A retrospective review of patients with necrotizing fasciitis presenting to an emergency department in Hong Kong

Transcription

1 Hong Kong Journal of Emergency Medicine A retrospective review of patients with necrotizing fasciitis presenting to an emergency department in Hong Kong FP Sin, MC Yuen, KW Lam, CW Wu, WK Tung Background: Necrotizing fasciitis is a soft tissue gangrenous infection that require early diagnosis, radical debridement and broad-spectrum antibiotics. Aim: To review the clinical spectrum and outcome of necrotizing fasciitis in Kwong Wah Hospital during a period of 18 months. Method: Cases of necrotizing fasciitis were identified from discharge statistics for the period January 1999 to June Accident and Emergency Department (AED) notes and clinical records after admission were reviewed for clinical features, predisposing factors, microbiology, histology, treatment and outcome. Results: Fifteen cases of necrotizing fasciitis were found but two of them had wrong diagnosis made. Of the thirteen cases, ten were male and three were female. The average age was 61.7 years old. Most of them presented with different combinations of swelling, pain, erythema and fever. They attended the emergency department with an interval of 3.5 days from the onset of symptoms. Risk factors were identified in 64% of patients, with diabetes mellitis (DM) and hypertension (HT) being the most common. Monomicrobial and polymicrobial infections were equally common in our study. Streptococcus pyogene was the most common pathogen. Only two NF (18%) were diagnosed in AED. Six patients were admitted to either surgical or orthopaedic wards and all of them underwent operations within 24 hours although two of them died. Other five patients were managed in medical ward and four of these patients underwent delayed operations but survived whilst one of them died despite of early surgical intervention. Overall mortality was 23%. Conclusions: This condition affects a wide age group and have associated morbidities. It is often a fatal disease. Early recognition, high dose antibiotics and surgical debridement are important in its management. (Hong Kong j.emerg.med. 2002;9:10-17) Keywords: Group B streptococcus, necrotizing fasciitis, review Background Necrotizing fasciitis (NF) is a soft tissue gangrenous infection, which is uncommon but often fatal. Treatment includes early surgical debridement, parenteral antibiotics, and nutritional support. Correspondence to: Sin Fu Ping, MBBS, FRCS(Edin) Kwong Wah Hospital, Accident and Emergency Department, 25 Waterloo Road, Kowloon sinfp@sinatown.com Yuen Man Cheuk, MBBS, FRCS(Edin) Lam Kam Wah, MRCP, FHKAM(Emergency Medicine) Wu Chun Wah, MRCP, FHKAM(Emergency Medicine) Tung Wai Kit, FRCS(Edin), FHKAM(Emergency Medicine) However, the diagnosis is usually made late and results in increased morbidity and mortality. 1-5 It is because the presentation of the disease is non-specific and is easily confused with other soft tissue infections e.g. cellulitis. In addition, there is no sensitive nor specific investigation which aids the early diagnosis of this disease. Recent reports have suggested that magnetic resonance imaging and frozen section tissue biopsy can accurately distinguish necrotizing fasciitis from non-necrotizing fasciitis infection but such studies are usually not routinely available. 6 Conventionally, the diagnosis relies on high clinical suspicion of the disease, followed by surgical exploration which typically show a thin brownish discharge, and dull grey, oedematous and necrotic fascia and subcutaneous tissue. Necrotizing fasciitis must be considered if there

2 Sin et al./necrotizing fasciitis patients presenting to an ED in Hong Kong 11 is severe pain, history of trauma or any unexplained soft tissue pain and swelling. In addition, emergency physicians must be aware of those with increased risk including those who are immunocompromised, diabetic and others with abnormal peripheral circulation, as well as patients with burns, traumatic wounds, or surgical incision. This article is designed to identify any peculiar features of the presentation of NF through a retrospective review of patient with NF managed in a district hospital in Hong Kong. The result of this study may help emergency physicians familiarise themselves with the presentation and make a promptly diagnosis in this serious condition. Aims To review the presentations and outcomes of necrotizing fasciitis who presented to the Accident and Emergency department (AED) of Kwong Wah Hospital in previous 18 months. Materials and methods Cases of necrotizing fasciitis were identified from discharge statistics using CMS system interface, using the keyword "necrotizing fasciitis", for the period from January 1999 to June Clinical notes of AED and clinical records after admission were retrieved from the medical record office. Clinical presentations including symptoms, signs, duration, predisposing factors and disposals in AED were reviewed. Microbiology, pathology, treatment and outcome after admissions were also summarized. Patients with necrotizing fasciitis developed during in-patient hospitalization were excluded. Necrotizing fasciitis was determined by operative and pathological findings after admission. It was defined as the presence of necrotic fascia and/or muscle noted at surgery or on pathologic examination of debrided tissue. Lack of resistance of normally adherent fascia to blunt dissection is diagnostic of necrotizing fasciitis. "Suspected" NF was considered if the disease was diagnosed intra-operatively but was not accompanied with appropriate documentation of typical findings of fascial necrosis in operative record and pathological evidence provided by biopsy. In other words, the diagnosis of the disease was based on assumption that the intra-operative findings were accurate but were not properly written down. The reliability of the diagnosis, therefore, could not be evaluated objectively by sole assessment of clinical notes. Results Fifteen cases were identified as necrotizing fasciitis on the discharge summaries for the period from January 1999 to June One patient had Fournier's gangrene (necrotizing fasciitis of perinum) during hospitalization and was excluded. Another two cases have alternative diagnoses instead of necrotizing fasciitis after reviewing the clinical notes and pathological reports. Seven necrotizing fasciitis were confirmed based on the above definitions. Biopsies were taken amongst five cases but only one biopsy was satisfactory and revealed necrosis of fascia. A satisfactory tissue biopsy should include skin, deep soft tissue and fascia and/ or underlying muscle. Biopsies in other cases, however, only included soft tissues, rather than skin, subcutaneous tissue, fascia and underlying muscle, and histological examinations reported necrosis of fibrofatty tissue, acute inflammation or abscess only. The remaining five cases were considered as "suspected" NF because of lack of proper detailed documentation of operative findings and pathological evidences. The average age of the patients was 60.3 years (37-77 years). Nine patients were male and three of them were female (75% vs 25%). All patients with NF required intravenous antibiotics and surgical debridements under general anaesthesia after admissions. The first consultation and disposal The clinical presentations and provisional diagnoses in emergency department were summarized in Tables 1 and 2. Nearly all patients were admitted for further management and one was discharged home with

3 12 Hong Kong j. emerg. med. Vol. 9(1) Jan 2002 Table 1. Diagnosis and disposal in emergency department. Diagnosis Wards No Necrotizing fasciitis Orthopaedic 2 Cellulitis Surgical 1 Orthopaedic 1 Medical 1 Abscess Orthopaedic 2 Septic shock Orthopaedic 1 Deep vein thrombosis Medical 3 Knee pain Discharge 1 N.B. Total number of patients in this table=12 diagnosis of "knee pain". (Patient 11 in Table 2) Six patients were admitted to orthopaedic ward, one into surgical ward and four into medical ward. Only two necrotizing fasciitis (16.7%) were diagnosed correctly in ED before any surgical opinion. However, one of them was diagnosed in Our Lady of Maryknoll Hospital before being transferred to Kwong Wah Hospital. Another patient was a female intravenous drug abuser, who presented with right limb numbness, pain and swelling for seven days. She was discharged Table 2. Presentations, risk factors, chronic diseases and provisional diagnoses in accident and emergency department (ED). Patients Presentations on Risk factors/ Diagnosis & disposal Remarks (Age/Sex) attendance to ED Chronic diseases (Ward/Discharge) 1. M/61 Left leg swelling x 3/7 DVT, medical 2. F/72 Left leg swelling, pain x 5/7 HT NF, orthopaedic Transferred from OLMH 3. M/64 Left groin pain, swelling Left groin cellulitis, surgical 4. F/46 Right thigh pain & swelling IVDA NF, orthopaedic DAMA from CMC x 1/52; right LL numbness before 5. M/77 Multiple bedsores on left hip, IHD, AF, PVD, Septic shock, orthopaedic Transferred from sacrum, right BKA stump, left right BKA, old CVA, WTSH hand, hypotension bed-bound 6. M/65 Right leg swelling x 2/7; fever History of right leg Cellulitis right leg, abrasion orthopaedic 7. M/37 Left middle finger erythema DM Left middle finger abscess, and swelling orthopaedic 8. M/66 Right thigh pain, swelling DM, cirrhosis Abscess, orthopaedic and discharge x 1 week 9. M/66 Left foot swelling and pain x 3/7 DM, HT DVT medical 10. M/43 Left calf swelling x 4/7; fever IVDA DVT medical 11. M/53 Both knee pain DM, old PTB Knees pain, discharged Missed diagnosis (Appendix) decreased GC and confusion Septic shock, medical 3/7 later 12. F/74 Right ankle pain and DM, HT, old PTB, Cellulitis, medical swelling x 3/7 dementia DAMA discharged against medical device; IVDA intravenous drug abuser; OLMH Our Lady of Maryknoll Hospital; WTSH Wong Tai Sin Hospital

4 Sin et al./necrotizing fasciitis patients presenting to an ED in Hong Kong 13 against medical advice from Caritas Medical Center because there was no active intervention. On the next day she attended Kwong Wah Hospital and examinations showed obvious black discolouration and necrosis over left thigh, which made this diagnosis obvious. Clinical manifestations On average, time from onset of symptoms to first consultation was 3.5 days (1-7 days). Symptoms and signs of patients were summarized in Table 3; although some of them were only present during observation in hospital. The most common presentations of NF were swelling (92%), pain (92%), erythema (75%) and fever (67%). Hypotension was identified in emergency department in two cases (16.7%), and one of them required resuscitation and intubation because of mental confusion. Another two patients developed hypotension during hospitalization, signifying deterioration of the disease. Lower extremities were affected in nine patients (75%, see Table 2). One NF arose from the bedsore on left hip. Other sites of diseases included left groin and left middle finger. Associated diseases/risk factors (Table 2) Fifty eight percent of patients (7 out of 12) had concomitant medical diseases, with diabetes mellitus Table 3. Summaries of symptoms/signs of NF. Signs /symptoms No. (percentage) Swelling 11 (92) Pain 11 (92) Erythema 9 (75) Fever 8 (67) Bullae 5 (42) Draining wounds 3 (25) Necrosis 3 (25) Hypotension 4 (33) Black discolouration 1 (8) Ulcer 1 (8) Bedsore 1 (8) Numbness 1 (8) and hypertension being the most common: 42% and 33% of patients respectively. Overall, nine patients (75%) had risk factors that were shown to be associated with NF in other studies, which included diabetes mellitus, cirrhosis, peripheral vascular disease, injury and intravenous drug abuser. Only one patient had preceding injury in our series. Two patients were intravenous drug abusers. Organisms The frequencies of organisms of NF were summarized in Table 4. Streptococcus was the most common organism (9 patients) whereas bacteriodes fragilis and peptostreptococcus were the second most common pathogens. Amongst the various species of streptococcus, group A streptococcus was isolated most often. Single causative organism was identified in six patients (50%). Streptococcus pyogene was the most common single causative isolated organism (three patients). Five patients (41.7%) had cultures of mixed bacteria, all of which were mixed growth of anaerobic and aerobic bacteria. On average, 3.3 bacteriae were isolated in mixed bacterial infections. Blood culture of one patient grew bacteriode fragilis and peptostreptococcus. One patient had negative culture. Table 4. Bacteriae isolated. Organisms Streptococcus pyogenes Group B streptococcus (GBS) Group G streptococcus Streptococcus milleri Streptococcus viridans Staphylococcus aures Bacteriode fragilis Peptostreptococcus species Enterobacter No. / single or mixed infection 4 (3 single, 1 mixed) 3 (1 single, 2 mixed) 1 (single) 1 (mixed with GBS and others) 1 (mixed) 2 (1 single, 1 mixed) 3 (mixed) 3 (mixed) 2 (mixed) E. Coli 1 (mixed) Klebsiella Proteus mirabilis Clostridium perfringe 1 (mixed) 1 (mixed) 1 (mixed) Arcanobacteridum hemolyticum 1 (mixed)

5 14 Hong Kong j. emerg. med. Vol. 9(1) Jan 2002 Progress and outcomes (Table 5) All patients were treated with intravenous antibiotics and debridements after admissions. The mortality was 25% and was detailed in Table 5. On average, each patient received 3 operations (1-7 operations). Seven patients required reconstruction of defects by skin or flap grafting. Two patients required above-knee amputations (all were admitted to medical ward initially). Patients in surgical or orthopaedic ward underwent early operations within 24 hours although one orthopaedic and one surgical patient required few hours' observation. Only one patient, (Appendix in Table 2) who had accompanied septic shock, in medical ward underwent early operative debridement. However, the remaining four patients in medical ward were initially treated with antibiotics and were kept under observation following orthopaedic assessment. These patients had provisional diagnoses of either "DVT" or "cellulitis" and DVT was excluded by Doppler ultrasound examination. Debridements were ultimately carried out for these patients but were delayed by 7 days on average (day 4, 6, 8 and 10 respectively). Fortunately, all four patients survived although two of them required amputations. The average duration of hospitalization for those who survived was 38.8 days (9-90 days). Three patients were transferred to Wong Tai Sin Hospital for rehabilitation. One was able to walk with the aid of a walking frame upon transferral. Another was wheelchair bound but was being trained to use walking aid. Six patients were discharged home. Amongst them, three patients required walking frame and one needed tripod for support. One was able to walk independently without walking aid. One of them suffered NF of middle finger from middle phalanx to terminal phalanx and was follow-up at hand clinic. Discussion Necrotizing fasciitis is a soft tissue gangrenous infection that is optimally treated by early diagnosis, radical surgical debridement of all involved necrotic tissue, broad spectrum antibiotics, and aggressive nutritional support. 1 The goal of initial antibiotic therapy is to assure broad coverage of aerobic Grampositive (streptococci, staphylococci) and Gramnegative enteric organisms and anaerobes. 7,8 Specific initial antibiotic recommendations vary. They include Table 5. Operations and outcomes. Patients Time to first Total no. of operation/ Length of hospitalization/outcomes (Age/Sex) operation graft or amputation required 1. M/61 Day 4 4, SSG 46 days, to WTSH, walk with frame 2. F/72 3 hr 34 min 3, SSG 21 days, walk with frame 3. M/64 8 hr 6 min 7, STSG 90 days, walk with frame 4. F/46 21 hr 27 min 1 (refused further operation) 20 days, to WTSHDAMA after transferal 5. M/77+ 5 hr 23 min 1 (no further debridement due Dead on Day 15 to poor prognosis ) 6. M/65 5 hr 53 min 2, SSG 20 days, walk without aid 7. M/37 2 hr 17 min 3, cutaneous flap 9 days 8. M/66+ 8 hr 30 min 1 Dead on Day M/66 Day 8 3, AKA 24 days, to WTSH, wheel-chair bound, training for prosthesis 10. M/43 Day 10 3, left AKA, left hip disarticulation 64 days, walk with frame 11. M/53*+ 2 hr 35 min 1 Dead 12 hours 12. F/74 Day 6 2, free gracilis muscle flap, STSG, 55 days, walk with tripod fascia lata graft *missed diagnosis; + mortality SSG split skin graft; STSG split thickness skin graft; AKA above knee amputation; DAMA discharge against medical advice

6 Sin et al./necrotizing fasciitis patients presenting to an ED in Hong Kong 15 the combination of penicillin or cephalosporin, an aminoglycoside, and anaerobic coverage with either clindamycin or metronidazole. 7 Hyperbaric oxygen therapy is controversial. 1,3 This review aims to summarize the common symptoms and signs of patients with necrotizing fasciitis who presented to our Accident & Emergency department. However, this review only involved 12 cases of necrotizing fasciitis and this small-scale review is not eligible to produce any statistically significant conclusion. In addition, the results are further complicated by the presence of "suspected" cases of necrotizing fasciitis in which the accuracy of the diagnosis cannot be assessed objectively. This "operative diagnosis" was based on the assumption that the intra-operative findings were reliable and accurate in the absence of pathological evidence. The accuracy of diagnosis therefore totally depend on experience and knowledge of in-charge surgeons. Similar to other studies, the most common presentations in our series were swelling (92%), pain (85%) and erythema (77%). 1,4,6,8 Prior studies have identified symptoms and signs that are highly suggestive of NF, such as haemodynamic instability, crepitance, skin necrosis and bullae. In a series of 198 patients with necrotizing soft tissue infection, Elliott et al 4 reported hypotension in 11.1%, skin necrosis in 31.1%, bullae in 23.7% and crepitance in 36.5%. Our series revealed similar incidence of necrosis (25%) and hypotension (17%). Bullae, another useful predictor of NF, were more common in our patient (42%). Crepitus and soft tissue air, although very suggestive of an anaerobic infection, do not occur. Necrotizing fasciitis typically affects the extremities, but sometimes is seen on the perineum, face, and other parts of the body. 5-9 Seventy five percentage of NF affected extremities in our patients. There is no age or sex predilection for NF in other studies. The disease occurs more frequently in intravenous drug users, renal or liver disease, alcoholics, diabetes, immunosuppressed patients, and patients with peripheral vascular disease, 6-11 although it also occurs in young, previously healthy individuals. In this review, nine patients had risk factors of NF. Diabetes was the most common associative disease (42%), similar to other studies. 2,4 Other risk factors present included preceding injury (8%), peripheral vascular disease (8%), cirrhosis (8%) and intravenous drug abusers (17%). Necrotizing fasciitis is caused by a variety of aerobic and anaerobic organisms. With respect to the organisms present, aerobes are found 10% of the time and anaerobes approximately 20% of the time. The remaining 70% are mixed infection with anaerobic and aerobic organisms. Overall, streptococci are the most common causative organisms. 1,8 and approximately 10% of NF are caused by group A streptococcus. 11 A single organism is isolated from wound cultures in less than 10% of cases. An averages of 3.1 to 4.6 organisms were isolated per culture specimen. 11 The usual aerobic organisms include group A Streptococcus, Staphylococcus aureus, Escherichia coli, and other enterobacteriaceae. Anaerobic organisms include Peptostreptococcus spp, Prevotella spp, Porphyromonas spp, Fusobacterium spp, Bacteroides spp, and Clostridium spp Unusual pathogens include group B, C, G, or F Streptococcus, Haemophilus influenzae type b, Pseudomonas aeruginosa, Vibro cholerae, Vibro vulnnifcus, and Flavobacterium odoratum. 8,11 In the study of Elliott 4 of 198 patients, one organism from wound culture grew in 15%, and 54% of these were attributed to streptococcus. Only 7% of patients had only anaerobic organisms; 47% of patients grew out only aerobes, and another 47% had mixed aerobic and anaerobic organisms grow on initial wound cultures. In contrast to other studies, the percentage of single causative organisms in our series was much higher (50%) and streptococcus was identified in 66.7% of single microbial infection and group A streptococcus was the most common strain. For other patients, culture specimens on average grew 3.3 organisms. Mortality rates range from 9% to 74% 5,6,8,10 and as high as 76% has been reported. 7 In the largest series

7 16 Hong Kong j. emerg. med. Vol. 9(1) Jan 2002 to date, the overall mortality rate was 29%. 7,8 Some studies found that delay in diagnosis and treatment correlated with poor outcome. 3,5,7,8,11 Other risk factors that have been shown to correlate with increased mortality include age over 50 years, diabetes mellitus, peripheral vascular disease and chronic renal disease, other systemic disorders, malnutrition and anatomic site of infection involving the trunk. 4,7,8 Elliott reported other risk factors for death including age, female gender, extent of infection, delay in first debridement, elevated serum creatinine level, elevated blood lactate level, and degree of organ system dysfunction. 4 Bosshardt et al found that the extent of initial infection, initial blood pressure, and initial temperature were independent predictors of outcome. 2 Mortality in our case series was 25%. The three succumbed patients had delayed diagnosis, poor premorbid state or chronic diseases including diabetes mellitus and cirrhosis. Surprisingly, all patients with delayed first debridements survived, which contradicted the general belief of delayed debridement being the poor prognostic factor. However, no conclusion can be drawn due to the small sample size. Definitive management of necrotizing fasciitis relies on early and invasive operative intervention by surgeon. In our settings, any suspected case must be admitted before any assessment by experienced surgeons. All seven patients in surgical wards (six admitted to orthopaedic wards; one to surgical ward) could undergo early operations within 24 hours. In contrast, the first debridements were delayed for patients with "DVT" or "cellulitis" in medical ward. Fortunately, these patients survived although two of them required above-knee amputation, which implied the rapid progression of the disease. It is obvious that these misdiagnoses might be ascribed to presence of "swelling", which is common for DVT, cellulitis and necrotizing fasciitis. In a retrospective study by Wall et al, 2 the NF patients differed from the non-nf patients with respect to the presence of tense oedema (38% vs 0%) and bullae (24% vs 0%). In the presence of tense oedema in addition to cellulitic skin change, the admitting doctors in emergency department should be more prudent in making diagnosis and should have a high index of suspicion of necrotizing fasciitis. Conclusion Necrotizing fasciitis is an uncommon soft-tissue infection that is characterized by widespread fascial necrosis with relative sparing of skin and underlying muscle. It is often associated with severe systemic toxic reactions and is usually rapidly fatal if not promptly recognized and aggressively treated. Diagnostic clues include severe local pain, fever, necrosis, hypotension and bullae. Treatment included early and adequate surgical debridement, parenteral antibiotics and nutritional support. The junior doctors in emergency department should be familiar with the common presentations of necrotizing fasciitis and should have a high index of suspicion of necrotizing fasciitis, especially when "cellulitis" is associated with tense oedema. References 1. Majeski J, Majeski E. Necrotizing faciitis: improved survival with early recognition by tissue biopsy and aggressive surgical treatment. South Med J 1997;90(11): Wall DB, de Virgilio C, Christian MD, et al. Objective criteria may asist in distinguishing necrotizing fasciitis from nonnecrotizing soft tissue infection. Am J Surg 2000;179(1): Brogan TV, Nizet V. A clinical approach to differentiating necrotizing fasciitis from simple cellulitis. Infect Med 1997;14(9): Elliott DC, Kufera JA, Myers RAM. Necrotizing aoft tissue infections-risk factors for mortality and strategies for management. Ann Surg 1996;224(5): Wang KC, Shih CH. Necrotizing fasciitis of the extremities. J Trauma 1992;32(2): Botte MJB, Hamner DH. Necrotizing fasciitis of the extremities. J Am Acad Orthop Surg 1991; Green RJ, Dafoe DC, Raffin TA. Necrotizing fasciitis. Chest 1996;110(1): Chapnick EK, Abter E. Necrotizing soft-tissue infections. Infect Dis Clin North Am 1996;10(4):

8 Sin et al./necrotizing fasciitis patients presenting to an ED in Hong Kong Hill MK, Sanders CV. Skin and soft tissue infections in critical care. Crit Care Clin 1998;14(2): Jarrett P, Rademaker M, Duffill M. The clinical spectrum of necrotizing fasciitis. A review of 15 cases. Aust N Z J Med 1997;27(1): Stone DR, Gorbach SL. Necrotizing fasciitis. The changing spectrum. Dermatol Clin 1997;15(2): RegevA, Weinberger M, Fishman M, et al. Necrotizing fasciitis caused by Staphylococcus aureus. Eur J Clin Microbiol Infect Dis 1998;17(2): Gardam MA, Low DE, Saginur R, et al. Group B streptococcal necrotizing fasciitis and streptococcal toxic shock-like syndrome in adults. Arch Intern Med 1998; 158(15); Appendix This 53 years old man, with history of diabetes mellitus and old pulmonary tuberculosis, presented with bilateral knee pain for two days to the Accident and Emergency department. He was afebrile and there was no obvious swelling or erythema. He was then discharged with oral NSAID (Naprosyn) with the diagnosis of "knees pain". Subsequently, the patient consulted a GP because of chills and rigors, and he was diagnosed to be suffering from "flu". The patient later sought the opinion of a private orthopaedic surgeon for his persistent left leg pain and chills and rigors. He was still afebrile and his left leg was swollen. His white cell count was normal (8.4 x 10 9 /L). The next day, his condition deteriorated and was referred to our emergency department by the private doctor. On arrival, he was hypotensive and confused, and required airway intubation and fluid resuscitation. He was admitted to medical ward with provisional diagnosis of "septic shock". On detailed examination, his left leg was warm and swollen, and his left elbow was cyanotic and had multiple bullae. Clinical diagnosis of 'necrotizing fasciitis' was made and fasciotomy and debridement were performed less than three hours after admission. Intra-operative findings included necrotic subcutaneous fat and fascia, thrombosis of superficial vessels of both left elbow and left calf. The patient succumbed 12 hours after admission. Blood culture and wound swabs of left calf and right elbow all showed positive growth of group B streptococcus.