity penetrating abdominal trauma comparing DL with CECT following secondary survey demonstrated that the CECT group had significantly lower rates of non-therapeutic laparotomy without an associated increase in missed injuries.¹⁰

Finally, computed tomography (CT) demonstrates high diagnostic accuracy, with a sensitivity of 94% and a specificity of 95% for injury detection.¹¹ However, mesenteric and bowel injuries remain the most frequently missed lesions on CT and are often identified only during operative exploration. A single-center study has shown that multidetector computed tomography is superior in detecting bowel injuries in patients with penetrating abdominal trauma. CECT remains the investigation of choice for evaluating suspected delayed intra-abdominal complications, especially in patients who develop signs of infection or obstruction after penetrating trauma.

CONCLUSION

This case reinforces the maxim that no wound is small. Even seemingly minor penetrating injuries can harbor serious intra-abdominal pathology with delayed manifestations. Proper evaluation at the time of injury, serial clinical examination, and timely imaging are essential to avoid missed or delayed diagnoses that may lead to serious complications.