Management and Surgical Dressing Protocol for Cutaneous Mucormycosis After a Blast Injury: A Case Report

Introduction

The incidence of fungal infections, a serious threat to public health, is rising in hospitals worldwide. The dilemma with these invasive infections is that they are often challenging to diagnose and are increasingly resistant to known anti-fungal therapies [1]. Mucormycosis is an opportunistic infection caused by fungi from the Mucorales order and has been increasing in incidence in multiple parts of the world [2]. It is still rare, but it spreads rapidly, significantly affecting morbidity and mortality in infected patients [3]. The disease typically manifests after inhalation or ingestion of food contaminated with spores; however, it can also cause cutaneous infection by accessing skin through cracks or wounds [2]. Blast injuries pose a risk factor for the development of invasive fungal infections, such as mucormycosis, due to disrupted tissue perfusion and the resulting hypoxic environment. Victims of blast injury display extensive trauma and multiple penetrating wounds, sometimes exposed to fertile soil that can aid in the inoculation of the disease [4]. The diagnosis of mucormycosis is challenging and requires a high level of suspicion as it is rare and lacks distinctive clinical features; a confirmed diagnosis is established through microbiological identification of mucormycosis species via culture or microscopy. Various treatment strategies have been proposed, but no consensus management guidelines have been established in the literature [2]. In this article, we report a case of cutaneous mucormycosis encountered at our hospital following a blast injury, along with a proposed management strategy aimed at improving clinical outcomes for patients with this condition.

Case Report

This is a case of a previously healthy, 40-year-old man who was transferred to a tertiary hospital 3 days after sustaining a blast injury. Upon arrival, his body was covered in soil, he was in pain all over his body, and he was tachycardic. Otherwise, he was conscious, alert, and oriented, maintaining his blood pressure and saturation on room air. His hemoglobin at the time was 68 (normal 125–180 g/L), he had a white blood cell (WBC) count of 2.2 (normal 4–11×109/L), and a platelet count of 83 (normal 150–450×109/L). His inflammatory markers were elevated: C-reactive protein (CRP) level was 273.6 mg/L (normal range 0–6 mg/L), erythrocyte sedimentation rate (ESR) was 79 mm/h (normal range 0–15 mm/hr), and procalcitonin was 7.25 mcg/L. Therefore, he was admitted to the intensive care unit, underwent resuscitation with fluids, received a packed red blood cell transfusion, analgesia, and regular paracetamol, and was started on empiric antibiotics.

His injuries included traumatic amputation of the left middle and index fingers, with left forearm laceration and exposed tendons and vessels. He also had a right-hand injury with a fractured thumb and middle finger. In addition, he had a traumatic right above-knee amputation with collection and infection that was on surgical drain upon presentation. The left lower limb was burnt, with multiple infected wounds, abscesses, and shrapnel, and there were numerous shrapnel and lacerations in the scrotum and penis. Moreover, he had a left 10th rib fracture and a right knee fracture, which were managed conservatively (Figure 1).

During admission, he underwent intraoperative sessions of debridement and dressing changes on all limbs and affected areas, as per our personally developed protocol, which was performed every 3 to 5 days. Our protocol consisted of the following, starting, while the patient is under general anesthesia, and utilizing an aseptic technique, all the affected areas would be irrigated with normal saline. Then, aggressive debridement of all infected wounds and tissue as required is performed. Re-irrigation follows debridement, and the wounds are then covered or packed with large surgical gauze. After that, the packed gauzes are irrigated with 80 mg of gentamicin in 1 L of normal saline, and kept for 2 minutes. Another irrigation with a 500 ml octenidine-containing solution is performed, leaving it for an additional minute. Next, the affected areas are washed with sterile water, then we apply a gel containing octenidine dihydrochloride. Finally, chlorhexidine paraffin gauzes, cotton rolls, and crepe bandages or a vacuum-assisted closure (VAC) device are applied over the wounds, as indicated.

By hospital day 9, he had chills, rigors, and sweating at night, prompting an antibiotics upgrade from ceftazidime to piperacillin-tazobactam. The symptoms became more frequent the next day, occurring every 3 hours for 2 days. On hospital day 12, during the fourth session of wound change and minimal debridement intra-operatively, the wounds had developed more slough tissue and an area of necrosis, and the stump exhibited a serous-to-clear whitish discharge, which initially decreased with each intraoperative session. We suspected a mucormycosis infection because the patient was a bomb blast survivor with extensive multiple penetrating wounds and skin breaks, prolonged unattended exposure to soil, unexplained worsening generalized symptoms, and deteriorating wound condition despite appropriate debridement and dressing. Various tissue specimens were taken from the upper and lower limbs and were sent for culture and histopathology. Moreover, liposomal amphotericin B was administered empirically with a dose of 255 mg intravenously daily. By day 14, he had received 2 sessions of anti-fungal therapy; subsequently, the chills and rigors resolved. By the fifth intraoperative session, on hospital day 15, there was significant wound healing. Hence, we decided to continue amphotericin without clear microbiological evidence of the infection. Two weeks later, mucormycosis infections were evident histologically, while all the cultures taken were negative (Figures 2, 3).

By hospital day 44, he had completed 32 days of liposomal amphotericin B treatment and 11 sessions of intraoperative debridement and dressing, resulting in healed wounds and a stump (Figure 4). He was eventually referred to our prosthetics program. He completed his rehabilitation therapy and was discharged home in good condition. He visited the clinic 6 months after discharge; having resumed his normal lifestyle, living independently, walking using an above-knee prosthesis, and attending social events (Table 1, summary of clinical timeline and treatment progression).

Discussion

Mucormycosis is a fulminant form of severe fungal infection and is frequently fatal unless diagnosed early and treated aggressively. It is the third most common angioinvasive fungal infection, following candidiasis and aspergillosis [5,6]. It usually affects immunocompromised patients, commonly diabetics, and is rarely seen in apparently healthy individuals. Patients who receive severe burn injuries are also at risk of cutaneous mucormycosis, which can be a challenge to diagnose. In such patients, especially after trauma, standard antimicrobial therapy may be insufficient until mucormycosis is suspected or diagnosed [7–9].

Zahoor et al. presented the case of a trauma patient with mucormycosis, hypothesizing that trauma might induce immune deficiency and facilitate the occurrence of mucormycosis [10]. In their case, the infection was transmitted via soil contamination from a motor vehicle accident, which was consistent with our case, as our patient was a bomb blast survivor who was covered with soil for a few days before arriving at our hospital. Similarly to our patient, their patient underwent multiple consecutive operations and procedures and was on regular antipyretics, which was masking the fever. However, our patient had significant persistent chills in addition to worsening wound condition despite the use of broad-spectrum antibiotics. Later, histopathological examination revealed the presence of mucormycosis infection. In addition, as in our case, the infection was not evident in cultures [10].

Furthermore, increased suspicion is needed when dealing with non-healing wounds, especially in immunocompromised individuals. In a case report of a 63-year-old diabetic man with poorly controlled diabetes who presented with a chronic, persistent wound, further investigations and biopsy showed fungal hyphae, which confirmed the diagnosis of mucormycosis [5]. Mucormycosis can present in a variety of ways; it can also present atypically, as mentioned in the literature. A 50-year-old woman presenting with swelling and erythema of the face for more than 4 months after tooth extraction was investigated, biopsied, and later diagnosed with mucormycosis histopathologically [11].

Alshammary et al reported a case of a 26-year-old patient who had a large, penetrating, foul-smelling wound after a blast injury. Their medivac patient arrived 2 days after the incident; his wounds had contact with soil after the trauma, and he was also kept on empirical antibiotics. On hospital day 2, he underwent the first session of intraoperative debridement and irrigation. Unlike our patient, theirs was washed only with saline; no use of octenidine-containing solution or antibiotics topically was mentioned. He underwent another intraoperative session on the next day, at the end of which the VAC machine was applied to the wound. However, on hospital day 4, the wound worsened significantly, developing a whitish, feathery necrotic tissue. Similarly, in our case, mucormycosis was suspected, and amphotericin was started empirically after sending samples for fungal cultures and histopathology. Eventually, Alshammary’s patient required hip disarticulation surgery of the right lower limb, a form of amputation, due to the development of systemic disease and a worsening wound condition. In contrast to our case, the cultures after surgery showed mucormycosis infection with Rhizopus species and concomitant group A streptococcus. Their patient was discharged home 21 days after the operation, with close infectious disease and rehabilitation therapy follow-up [4].

Early diagnosis and management while the disease remains confined to the skin and subcutaneous tissue are associated with improved patient outcomes. However, if the disease disseminates, it can have a catastrophic consequence. A systematic review conducted in 2023 recently showed that disseminated mucormycosis had an 80% mortality rate, compared to a 36% mortality rate in patients with localized disease (P<.001) [11], which shows the importance of adequate wound care, as inadequate management may lead to the development of systemic disease. Debridement of such wounds in an appropriate setting and obtaining a sample for histopathology are the cornerstones of early diagnosis and avoiding catastrophic complications.

In our experience, performing a proper surgical debridement and selecting an appropriate dressing protocol, including washing with antibiotics and applying a VAC machine, can aid in managing mucormycosis infections, as also reported in another paper not listed by Loese et al [12]. Currently, there are no clear guidelines for managing mucormycosis in surgical patients, particularly in the context of blast injuries. Further research is needed to establish consensus on the optimal frequency and duration of wound assessments, the extent of surgical debridement, and the most appropriate type of dressing. We present this case to contribute to the growing body of literature and in the hope of enhancing clinical decision-making and patient care in similar complex scenarios.

Conclusions

Mucormycosis is a fungal infection that can present in a trauma setting and can affect immunocompetent patients, associated with devastating health outcomes. Having a high level of suspicion is essential to start treatment early to reduce or avoid complications. Given that blast trauma patients are often exposed to soil for extended periods and typically sustain extensive skin injuries, these factors should raise clinical suspicion of an underlying mucormycosis infection. A combination of early anti-fungal therapy and aggressive surgical debridement, which can reach up to amputation, can help in treating the disease. Maintaining short intervals between debridement sessions and dressing changes is crucial, as it allows for early detection of wound complications and supports optimal wound condition throughout the treatment course. While irrigating wounds with antibiotic and octenidine-containing solutions may offer therapeutic benefits, further research is needed to explore alternative approaches.