Contrast media extravasation occupies an unusual position in modern radiology practice: it is simultaneously one of the most frequently encountered procedural complications and one of the least systematically studied. The reported incidence range of 0.1% to 1.2% may appear reassuringly narrow, but when applied to the enormous global volume of contrast-enhanced imaging—millions of examinations performed annually across hospitals of every size—the absolute number of affected patients becomes considerable. The recent analysis of 378,082 intravenous contrast-enhanced CT scans cited in the source literature underscores this point: even at the low end of the frequency spectrum, a busy imaging department can expect to encounter extravasation events on a regular basis, making familiarity with recognition and management protocols a practical necessity rather than an academic exercise.

The severity grading framework used in the radiology literature helps to contextualize why the blistering described in this case deserves attention. In the national registry analysis of 1,085 extravasation events, the overwhelming majority—94.6%—were classified as mild injuries, typically limited to swelling and discomfort that resolve without specific intervention. Moderate injuries accounted for 4.7% of events, and severe injuries for only 0.8%. Yet the outcome data attached to these categories reveal a striking pattern: in the observational cohort with detailed follow-up, 29 of 32 patients with moderate extravasation developed skin blisters, with a mean recovery time of five days and a range spanning two to twelve days. All five patients with severe extravasation developed blisters as well, and their recovery was markedly prolonged, averaging 23 days with a range of 17 to 30 days. Blister formation, in other words, functions as a clinical marker that the injury has crossed from trivial into a more consequential category, and it is precisely this transition that the present case illustrates.

Several patient-specific and procedural factors converge to explain why a relatively modest estimated extravasated volume of approximately 5 mL could produce tense, fluid-filled blisters within five hours. The osmolality and viscosity of the contrast agent, the injection rate, the volume delivered before the injection was halted, and the anatomical characteristics of the injection site all influence the degree of tissue injury. Iobitridol at 350 mgI/mL is a non-ionic low-osmolar agent, a class considerably safer than the older ionic high-osmolar compounds, but hyperosmolarity remains an inherent property of iodinated contrast. When such fluid enters the interstitial space, it creates an osmotic gradient that draws additional water into the tissue, amplifying swelling and pressure. The power injector flow rate of 3.5 to 4.0 mL/s used for lower-extremity CT angiography, while standard for vascular imaging, delivers contrast under sufficient pressure to dissect along tissue planes once the vessel wall is breached. The forearm, with its relatively tight fascial compartments and thin overlying skin, offers less accommodating space for leaked fluid than looser subcutaneous regions, which may partly explain the rapid emergence of blistering at this site.

The temporal course of the injury is also instructive. The patient reported distending pain at the puncture site during injection—an early warning sign that prompted immediate termination of the injection at 80 mL delivered—and bedside ultrasound subsequently quantified the residual extravasated volume. Yet the visible skin changes did not appear immediately. Only at routine nursing rounds five hours later did the blisters become evident, on a background of erythema and mild swelling. This delayed presentation reflects the physiology of contrast-induced tissue injury: osmotic fluid shifts, inflammatory mediator release, and endothelial changes evolve over hours rather than seconds. The practical implication is that a patient who appears unharmed immediately after an extravasation event still requires structured follow-up observation, as the source case demonstrates through hourly nursing reassessment of the affected limb.

Equally important is what the clinical course did not show. At no point did the patient develop evidence of compartment syndrome—the most feared complication of large-volume extravasation, in which rising interstitial pressure within a confined fascial space compromises capillary perfusion and threatens nerve and muscle viability. The assessment of capillary refill, distal sensation, and passive finger movement, repeated throughout the observation period, represents the bedside evaluation that nursing and medical staff should perform whenever significant extravasation occurs. Pain that intensifies with passive stretch, progressive swelling with tenseness of the compartment, paresthesia, and diminished pulse are the classic warning features, and their absence in this case allowed management to remain entirely conservative. The distinction matters because compartment syndrome from contrast extravasation, while rare, may necessitate urgent surgical fasciotomy, whereas blistering injuries without compartment involvement can generally be managed with topical and supportive measures.

The management regimen applied in this case draws on two distinct therapeutic traditions. Hirudoid cream, whose active constituent is mucopolysaccharide polysulfate, has long held a place in European and Asian practice for superficial phlebitis, bruising, and extravasation injuries. Its proposed mechanisms include anti-inflammatory effects on local tissue and promotion of connective tissue repair and resorption of edema. Guidelines from both the American College of Radiology and the European Society of Urogenital Radiology emphasize conservative first-line measures—cessation of injection, limb elevation, appropriate compresses, and close monitoring—with topical agents such as mucopolysaccharide polysulfate commonly incorporated into that framework. The intermittent ice compresses used here, applied for 15 to 20 minutes every 2 to 4 hours with a cloth barrier protecting the skin, serve the dual purpose of vasoconstriction, which limits further spread of the osmotically active contrast within the tissue, and mild analgesia. Cold application must be timed and barriered carefully, since prolonged direct icing risks adding a cold injury to the existing chemical one.

The third component, Jinhuang San—Golden Yellow Powder, also known by its fuller name Ru-Yi-Jin-Huang-San—is a classical traditional Chinese medicine external formula with a documented history of use for traumatic swelling, carbuncles, and drug extravasation injuries. The supporting evidence cited in the source literature is twofold. A clinical study found that early wet compresses with the formula shortened mean healing time of extravasation-induced skin injury to 6.44 days. Separately, an experimental model of iohexol extravasation demonstrated significant reductions in swelling area and inflammatory infiltration at 24 and 48 hours respectively. The preparation method used in this case—mixing the powder with green-tea water to form a wet poultice—follows customary practice, in which the tea may contribute additional astringent and anti-inflammatory properties while providing the moisture needed for transcutaneous delivery of the herbal constituents.

The rationale for combining these three modalities is plausible at the level of mechanism. Mucopolysaccharide polysulfate addresses inflammation and tissue repair; cold compresses limit the osmotic spread of the extravasated agent and relieve pain; and the herbal poultice, according to the experimental data, reduces both edema and the cellular inflammatory response. Each component targets a different phase or aspect of the injury process, and their combination is conceptually complementary rather than redundant. Nevertheless, the authors are appropriately careful to frame the outcome as hypothesis-generating. A single uncontrolled case cannot establish efficacy, and the natural history of even moderate extravasation injuries includes spontaneous improvement in many patients, making attribution of the rapid 48-hour resolution to the specific regimen inherently uncertain. Prospective, controlled studies would be required to determine whether this integrated approach genuinely accelerates healing compared with standard conservative care alone.

The patient’s underlying vascular disease adds a further dimension of clinical interest. Lower-extremity atherosclerotic occlusive disease, with the severe aortoiliac and iliac stenoses and occlusions documented on the completed CT angiography, indicates widespread arterial compromise. Although the extravasation occurred in the forearm rather than the diseased lower limbs, the systemic atherosclerotic burden raises questions about whether impaired microvascular reserve might influence tissue tolerance to interstitial contrast exposure. The patient’s preserved renal function, with estimated glomerular filtration rates above 125 mL/min/1.73 m² on both assessments, and her regimen of clopidogrel, atorvastatin, nifedipine, and telmisartan reflect the standard pharmacological management of high-risk atherosclerotic disease. Whether antiplatelet therapy, statin-associated effects on endothelial function, or antihypertensive agents modify the local inflammatory response to extravasated contrast remains unexplored, but such interactions represent a legitimate direction for future investigation.

From a prevention standpoint, the case reinforces several established principles of contrast administration. Power injectors deliver contrast at flow rates and pressures that exceed what manual injection can achieve, and they demand correspondingly careful venous access assessment before use. A 20-G peripheral cannula in a forearm vein is an appropriate choice for CT angiography, but cannula position, vein caliber, and patient factors such as fragile veins in older adults all influence extravasation risk. The patient’s complaint of distending pain at the puncture site, rated 6 on a 10-point numeric scale, functioned exactly as an early warning should: the injection was stopped immediately, the cannula removed, and the examination completed through a new puncture site. This responsiveness likely limited the extravasated volume and, by extension, the severity of the injury. Patient-reported symptoms during power injection should never be dismissed, because the interval between the first symptom and tissue damage can be short.

The reporting of this case according to the CARE guidelines also reflects a broader movement toward methodological rigor in case-based evidence. Single-case reports occupy the lowest tier of the evidence hierarchy, but they serve indispensable functions: they document rare presentations, describe novel management combinations, and generate testable hypotheses for controlled research. The observation that blistering from iobitridol extravasation resolved within 48 hours under a three-component topical regimen, without skin breakdown, provides a concrete clinical trajectory that future studies can measure against. Until such studies exist, the case stands as a well-documented example of early recognition, structured multidisciplinary management, and a favorable outcome in an uncommon manifestation of a common complication.

For clinicians and nursing teams, the practical takeaways are straightforward. Every contrast-enhanced examination carries a small but real extravasation risk; patients should be monitored both during and after injection, with particular vigilance in the hours following an event; blistering signals a moderate-to-severe injury requiring escalation of care; and conservative management—elevation, appropriate compresses, topical agents, and serial assessment for compartment syndrome—remains the cornerstone of treatment for injuries without surgical indications. The integration of traditional Chinese medicine external therapies with conventional topical treatment, while promising in this instance, should be viewed as an avenue for further research rather than a settled standard, and the authors’ call for prospective controlled studies is a fitting conclusion to a carefully documented clinical observation.

Subject of Research: …

Article Title: Contrast media extravasation following CT angiography in a patient with lower-extremity atherosclerotic occlusive disease: a case report

Article References: Yan, C., Zhang, T., Xu, Q., & Bi, S. (2026). Contrast media extravasation following CT angiography in a patient with lower-extremity atherosclerotic occlusive disease: a case report. Frontiers in Medicine, 13, Article 1888394. https://doi.org/10.3389/fmed.2026.1888394

Image Credits: AI Generated

DOI: 10.3389/fmed.2026.1888394

Keywords: Contrast, media, extravasation, following, angiography, patient, lower-extremity, atherosclerotic, occlusive, disease, case, report