SUMMARY. Mucor fungus infection is an opportunistic infection that can occur in immunocompromised patients. The case is presented of a burn patient with mucormycosis. A previously healthy 38-yr-old male was admitted to a non-urban hospital having sustained a burn injury (50% TBSA) combined with inhalation injury. Uneventful healing was achieved in 35% TBSA. On day 28 post-burn day, a groin flap was raised to cover a full-thickness burn on the right forearm and wrist. Signs of infection in both the hand and the flap area appeared on day 5 post-operation. Consequently, the flap was completely detached. The infection persisted and led to multiple organ failure, and in the end a forearm amputation was performed. The patient was then admitted to our burn unit. Immediate swab culture detected Mucor fungus. Despite appropriate treatment (amphotericin B and repeated debridement), the patient succumbed. This case serves to emphasize the possibility of rare but serious infections due to fungi other than Candida albicans in burn patients. Early diagnosis and treatment of these mycoses can be lifesaving, as the mortality is reported to be very high.
Fungi are common in nature and present low intrinsic pathogenicity to healthy individuals, although they can cause very aggressive infections in certain clinical conditions.
There are two main categories of fungal infections: pathogenic and opportunistic mycoses. To the group of pathogenic mycoses belong histoplasmosis, blastomycosis, coccidioidomycosis, paracoccidioidomycosis, and cryptococcosis, which can cause progressive, uncontrolled infections in patients with T-cell deficiency.
The opportunistic mycoses include candidiasis, aspergillosis, and mucormycosis. Candida species are frequently encountered as part of the human flora, while Aspergillus and Mucor are soil fungi. Opportunistic mycoses can occur only where there is phagocyte dysfunction. Mucormycosis is an infection caused by diverse fungal species, including Rhizopus, Absidia, Rhizomucor, and Basidiobolus, which belong to the taxonomic order Mucorales.1,2 There is an increasing emergence of fungal sepsis in burn patients, due to the suppression of bacteria by topical and systemic chemotherapy. The recovery of fungi from burn wounds has doubled.3,4
Immunosuppression, malignancy, trauma, prolonged treatment with high doses of glycocorticoids and antibiotics, diabetes mellitus, and other degenerating diseases are generally considered predisposing factors for severe fungal infections. True fungi are not uncommon and have much greater invasive potential. Unlike Candida infections, true fungal infections occur early in the hospital course of patients with predisposing characteristics. Patients with extensive burn injuries treated with antibiotics for a prolonged period are susceptible to serious, life-threatening fungal infections.5-8
Most commonly, Candida spp. colonize the burn wound. Arterial and venous blood cultures, dermal tissue biopsies, fungal cultures from bronchoscopy, urine cultures, and retinal examination for the characteristic lesions of Candida can be very useful.9
The early diagnosis of fungal sepsis remains a major clinical problem, as the clinical signs can be similar to those of a bacterial infection.
Mucormycosis may involve the skin, lung, brain, or other sites by haematogenous dissemination. Vascular invasion by hyphae leads to progressive tissue necrosis. Skin biopsies reveals broad, non-septate hyphae of irregular diameter. Some tissue samples may be negative, as the necrotic debris contains no organisms.
The systemic intravenous and topical administration of amphotericin B, immediate wound debridement, and early wound closure are reported to be the appropriate treatment.9,10 In this paper we report a case of mucormycosis in a male patient with a 50% TBSA burn injury.
A previously healthy 38-yr-old male patient was admitted to a non-urban hospital for a burn injury sustained during a forest blaze. There was no history of diabetes mellitus or any immunosuppressive disease.
The burn injury was estimated to extend for 50% TBSA, approximately 20% of which was full-thickness burn. The patient was reported to have suffered severe inhalation injury and was resuscitated successfully. Thirty-five per cent TBSA was healed conservatively. Escharectomy was performed on 15% of the full-thickness burn.
On day 28 post-burn, a groin flap was raised to cover a full-thickness defect in the right forearm and wrist. On day 33 he presented signs of severe infection with acute necrosis of the skin and subcutis in both the hand and flap. This local condition was also the indication for a forearm amputation and debridement of the flap’s donor site. Meanwhile the patient became septic and developed multiple organ failure. On day 39 he was admitted to our burn unit presenting a necrotizing infection in the abdominal wall, groin, and thigh and a remaining 5% TBSA burn (Fig. 1).
<% immagine "Fig.1","gr0000027.jpg","Groin and lower abdominal area of patient on day 39 post-burn (day of admission)","450" %>The patient’s overall condition was critical: he was intubated, with low blood pressure, extensive oedema, jaundice, and impaired hepatic and renal function.
An immediate specimen for swab culture and incisional biopsy from the infected area revealed Mucor fungus infection. The patient was treated with amphotericin B 0.5 mg/kg body weight/day intravenously according to the serum creatinine levels. The patient also received enteral nutrition solutions.
Repeated surgical debridement down to the fascia level of the femoral vessels was performed (Fig. 2). The excised areas were locally covered by dressings soaked in amphotericin B twice a day. The necrosis expanded rapidly around the wound margins. The patient’s condition gradually deteriorated and the patient succumbed on day 48 post-burn.
<% immagine "Fig.2","gr0000028.jpg","Groin and lower abdominal area after surgical debridement","450" %>Bacteria, viruses, and fungi cause all kinds of infections in burn patients.
The predisposing factors of fungal infections are mainly:
* a prolonged period of treatment with antibiotics
* immunosuppression (pre-existent or provoked by the burn wound)
* initial colonization caused by fungi at the place of accident or by fungi from sources in the nosocomial environment
The commonest fungal opportunistic infections in burn patients are from Candida. Infections from true fungi such as Aspergillus, Rhizopus, Mucor, and Rhizomucor are less common and are usually provoked by exposure to spores in the environment.
In our case, the accident occurred in the open air and specifically in a forest during a forest blaze; the burn wound sustained was extensive (50% TBSA), and accompanied by inhalation injury. The patient had no history of immunosuppression, but was treated with antibiotics for almost thirty days before the establishment of fungal sepsis.
Pre-mortem diagnosis of fungal sepsis occurs only in 15-40% of cases, since the condition is rare and there are no special, pathognomonic signs to facilitate diagnosis. The mortality is reported to be very high, reaching over 90%.3,11-16
Some topical agents used for wound dressings (Dakin’s solution, Polysporin, and silver sulphadiazine) have been found to enhance survival only prior to the first positive fungal culture. Once fungal sepsis is present, changes of the topical agents do not influence the survival rate.10
Immediate and extensive wound debridement and early coverage of the wound defect, preferably with allografts, are considered to be the proper surgical approach to the treatment of fungal infections in burn patients.2,4,10,15
The coverage of a burn area by skin grafts or flaps should be performed only when the wound infection is controlled (negative swab cultures and biopsies) and there is no clinical evidence of fungal sepsis. Free flaps are indicated, while pedicled flaps should be avoided owing to the possibility of the dissemination of infection. In the case we report, the infection was carried through the inguinal flap to the area of the femoral vessels, an area where surgical debridement is limited by anatomical landmarks. The patient presented infected areas around the umbilicus and right foot (Fig. 3). This last feature is a sign that distal sites may also be involved through haematogenous dissemination.
In order to avoid the fatal results of these rare but life-threatening infections, continuous and careful wound surveillance is needed. Regular fungal cultures and biopsies must be performed immediately when there are clinical signs of fungal sepsis, particularly in patients who have been hospitalized and treated for a long period with antibiotics and in whom the bacterial cultures remain negative.
Intravenous and local administration of amphotericin B, extensive and repeated debridement, and cautious coverage of the burn wound are the milestones of the treatment of mucormycosis in burn patients.
<% immagine "Fig.3","gr0000029.jpg","Necrotizing area around umbilicus","450" %>RESUME. L’infection causée par les champignons Mucor est une infection opportuniste qui peut se produire dans les patients immunocompris. Les Auteurs décrivent le cas d’un patient atteint de mucormycose. Un homme sain âgé de 38 ans a été hospitalisé dans un hôpital non urbain atteint de brûlures (50% de la surface totale corporelle) associées à des lésions par inhalation. Le 35% s’est cicatrisé sans problèmes. Le jour 28 après la brûlure un lambeau inguinal a été créé pour couvrir une brûlure à toute épaisseur sur l’avant-bras droit et le poignet. Des indications d’une infection dans la main et dans la zone du lambeau se sont manifestées le jour 5 après l’opération chirurgicale. Le lambeau à été donc détaché totalement. L’infection persistait jusqu’à porter à une insuffisance multiorganique et à la fin il a été nécessaire d’effectuer l’amputation de l’avant-bras. Le patient à ce point a été transféré à l’unité des brûlures des Auteurs. L’immédiate culture des écouvillons a indiqué le champignon Mucor. Malgré tous les traitements effectués (Amphotericin B et débridement répété), le patient est mort. Ce cas souligne la possibilité de la manifestation dans les patients brûlés de maladies rares mais graves causées par les champignons en dehors de Candida albicans. Le diagnostic et le traitement précoces de ces mycoses peuvent sauver la vie pusque la mortalité, selon les données de la littérature, peut être très élevée.