Soft Tissue Infection Flashcards
A 30-year-old Florida fisherman comes to the emergency department 24 hours after cutting his palm with a fish-scaling knife. Blood pressure is 90/50 mmHg and heart rate is 120 bpm. Physical examination shows severe swelling of the hand, hemorrhagic bullae of the hand, and erythema to the mid forearm. X-ray study shows no gas within the soft tissues. A Gram stain of drainage from a bulla reveals gram-negative bacilli. Which of the following infectious agents is the most likely cause of the patient’s symptoms?
A) Clostridium perfringens B) Mycobacterium marinum C) Pseudomonas aeruginosa D) Staphylococcus aureus E) Vibrio vulnificus
The correct response is Option E.
The patient described has necrotizing fasciitis and sepsis. Vibrio vulnificus is a gram-negative bacillus, a cause of necrotizing fasciitis, and is commonly associated with warm saltwater environments (Florida). It also tends to present with hemorrhagic bullae. Staphylococcus aureus is a gram-positive coccus, is not associated with watery environments, and is more commonly associated with pustules rather than hemorrhagic bullae. Clostridium perfringens is a gas-forming, gram-positive bacillus, and is associated with marine sediment. Pseudomonas aeruginosa, also a gram-negative bacillus, although associated with moist environments, is more typically associated with less aggressive soft-tissue infections. Mycobacterium marinum is also associated with watery environments, but tends to affect aquarium owners with an indolent granulomatous process.
2018
A 53-year-old woman undergoes bilateral mastectomy and autologous breast reconstruction. Four days postoperatively, the patient reports moderate abdominal discomfort and multiple episodes of diarrhea. Vital signs are within normal range. Physical examination shows a mildly distended abdomen. Stool sample is positive for Clostridium difficile toxin. Treatment with which of the following drugs is most appropriate first-line treatment in this patient?
A) Fidaxomicin B) Metronidazole C) Rifaximin D) Teicoplanin E) Vancomycin
The correct response is Option B.
Oral metronidazole is the most appropriate treatment for this patient with a mild/moderate form of Clostridium difficile infection.
Oral vancomycin is recommended for treatment of those with severe disease, or with mild/moderate disease who did not respond to metronidazole.
Patients who cannot tolerate oral medications (eg, postoperative ileus) or who have an intestinal diversion (eg, ileostomy) can be treated with intravenous metronidazole or with vancomycin enemas. Vancomycin is not excreted into the colon and therefore should not be given intravenously to treat C. difficile infection.
Oral fidaxomicin has been shown to be as effective as oral vancomycin in the treatment of C. difficile infections. Although further clinical experience is still needed, this drug has been associated with increased cure rate in patients receiving concomitant antibiotics and decreased infection recurrence when compared to vancomycin.
Teicoplanin and rifaximin are not generally recommended for treatment of C. difficile, although isolated reports of successful therapy can be found in the literature.
2018
Which of the following time frames for onset most accurately reflects the CDC’s definition of surgical site infection?
A) Within 3 days of surgery or within 30 days of prosthetic implant placement
B) Within 7 days of surgery or within 3 months of prosthetic implant placement
C) Within 14 days of surgery or within 6 months of prosthetic implant placement
D) Within 21 days of surgery or within 9 months of prosthetic implant placement
E) Within 30 days of surgery or within 1 year of prosthetic implant placement
The correct response is Option E.
The CDC defines a surgical site infection as an infection that occurs at the incision site or within the organ or space operated on within 30 days after surgery or within 1 year if a prosthetic implant is placed. Infection requires at least one of the following:
- Purulent drainage from the surgical site
- Organisms isolated from an aseptically obtained culture of fluid or tissue at the surgical site
- Spontaneous dehiscence of a deep incision or deliberate opening of the incision by a surgeon when the patient has at least one of the following signs or symptoms: fever (greater than 100.4°F [38.0°C]), localized pain or tenderness, localized swelling, redness, or heat, unless site is culture-negative
- An abscess or other evidence of infection involving the incision or operative site that is found on direct examination, during reoperation, or by histopathologic or radiologic examination
- Diagnosis of a surgical site infection by a surgeon or attending physician
2018
A 30-year-old man with AIDS is evaluated for a 6-week history of painless but increasing swelling of the flexor surfaces of the right wrist. Physical examination shows limited motion of the wrist and positive Phalen and Tinel signs. At the time of surgical exploration, rice bodies are present in the flexor tenosynovium. Which of the following is the most likely diagnosis in this patient?
A) Aspergillus fumigatus B) Mycobacterium tuberculosis C) Nocardia asteroides D) Sporothrix schenckii E) Vibrio vulnificus
The correct response is Option B.
Rice bodies are pathognomonic for tuberculosis.
Ziehl-Neelsen staining confirms the presence of acid-fast bacilli. All Mycobacterium and Nocardia species are potentially acid-fast. Many of these organisms are fastidious, so false-negative results are common. Surgeons should obtain multiple tissue samples and alert the laboratory that a diagnosis of tuberculosis is suspected. M. tuberculosis is traditionally cultured in Löwenstein-Jensen culture medium under specific temperature conditions 37.0°C (98.6°F). Histologic examination of specimens shows a granulomatous inflammatory process with the central portion of the granulomas appearing caseated.
If a mycobacterial infection is suspected, a Mantoux test should be performed. The test involves purified protein derivative injection into the dermis and evaluation of the cutaneous site after 48 to 72 hours.
M. tuberculosis should be considered in all immunocompromised patients. The other organisms can all be seen in hand infections in immunocompromised patients but do not produce rice bodies.
2017
A 28-year-old, right-hand–dominant woman is brought to the emergency department 18 hours after sustaining a cat bite to the dorsum of the hand proximal to the fifth metacarpophalangeal (MCP) joint. Which of the following organisms is most likely to be cultured from this abscess?
A) Eikenella corrodens B) Group A Streptococcus C) Methicillin-resistant Staphylococcus aureus D) Pasteurella multocida E) Pseudomonas aeruginosa
The correct response is Option D.
Pasteurella multocida is a small, gram-negative coccobacillus that is frequently associated with infections caused by dog and/or cat bites. Local findings are consistent with infection including erythema, warmth, pain and tenderness, and fluctuance or purulent discharge. Delayed treatment may result in chronic deep-space infection and/or osteomyelitis. Treatment involves starting penicillin combined with local wound care as well as surgical incision and debridement if needed.
Methicillin-resistant Staphylococcus aureus (MRSA) is becoming more common in community-acquired hand infections, but is not typically associated with dog or cat bites. Eikenella corrodens is more commonly associated with infections occurring after human bites. Pseudomonas infection is often seen as a nosocomial infection that is very resistant to antibiotics. Group A Streptococcus is a common bacterial infection associated with strep throat.
2017
A healthy 5-year-old boy is evaluated after he is bitten on the hand by a dog. He has an allergy to penicillin. Which of the following prophylactic antibiotic regimens is most appropriate to prescribe?
A) Amoxicillin and clindamycin B) Ciprofloxacin and metronidazole C) Clindamycin only D) Doxycycline and metronidazole E) Trimethoprim-sulfamethoxazole and clindamycin
The correct response is Option E.
The most appropriate prophylactic regimen to prescribe in this clinical scenario is trimethoprim-sulfamethoxazole and clindamycin.
Dog bites to the hand are potentially dangerous bites that could lead to serious hand infections. The common microorganisms that cause infections in such bites are Pasteurella species, anaerobes, Staphylococcus aureus, and Streptococcus. The ideal antibiotic would have been amoxicillin-clavulanic acid, which covers most of these microorganisms. However, the child is allergic to penicillin, and, therefore, this drug is contraindicated. Another good option would have been amoxicillin and clindamycin (for the anaerobic coverage). However, for the same reason described above, it too cannot be used. Tetracyclines are contraindicated in children under 8 years of age owing to the ill effects on growing teeth and bones. Quinolones are also contraindicated in children under 18 years of age owing to their harmful effects on cartilage and joints. Although this is debatable, currently the use of quinolones in children is restricted by the Food and Drug Administration to certain specific conditions (cystic fibrosis, multidrug-resistant urinary tract infection, and inhalational anthrax). Clindamycin alone does not adequately cover most of the organisms involved, including Pasteurella, which is gram-negative.
2016
A 34-year-old woman comes to the emergency department 5 days after sustaining a cat bite to the left index finger. A photograph is shown. Medical history includes diabetes mellitus type 1. Physical examination shows punctures to the dorsum and volar surfaces of the proximal phalanx, mild fusiform swelling of the digit with tenderness over the flexor tendon sheath, pain with passive extension, and partially flexed posture of the digit. The symptoms have worsened over the past 3 days. Temperature is 99°F (37.2°C). Which of the following is the most appropriate next step in management?
A) Incision and drainage of the puncture sites
B) Inpatient intravenous antibiotics
C) Irrigation of the flexor sheath
D) Outpatient oral antibiotics
E) Splinting immobilization and elevation
The correct response is Option C.
The most appropriate option for this patient is to proceed to the operating room for decompression/drainage of the flexor tendon sheath. This patient has all four of Kanavel’s signs, specifically pain on passive extension, fusiform swelling, flexor tendon sheath tenderness, and flexion of the affected digit. These point towards a diagnosis of flexor tenosynovitis, with the cause being the cat bite she sustained several days prior. Although cat bites only reflect 5% of all animal bites, they represent 76% of all infected bites, thought to be because of the morphology of their long teeth, which simulate a deep puncture wound.
Outcomes studies demonstrate that because of this patient’s diabetes, she is at risk for a poor outcome, specifically the need for amputation and/or decreased total active motion. Other risk factors that can lead to these outcomes include age greater than 43 years, presence of subcutaneous purulence, digital ischemia, and polymicrobial infection. Given that she is at risk and that she has all four Kanavel’s signs, any intervention that is more conservative than operative decompression and drainage may lead to suboptimal outcomes.
Administration of antibiotics (orally or intravenously) is not a substitute for drainage of the flexor sheath, especially in a case that presents more than 48 hours out from initiation of symptoms. Drainage in the emergency department is not as optimal as in the operating room given that the infection may limit efficacy of local anesthesia as well as the need for possible conversion to an open drainage procedure if closed catheter irrigation is insufficient.
2016
A 60-year-old woman who works as a nurse in the intensive care unit (ICU) is scheduled for cardiac bypass surgery. Because she has taken care of many patients with methicillin-resistant Staphylococcus aureus infection, she is interested in topical agents for decolonization. Which of the following regimens is most appropriate for this patient?
A) Clindamycin B) Linezolid C) Mupirocin and chlorhexidine D) Trimethoprim-sulfamethoxazole E) Vancomycin
The correct response is Option C.
The currently accepted decolonization protocol from the Infectious Diseases Society of America is a combination of topical nasal mupirocin ointment and a chlorhexidine body wash for 5 days. The most robust data for decolonization are in the cardiac surgery literature; the Society of Thoracic Surgeons guidelines recommend routine prophylaxis for all patients undergoing cardiac surgery. These guidelines are based on studies that show a decreased rate of sternal wound infections.
The carriage rate of methicillin-resistant Staphylococcus aureus for health care workers is approximately 5% based on large review studies. As a substantial portion of cases originate from nasal colonization, routine screening and decolonization are recommended in areas where the carriage rate exceeds 10% (Centers for Disease Control and Prevention recommendation).
The other antibiotics listed are reserved for the treatment of infection rather than as part of a decontamination protocol.
2016
Which of the following antibiotics is most effective in decreasing Staphylococcus aureus infections in irradiated wounds?
A) Cefazolin
B) Doxycycline
C) Nafcillin
D) Trimethoprim-sulfamethoxazole
Please note: Upon further review, this item was not scored as part of the examination.
The correct response is Option D.
The prophylactic use of trimethoprim/sufamethoxazole (TMP/SMZ) in irradiated wounds, primarily in the setting of implant-based breast reconstruction, has been shown to reduce the rate of skin-derived infections. Mirzabeigi et al1 reported a 28% reduction in infection rates with the use of TMP/SMZ when compared with cephalosporins, in an irradiated chest wall wound. Based on their data, the authors advocate a monthlong prophylactic course of TMP/SMZ to reduce infection rates in this high-risk population. This is likely due to the ability of TMP/SMZ to treat both methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus epidermidis. This has been supported by other published reports.2,3
Cefazolin and nafcillin do not effectively treat MRSA, reducing their clinical ability to prevent skin-related infections in this high-risk population. Doxycyline has some efficacy in treating most skin flora, including MRSA, but there is no clinical evidence to suggest it outperforms TMP/SMZ.
2016
A 15-year-old girl has two draining nodules of axillary hidradenitis suppurativa. Each lesion is approximately 10 mm in diameter. The remaining axillary skin shows no abnormalities. After a 6-week course of oral doxycycline and topical mupirocin, the lesions drain less but are still present. Which of the following is the most appropriate treatment for this patient?
A) Complete axillary excision and skin grafting B) Excision and closure C) Incision and drainage D) Intravenous antibiotics E) Kenalog injection
The correct response is Option B.
This young patient has limited, focal disease that has failed medical management. Local excision is useful for isolated, scattered individual, or linear lesions. More extensive disease that occupies a significant portion of the skin area may be better treated by complete axillary excision. In this younger patient with limited disease, direct excision of the affected areas is a less morbid approach. Negative pressure wound therapy and skin grafts may be optimal coverage treatments for extensive disease, and some local flaps have been described as well. This stubborn disease originates from the apocrine glands and can often be chronic and disabling. The axillae, groin, perineum, and submammary areas can all be affected. Initial treatments include local care, antibiotics, hygiene, and weight loss. Steroid injections may help in early, small lesions, but have limited effectiveness and are painful. After a 6-week course of antibiotics, this patient is not likely to benefit from more treatment. Only excision of the diseased apocrine glands is likely to be effective. Incision and drainage is a suitable treatment for a closed abscess associated with hidradenitis, but incising this patient’s lesions would not improve her situation.
2016
An otherwise healthy 10-year-old girl is brought for evaluation because of a chronic ulcer of the right leg. The ulcer first appeared 6 months ago when she scraped her leg on a boat dock at her family’s lake house. The wound has increased in size despite treatment with a course of oral antibiotic therapy prescribed by her primary care physician. A photograph is shown. On evaluation today, the patient is afebrile and has no systemic signs of infection. Which of the following organisms is the most likely cause of these findings?
A) Candida tropicalis B) Group A beta-hemolytic Streptococcus C) Methicillin-resistant Staphylococcus aureus D) Mycobacterium marinum E) Vibrio vulnificus
The correct response is Option D.
The history and presentation are classic for an atypical mycobacterial infection. Unlike bacterial infections, atypical mycobacteria rarely produce systemic signs of infection and often manifest as a nonhealing (sometimes progressive) wound. Given the history of injury on a boat dock, the most likely causative organism is Mycobacterium marinum, an acid-fast bacillus that lives in water environments. This pathogen results in localized granulomas such as the one seen in this patient. Staphylococcus aureus is the most common source of skin infections but typically results in a more pronounced and acute immune reaction with localized redness and purulence. These findings are not present in this patient. Cutaneous infections with Group A beta-hemolytic Streptococcus and Vibrio vulnificus tend to increase rapidly and are often accompanied by severe systemic response (i.e., necrotizing fasciitis). Candida tropicalis is a fungus that is often part of normal skin flora. It is related to Candida albicans and can produce opportunistic internal infections in susceptible individuals.
2016
A 46-year-old woman comes to the emergency department because of a 5-day history of profound physical deterioration, nausea, and vomiting. She underwent breast reconstruction 3 weeks ago. Medical history includes delayed right latissimus dorsi tissue expansion breast reconstruction 1 year after completing radiation therapy. She has no other comorbidities. Physical examination shows erythematous rash involving and extending beyond the surgical sites. There are no notable fluid collections and the surgical wounds are not draining. Temperature is 103.5°F (39.7°C) and blood pressure is 90/50 mmHg. Laboratory studies show:
- Leukocyte count: 15,000/mm3
- K+ 6.0 mEq/L
- Na+ 122 mEq/L
- HCO3- 12mEq/L
Intraoperative cultures of the explored surgical sites are most likely to grow which of the following organisms?
A) Bacteroides B) Clostridium C) Enterobacter D) Pseudomonas E) Streptococcus
The correct response is Option E.
The Centers for Disease Control and Prevention support criteria indicate that toxic shock syndrome may be diagnosed when patients present with a temperature exceeding 102°F (38.9°C), multisystems organ failure, rash, and/or multiple constitution symptoms.
Exotoxin1 and exfoliative toxin-producing Staphylococcus aureus are the most common pathogen, but enterotoxin A, B, and C, producing Streptococcus pyogenes infections, yield a worse prognosis. Blood cultures may be negative for the causitive organism.
Although Clostridium, Enterobactor, Pseudomonas, and Bacteroides species are polymicrobial species associated with necrotozing fasciitis, the description of this otherwise healthy patient is not consistent with its typical presentation of discolored blistered skin and crepitus.
2016
A 45-year-old man is brought to the emergency department with a Gustilo IIIB tibial fracture that he sustained falling off a tractor in a pasture. Medical history shows no drug allergies. Administration of which of the following antibiotics is most appropriate in this patient?
A) Amoxicillin B) Ceftriaxone C) Ciprofloxacin D) Clindamycin E) Vancomycin
The correct response is Option B.
The most appropriate antibiotic prophylaxis for this patient with a Gustilo grade III fracture is a third generation cephalosporin. Although much debate exists regarding antibiotic prophylaxis in open tibial fractures, it is generally accepted that antibiotic prophylaxis reduces the rate of infection. When antibiotic prophylaxis is not used, infection occurs in approximately 24% of open fractures. Thus, selecting the appropriate antibiotic, as well as duration, is of utmost importance. Antibiotic prophylaxis should be administered as soon as possible after injury and should be limited to a 72-hour course. In general, broad-spectrum antibiotics and multiple antibiotics should be avoided because they have been shown to increase the risk of nosocomial infections, including pneumonia. Of the antibiotics listed, the most appropriate choice for a patient with no drug allergies is ceftriaxone. Clindamycin and vancomycin should be reserved for cases of true penicillin allergy. Ciprofloxacin alone has been shown to be inferior to prevent infection after open tibial fractures.
2016
A 29-year-old woman is evaluated because of a 2.5-year history of painful, draining lesions from the axillae and groin. Physical examination shows multiple nodules and abscesses. Conservative treatment with loose clothing, topical antibiotics, and antibacterial washes is unsuccessful. These findings are most consistent with which of the following disease processes?
A) Candidal infection of the intertriginous areas
B) Follicular occlusion of the apocrine sweat gland areas
C) Follicular occlusion of the eccrine sweat glands areas
D) Inflammatory and ulcerative skin condition mediated by neutrophils
E) Sexually transmitted infection caused by Klebsiella granulomatis
The correct response is Option B.
Hidradenitis suppurativa (HS), also known as acne inversa, is a chronic inflammatory disease of the skin and subcutaneous structures. Initially presenting as tender, subcutaneous nodules, the disease can advance to cause abscesses and large areas of subcutaneous scarring and draining sinus tracts.
Historically, HS has been thought to originate from the apocrine sweat glands. However, research in recent years has demonstrated that the mechanism is one of follicular occlusion: hair follicles become occluded due to an overproliferation of ductal keratinocytes, rupture, and subsequently re-epithelialize. As this cycle continues, sinus tracts form that house bacteria and cause chronic, painful infections and inflammation that can involve the skin and subcutaneous structures including muscle, fascia, and lymph nodes.
HS lesions typically occur predominately in the apocrine-gland bearing areas of the axillary, inguinal, perianal, and perineal areas. Lesions typically correspond with the “milk-line” pattern of apocrine-related mammary tissue in mammals.
Eccrine, or merocrine, sweat glands are found throughout the body, but their highest concentrations are in the palms and soles. These areas are typically spared by HS.
Follicular pyodermas, including folliculitis, furuncles, and carbuncles, arise primarily from the infection of hair follicles. They do not cause the sinus tracts, comedones, and scarring caused by HS.
Granuloma inguinale is a sexually transmitted infection of the genitalia, perineum, and/or perineal area caused by Klebsiella granulomatis.
Pyoderma gangrenosum is a dermatologic condition mediated by neutrophils that causes skin ulceration and breakdown.
2016
A 5-year-old boy is brought to the emergency department after sustaining a traumatic amputation of the right thumb. Medical history includes an allergy to sulfa drugs. The thumb is successfully replanted, and the patient is admitted for observation. Twenty-four hours postoperatively, venous congestion of the replanted thumb is noted. Leeches are placed to improve congestion. It is suspected that the leeches will be required for several days until venous outflow is reestablished. Administration of which of the following antibiotics is most appropriate?
A) Cefotaxime B) Ciprofloxacin C) Clindamycin D) Tetracycline E) Trimethoprim-sulfamethoxazole
The correct response is Option A.
Medicinal leeches are still commonly used as an adjunct in the treatment of venous congestion. They secrete a powerful anticoagulant called hirudin that promotes bleeding in the congested tissues until venous outflow can be reestablished. Leeches are also known to harbor the gram-negative bacterium Aeromonas. Because leeches can be exposed to open wounds on the patient for several days during treatment, antibiotic prophylaxis against Aeromonas is recommended.
Ciprofloxacin, tetracycline, trimethoprim-sulfamethoxazole (Bactrim), and third-generation cephalosporins have all been shown to be effective against Aeromonas. However, in the scenario above, all of these antibiotics have a contraindication except cefotaxime, a third-generation cephalosporin.
Ciprofloxacin is contraindicated in children when a suitable alternative exists secondary to the risk of arthropathy and arthrotoxicity. Similarly, the use of tetracycline is relatively contraindicated in children owing to the potential for abnormalities with the teeth, including permanent staining and growth retardation. While Bactrim is often used in children to treat various infections, this child has an allergy to sulfa drugs and should not be given this antibiotic.
Clindamycin does not provide effective antibiotic coverage against Aeromonas.
2016
A 67-year-old man with type 1 diabetes mellitus is evaluated for full-thickness perineal burns sustained by falling onto a space heater. Forty-eight hours after admission, he has onset of fever and tachycardia. Complete blood cell count grows leukocytosis, and wound culture shows gram-negative rods consistent with Pseudomonas. Pending sensitivity report, empiric coverage is initiated. Which of the following antibiotics is clinically CONTRAINDICATED for initial therapy?
A) Ceftazidime B) Ceftriaxone C) Ciprofloxacin D) Imipenem E) Tigecycline
The correct response is Option E.
Although tigecycline has excellent coverage of most staphylococcal and many gram-negative rod infections, this tetracycline derivative is not effective against pseudomonal infections. Patients with pseudomonal sepsis benefit from double coverage. Furthermore, sensitivities to different antimicrobial agents are quite variable from one health care system to another, so providers must remain vigilant after beginning therapy and change coverage based on lack of clinical response and determination of final sensitivities. An essential component of this patient’s care would be urgent burn wound excision, after he has been resuscitated and empiric antibiotics have been initiated.
2016
A 34-year-old woman undergoes laser-assisted liposuction of the abdomen, hips, and inner and outer thighs using a tumescent technique. A total of 2500 mL of aspirate is removed. Postoperative recovery is uneventful, and the patient is discharged home the same day. She comes to the emergency department 4 days later with intense pain over the lower abdomen and flanks. Temperature is 101°F (38.3°C). Physical examination shows the skin has well-demarcated erythema, induration, and bullae forming at multiple sites. Her incisions are seeping clear, grey fluid. Which of the following is the most appropriate management?
A) Exploratory laparotomy for presumed bowel perforation
B) Intravenous administration of antibiotics and local burn care
C) Intravenous administration of antibiotics only
D) Oral administration of antibiotics
E) Surgical debridement of the involved tissue
The correct response is Option E.
Necrotizing fasciitis is a rapidly progressive soft-tissue infection characterized by necrosis of the fascia and subcutaneous fat with subsequent necrosis of the overlying skin. Although complication rates associated with liposuction are not unduly increased, infection is a major concern, and cases of prolonged inflammation, septic shock, and infections have been documented. Likewise, cases of necrotizing fasciitis following liposuction have been reported on several occasions and, according to data reported in the literature, the overall incidence of necrotizing fasciitis is equal to 0.4 per 100,000 patients.
There are two common forms that are reported: infections caused by Streptococcus pyogenes and mixed infections caused by a variety of microbes, including Escherichia coli, Proteus, Serratia, and Staphylococcus aureus. A detailed case of necrotizing fasciitis sustained by Mycobacterium chelonae after a combined procedure of liposuction and lipofilling has also been described. The progressive necrosis of the tissues typically involves the superficial fascia and the subcutaneous layer, but is limited in extension to the skin; the extent of the gangrene at the fascial layer is usually more severe and greater than at the skin level.
Necrotizing fasciitis is virtually unnoticeable in the first 48 hours with nonspecific symptoms. In the days that follow, an extensive, hardened region forms, which is often dark in the center. Severe pain and necrosis follow at the level of the infection.
Drainage of “dishwater fluid” is often pathognomonic. Metabolic changes occur, ending with respiratory distress, oliguria, acidosis, increased troponin concentrations, and sepsis. Diagnosis and treatment consist of surgical exploration and debridement that reveal necrotic, edematous, subcutaneous fat. Bacteriologic analysis of exudate, cultures, and histologic evaluation complete the diagnosis.
Early diagnosis is imperative to avoid a fatal outcome. Treatment is based on immediate and aggressive surgical debridement with combined antibiotic therapy. Because necrotizing fasciitis is a progressive, rapid infection, the wound typically is left open for a planned “second-look” operation and additional debridement if necessary. The mortality rates are increased and range up to 70% but decrease to 4.2% after immediate surgical intervention. Delay in debridement increases mortality.
2015
A 40-year-old woman with chronic hidradenitis suppurativa of the bilateral axillae is referred for surgical management after 4 years of local wound care, multiple corticosteroid injections, and oral antibiotics failed to improve her symptoms. Physical examination shows multiple inflamed nodules and draining sinuses. Photographs are shown - extensive disease in entire axilla b/l. Which of the following treatment options is most likely to provide long-term resolution of this patient’s symptoms?
A) Axillary lymphadenectomy and coverage with a trapezius flap
B) Carbon dioxide laser and silver sulfadiazine
C) Fistulotomy and negative pressure wound therapy
D) Lesion excision and primary closure
E) Total axillary excision and skin grafting
The correct response is Option E.
Hidradenitis is a chronic and often disabling skin condition of the apocrine glands. It results in abscesses, inflammatory nodules, and draining sinuses in the axillae, groin, perineum, and occasionally the submammary area. It affects approximately 1 in 300 people, and it is more common in women, people who smoke, and people who are overweight. The axillae are more commonly involved in women, and the perineum more commonly in men.
Early treatment centers around local wound care, oral antibiotics, corticosteroid injections, hygiene, weight loss, and smoking cessation. Decreased estrogen levels may also contribute, and disease often subsides with oral contraceptives and during pregnancy. Unresponsive or extensive disease requires surgical intervention for long-term resolution. Relapse rates are high, and healing is often slow. Although limited excision and closure of solitary lesions is an effective short-term treatment, new lesions are likely to develop. Fistulotomy alone has an unacceptably high recurrence rate.
A long-term resolution in this severely affected patient requires complete excision of the hair-bearing skin of the affected area. The large defect created needs broad skin coverage. The best options include split-thickness skin grafting or grafting with negative pressure wound therapy immobilization. Negative pressure wound therapy followed by healing by secondary intention or coverage with local flaps are additional options, though scar contractures and shoulder stiffness are risks.
Laser treatments are too superficial to treat the deeper apocrine structures. Lymphadenectomy is not necessary for a cure.
2015
A 48-year-old right-hand–dominant man with a history of cadaveric renal transplantation comes to the emergency department because of a swollen, painful left hand. A photograph is shown. He works as a crab fisherman and reports that he was bitten in the first web space by a crab 18 hours ago. He is taken to the operating room for emergent debridement. Intraoperative Gram stain shows a gram-negative, curve-shaped rod. In addition to aggressive surgical treatment, administration of which of the following antibiotics is most appropriate to treat this patient?
A) Cephalexin B) Levofloxacin C) Linezolid D) Nafcillin E) Vancomycin
The correct response is Option B.
Vibrio vulnificus is a common Vibrio species causing soft-tissue infections of the hand. Vibrio species are ubiquitous in aquatic environments including saltwater bodies. Immunocompromised hosts are at greater risk for amputation and death. The best chance for patient survival includes early diagnosis and initiation of appropriate antibiotics, as well as urgent surgical debridement for any evidence of necrotizing infection.
A broad range of antibiotics are effective against Vibrio species, including V. vulnificus. Agents effective against gram-negative rods, including quinolones, aminoglycosides, and aminopenicillins, are all effective against V. vulnificus. While all cephalosporins are effective against Vibrio species, third-generation cephalosporins are up to 130 times more potent than first- or second-generation cephalosporins. Vancomycin, nafcillin, and linezolid are all narrow-spectrum antibiotics, primarily effective against gram-positive cocci, and are not effective against Vibrio species.
2015
A 55-year-old man with a history of smoking and poorly controlled diabetes mellitus comes to the emergency department because of a 12-hour history of unilateral proptosis, impaired vision, and severe headaches. Intranasal examination shows dried crusting and black discoloration of the lateral nasal wall and turbinates. Radiology shows a 4-cm mass within the maxillary sinus that extends into the orbit. Biopsy of the mass shows nonseptate hyphae. Which of the following is the most appropriate next step in management?
A) Craniofacial resection and free flap
B) Emergent debridement of the sinuses and orbital exenteration
C) Intravenous administration of an antibiotic
D) Outpatient oral antifungal medications
E) Referral to medical oncology
The correct response is Option B.
Rhinocerebral mucormycosis is a rare opportunistic infection of the sinuses, nasal passages, oral cavity, and brain caused by saprophytic fungi. The infection can rapidly result in death. Rhinocerebral mucormycosis commonly affects individuals with diabetes and those in immunocompromised states. The diagnosis of mucormycosis is established by obtaining a biopsy specimen of the involved tissue, and frozen tissue samples should be immediately evaluated for signs of infection. Microscopic characterization of non-septate hyphae, rhizoids, columellae, sporangia, and sporangiospores helps to define genus and species within the order Mucorales. Optimal therapy requires a multidisciplinary approach that relies on prompt institution of appropriate antifungal therapy with amphotericin B (AmB), reversal of underlying predisposing conditions, and, where possible, surgical debridement of devitalized tissue. Surgery should be considered early, and if possible, emergently with the goal of removing all necrotic tissue. Repeated debridements are frequently necessary and the extent of surgery should ideally be guided by evaluation of frozen tissue sections examined histologically. In the scenario provided, orbital involvement will most likely require sacrifice of the eye.
2015
A 15-year-old girl comes to the office because of a 1-day history of infection of the right index finger. Physical examination shows the tip of the finger is tender and swollen over the pulp. There is no history of trauma. Which of the following organisms is the most likely cause of this patient’s condition?
A) Candida albicans B) Eikenella corrodens C) Listeria monocytogenes D) Pasteurella multocida E) Staphyloccus aureus
The correct response is Option E.
Staphylococcus is still the most common organism in hand infections. The most common in felons is Staphylococcus aureus. Methicillin-resistant Staphylococcus aureus community-acquired (MRSA-CA) infections are now the most predominant strain in hand infections, comprising 60% of Staphylococcus aureus infections.
Pasteurella multocida should be considered with most animal bites, although it is most common with cat bites. Eikenella corrodens is associated with human bites. There is no history of bites in this case.
Listeria monocytogenes has been reported in flexor tenosynovitis in immunocompromised patients.
Candida albicans is usually associated with chronic paronychia.
2014
A 55-year-old man undergoes microsurgical replantation of an amputated ear. There is venous congestion, and leeches are applied. This patient is at risk for infection by which of the following organisms?
A) Actinobacillus lignieresii
B) Aeromonas hydrophila
C) Eikenella corrodens
D) Pasteurella canis
The correct response is Option B.
Aeromonas hydrophila is an organism present in the leech species Hirudo medicinalis gastrointestinal tract that can lead to an infection if used medicinally. In this patient with venous congestion and application of leeches, antibiotic prophylaxis is recommended with fluoroquinolones, tetracycline, or trimethoprim-sulfamethoxazole.
Actinobacillus lignieresii is seen in horse bites, Pasteurella canis in dog bites, and Eikenella corrodens in human bites.
In a recent review of ear reattachment methods, a variety of approaches have been used including microsurgical reattachment, burying of the part in a subcutaneous pocket, periauricular tissue flaps for coverage of the part, and direct reattachment as a composite graft. Microsurgical replantation is associated with the best aesthetic outcome even if venous anastomosis is not possible and leeching is necessary.
2014
A 35-year-old woman with type 2 diabetes mellitus is evaluated in the emergency department because of severe pain and drainage from the right buttock 36 hours after undergoing bilateral buttock augmentation with autologous fat harvested from the thighs. Temperature is 102.0°F (38.9°C), heart rate is 105 bpm, respiratory rate is 16/min, and blood pressure is 90/60 mmHg. Physical examination of the right buttock shows brawny erythema and drainage of turbid fluid from an injection site. The patient has marked tenderness of the buttock, and the abdomen is nontender. White blood cell count is 18.5 × 109/L and serum creatinine concentration is 1.5 mg/dL. After resuscitation, which of the following is the most appropriate next step in management?
A) CT scan of the abdomen and pelvis B) Inpatient intravenous antibiotic therapy C) Outpatient oral antibiotic therapy D) Surgical exploration of the wound E) Ultrasonography of the buttock
The correct response is Option D.
The most appropriate next step in management is to surgically explore the wound in the operating room. The clinical picture is of a severe, rapidly progressing infection, possibly necrotizing fasciitis. A high index of suspicion and early treatment are vital for successful outcomes. Necrotizing fasciitis is a rare and rapidly progressive infection of the deeper layers of skin and subcutaneous tissues, easily spreading across the superficial fascial plane, with subsequent death of the overlying skin and severe systemic toxicity. Liposuction is the most frequently associated cosmetic surgery with this infection. Signs and symptoms are insidious, nonspecific, or virtually unnoticeable early in the course of the disease. Later, erythema, prominent edema, and induration appear, accompanied by intense or intolerable pain. The clinical picture evolves into systemic toxicity and eventually multiple organ failure. Risk factors for necrotizing fasciitis include diabetes mellitus, immunosuppression, age older than 50 years, malnutrition, and peripheral vascular disease.
There are two forms of the disease: one caused by Streptococcus pyogenes, and the other by mixed infections caused by a variety of microbes, including Escherichia coli, Proteus, Serratia, and Staphylococcus aureus. The progressive necrosis of the tissues typically involves the superficial fascia and the subcutaneous layer. The extent of the gangrene at the fascial layer is typically more severe and greater than at the skin level. This insidious infection is virtually unnoticeable and nonspecific in the first 24 to 48 hours; however, in the following days, an extensive, hardened area appears, which is often dark colored in the center. Intense pain and skin necrosis follow at the level of the infection. Metabolic changes occur, ending with respiratory distress, oliguria, acidosis, increased creatine kinase activity, increased troponin concentrations, and toxic syndrome. Diagnosis and treatment consists of surgical exploration and debridement that reveal necrotic, edematous subcutaneous fat. Bacteriologic analysis of exudate, cultures, and histologic evaluation complete the diagnosis.
Early diagnosis is imperative to avoid a fatal outcome. Because necrotizing fasciitis is a progressive, rapid infection, a staged “second-look” operation and, if necessary, additional debridement should be performed. The mortality rates are high and range from 20 to 70%, but decrease to 4.2% after immediate surgical intervention.
Though antibiotic therapy is an integral part of the treatment, surgical exploration is key. CT scans and ultrasonography will not change the treatment plan and are therefore not the appropriate next step in management.
2014
An otherwise healthy 35-year-old man comes to the emergency department because of a 2-day history of swelling and pain in the index and long fingers of the right hand. He reports pain when he attempts to flex these fingers or bring them together. Physical examination shows no pain with passive extension of the fingers or during axial loading. There is pain with passive adduction of the fingers. A photograph is shown - swelling over IF P1 w puncture wound. Which of the following is the most appropriate management?
A) Arthrotomy of the metacarpophalangeal joint of the long finger
B) Division of ulnar-sided Cleland ligament of the index finger
C) Dorsal and volar incisions in the proximal second web space
D) Drainage of the mid-palmar space
E) Release of the A1 pulley of the index and long fingers
The correct response is Option C.
The patient described has a web space (collar-button) abscess. Pus resides dorsal to and volar to the natatory fibers of the palmar fascia with a small connection between the two spaces passing through the natatory fibers. It is drained through proximal dorsal and volar incisions in the web space. One should not incise through the apex of the web space, as this may lead to a web space contracture.
Incisions are allowed to heal by secondary intention.
Cleland ligament is a separate portion of the palmar fascia located within the finger dorsal to the neurovascular bundle. It is distal to the purulence in a web space abscess. Absence of pain with axial loading of the digits makes a joint space infection unlikely, so drainage of the metacarpophalangeal joint is unnecessary. Some approaches to drainage of flexor tenosynovitis involve release of the proximal sheath through the A1 pulley; the appearance in the photo (lack of fusiform swelling), and absence of pain with passive extension of the fingers, make flexor tenosynovitis unlikely in this patient. Infection of the mid-palmar space would produce more proximal pain and swelling in the palm, which is not present in this patient.
2014
A 21-year-old man with type 1 diabetes mellitus comes to the emergency department because of a large necrotizing, non-purulent infection after minimal trauma to the right cheek. Radical surgical debridement of the ulcer is performed, and the tissue is sent for histologic and microbiologic evaluation. Which of the following organisms are most likely to be found on light microscopy?
A) Chain-like collections of gram-positive bacteria
B) Grape-like clusters of gram-positive bacteria
C) Right angle nonseptate branching hyphae
D) Septate nonbranching hyphae and yeast forms
E) Tiny yeast forms with occasional unequal bud formation
The correct response is Option C.
Given the patient’s history of diabetes and necrotizing non-purulent infection after minimal trauma, he is likely to have mucormycosis, a life-threatening fungal infection caused by organisms from the class Zygomycetes. On microscopy, tissue samples from patients with mucormycosis demonstrate right-angle nonseptate branching hyphae.
Grape-like clusters of gram-positive bacteria is not appropriate. This option describes the characteristic appearance of a staphylococcal infection. Given the patient’s lack of cellulitis or purulent infection, it is an unlikely mechanism for this necrotizing ulceration.
Septate nonbranching hyphae and yeast forms is not appropriate. This option describes the characteristic appearance of a candidal infection. Given the patient’s lack of marked erythema and excoriation, and location of the infection on the face, rather than in skin folds, the likelihood of Candida as the primary pathogen is extremely low.
Chain-like collections of gram-positive bacteria is not appropriate. This option describes the characteristic appearance of a streptococcal infection. Although streptococcal infections are common in the head and neck region, the patient’s history and appearance of the lesion do not support Streptococcus as the causative organism.
Tiny yeast forms with occasional unequal bud formation is not appropriate. This option describes the characteristic appearance of Histoplasma capsulatum, an opportunistic fungus, which may cause marked pulmonary infections in immunocompromised patients.
Often emergent debridement is required, and that decision will need to be made on Gram stain, not on final culture.
2014
A 37-year-old man comes to the emergency department 4 hours after he sustained a human bite wound to the nondominant hand. Examination shows no erythema, swelling, purulent drainage, lymphangitis, or fever. Exploration of the wound shows no joint or tendon involvement. Debridement and irrigation of the wound is performed. Which of the following is the most appropriate next step in management?
A) Administration of amoxicillin-clavulanate 875/125 mg twice daily
B) Administration of clindamycin 450 mg three times daily
C) Administration of doxycycline 100 mg twice daily
D) Administration of trimethoprim-sulfamethoxazole 1 double-strength tablet twice daily
E) Observation
The correct response is Option A.
A prospective, randomized study has shown that antibiotic prophylaxis is superior to placebo in decreasing infections after human bites that are less than 24 hours old. The most common pathogens in human bite wounds are S aureus, E corrodens, H influenzae, and beta lactamase-producing anaerobic bacteria. Eikenella species are resistant to clindamycin. Meanwhile, doxycycline and trimethoprim-sulfamethoxazole are not effective against anaerobes. Of the options mentioned, only amoxicillin-clavulanate has good activity against all common oral pathogens.
2013
A 65-year-old woman undergoes treatment for breast cancer with intravenous doxorubicin through a subcutaneous port on the left side of the chest. The patient complains of severe pain around the port 5 minutes after the treatment is initiated, and the infusion is discontinued. Examination shows marked swelling (8 × 6 cm) and erythema of the skin. Which of the following is the most appropriate next step in management?
A) Flushing of the port with a saline solution
B) Intravenous administration of dexrazoxane
C) Removal of the port
D) Subcutaneous injection of dimethyl sulfoxide
E) Subcutaneous injection of saline solution
The correct response is Option B.
The most appropriate next step in management is to initiate intravenous dexrazoxane. Recent data support the use of this agent in extravasation of anthracyclines (e.g., doxorubicin) as an antidote. It has been shown to decrease the frequency and severity of tissue injury. The mechanism by which dexrazoxane diminishes tissue damage is unknown. However, two mechanisms of action are hypothesized: 1) reduction of oxidative stress due to complexes of metal ions and anthracyclines by chelating metal ions; 2) and blockade of topoisomerase II poisons by catalytic inhibition of topoisomerase II. Patients receive treatment with dexrazoxane 1000 mg/m2 administered intravenously on days 1 and 2, and 500 mg/m2 on day 3. The infusion is given in the opposite arm of the extravasation site and is administered as soon as possible and no longer than 6 hours after the extravasation accident.
Flushing the port is not indicated because the port may be malfunctioning and this action could extravasate the flushing agent. Adding more fluid to the area (extravasation of saline from the port, subcutaneous saline injection, etc.) will only add to the pressure on the overlying skin, injuring the skin further. Removal of the port is not indicated until it has been ascertained it is malfunctioning.
Dimethyl sulfoxide (DMSO) is a known treatment option for anthracycline extravasations. However, it is used as a topical agent with or without cortisone, not as a subcutaneous injection. Additionally, it should not be used in patients who are receiving dexrazoxane because it has been shown to decrease the efficacy of the dexrazoxane therapy.
2013
A 55-year-old man who is a commercial fisherman comes to the office because of a 3-week history of a swollen index finger. The patient holds the finger in a flexed position. Extension of the digit is difficult but not painful. Surgical exploration shows nonpurulent fluid in the tendon sheath. Culture of the fluid is most likely to show which of the following pathogens?
A) Eikenella corrodens B) Mycobacterium marinum C) Sporothrix schenckii D) Staphylococcus aureus E) Vibrio vulnificus
The correct response is Option B.
The patient described has an occupation that exposes him to contaminated water and raw seafood. Infections from Mycobacterium marinum and Vibrio vulnificus are both possible.
Mycobacterium marinum is the most common atypical mycobacterium seen in hand infections, often seen after penetration by aquatic equipment, colonized marine life, or contact with contaminated water. The most common deep infection is flexor tenosynovitis, and may present as a chronic tenosynovitis.
Sporothrix schenckii is a fungus found in plants and soil. Inoculation with the pathogen results in a papule at the entry site, followed by development of lesions along the lymphatic chain.
Suppurative flexor tenosynovitis typically presents with pain over the tendon sheath, semiflexed position of the involved digit, pain on passive extension, and symmetrical swelling of the finger. This classic presentation is commonly caused by pathogens such as Staphylococcus aureus or Eikenella corrodens (often seen in association with human bite injuries). In tenosynovitis infections involving atypical mycobacterium, however, there is absence of pain.
Vibrio vulnificus is a species of gram-negative, motile, curved bacterium found in the coastal waters of the United States. Infections from V vulnificus may be caused by direct exposure of an open wound to warm seawater containing the organism or from handling raw seafood or marine wildlife. Infections caused by V vulnificus result in painful cellulitis that progresses rapidly and presents with marked local tissue swelling with hemorrhagic bullae. Bacteremia with systemic symptoms is commonly seen.
2013
A 22-year-old man who has type 1 diabetes mellitus comes to the office because of a 1-day history of cervical and chest pain. Temperature is 102.2°F (39.0°C). Physical examination shows right-sided cervical erythema and moderate swelling. A broad-spectrum antibiotic is administered, and he undergoes incision and drainage. During the procedure, extensive soft-tissue necrosis not confined by fascial planes is noted. Which of the following is the most likely cause of this infection?
A) Mastoiditis B) Meningitis C) Parotitis D) Pharyngitis E) Sinusitis
The correct response is Option D.
The patient described has cervical necrotizing fasciitis (CNF) that likely extends into the mediastinum. Pharyngeal and tonsillar infections, along with dental abscesses, are the most common sources of infection. Diabetes and other immunocompromised states are frequent comorbidities in this disease. Early presentation may be clinically indistinguishable from a superficial soft-tissue infection and, therefore, requires a high index of suspicion. Skin necrosis is often a late finding, as the infection begins in the fascial and deep tissues of the neck. CT scan is usually obtained to define the extent of the disease and may or may not show gas within the soft tissues. Patients are treated with broad-spectrum antibiotics and aggressive surgical debridement.
Mastoiditis is an infection of the mastoid air cells usually arising in the setting of untreated otitis media. Mastoiditis can spread to surrounding structures, including the brain.
Meningitis is an infection of the meninges that is associated with neck pain as well as fever, headache, and photophobia. It does not present with unilateral neck erythema and swelling.
Parotitis is an infection of the parotid gland that usually arises in the setting of an obstructed parotid duct and is a very rare but potential cause of CNF.
Sinusitis is not usually associated with CNF but may spread to the orbit, resulting in orbital cellulitis or orbital abscess, and, occasionally, cavernous sinus thrombosis. Cavernous sinus thrombosis is a life-threatening condition.
2013
A 50-year-old man comes to the office because of a 2-day history of worsening erythema, swelling, and tenderness of the interphalangeal (IP) joint of the thumb. He reports similar episodes in the past involving other joints but does not recall any history of trauma or skin breakage in the area. X-ray study of the thumb shows soft-tissue swelling only. No bony abnormalities are noted. Which of the following is the most appropriate first step in management?
A ) Administration of antibiotics B ) Aspiration of joint fluid C ) Elevation and splinting of the joint D ) MRI of the joint E ) Surgical washout
The correct response is Option B.
The most appropriate first step in management in the scenario described is to aspirate fluid from the joint for analysis. There are several conditions that mimic acute hand infections, and it is important to recognize them so that the appropriate treatment can be initiated. Crystalline deposition diseases, such as gout and pseudogout, tend to present with joint swelling, erythema, pain with motion, and fever, much like the signs of infection. The only way to confirm the diagnosis is to aspirate the joint and look for crystals with polarizing microscopy. Though the description of the thumb in the scenario described is consistent with possible infection, the fact that there has been no trauma or break in the skin around the joint, and the patient’s history of acute arthritic episodes in other joints, raises some suspicions that this could be noninfectious. Therefore, joint aspiration to rule out other causes of acute arthritis is warranted. Administration of antibiotics and elevation and splinting should begin after the aspiration, if indicated. MRI of the joint and surgical washout are not indicated at this time.
2012
An otherwise healthy 25-year-old woman comes to the emergency department because of pain, redness, swelling, and stiffness in the long, ring, and little fingers of her right hand 36 hours after being bitten by her cat. The cat is up-to-date with rabies vaccinations. The patient does not take any medications. The patient states that she was told never to take penicillin because she “stopped breathing” when she took it as a child. Examination shows multiple small, draining puncture wounds along the proximal volar and ulnar aspects of the proximal phalanges, a collar-button abscess between the ring and little fingers, and edema over the dorsum of the hand. Pending results of culture, which of the following is the most appropriate empiric antibiotic therapy?
A ) Ampicillin-sulbactam B ) Cefazolin C ) Ciprofloxacin and clindamycin D ) Tetracycline and trimethoprim-sulfamethoxazole E ) Trimethoprim-sulfamethoxazole
The correct response is Option C.
For the patient described with a penicillin or cephalosporin allergy, trimethoprim-sulfamethoxazole (TMP/SMX) and clindamycin or metronidazole, or a fluoroquinolone and clindamycin or metronidazole, are good antibiotic therapy combinations.
Cat bites account for 5 to 15% of animal bites and occur more often in women and adults (median age is 20 years). Most cat bite injuries occur on the upper extremity with ‘scratches’ on the finger or hand. Infection rates after cat bites range from 50 to 75%. This is typically attributed to the fine, sharp teeth of cats, which produce puncture wounds and penetrate deeply into the soft tissues and joint capsules of the hand.
Wounds to the hand demonstrate an increased risk of infection; closed fist injuries have the highest risk. Initial medical management of bite wounds includes ascertaining the rabies status of the animal and updating the tetanus immunization of the patient if necessary. If rabies is suspected, irrigation with povidone-iodine solution will reduce the development by up to 90%. A careful examination of the affected hand/extremity should address the surrounding soft tissues and potential spaces of the hand, tendons, joint and joint capsules, and underlying bone. The wound should be irrigated with saline after obtaining wound cultures. Necrotic tissue should be debrided, and any cat bite with worsening pain will require incision and irrigation of the puncture site. All cat bite wounds should be left open, although large gaping wounds can be loosely approximated. Before definitive surgical treatment of any associated abscess or debridement of devitalized tissue, empiric antibiotic therapy should be started.
The majority of cat bite wounds are polymicrobial and the anaerobic organisms are often overlooked. Common aerobic pathogens include Staphylococcus aureus, viridans streptococcus, Corynebacterium, Pasteurella multocida, and various gram-negative enteric organisms. The most common anaerobic pathogens include Bacteroides, Fusobacterium, Peptostreptococcus, and Actinomyces species. Pasteurella multocida, an aerobic, facultative anaerobic gram-negative pathogen, is the most commonly isolated pathogen in cat bites and is present in up to 50% of infected wounds. Symptoms of Pasteurella multocida infection develop rapidly within 24 hours and typically include cellulitis and seropurulent drainage. Other uncommon infections have been reported after cat bites, including tularemia (Francisella tularensis) and cat-scratch disease (Bartonella henselae).
Patients with severe wounds (crush injury, joint involvement, deep space infection), cellulitis, sepsis, diabetes, immunosuppression, or other high-risk factors for treatment failure should receive parenteral antibiotics. Alternatives to amoxicillin and clavulanate potassium or ampicillin and sulbactam include other penicillins or cephalosporins, provided they display adequate anaerobic coverage. In the scenario described, the choices containing amoxicillin, ampicillin, and cefazolin are not appropriate because of the patient’s penicillin allergy. Additionally, this patient will require intravenous antibiotics because of the wound severity, so amoxicillin and clavulanate potassium would not be appropriate. The combination of tetracycline and TMP/SMX alone does not provide adequate anaerobic coverage.
2012
A 43-year-old healthy man comes to the office because of acute swelling over the dorsum of his dominant right wrist. He says that movement of the wrist is painful. No preceding trauma is noted. Which of the following is the most sensitive test to diagnose septic wrist arthritis in this patient?
A ) Carpal bone radiographic destructive changes B ) Joint aspirate Gram stain C ) Serum erythrocyte sedimentation rate D ) Serum white cell count E ) Synovial fluid white cell count
The correct response is Option E.
Analysis of synovial fluid is the most useful diagnostic test. The most definitive test of the joint fluid, bacterial Gram stain and culture, is unfortunately not consistently positive in an acute septic joint. Culture may be negative in about 50% of cases, especially gonococcal, and Gram stain is even less frequently positive. One has to wait a few days for culture results.
As one lowers the threshold for the white cell count in a joint aspirate, the test becomes more sensitive, but less specific. If the white cell count threshold is set at 50,000/mL, which is traditionally the value considered to be the threshold for diagnosis of a septic joint, the sensitivity is 61%. If a white cell count at 17,500 is set as the threshold, the sensitivity is 83%, but specificity is 67%. The specificity rises to 77% if the threshold for the white cell count is raised to 100,000.
Sedimentation rate, serum white cell count, and C-reactive protein do little to change pretest probability of a septic joint.
Radiographic changes are a late finding in septic arthritis.
2012
A 25-year-old man comes to the emergency department because of swelling and pain in the finger. He says that he first started noticing symptoms 4 days ago. Physical examination shows warmth of the fingertip and fluctuance of the nail fold. A photograph is shown. Which of the following bacteria is the most likely cause of this infection?
A ) Enterococcus faecalis B ) Mycobacterium marinum C ) Pasteurella multocida D ) Pseudomonas aeruginosa E ) Staphylococcus aureus
The correct response is Option E.
A paronychia is an infection occurring in the space between the nail plate and the paronychial or eponychial fold. Common causes include nail biting and aggressive manicuring. In an otherwise healthy individual, Staphylococcus aureus and Streptococcus species are the most common pathogens causing a paronychia.
The remaining bacteria listed would only be expected to cause a paronychia in special circumstances. Enterococcus is an enteric bacterium. Mycobacterium marinum can be present in aquatic environments including fish tanks and has also been reported in the Chesapeake Bay. Pasteurella multocida is a common flora of cat mouths. Pseudomonas occurs in areas with moist environments and can be problematic in a burn unit.
2012
A 3-year-old boy is brought to the office because of swelling of the right upper and lower eyelids 4 days after sustaining a dog bite to the ipsilateral cheek. Oral temperature is 101.3°F (38.5°C). Examination shows two puncture marks with scant purulent discharge on the right mid cheek, proptosis of the right eye, and swelling of the right eyelids. Which of the following is the most appropriate next step to establish the diagnosis?
A ) Blood cultures B ) Complete blood count C ) CT scan D ) Waters view x-ray study E ) Wound swab
The correct response is Option C.
Orbital cellulitis may be caused by local extension of a superficial infection such as a hordeolum, or from adjacent infected sinuses, or by hematogenous seeding from a dental or facial abscess. It is important to distinguish between preseptal and orbital cellulitis, which should be suspected when unilateral proptosis is present, and to identify the presence of an intraorbital abscess. Infection within the orbit has implications for management and prognosis due to the effect of high mechanical pressures generated in an unyielding compartment, which will manifest as proptosis, and other symptoms including diplopia, ophthalmoplegia, and chemosis. Orbital cellulitis requires hospitalization and prompt initiation of parenteral antibiotics. An intraorbital abscess can form if treatment is delayed, further compounding the intraorbital pressure and causing tissue necrosis. An intraorbital abscess requires immediate surgical drainage due to risk of blindness. Preseptal cellulitis is an infection of periorbital tissues superficial to the orbital septum, and if the source is from a nearby superficial skin infection, then initial management may be done with oral antibiotics and close follow-up. Preseptal cellulitis from a hematogenous source is more likely to become complicated with orbital cellulitis and abscess if it is not managed with parenteral antibiotics. Infections inside the orbit may extend to the central nervous system and may also cause cavernous sinus thrombosis. CT scan or MRI will confirm intraorbital infection, and related sources such as a facial or dental abscess or a sinusitis, and can direct the surgeon to areas requiring surgical drainage.
Blood cultures are useful in identifying the causative organism of the infection during periods of bacteremia, and are an appropriate test in the general workup of the patient; however, blood cultures alone do not diagnose or exclude intraorbital infection.
Cell counts are also useful in the general workup of the patient to characterize the systemic impact of the infection, and to be used as a guide in the responsiveness to treatment. The counts do not diagnose or exclude intraorbital infection specifically.
On Waters view x-ray studies, increased facial or eyelid edema may be seen as a slight diffuse opacification, but they are unable to delineate orbital and periorbital soft tissues individually. Sinus opacification can be suggestive of active sinusitis and a potential cause of orbital cellulitis. In general, plain x-ray study offers far less information than CT scan or MRI and is not diagnostic of intraorbital infection.
Wound swabs are helpful in identifying the causative organism of the infection when there is an obvious source, and are an appropriate test in the general workup of the patient; however, wound swabs alone do not diagnose, exclude, or characterize the extent of intraorbital infection.
2012
A 45-year-old gardener with a 10-year history of poorly controlled type 2 diabetes mellitus comes to the emergency department because of excruciating pain and swelling of the left forearm 1 day after he scraped his left arm on a rosebush. Physical examination shows extreme tenderness, edema, and crepitus. Which of the following is the most appropriate management?
A) CT scan
B) Econazole
C) Hyperbaric oxygen
D) Immediate surgical debridement
The correct response is Option D.
Necrotizing fasciitis is a severe soft-tissue infection affecting the skin, subcutaneous tissue, and fascia. It characteristically spares the underlying muscle, progresses quickly, and is associated with high morbidity and mortality rates and severe systemic sepsis. The inciting event is often trauma, even minor trauma and small puncture wounds, but hematogenous spread is also a recognized etiology.
The vast majority of patients have some form of chronic debilitating disease that weakens the immune system. Diabetes mellitus appears to be the most common disease, but these may include substance abuse and renal failure. These patients are at higher risk for increased mortality.
Two types of necrotizing fasciitis have been described. Type I are mixed aerobic and anaerobic infections, with facultative anaerobic bacteria and non-group A streptococci being present. This is the most common type and is present in about 75% of cases. Type II infections are monomicrobic and are caused by group A Streptococcus species alone or in combination with staphylococcal species. For this reason, antibiotic coverage should be broad.
The disease progresses quickly but does evolve through several stages. Initial symptoms include tenderness, erythema, edema, warm skin, and fever; however, symptoms may vary depending on patient characteristics. Initial lab findings may include leukocytosis, thrombocytopenia, and hyperkalemia, but these are variable. When critical skin ischemia occurs, blisters or bullae are formed. In the late stage, lesions turn black and necrotic and are anesthetic as the nerves become involved.
Diagnosis begins with a high clinical suspicion in all patients, particularly those with risk factors. Appropriate treatment is surgical debridement, broad-spectrum intravenous antibiotic therapy covering gram-positive, gram-negative, and anaerobic organisms, and careful monitoring and correction of fluid and electrolytes in an intensive care setting.
Most authorities agree that hyperbaric oxygen is to be recommended for the treatment of necrotizing fasciitis as an adjunct, if facilities are available and there is no delay in surgical debridement. However, most studies regarding the efficacy of hyperbaric oxygen are anecdotal with a distinct lack of properly designed prospective randomized controlled trials.
Mortality rates are reported to be 10 to 75% and are increased in patients with underlying immune compromise, delayed treatment, or involvement of the chest wall.
2011
A 24-year-old man comes to the emergency department 6 hours after sustaining an open distal radius fracture and loss of soft tissue while he was working on a farm. History includes diabetes mellitus. On physical examination, distal pulses and sensation are intact. Debridement and repair with open reduction and internal fixation are planned. Which of the following factors places this patient at greatest risk for infection postoperatively?
A) Gustilo fracture classification B) History of diabetes mellitus C) Method of fracture fixation D) Period of time from injury to initial debridement E) Type of contamination
The correct response is Option E.
Of the listed factors relating to risk of postoperative infection in this scenario, the strongest correlation is with contamination type. The Gustilo–Anderson fracture classification has been found to have some correlation with open fracture infection rates, but this relationship is not as strong in the distal radius as it is in long bones of the lower extremity. Recent studies by Glueck, et al, and Swanson, et al, have shown that contamination is a much stronger correlate.
A history of systemic illness, such as diabetes mellitus, and the type of fracture fixation seem to have a modest correlation to postoperative infections in distal radius fractures, but the findings are generally not statistically significant.
The timing of the initial debridement, as long as it occurs within the first 24 hours of injury, does not significantly affect infection rate. In contrast, there is evidence to suggest that performing multiple serial debridements in significantly contaminated wounds is of benefit in preventing postoperative infection.
2011
A 45-year-old woman comes to the emergency department because of redness at the site of injury 24 hours after being bitten by a cat. Temperature is 98.6 °F (37.0 °C), heart rate is 77 bpm, respirations are 16/min, and blood pressure is 125/82 mmHg. Physical examination shows mild erythema and edema around the puncture marks over the volar second phalanx of the long finger of the left hand. No purulent material is expressed. Resting position of the digit is normal, and there is no pain with passive extension. Assuming that the patient has no allergies to medications, which of the following is the most appropriate antimicrobial therapy?
A ) Amoxicillin-clavulanate B ) Cefazolin C ) Cephalexin D ) Erythromycin E ) Vancomycin and gentamicin
The correct response is Option A.
Cat bites usually result in puncture wounds because of their long, slender, sharp teeth. It has been reported that as many as 80% of cat bites become infected. Pasteurella species are the most common, occurring in as many as 75% of cat bite infections. Other types of bacteria can also be involved as well, including Streptococci, Staphylococci, and anaerobes.
Appropriate antimicrobial treatment for bite wounds must take into account the usual bacteriology of these infections. Pasteurella species are susceptible to penicillin, ampicillin, second- and third-generation cephalosporins, doxycycline, trimethoprim-sulfamethoxazole, fluoroquinolones, clarithromycin, and azithromycin, but are resistant to cephalexin, dicloxacillin, erythromycin, and clindamycin. Appropriate choices for prophylaxis and treatment of cat bite wounds would include amoxicillin and clavulanate or a combination of penicillin plus cephalexin. For those patients who have an allergy to penicillin, moxifloxacin or combination therapy with ciprofloxacin and clindamycin are appropriate choices. Azithromycin may also be effective for the penicillin-allergic patient, but it has less activity against anaerobes. Coverage for community-acquired MRSA (CA-MRSA) infection is not recommended because oral colonization of the human and animal mouth with CA-MRSA is unlikely.
Cefazolin, an intravenous form of a first-generation cephalosporin, is not an appropriate treatment for this wound as Pasteurella species are resistant, just as they are to cephalexin, the oral form.
2010
A 40-year-old woman is undergoing chemotherapy for metastatic lung cancer. During administration of her first dose of doxorubicin, she reports pain at the site of injection. The following day, physical examination shows the hand to be swollen and an ulcer measuring 2 - 3 cm is seen over the dorsum surrounded by an area of ischemia. Which of the following is the most appropriate immediate treatment?
A ) Administration of hyperbaric oxygen
B ) Application of cold packs
C ) Application of hot packs
D ) Application of topical dimethyl sulfoxide
E ) Immediate surgical excision and autografting
The correct response is Option D.
The specific treatment of an extravasation injury is dependent on the drug infused. Application of topical dimethyl sulfoxide has been advocated for the treatment of extravasation of anthracyclines and is supported by several studies.
The value of hyperbaric oxygen therapy has not been proven. In the case of doxorubicin extravasation injury, cold compresses may exacerbate the complication by venous constriction, which localizes the drug, whereas hot packs may cause vasodilatation with further extravasation. Inflammation and pain can be managed with anti-inflammatory analgesics.
Early excision is rarely performed without evidence of at least ulceration, and the main indication would then be for pain control. In the scenario described, an option would be early surgical debridement and delayed closure of the wound; however, some of the surrounding skin may heal. Thus, a conservative initial approach with later excision after 2 to 3 weeks is recommended since this will give a better cosmetic result.
2010
A 43-year-old man who is HIV positive comes to the emergency department because of a 1-month history of gradually progressive swelling and pain in the tip of the right index finger. Examination shows significant swelling, erythema, and small vesicles on the fingertip and perionychium. A few nodular, reddish brown lesions are noted on the chest and forearms. Which of the following is the most appropriate management?
A ) Administration of acyclovir B ) Administration of cefuroxime C ) Administration of ketoconazole cream D ) Excision of proximal nail plate E ) Incision and drainage
The correct response is Option A.
Herpes simplex virus (HSV) infection of the hand is clinically diagnosed when characteristic multiple vesicular lesions on an erythematous base are present. The infection generally resolves within 3 weeks. If symptoms last longer than 3 weeks, suggestion of immunosuppression or AIDS should be raised. This is particularly true for the patient described, given his sickly appearance and lesions that are suggestive of Kaposi sarcoma. The staining of scrapings from the base of the lesions with a Tzanck preparation for a Papanicolaou stain demonstrates giant cells or intranuclear inclusions of HSV infection. Treatment with an antiviral such as acyclovir is recommended.
The scenario described does not primarily involve a fungal or bacterial infection. Oral/topical bacterial or antifungal treatments by themselves will not be effective. However, acute paronychia is most commonly caused by bacterial inoculation, and the most common agent is Staphylococcus aureus. Chronic bacterial infections of the subungual space are usually secondary infections of a preexisting fungal infection. Treatment consists of nail removal and application of appropriate topical antibiotics until the nail regrows.
The fungal organisms are the primary cause of chronic paronychia. Candida is the most common infecting organism. Most often affecting women, this low-grade smoldering infection causes thickening and fibrosis. Topical and systemic antifungal agents have been used for treatment of minimal-to-moderate fungal infections. For extensive infection, the nail plate is removed and topical antifungals are used. Recurrence is common.
Herpetic infections of the pulp should not be mistaken for felons or paronychia, and they should not be violated with incision and drainage. Inappropriately treated with surgery, patients may develop a local secondary bacterial bone lysis or metastatic viral encephalitis.
2010
A 60-year-old woman with type 1 diabetes mellitus has a 1-cm puncture wound to the lower leg sustained 2 days ago. Physical examination shows erythema of the surrounding tissue, tenderness of the entire calf, and crepitus. Which of the following is the most appropriate initial management of the wound?
A ) Hyperbaric oxygen therapy B ) Silver sulfadiazine dressing C ) Surgical debridement D ) Unna boot compression dressing E ) Vacuum-assisted closure therapy
The correct response is Option C.
The patient described has a severe, necrotizing soft-tissue infection, as suggested by tenderness and swelling of the entire limb compartment. Urgent debridement is required. Necrotizing fasciitis must be suspected in any patient with a compromised immune system, even when he or she has a relatively small surface wound. The infection spreads along deep tissue planes in this scenario, the muscle fascia. Severe inflammation may result in elevated compartment pressures, requiring fasciotomy. Intraoperative bacterial cultures should guide specific antibiotic therapy. Patients with severe continued or extensive necrosis may benefit from hyperbaric oxygen (HBO) therapy. After all of the necrotic tissue is removed, vacuum-assisted compression (VAC) dressings may be applied to expedite granulation. Definitive closure may involve healing by second intention, skin grafts, or flaps as clinically indicated.
2010
A 25-year-old man who is a soldier from Afghanistan is evaluated because of deep frostbite of the right hand after being in the field for 36 hours. Rewarming is performed in the field. He is transferred to a hospital for further evaluation. Physical examination shows hemorrhagic blisters and eschar formation on the hand, erythema of the surrounding area, and streaking up the forearm. Which of the following is the most appropriate next step in management?
A ) Administration of dextran B ) Administration of penicillin C ) Hyperbaric oxygen therapy D ) Intra-arterial injection of reserpine E ) Observation
The correct response is Option B.
Field management for frostbite includes rapid rewarming of the affected area with circulating water at 104 to 107.6 °F (40 to 42 °C) for a period of 15 to 30 minutes, protection from mechanical trauma, and appropriate analgesia.
Next steps in management include elevation, antitetanus prophylaxis, debridement of clear blisters, leaving hemorrhagic blisters intact, and application of aloe vera. Penicillin should be administered for cellulitis.
Adjuvant therapies can include anticoagulation, thrombolytics, hyperbaric oxygen, and sympathetic blockade; however, data to support these therapies are scant and equivocal at best. Definitive surgical amputation should be delayed for at least 3 weeks to allow for tissues to demarcate, in terms of viability.
2010
An otherwise healthy 23-year-old man is brought to the emergency department after a motor vehicle-pedestrian collision causing compartment syndrome, myonecrosis, and need for radical resection of devitalized tissue of the right thigh. He is hemodynamically stable. A photograph taken two days after his first debridement is shown. Which of the following is the most appropriate next step in management?
A) Bilaminate neodermal reconstruction B) Free contralateral anterolateral thigh flap C) Negative pressure wound therapy D) Skin grafting E) Surgical debridement
The correct response is Option E.
Given the obvious devitalized tissue in the associated photograph, the most appropriate next step would be further debridement. This is an often overlooked, but still critical, cornerstone to reconstruction, because without it, complication rates from infection are significantly increased.
Debridement involves the removal of nonviable or contaminated tissue that impedes normal tissue growth. It renews the wound and surrounding tissue to promote normal healing by removing infection, biofilm, and senescent cells.
Different debridement options are available, including mechanical, biologic, technical, and surgical methods. In this acute scenario with an otherwise healthy patient and a large amount of devitalized tissue, surgical debridement is the most appropriate choice.
All other modalities/choices are not appropriate until the wound bed is stabilized. Negative pressure wound therapy may be used in conjunction with debridement, but is not a replacement for it.
2019
A 28-year-old woman comes to the office for evaluation of excessive sweating and odor. She reports that she has a long history of heavy perspiration, mainly from the axillary and groin area. Which of the following glands contributes to her excessive and malodorous sweating?
A) Apocrine B) Eccrine C) Holocrine D) Merocrine E) Sebaceous
The correct response is Option A.
Apocrine glands are associated with sweat production and when mixed with bacteria produce body odor, which can be malodorous. There are two types of sweat glands, eccrine and apocrine. Eccrine glands are located throughout the body and secrete primarily water and salt. Apocrine glands are located in hair-bearing areas such as the axilla and groin and secrete watery fluid that is higher in protein.
There are three types of exocrine secretion. Merocrine glands secrete via exocytosis and no part of the glands is damaged or lost. Eccrine glands are a type of merocrine gland. Apocrine glands secrete via membrane budding and loss of cytoplasm. The mammary glands are a type of apocrine gland. Finally, holocrine glands secrete via membrane rupture, which destroys the cell. Examples include sebaceous glands, which contain remnants of dead cells, as well as meibomian glands of the eyelids.
Hyperhidrosis describes excessive sweating through the eccrine glands where there is an increase in number and size of these glands. Osmidrosis, or bromhidrosis, involves excess secretion of the apocrine glands combined with bacterial proliferation with corynebacterium. Enzymatic breakdown of the glandular secretions results in the malodor.
2019
A 27-year-old man comes to the emergency department for evaluation after being involved in an altercation earlier in the evening during which he sustained multiple injuries to his right hand. Physical examination shows a deep laceration over his right index and long finger metacarpophalangeal (MCP) joints. There is no evidence of tendon or neurovascular injury. The wound is debrided at bedside, packed with moistened gauze, and placed in a sterile dressing. Prior to discharge, the patient should be provided with prophylactic antibiotic coverage for which of the following microorganisms?
A) Eikenella B) Flavobacterium C) Mycobacterium D) Pasteurella E) Vibrio
The correct response is Option A.
It is important to recognize dorsal hand lacerations as a possible site for serious infection, especially in the context of altercations where a “fight bite” might have occurred. In some cases, patients may be apprehensive to admit to the source of their injury, and in these cases, physicians should err on the side of caution and provide antibiotic prophylaxis. The primary bacteria isolated from human bite wounds is Eikenella.
Pasteurella is commonly found in wounds resulting from the bites of dogs, cats, or farm animals. Flavobacterium is associated with bites from freshwater fish. Mycobacterium can be seen in bites from bears and ferrets. Vibrio is associated with shark bite wounds and other marine injuries.
2019
A 21-year-old man comes to the emergency department 10 days after undergoing a septorhinoplasty, with new-onset fever, malaise, throat pain and a painful skin rash. He recently completed a course of amoxicillin and clavulanate potassium (Augmentin). Temperature is 39.1°C (102.4°F), blood pressure is 75/40 mmHg, and heart rate is 140 bpm. Physical examination shows multiple cutaneous blisters involving the face and entire trunk (45% total body surface area [TBSA]). Intraoral examination shows mucosal erythema and erosions. Nasal examination shows nasal septal splints that were placed at the time of surgery. The patient is admitted to the hospital. Biopsy of the skin rash shows full-thickness epidermal necrosis with dermal edema and sparse dermal infiltrates. Which of the following is the most likely diagnosis?
A) Acute generalized exanthematous pustulosis
B) Drug reaction with eosinophilia and systemic symptoms
C) Stevens-Johnson syndrome
D) Toxic epidermal necrolysis
E) Toxic shock syndrome
The correct response is Option D.
Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are in the spectrum of the same disease process, characterized by a severe drug-induced immune reaction. The drug or its metabolite acts as a hapten and provides antigenic stimulation for a T-cell–mediated delayed hypersensitivity reaction. The list of offending medications is extensive and includes antibiotics, anticonvulsants and NSAIDs. Onset is within the first 8 weeks of starting the medication, and is characterized by fever, mucositis and a painful generalized vesiculobullous rash. Histology of skin specimens reveals keratinocyte apoptosis, full-thickness necrosis of the epidermis, and minimal dermal inflammation. Mucosal inflammation can involve any mucosal surface. Cutaneous involvement consists of blisters and erosions, with skin separation. Application of shear forces on the skin results in separation of the epidermis (Nikolsky sign). Skin separation of less than 10% of total body surface area is classified as SJS, greater than 30% of total body surface area as TEN, and 10 to 30% of total body surface area as SJS-TEN overlap. Multisystem organ dysfunction can occur. Treatment is supportive, with the best outcomes in patients treated early in a burn center. Intravenous corticosteroids are usually given, although their use is controversial. Mortality is 1 to 5% in SJS and 25 to 40% in TEN. Survivors are often left with skin scarring, mucosal strictures, and ocular complications.
Toxic shock syndrome (TSS) is caused by toxin-producing strains of Staphylococcus aureus and Streptococcus pyogenes. The toxin acts as a super antigen and causes widespread immune stimulation. Staphylococcal Toxic Shock Syndrome can occur after surgical or traumatic skin break or from colonization of a foreign body. Onset is within 48 hours of surgery and consists of influenza-like symptoms, fevers, and shock. Multisystem organ failure can occur. Skin desquamation usually occurs 2 to 3 weeks later. Treatment consists of source control, antibiotic therapy, and in some cases, immunoglobulins.
Acute generalized exanthematous pustulosis (AGEP) is a T-cell–mediated cutaneous drug reaction. Onset is usually within 48 hours and consists of fever, leukocytosis, and a rash consisting of many small sterile non-follicular pustules distributed predominantly on the trunk and intertriginous areas. Mucous membrane involvement is uncommon and occurs mostly in the lips and buccal mucosa. Internal organ involvement occurs in a minority of cases but can lead to multisystem organ dysfunction. Histology shows intracorneal, sub-corneal, and intraepidermal pustules and a dermal neutrophilic and eosinophilic infiltrate. Treatment is discontinuation of the offending drug, after which the condition quickly resolves. Prognosis is excellent.
Drug reaction with eosinophilia and systemic symptoms (DRESS) is a severe drug reaction of unclear pathogenesis that is characterized by fever, hematological abnormalities (leukocytosis, eosinophilia), and internal organ dysfunction. Onset is typically 2 to 8 weeks after drug exposure. Antiepileptics are most commonly implicated, although a variety of drugs, including antibiotics, can be the causative agent. Cutaneous involvement consists of a morbilliform rash. Mucosal involvement is frequent. Facial edema can be severe. Blood leukocytes are markedly elevated, with 30% of cases having eosinophilia. Multisystem organ dysfunction can occur. Histopathology reveals a perivascular lymphocytic infiltrate in the papillary dermis and dermal edema with extravasated erythrocytes and eosinophils. Treatment consists of cessation of the offending drug, systemic glucocorticoids and supportive care.
2019
A 40-year-old man presents to the emergency department because of the infection shown. Medical history includes type 2 diabetes mellitus, hypertension, kidney transplantation 5 years ago, and a 10 pack-year history of smoking (former smoker). Temperature is 39.7°C (103.5°F) and blood pressure is 80/45 mmHg, white blood cell count is 25,000/μL. He is transferred to the surgical intensive care unit for fluid resuscitation and intravenous antibiotics prior to operative debridement in six hours. Which of the following is the strongest risk factor for mortality in this patient?
A) Age B) Delay in operative debridement C) History of kidney transplantation D) History of smoking E) Type 2 diabetes mellitus
The correct response is Option B.
Necrotizing fasciitis is a rapidly progressive soft-tissue infection. Patients usually present with systemic sepsis, fever, high leukocytosis (higher than 25,000), skin findings of edema with blue discoloration, weeping blisters and cellulitis. The more severe cases can present with multisystem organ failure and altered mental status. Polymicrobial infections are most common. Streptococcal species are isolated in more than 60% of polymicrobial infections. Other organisms identified include Staphylococcus aureus, Escherichia coli, Pseudomonas, Enterobacter, Klebsiella, Proteus, Bacteroides, Clostridium, and Peptostreptococcus.
Multiple studies have reported a mortality rate of approximately 20% from necrotizing fasciitis. Mortality is directly proportional to time of intervention. Delayed surgical debridement has been shown to significantly increase the mortality risk. After diagnostic delay, the most common pitfall in treatment is inadequacy and delay in surgical debridement.
Type 2 diabetes mellitus is incorrect. Comorbid conditions such as diabetes, vascular disease and venous insufficiency are very common in these patients. Diabetes specifically is associated with higher morbidity and mortality. Studies have shown that patients with diabetes have a higher chance of a negative outcome compared to patients without diabetes. However, it has not been shown to be the most severe risk factor associated with mortality.
Smoking is incorrect. Smoking is a risk factor for delayed healing, but there are no studies that show smoking alone to be a risk factor in the progression of necrotizing fasciitis.
After delay of operative debridement, immunosuppression is the second most significant risk factor for mortality. Patients with solid organ transplantation or undergoing treatment for hematologic malignancies are most at risk. Age has been reported as another risk factor of mortality in patients with necrotizing fasciitis. Studies have shown that extremes of age, younger than 1 year or older than 60 years, were associated with mortality, but age is not the strongest risk factor among the others reported.
2019
A 59-year-old man with type 2 diabetes mellitus comes to the office because he has had swelling, pain, and decreased function of the right small finger after he injured it slightly 2 weeks ago. The patient reports similar symptoms of the right thumb, although it sustained no inciting injury. Examination of both digits shows signs and symptoms of pyogenic flexor tenosynovitis. In addition to washing out the respective tendon sheaths, exploration of which of the following additional sites is necessary?
A) First web space B) Flexor carpi radialis tendon sheath C) Hypothenar compartment D) Ring finger flexor tendon sheath E) Space of Parona
The correct response is Option E.
Infectious flexor tenosynovitis can spread from the tendon sheath of the fifth digit to the flexor tendon sheath of the thumb by way of the space of Parona: the potential space in the volar wrist, deep to the flexor tendons but superficial to the pronator quadratus muscle. In this area, the proximal extent of the tendon sheaths of both the small finger and the thumb are in close proximity. This has been termed the “horseshoe abscess” of the upper extremity.
2019
