Post‑Cesarean Posterior Rectus Sheath Infections and Collections

Pathophysiology

Subfascial hematomas and fluid collections are recognized complications after cesarean delivery, especially when they develop beneath the rectus sheath. 1
Blood or seroma may accumulate in the subfascial space and become secondarily infected with skin or vaginal flora because cesarean sections are classified as clean‑contaminated procedures. 2

The triad of fever, chills, and a rapid rise in white‑blood‑cell count from ~12 × 10³/µL to ~35 × 10³/µL together with supra‑umbilical tenderness indicates an infected collection that requires drainage. 3
A leukocytosis of ~35 × 10³/µL far exceeds the typical post‑cesarean elevation and signals a significant infection. 4

MRI that demonstrates a linear collection along the posterior rectus sheath in the described clinical context strongly suggests an infected subfascial collection. 5
The American College of Radiology (ACR) guidelines state that subfascial hematomas larger than 4 cm or those with clinical signs of infection warrant intervention. 1
Contrast‑enhanced CT is preferred for characterizing rim enhancement (suggestive of abscess) or active extravasation, providing clearer delineation than MRI alone. 5

Obtain an urgent contrast‑enhanced CT of the abdomen/pelvis to define the collection, assess for rim enhancement, and evaluate for additional complications such as uterine dehiscence or rupture. 6

Arrange prompt CT‑guided percutaneous catheter drainage for any infected collection measuring ≥3 cm. 3
Do not postpone drainage based solely on collection size; systemic infection signs mandate immediate intervention regardless of dimensions. 3

Interpreting the rising leukocytosis (from ~12 × 10³/µL to ~35 × 10³/µL over four days) as normal postoperative change is erroneous; it reflects progressive infection. 4
Subfascial hematomas exceeding 5 cm should raise suspicion for uterine dehiscence or rupture, prompting further evaluation. 6

Presence of gas within the collection on imaging favors uterine rupture rather than an isolated rectus sheath abscess. 6
Ovarian vein thrombosis is a recognized postpartum complication that can mimic the clinical picture and should be assessed for on imaging. 7

The American College of Radiology suggests that wound dehiscence is characterized by separation of the incision layers, which may occur with or without infection 8
Seroma characteristics include fluctuant swelling with serous drainage, minimal erythema, no systemic signs, and absence of purulent discharge, as indicated by Praxis Medical Insights 9
Surgical site infection (SSI) characteristics include purulent drainage, pain, tenderness, erythema extending >5 cm from wound edge, induration, fever >38.5°C, or tachycardia >110 bpm, according to Praxis Medical Insights 9

Praxis Medical Insights recommends prompt drainage as the cornerstone of treatment for sterile seroma, followed by wound care with dressing changes to promote healing by secondary intention 9
For infected wounds, Praxis Medical Insights suggests draining any fluid collections and opening the wound as needed, and initiating antibiotic therapy until systemic signs resolve and wound shows improvement 9

Praxis Medical Insights proposes considering negative pressure wound therapy (NPWT) for recurrent or large seromas, which promotes granulation tissue formation and obliterates dead space, with a significant reduction in SSI (pooled OR 0.25; 95% CI 0.12-0.52) 9
The World Journal of Emergency Surgery recommends using NPWT for thick subcutaneous tissue (>3 cm) to prevent recurrent fluid collections 10

Praxis Medical Insights advises against using prophylactic antibiotics for sterile seromas, as this promotes antibiotic resistance without benefit 9
The World Journal of Emergency Surgery warns against placing subcutaneous drains prophylactically in already dehisced wounds, as drainage is achieved by opening the incision 10

Praxis Medical Insights recommends evaluating wound healing progress at regular intervals (every 2-3 days initially) and watching for development of infection signs if initially presenting as sterile seroma 9