Infections Requiring Surgical Intervention

Author: Nicholas Smith, MD (EM Resident Physician, University of Tennessee-Nashville/Murfreesboro EM Residency) and David Pillus, MD (EM faculty, University of Tennessee-Nashville/Murfreesboro EM Residency) // Edited by: Alex Koyfman, MD (@EMHighAK) and Brit Long, MD (@long_brit)

Case

A 76-year-old male patient with history of type 2 diabetes and mild cognitive impairment presents from an assisted living facility by EMS with altered mental status.

Initial vitals include Temp 102.1, HR 120, BP 100/60, RR 18, Sp O2 96% on 2L nasal cannula.

Exam reveals a diaphoretic and agitated patient but otherwise no specific findings. The patient is not fully exposed.

Imaging reveals negative CT head and CXR. Laboratory studies are notable for Na of 126, Cr of 3.4, WBC of 30, and lactate of 8. CSF is normal.

The patient is empirically started on broad-spectrum antibiotics, and the decision is made to obtain a CT of the abdomen and pelvis due lack of obvious source of infection. Radiology calls to inform you of severe scrotal and inguinal swelling with gas in the subcutaneous tissue concerning for Fournier’s gangrene. You go back to the bedside and remove the patient’s underwear to reveal an edematous perineum with scattered hemorrhagic bullae and palpable crepitus.

Background

Prompt identification and appropriate management of the infectious source is crucial when dealing with serious bacterial infections. Some of these infections can become rapidly fatal or can result in permanent disability without proper intervention. Many of these conditions require operative intervention in addition to antibiotic therapy in order to gain optimal source control, and often these particular infections can be elusive early in their course. Some of the most prominent of these include necrotizing fasciitis, septic arthritis, and various deep tissue infections.  This post will evaluate infections requiring surgical intervention.

Necrotizing Fasciitis

• Basics
  • Usually polymicrobial but may be monomicrobial.
  • Streptococcus, Staphylococcus (including MRSA), gram negatives, Clostridium.^1,2
    • MRSA necrotizing fasciitis tends to be more indolent.¹
  • Risk factors include diabetes, immune-compromised status, chronic alcoholism, IV/IM drug use.
  • Necrotizing fasciitis involving the perineal area is termed Fournier’s gangrene.
  • Mortality rate approaching 27%, especially when involving the trunk.³
• History and Exam
  • Patients classically have pain out of proportion to exam. Early in the course, there may be no findings on physical exam.
  • Alternatively, some patients may present with what appears to be severe disease on physical exam but will be relatively comfortable appearing or even indifferent.
  • Exam findings concerning for necrotizing fasciitis include edema, blistering/bullae (especially hemorrhagic lesions), numbness of the affected area secondary to sensory nerve damage, frank necrosis, and palpable crepitus.
  • Pay special attention to patients with apparent cellulitis but vital sign abnormalities. Patients with necrotizing fasciitis can have significant tachycardia and/or hypotension.^2,4
• Diagnostics
  • LRINEC score (MDCalc)
    • This scoring system was developed as a clinical decision tool to risk stratify patients according to their risk of having a necrotizing soft tissue infection.
    • Based on 6 components including: CRP, WBC, hemoglobin, sodium, creatinine, and glucose.
    • Further validation of this score have questioned its utility as a screening tool with a sensitivity of close to 80%. In one study, nearly 64% of patients ultimately diagnosed with necrotizing fasciitis had a LRINEC score classifying them as low risk.⁵
  • Labs
    • Association with significant leukocytosis as well as hyponatremia, though these are not always present.
    • Suggestive physical exam findings in combination with leukocytosis and/or hyponatremia has been associated with increased likelihood of diagnosing necrotizing fasciitis.⁶
  • Imaging
    • Generally not needed if there is a high clinical suspicion and should not delay operative management.⁴
    • MRI > CT > X-ray in regards to both sensitivity and specificity. However, it should be noted that CT has high sensitivity, is more widely available, and leads to a more expedient diagnosis than MRI.⁷
  • Management
    • Minimizing time to operative intervention is crucial and has been associated with decreased mortality.⁸
    • Broad spectrum antibiotic coverage is also critical and associated with decreased mortality.
      • Coverage must include staph/strep species (including MRSA) as well as gram negatives. Antibiotics such as piperacillin-tazobactam, vancomycin, and clindamycin are first line medications.
      • Clindamycin is typically added due to anaerobic coverage as well as possibly suppressing bacterial toxin synthesis.⁹
    • Good general sepsis care, including appropriate fluid resuscitation.
    • Disposition is to a critical care unit.
    • For more, see this emDocs post and this post.

Septic Arthritis

• Basics
  • Early recognition is crucial as delays in treatment can lead to irreversible joint damage.
  • Similar to necrotizing fasciitis, the most common organisms include staph/strep as well as gram negative species.¹⁰
  • Additional considerations include gonorrhoeaein young, sexually active patients and Salmonella in sickle cell patients.¹⁰
  • Major risk factors include diabetes, immune-compromised status, and history of joint damage including trauma, rheumatoid arthritis, joint surgery, IV/IM drug use, infective endocarditis, and joint prostheses.⁶
• History and Exam
  • Typical presentation is the sudden onset of severe monoarticular joint pain, edema, overlying erythema, marked difficulty with weight bearing on the affected extremity, fever, and chills.
  • Exam may reveal the above findings in addition to pain with both active and passive range of motion, tachycardia, fever, and hypotension depending on the severity of disease.¹⁰
• Diagnostics
  • Labs
    • When used alone, peripheral WBC count and ESR/CRP measurements are not recommended as screening tools for septic arthritis, as their sensitivities reach only 75% with very poor specificity.⁷
    • Joint fluid analysis with culture is essential, and a synovial WBC count greater than 50,000 is suggestive of septic arthritis, while a count less than 25,000 makes it significantly less likely.¹¹
      • Notably, septic arthritis due to MRSA may have a lower than expected synovial WBC count with a significant proportion being less than 25,000.¹²
    • Management
      • Rapid surgical consultation is again crucial as a majority of these patients will require arthroscopy or open surgical drainage for effective source control.
      • Broad spectrum antibiotics are appropriate initially with coverage of staph/strep (including MRSA) as well as gram negative organisms.¹³
      • For more on septic arthritis, see this post.

Deep Tissue Infections

• Basics
  • Involve infections that are not easily treated with antibiotics alone and most commonly include abscesses, empyema, and severe C. difficile colitis.
  • Development of these infections is associated with previously mentioned risk factors including diabetes and immune-compromised state, in addition to recent surgery and IV drug use.
• History and exam
  • Physical exam is notoriously unreliable for these infections and is highly dependent on the location of the infection.
  • Often, these patients will have non-specific symptoms such as fever, chills, tachycardia, and fatigue.
  • Intra-abdominal infections may present with abdominal or back pain.
  • Acute appendicitis often presents atypically and is highly dependent on the location of the appendix in relation to its position on the cecum as well as its length, which is also highly variable.¹⁴
    • Classically presents as peri-umbilical pain migrating to the right lower quadrant with vomiting developing later in the course with associated anorexia.
    • Due to the variability in appendiceal anatomy, the presentation may include low back pain, pelvic pain, or even pain in the left lower quadrant.¹⁴
  • Biliary pathology such as acute cholecystitis and cholangitis can also have a highly variable presentation, particularly in the elderly and immunocompromised.
    • Right upper quadrant or epigastric pain and tenderness are often present along with fever and may include jaundice if the common bile duct is occluded.
    • As mentioned above, certain populations tend to present atypically, and altered mental status may be the only initial finding.¹⁵
  • Acute diverticulitis, while typically not a surgical disease, can become complicated by abscess, fistulae, and perforation and necessitate operative management.
    • The typical presentation is dull left lower quadrant abdominal pain with fever, as diverticuli most commonly develop in the sigmoid colon.
    • Atypical presentations occur in immunocompromised and elderly patients.
    • Patients with right sided diverticuli can present with right lower quadrant pain that can mimic appendicitis. This is classically seen in Asian populations.¹⁶
  • Patients with peri-rectal abscess may have pain in the area and with defecation.¹⁷
• Evaluation
  • Unlike necrotizing fasciitis and septic arthritis, the diagnosis of deep space tissue infections is highly reliant on imaging, as there are no exam findings or laboratory studies that are sufficiently sensitive or specific.
  • Chest x-ray may identify empyema.
  • CT with IV contrast is helpful in identifying intra-abdominal and pelvic processes such as complicated appendicitis, cholecystitis, diverticulitis, retroperitoneal abscess, and peri-rectal abscess.¹⁸
  • Ultrasound is the preferred initial imaging modality for biliary pathology and acute appendicitis in children and young adults given its relatively high sensitivity and lack of radiation.¹⁹
• Management
  • In keeping with the theme of this discussion, many of these infections require surgical intervention in addition to tailored antibiotic therapy to attain source control to prevent progression to life-threatening illness.
  • Some more recent data suggest that young, healthy patients with uncomplicated appendicitis may do well with antibiotics alone. However, it’s important to keep in mind that evidence is limited and a significant proportion of these patients eventually required appendectomy.^20,21 For now, stick with surgical consultation with likely appendectomy.

Key Points

• In some cases, antibiotics alone are not adequate for infectious source control.
• Complete exposure and skin examis crucial in making the timely diagnosis of several life-threatening diseases.
• For many of these infections, getting a surgeon on board as soon as possibleis associated with source control and reduction in both morbidity and mortality.
• Keep a broad differential in patients presenting with apparent infection without a source, and don’t forget the possibility of not readily apparent skin and soft tissue infections.

References / Further Reading

1. Miller, L.G., et al. Necrotizing fasciitis caused by community-associated methicillin- resistant staphylococcus aureus in Los Angeles. N Engl J Med 352(14):1445, April 7, 2005.
2. Wong, C., et al. Necrotizing fasciitis: clinical presentation, microbiology, and determinants of mortality. JBJS: August 2003 – Volume 85 – Issue 8 – p 1454–1460.
3. Rajput, A., et al. Mortality in necrotizing fasciitis. J Ayub Med Coll Abbottabad. 2008 Apr-Jun;20(2):96-8.
4. Chan, T., et al. Low sensitivity of physical examination findings in necrotizing soft tissue infection is improved with laboratory values: a prospective study. Am J Surg 196:926, December 2008.
5. Neeki, M., et al. Evaluating the laboratory risk indicator to differentiate cellulitis from necrotizing fasciitis in the emergency department. West J Emerg Med. 2017 Jun; 18(4): 684–689.
6. Evans, J., et al. The increased use of computed tomography scanning for diagnosing superficial soft tissue infections: a disturbing trend of increased radiation with no benefit. Am J Surg 204(6):988, December 2012.
7. Zacharias, N, et al. Diagnosis of necrotizing soft tissue infections by computed tomography. Arch Surg. 2010 May;145(5):452-5. doi: 10.1001/archsurg.2010.50.
8. Tiu A., et al. Necrotizing fasciitis: analysis of 48 cases in South Auckland, New Zealand. ANZ J Surg 75(1-2):32, Jan-Feb 2005.
9. Edlich, R.F., et al. Modern concepts of the diagnosis and treatment of necrotizing fasciitis. J Emerg Med 39(2):261, August 2010.
10. Margaretten, M.E., et al. Does this adult patient have septic arthritis? JAMA 297(13):1478, April 4, 2007.
11. Carpenter, C.R., et al, Acad. Evidence-based diagnostics: adult septic arthritis. Emerg Med 18(8):782, August 2011.
12. Frazee, B.W., et al. How common is MRSA in adult septic arthritis? Ann Emerg Med 54(5):695, November 2009
13. Mathews, C., et al. Bacterial septic arthritis in adults. The Lancet Volume 375, Issue 9717, 6–12 March 2010, Pages 846-855.
14. Lameris, W., et al. Single and combined diagnostic value of clinical features and laboratory tests in acute appendicitis.Acad Emerg Med 16(9):835, September 2009.
15. Trowbridge, R.L., et al. Does this patient have acute cholecystitis? JAMA 289(1):80, January 1, 2003.
16. Morris, A.M., et al. Sigmoid diverticulitis: systematic review. JAMA 311(3):287, January 15, 2014.
17. Nichols, RL, Florman, S. Clinical presentations of soft-tissue infections and surgical site infections. Clinical Infectious Diseases, Volume 33, Issue Supplement_2, 1 September 2001, Pages S84–S93.
18. Paslawaski, M, Szafranek-Pyzel, J, Zlomaniec, J. Imaging of abdominal abscesses. Ann Univ Mariae Curie Sklodowska Med. 2004;59(2):284-8.
19. van Randen, A., et al. A comparison of the accuracy of ultrasound and computed tomography in common diagnoses causing acute abdominal pain. Eur Radiol 21(7):1535, July 2011.
20. Salminen, P., et al. Antibiotic therapy vs. Appendectomy for treatment of uncomplicated acute appendicitis: the APPAC randomized trial. JAMA 313(23):2340, June 16, 2015.
21. Steiner, Z., et al. A role for conservative antibiotic treatment in early appendicitis in children. J Ped Surg 50(9):1566, September 2015.