A 25-year-old male with no significant past medical history presents to the emergency department complaining of pain and “redness” of his left lower extremity. He denies any history of trauma or injury to the area. His vital signs are notable for:
On examinaton, he is clearly agitated and in pain. His left lower extremity is erythematous and tender to palpation without any noticeable skin breakdown, crepitus, or evidence of external trauma. All of the following statements about the evaluation and diagnosis of a necrotizing soft tissue infection (NSTI) are true EXCEPT:
Correct Answer: C
NSTIs are severe infections that can be found in any layer of soft tissue and are associated with a high mortality rate. These infections can be classified based on imaging findings, specifically the presence of gas in the tissues, as well as microbiology (polymicrobial vs monomicrobial). Clinically, NSTIs classically present with erythema, edema, pain out of proportion to examination, overlying skin changes, and systemic signs of infection including fever and hypotension (Answer A). Symptoms are typically acute in onset and rapidly progressive over a short period of time, making the time from presentation to diagnosis crucial in the overall outcome of the patient (Answer B). When clinical suspicion is high, surgical consultation should be obtained immediately with a low threshold to proceed to the operating room for surgical evaluation and extensive debridement as indicated (Answer D). More commonly, the differentiation between NSTI and severe cellulitis is not clear. The Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) score was developed to aid in differentiation between a severe cellulitis and NSTI with initial studies showing high negative predictive value. Of note, subsequent evaluation has called into question the sensitivity of the scoring system, which includes white cell count, hemoglobin, sodium, glucose, creatinine, and C-reactive protein. Although helpful in the evaluation, a negative score does not replace clinical evaluation and alone cannot rule out the presence of an NSTI (Answer C). Other diagnostic tools CT imaging with intravenous contrast, which has been deemed the best radiographic imaging modality in the evaluation of a NSTI. Findings include gas in the soft tissues, fluid collections, heterogeneous tissue enhancement, and inflammatory changes beneath the fascia (Answer E).
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A 55-year-old male with a history of methicillin-resistant Staphylococcus aureus (MRSA) colonization presents to the emergency department with complaints of purulent drainage from his surgical incision. He is now 7 days postop from his sigmoid colectomy. On examination, his temperature is 102°F and hemodynamically within normal limits. His incision has skin staples in place and moderate surrounding erythema extending >5 cm from the wound edge and associated induration. Purulent drainage is easily expressed from the most inferior aspect of the incision.
Which of the following is the most appropriate management of this patient?
Correct Answer: A
Surgical site infection following an abdominal operation can be further classified as superficial or deep infections. Common features include periincisional tenderness, erythema, and induration, with purulent drainage present at the site of the incision. More significant infections can present with systemic signs including fever, tachycardia, and hypotension in addition to the localized findings. Once diagnosed, the treatment of a surgical site infection involves opening the incision to allow for adequate irrigation and drainage, obtaining a fluid culture of the purulent fluid and initiation of antibiotic therapy if there is evidence of extension of the infection into the surrounding tissues or systemic signs of infection (Answer E). Choice of antimicrobial therapy depends on the type of operation (in this case an abdominal operation involving the colon, which would be considered a clean contaminated case) and risk factors for MRSA (prior colonization or infection, recent hospitalization, recent antibiotics). In this case, it would be appropriate to cover for gram negative organisms as well as anaerobes. Given his recent hospitalization and known MRSA colonization status, the most appropriate choice listed above would be Vancomycin and Piperacillin-Tazobactam. Of the other choices listed above, Vancomycin alone and Cephalexin alone do not provide appropriate gram negative and anaerobic coverage (Answer B, Answer C). Although Piperacillin-Tazobactam does provide appropriate coverage for gram negative and anaerobic organisms, the addition of MRSA coverage is recommended given that he is MRSA colonized and his recent hospitalization (Answer D). Answer A is best answer given that it recommends opening the incision, culturing the purulent fluid obtained, and initiating appropriate antimicrobial therapy.
A 30-year-old male presents with significant erythema overlying his right arm and a fever to 101.0°F. He explains that he sustained an abrasion over the affected area while at work, and when the redness started 2 days ago he was prescribed a course of antibiotics by the Urgent Care Clinic, which he has been taking without improvement of his symptoms. An ultrasound shows edema and a phlegmon without an obvious abscess collection. He is admitted to the hospital and started on IV cefoxitin. Over the next 48 hours it is noted that even though there is some regression of the erythema, a firm, fluctuant area can be palpated in the subcutaneous tissue measuring >2 cm.
What is the most appropriate next step in management?
An initial presentation of presumed uncomplicated cellulitis can be treated with a trial of oral antibiotic therapy, with or without coverage for MRSA as indicated. Failure of improvement in symptoms and systemic signs of infection (including fever greater than 100.5°F) are indications for parenteral antibiotic therapy. In the patient above, an ultrasound was obtained that showed no underlying abscess collection initially, but his new examination findings are concerning for interval development of an abscess. The most appropriate next step listed above would be to repeat an ultrasound to assess for the formation of an abscess or drainable fluid collection (Answer C, Answer E). There is no indication to further broaden the antibiotic regimen given that the cellulitis is improving and the treatment for an abscess is drainage (Answer A, Answer B). Although a CT scan will provide a more detailed image, it is not necessary in this scenario and subjects the patient to unnecessary radiation (Answer D).
A patient is admitted to the surgical critical care unit after being found down for an unknown period of time following presumed assault. The patient was intubated at the scene. In addition to a multitude of other injures, the patient is noted to have an acute kidney injury (AKI) with an elevated creatine kinase (CK) to 10,000. On examination, all extremity compartments are soft.
With regards to the management of AKI from traumatic rhabdomyolysis, which of the following statements is true?
Correct Answer: E
AKI following rhabdomyolysis is one of the more serious complications and is seen in an estimated 20% to 33% of patients. Accumulation of myoglobin from muscle injury combined with hypovolemia can lead to a mixed acute tubular necrosis picture and resultant AKI. Causes of rhabdomyolysis are not limited to, but include traumatic injury or compression, exertional (metabolic myopathies, hyperthermia) and infections, toxins, or pharmacologic agents. Commonly seen laboratory abnormalities include elevated CK, hypocalcemia, hyperphosphatemia, and hyperkalemia, which can be potentially life threatening (Answer B). The only effective treatment of rhabdomyolysis-induced AKI is aggressive fluid resuscitation with treatment of the associated metabolic and electrolyte abnormalities as they arise (Answer E). Adjuncts such as the addition of mannitol and sodium bicarbonate solution have not been shown to be effective and are currently not recommended as mainstays of treatment (Answer C, D). Additionally, the use of mannitol in the oligoanuric patient is contraindicated, and in that setting, consideration for the need for renal replacement therapy should be undertaken. The indications for dialysis are no different than the usual indications, including severe acidosis, uremia, volume overload, and refractory hyperkalemia. There has been no convincing evidence to show the benefit of prophylactic initiation of hemodialysis in the setting of rhabdomyolysis (Answer A).
A 60-year-old male with a past medical history notable for obesity, hypertension, hyperlipidemia, and type 2 diabetes presents to the emergency department with complaints of significant scrotal and perineal pain with associated drainage. He explains that the symptoms started about 24 hours before presentation and have been rapidly progressive since. His vital signs are as follows: Temp 102.5°F, HR 102 bpm, BP 90/65 mm Hg, RR 18, Sat 100% on room air. On examination, he is diaphoretic and noticeably uncomfortable. His scrotum and perineum are diffusely erythematous and tender to palpation, with a pinpoint area draining dishwasher color fluid that is malodorous. All of the following are appropriate next steps in the management of a patient presenting with Fournier’s gangrene EXCEPT:
NSTIs are rapidly progressive, life-threatening bacterial infections that can present following trauma, a surgical procedure, or even minor breaches of the skin. NSTIs can be further classified as Type 1 (polymicrobial) or Type II (monomicrobial) with Type 1 infections being more common. Diagnosis is made with a high index of suspicion and can be aided with use of the LRINEC Score. Initial management involves initiation of fluid resuscitation, starting broad spectrum antibiotic coverage with empiric coverage for NSTI-causing organisms after obtaining culture data, and early surgical consultation for emergent operative debridement (Answer A, Answer B, Answer D). Postoperatively, these patients require close hemodynamic monitoring and support, typically requiring an ICU setting (Answer E). Given the rapidly progressive nature of NSTIs, operative debridement should not be delayed. Once a diagnosis is made, there is no indication to obtain further imaging and delay operative intervention (Answer C).
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