Cellulitis. CT scanning is often the first imaging modality that is used because of its ease and availability at most medical institutions. If you have questions about ordering your patient's CT, we encourage you to speak with a radiologist about the study and the need for contrast. endobj The choice of contrast agent depends on route of administration, desired tissue differentiation, and suspected diagnosis. The information provided is for educational purposes only. Uncomplicated cellulitis is usually treated conservatively with antibiotics and locally supportive measures. Thank you for your interest in spreading the word on Cleveland Clinic Journal of Medicine. Occasionally sepsis may result. Bookshelf A 57-year-old diabetic male with pneumoscrotum. Fundic gland polyps: Should my patient stop taking PPIs? 70470 Metastases/Known cancer HIV Intracranial infection Note: CT can be used if there are contraindications for MRI. The most common contrast agents used with CT imaging are barium- and iodine-based. Biomed Res Int. The American College of Radiology recommends using IV iodinated contrast in pregnant women when the information needed affects the care of the patient and fetus and cannot be obtained without contrast, and when the referring physician thinks that imaging should not wait until after the pregnancy.7, Iodinated contrast media can saturate the thyroid gland and significantly reduce uptake of iodine 131, rendering the treatment ineffective. Alaia E, Chhabra A, Simpfendorfer C et al. During the injection you may feel flushed and get a metallic taste in your mouth. Saad A, Kho J, Almeer G, Azzopardi C, Botchu R. Br J Radiol. official website and that any information you provide is encrypted 1994;192(2):493-6. Emerg Radiol. References. endobj For the assessment of vascular disease, CT in most cases requires IV contrast to delineate the vessel lumen. CT pulmonary angiography with intravenous contrast in a patient being evaluated for arteriovenous malformation. <> Author disclosure: No relevant financial affiliations. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat, organs, and blood vessels. In cases where the plain film and nuclear medicine bone scan findings are complicated due to previous surgery, trauma, or underlying illness, the anatomic resolution and soft tissue contrast provided by MRI and CT are often necessary to determine if underlying infection exists. Epub 2017 Mar 30. This question is for testing whether or not you are a human visitor and to prevent automated spam submissions. The American Academy of Radiology recommends the use of IV contrast only if care of the patient cannot be accomplished without it. Contrast-enhanced CT demonstrates a horse-shoe shaped perirectal air collection (arrows), extending into the subcutaneous tissues of the ischiorectal fossa and medial gluteal region (b). 2009;39(10):957-71. This can be filled at Baystate Pharmacies at 759 Chestnut Street and 3300 Main Street as well as at many local pharmacies. In B, the native left lung is small, with evidence of bronchiectasis, bronchiolectasis, and areas of honeycombing (black arrow). Radiology. The American College of Radiology Appropriateness Criteria is a useful online resource. Soft-tissue infections and their imaging mimics: from cellulitis to necrotizing fasciitis, Necrotizing soft-tissue infection: diagnosis and management, Red flags for necrotizing fasciitis: a case control study, Sonographic detection of necrotizing fasciitis, Necrotizing soft tissue infections: a primary care review. Cellulitis occurs after disruption of the skin and invasion of the subcutaneous tissues by microorganisms that may be skin flora, such as beta-haemolytic streptococci (most often),Staphylococcus aureus(including methycillin-resistant), or other bacteria 9. Radiol Clin North Am. Before without access to clinical information or CT results. It results in pain, erythema, oedema, and warmth. The American College of Radiology proposes a three-tiered risk assessment for patients receiving metformin in whom IV contrast is to be administered (Table 3).7 Many institutions have their own protocols for metformin administration with IV contrast, so physicians should be aware of the standard of care in their community. A CT can help determine the underlying cause of orbital cellulitis. Signs of cellulitis are easy to appreciate on CT and MRI and include thickening of the fat, best appreciated on the preseptal space, fat infiltration, and contrast enhancement. Inflammatory cellulitis is frequently confused with infectious cellulitis. Hayeri MR, Ziai P, Shehata ML, Teytelboym OM, Huang BK. It is also not used in patients with suspected acute stroke. Other contrast media, such as those used for magnetic resonance imaging or barium enemas, do not contain iodine. A 39-year-old male with necrotizing fasciitis of the right ankle. Risk factors include chronic kidney disease, diabetes mellitus, heart failure, older age, anemia, left ventricular systolic dysfunction, and contrast volume. Shortness of breath Abdomen andPelvis Without IV contrast 1. NOTE: We only request your email address so that the person you are recommending the page to knows that you wanted them to see it, and that it is not junk mail. Zacharias N, Velmahos GC, Salama A, Alam HB, de Moya M, King DR, et al.. A 39-year-old-male with necrotizing fasciitis of the right thigh. Intrathecal iodinated contrast is given during myelography to evaluate spinal or basal cisternal disease and cerebrospinal fluid leaks.11 Plain radiography of the spine is then obtained under fluoroscopic guidance. sonographic hallmarks of cellulitis include abnormal echogenicity and increased thickness of the dermis with indistinct "haziness" and increased echogenicity of the subcutaneous tissue, it is often helpful to compare the area in question to the (presumably normal)contralateral side, progressive accumulation of edema in the subcutaneous tissue appears as branching, anechoic striations which impart a lobulated ("cobble-stone" appearance), presence of thickened and abnormally echogenic overlying skin will favor cellulitis over edema, linear anechoic bands of fluid deep to the subcutaneous layer favor lymphedema, ultrasound is more sensitive than MRI for the detection of a retained foreign body as the causative agent, especially if small and wooden 4,5. Fortunately, orbital fat provides intrinsic background contrast, and most orbital pathologies can be easily visualised without infusion of a contrast medium. At the time the article was created The Radswiki had no recorded disclosures. The major families of contrast agents are ionic and nonionic. Fasciae of the Musculoskeletal System: MRI Findings in Trauma, Infection and Neoplastic Diseases. Swartz M. Clinical Practice. Preparation: Please have only a clear liquid diet for 4 hours prior to exam. a central core consisting of necrotic inflammatory cells and local tissue peripheral halo of viable neutrophils surrounded by a 'capsule' with dilated blood vessels and proliferation of fibroblasts Terminology An abscesses is akin to an empyema, as both are defined inflammatory collections. Speak with a Radiologist: 541-284-4016 1998 Aug;6(3):537-59. Skeletal Radiol. We do not capture any email address. Clinical presentations include skin erythema without a well-defined border, increased skin temperature, swelling of the affected area, and regional lymphadenopathy and lymphangitis. 7 0 obj Evaluation of chronic obstructive pulmonary disease also does not require IV contrast. Radiologic Approach to Musculoskeletal Infections. ADVERTISEMENT: Supporters see fewer/no ads. 6. 2001;176(5):1155-9. <>stream In the emergency setting, CT of the neck is often performed to investigate symptoms of acute infection or inflammation or symptoms of aerodigestive tract compromise referable to the neck. Patients with peripheral vascular disease or diabetes mellitusare particularly susceptible to cellulitis since minor injuries to the skin or cracked skin in the feet or toes can serve as a point of entry for infection. 2021;50(12):2319-47. Cross-sectional imaging findings include asymmetric thickening of the fascia, soft-tissue air, blurring of fascial planes, inflammatory fat stranding, reactive lymphadenopathy, and nonenhancement of the muscular fascia. Ultrasound is usually the first investigation to evaluate a clinical suspicion of cellulitis. However, if contrast must be administered within two months of iodine 131 treatment, consultation with an endocrinologist should be considered.7 Administration of iodinated contrast may provoke thyrotoxicosis, although this is rare.12, Approximately 90% of absorbed metformin is excreted by the kidneys within 24 hours. There is subcutaneous emphysema (arrows) overlying the right ankle with plate and screw fixation seen (a). Even in osseous infection, CT and MRI can give better anatomic delineation of the extent of infection. As a library, NLM provides access to scientific literature. High Resolution Chest CT This is a specialized CT of the lungs performed without IV contrast. Oral contrast agents are barium- or iodine-based and are used for bowel opacification. Kim KT, Kim YJ, Won Lee J, Kim YJ, Park SW, Lim MK, et al.. Can necrotizing infectious fasciitis be differentiated from nonnecrotizing infectious fasciitis with MR imaging? Struk DW, Munk PL, Lee MJ, Ho SG, Worsley DF. Skeletal Radiol. Most healthcare facilities have protocols dictating the cutoff at which IV dye may be administered in patients with impaired renal function. Copyright 2023 American Academy of Family Physicians. N Engl J Med. Emergency Medicine: Clinical Essentials. Many practices have their own protocols for IV dye administration in patients using metformin so nurse practitioners must familiarize themselves with these policies. Use of this website is subject to the website terms of use and privacy policy. These agents for enhancing the image created on CT may be delivered by a number of different routes, the most common of which are oral and intravenous. In patients with normal renal function, repeat measurement of serum creatinine is not recommended after outpatient administration of intravenous contrast agents. Alaia E, Chhabra A, Simpfendorfer C et al. What is the rationale for the laboratory workup for suspected pheochromocytomas and paragangliomas? Swartz M. Clinical Practice. Check for errors and try again. 3. One study showed similar increases in serum creatinine levels between inpatient populations who received IV iodinated contrast and those who did not.16, Noncontrast-enhanced CT is used in patients with head trauma and acute stroke. BMJ. The LRINEC (Laboratory Risk Indicator for Necrotizing Fasciitis) score: a tool for distinguishing necrotizing fasciitis from other soft tissue infections. Citation, DOI, disclosures and article data. Radiographics. Case 1: orbital and periorbital cellulitis, see full revision history and disclosures. N.p. All rights reserved. Skeletal Radiol. Diffuse high signal can also be seen in the muscle and subcutaneous fat.13 If subcutaneous edema is not the predominant feature, one should consider necrotizing fasciitis rather than cellulitis.1, 13 A summary of spectrum of findings for necrotizing fasciitis is summarized in Figure 10 and Table 2. 2. 2 0 obj Of the 26 orbits assessed by both CT and rMRI, three were positive for retroseptal orbital cellulitis by CT and were correctly diagnosed by rMRI as . The need for enhancement with intravenous (IV) contrast depends on the specific clinical indication (Table 1). Search dates: November 2009 and April 27, 2010. . If youre a nurse practitioner who struggles with the same question, check out the following guide to contrast and CT scans. Contrast agents are used to differentiate between organs and improve lesion detection and characterization. Detailed protocols for premedication and management of contrast adverse reactions are beyond the scope of this review and the reader is advised to refer to dedicated manuals.10. It results in pain, erythema, edema, and warmth. Below is an overview of the following CTA studies and their indications: Regardless of the pathology youre looking for, contrast isnt right for everyone. In a patient with colon cancer undergoing a workup for metastases, axial CT without contrast (A) shows prominence of the right hilar region (arrow). Brothers TE, Tagge DU, Stutley JE, Conway WF, Del Schutte H, Byrne TK. Unable to process the form. Potential Harms of Computed Tomography: The Role of Informed Consent. Cellulitis can affect any region of the body, and commonly affects a lower limb. The site is secure. Reference article, Radiopaedia.org (Accessed on 01 May 2023) https://doi.org/10.53347/rID-15554. Initial radiographs show soft tissue gas (without puncture wound) or are normal with high clinical suspicion of necrotizing fasciitis. Although classically a clinical diagnosis, imaging is a powerful adjunct to facilitate early diagnosis in equivocal cases. Before The type of contrast agent and route of administration can increase the diagnostic yield of the study ordered. Epub 2015 Apr 29. It is important to tell the technician and your doctor if you have had a previous allergic reaction to iodinated contrast. This material may not otherwise be downloaded, copied, printed, stored, transmitted or reproduced in any medium, whether now known or later invented, except as authorized in writing by the AAFP. The US Preventive Services Task Force currently recommends low-dose CT without contrast, along with appropriate patient counseling, for patients with a history of smoking and an age range as detailed in the Task Force statement. Contrast-enhanced CT demonstrates air (arrows) and edema in the scrotum, surrounding the right testicle (a). The parapharyngeal space was the most commonly involved space. Contrast may also be avoided when the suspected pathology is likely to be visible on noncontrast-enhanced CT. A history should be obtained to determine if the reaction was mild (which typically requires observation but not treatment), moderate (which requires prompt treatment), or severe (which requires rapid intervention and, often, hospitalization). 2001;176(5):1155-9. The US Preventive Services Task Force currently recommends low-dose CT without contrast, along with appropriate patient counseling, for patients with a history of smoking and an age range as detailed in the Task Force statement.3. Diagnosis of necrotizing soft tissue infections by computed tomography. Insights Imaging. Skin findings, pain out of proportion, and signs of systemic shock should alert the clinician to the possibility of necrotizing fasciitis. Reference article, Radiopaedia.org (Accessed on 01 May 2023) https://doi.org/10.53347/rID-15554. A 45-year-old male with necrotizing fasciitis of the right thigh. Data Sources: We used the term radiologic contrast to search the following: PubMed Clinical Queries (systematic reviews); the OVID database (all evidence-based medicine reviews; Cochrane Database of Systematic Reviews, ACP Journal Club, Database of Abstracts of Reviews of Effects, Cochrane Central Trial Registry, Cochrane Methodology Register, Health Technology Assessment, and NHS Economic Effectiveness Database); Dynamed; and the U.S. Preventive Services Task Force and Agency for Healthcare Research and Quality clinical guidelines and evidence reports. The diagnostic algorithm for lung cancer screening is evolving. Nurse practitioners must be familiar with the contraindications for CT contrast administration. Barium suspensions are not nephrotoxic and can be used safely in patients with renal failure. T2 weighted images with fat saturation demonstrates extensive high signal within the intermuscular septa surrounding the gastrocnemius and soleus muscle bellies suggestive of subfascial fluid (white arrows). Ultrasonographic screening of clinically-suspected necrotizing fasciitis. bulldog electric panel,