Chronic Invasive Fungal Sinusitis Mimicking Malignancy Post-Radiotherapy: A Case Report.

Invasive fungal sinusitis is a life-threatening form of fungal rhinosinusitis. Due to the aggressive clinical presentation and radiological appearance, there is diagnostic difficulty in differentiating invasive fungal sinusitis from a malignant process. This is even more challenging in oncological patients who have undergone previous head and neck radiotherapy, due to possibility of a recurrence of primary malignancy and radiation-induced neoplasms. We report a rare case of invasive fungal sinusitis mimicking a malignancy in a post-radiotherapy patient. Our patient was a 68-year-old male, 25-years post-radiotherapy for nasopharyngeal carcinoma. He presented with a 3-month history of purulent sputum and right facial paraesthesia. Magnetic resonance imaging showed an irregular destructive enhancing mass of the greater wing of right sphenoid and pterygoid bone with extensive extension into nearby structures. In view of extensive local and bony invasion, and a history of radiotherapy, initial suspicions were that of primary malignancy, specifically radiation-induced sarcoma, and recurrence of nasopharyngeal carcinoma. He underwent transpterygoid biopsy of the lesion, and histopathology demonstrated Aspergillus species, with no malignancy identified. Our report highlights the diagnostic difficulties in the post-radiotherapy cancer patient presenting with symptoms suggestive of aggressive sino-nasal disease. Invasive fungal sinusitis closely mimics the clinical and radiological findings of several neoplastic processes. We discuss the clinical and radiological characteristics of pathologies that may mimic invasive fungal sinusitis. Histological examination remains the gold standard for diagnosis, and early fungal staining is crucial. Furthermore, one should not presume the initial histopathological diagnosis to be confirmatory of isolated fungal disease. Repeat radiological investigations for disease resolution and histopathologic re-evaluation if required should be performed, keeping in mind possibility of coexisting malignancy.

Rapid Vision Loss After Root Canal Treatment Due to Invasive Fungal Sinusitis.

We present a novel case of acute invasive fungal rhinosinusitis (AIFRS) following a maxillary molar root canal in a 69-year-old diabetic female, who subsequently developed unilateral vision loss. The patient reported a 1-week history of progressive left facial pain, trismus, and numbness following the procedure. Initial evaluation was unremarkable, but her condition rapidly deteriorated, culminating in complete vision loss in the left eye. Imaging studies revealed opacification of the left-sided sinuses and a rim-enhancing collection in the left pterygopalatine fossa. Surgical debridement confirmed mucormycosis. The therapeutic approach included systemic and retrobulbar amphotericin B administration, along with multiple sinonasal debridements. The patient's poorly controlled diabetes mellitus significantly contributed to the rapid progression of the infection. Retrobulbar amphotericin B injections were effective in managing orbital involvement, thus avoiding the need for exenteration. Early diagnosis and aggressive treatment are paramount in improving outcomes for patients with AIFRS.

Changing Spectrum of Invasive Fungal Infections of the Anterior Skull Base.

Objective To study the etiological and anatomical factors in pathophysiology of invasive fungal rhinosinusitis affecting the skull base. Design Retrospective clinical study over 5 years. Setting Single-center tertiary referral hospital. Materials and Methods All cases of invasive fungal rhinosinusitis with clinicoradiological and/or operative evidence of anterior and central skull base, orbit, and orbital apex involvement with or without intracranial disease were included in the study. Patients with a sinonasal-palatal disease without the involvement of the skull base or orbit were excluded from the study. In addition, we assessed the risk factors such as coronavirus disease 2019 (COVID-19) infection, diabetes mellitus (DM), and other immunocompromised conditions. Results There were 79 patients, of which 65.8% had skull base rhino-oribitocerebral mucormycosis (ROCM), and 34.2% had Aspergillus infection. The mean duration from onset of the symptom to presentation of ROCM was 36.75 ± 20.97 days, while for the Aspergillus group was 21 weeks. The majority of patients (66%) with ROCM presented after 30 days of symptom onset. Among ROCM patients, 88.7% had a history of COVID-19 infection, and 96% had DM. In 40.8% of patients with Aspergillus infection, the tissue diagnosis was unavailable, and galactomannan assay and clinicoradiological assessment were used for diagnosis. The most common area of the skull base involved was the pterygopalatine fossa (88.5%), followed by the infratemporal fossa (73.1%). The most common neurovascular structure (75%) involved was the pterygopalatine ganglion and the infraorbital nerve. Conclusion With the increasing incidence of invasive fungal infections worldwide, particularly after the COVID-19 pandemic, it is crucial to understand the evolving nature of this disease. ROCM, documented in the literature to cause fulminant disease, became a chronic illness, possibly due to the improvement of the patient's immunity during the disease course.

Chronic invasive fungal sinusitis mimicking pseudotumor: A case report.

Fungal sinusitis encompasses a wide range of diseases, including both invasive and noninvasive, acute, and chronic forms. The incidence of invasive sinusitis is on the rise, primarily affecting immunocompromised individuals and diabetics. This case report highlights a patient who developed invasive fungal sinusitis despite no other apparent cause of immunosuppression. Imaging studies suggested the diagnosis, confirmed by presence of Aspergillus flavus on mycological culture.

Impact of Biologics on Surgery in Chronic Rhinosinusitis with Polyps and Allergic Fungal Sinusitis.

OBJECTIVE: To compare the efficacy of th2-targeted biologic medications (dupilumab, omalizumab, and mepolizumab) on absolute risk reduction (ARR) of functional endoscopic sinus surgery (FESS) in patients with chronic rhinosinusitis with nasal polyposis (CRSwNP) and allergic fungal rhinosinusitis (AFRS). METHODS: The TriNetX Research Network database was queried for each mAb's market lifespan through March 2024. Adults with CRSwNP were propensity score matched against non-mAb controls based on age, sex, race, and asthma diagnosis. The primary outcome was rate of FESS, with secondary outcomes including inpatient admission, emergency department (ED) visit, and incidence of acute sinusitis. Subgroup analysis was performed for patients with AFRS. RESULTS: All mAbs decreased FESS risk (dupilumab, ARR 11.48%, 95% CI 9.82%-13.15%, p < 0.001; omalizumab, ARR 12.02%, 95% CI 4.36%-19.68%, p = 0.002; mepolizumab, ARR 10.32%, 95% CI 5.24%-15.40%, p < 0.001) in CRSwNP patients. Only dupilumab also reduced risk of inpatient admission (ARR 8.59%, 95% CI 7.04%-10.15%, p < 0.001), ED visit (ARR 5.94%, 95% CI 4.28%-7.61%, p < 0.001), and acute sinusitis (ARR 2.60%, 95% CI 1.09%-4.12%, p = 0.001). In AFRS patients, only dupilumab reduced the risk of all outcomes: FESS (ARR 6.97%, 95 CI 2.86%-11.09%, p = 0.001), inpatient admission (ARR 16.93%, 95% CI 11.30%-22.57%, p < 0.001), ED visit (ARR 13.15%, 95% CI 7.15%-19.14%, p < 0.001), and acute sinusitis (ARR 7.17%, 95% CI 2.18%-12.17%, p = 0.005). CONCLUSION: Although all mAbs reduced FESS risk in CRSwNP, only dupilumab reduced secondary outcomes as well. Similarly, only dupilumab improved all outcomes in AFRS patients. These data demonstrate the potential of mAbs in reducing disease burden and enhancing patient outcomes in CRSwNP and AFRS. LEVEL OF EVIDENCE: NA Laryngoscope, 2024.

Factors Impacting Outcome and Prognosis of Invasive Fungal Sinusitis: How Vital is Iron Metabolism?

Iron is an important micronutrient involved in cell biology through vital reactions. We examined the correlations between iron metabolism parameters and the course of invasive fungal sinusitis. Patients with invasive fungal sinusitis were enrolled. Serum iron and ferritin levels, total iron-binding capacity, and transferrin saturation were measured at the initiation of treatment. Patients were followed for 6 months, and the clinical course was categorised as improvement or worsening/death. A total of 35 patients were enrolled. The average ferritin levels in mucormycosis patients was 944.9 ng/ml, versus 110.7 ng/ml for aspergillosis patients. Iron levels were significantly lower in mucormycosis than in aspergillosis (29.14 µg/dl vs. 68.55 µg/dl). Total iron-binding capacity was significantly different between the two groups (16.76 µg/dl vs. 330.36 µg/dl). After 6 months, improvement, worsening, and death were noted for 18, 8, and 9 patients, respectively. Higher iron levels and lower ferritin levels were linked with improvement. Total iron-binding capacity was significantly higher in improved patients (2314 vs. 151). Iron metabolism parameters play significant roles in the preemptive judgment of the course of fungal sinusitis. Based on these findings, studies on drugs affecting iron metabolism should be conducted.

Orbital preservation in the treatment of acute invasive fungal sinusitis.

Acute invasive fungal sinusitis (AIFS) is an aggressive disease with significant mortality and morbidity. Surgical debridement is a mainstay of treatment. However, orbital involvement may limit its efficacy and is an independent risk factor for mortality. Traditionally, orbital exenteration has been utilized in cases with orbital invasion and ophthalmoplegia or vision loss. Retrobulbar liposomal amphotericin B injection may improve disease control and has the potential to spare the morbidity associated with exenteration. In this video article, we document the use of serial endonasal debridement with retrobulbar injections to salvage the eye in a patient with significant orbital involvement. A 28-year-old immunocompromised female patient presented with acute onset restricted right extraocular movement, progressive orbital pain, V2 trigeminal numbness, and 20/40 vision. The patient underwent recurrent debridement and retrobulbar injections of liposomal amphotericin B. Her serial exams, including changes in extraocular muscle appearance and gradual improvement in extraocular movement, were documented. The exam six months after initial presentation demonstrated 20/20 vision, minimal extraocular movement restriction, and proper healing of the orbit and ethmoid. The salvage of the patient's orbit suggests that liposomal amphotericin B injections with debridement may be a viable treatment alternative in patients with acute invasive fungal sinusitis and orbital involvement.

Unilateral Sinus Disease: What Is, and Is Not Odontogenic Sinusitis?

The differential diagnosis of unilateral sinus disease (USD) is broad, and while concerning etiologies like sinonasal neoplasia, invasive fungal sinusitis, and cerebrospinal fluid rhinorrhea should always be considered, most cases are due to noninvasive inflammatory or infectious conditions. To diagnose USD appropriately, clinicians must integrate the clinical history and examination, nasal endoscopy, computed tomography (CT), and possibly MRI. Odontogenic sinusitis (ODS) is the most common cause of unilateral maxillary sinus opacification on CT, with 45% to 75% of such cases being odontogenic in nature. This study provides USD diagnostic considerations and reinforces the diagnostic approach to ODS.

Multidisciplinary approach to severe intracranial, intraorbital allergic fungal sinusitis.

BACKGROUND: Allergic fungal sinusitis (AFS) is a form of paranasal mycosis that often involves bone destruction and can extend into the orbit and anterior skull base. Intracranial and intraorbital involvement are published but not both in each included patient of a series. The purpose of the present study was to review cases of extensive AFS with orbital or/and skull base erosion, including the presenting symptoms, patient socioeconomic background, imaging features, surgical technique, and post-operative outcomes. METHODS: The records of 30 patients with the histological diagnosis of AFS and both intracranial and intraorbital involvement were reviewed. RESULTS: The average age of the patients was 25.2 years. 83 % of patients were male. 70 % were African American. 66 % of patients had Medicaid or were uninsured. Presenting symptoms were headaches (80 %), nasal obstruction (33 %), proptosis (40 %), vision change (23 %), facial pressure (10 %), and decreased sense of smell (7 %). 100 % of patients had bone erosion observed on computerized tomography scans with disease extending intracranially through the anterior skull base or posterior wall of the frontal sinus along with disease that eroded through the lamina papyracea. All patients had failed medical management. All patients underwent surgery by Otolaryngology, Ophthalmology, and Neurosurgery with transnasal endoscopic approaches and orbitotomy. 80 % also underwent a bifrontal craniotomy for removal of intracranial extradural disease with cranialization. 53 % of patients had orbital implants remaining after surgery; 23 % had nasal stents. There were no postoperative cerebrospinal fluid leaks. Average hospital stay was 4.8 days. Preoperatively, 13 % of patients underwent allergy testing. 94 % saw an Allergist postoperatively. 21 % required follow up surgery. CONCLUSIONS: A team approach of Otolaryngologists, Ophthalmologists, and Neurosurgeons is recommended for this slowly growing but locally destructive disease. Most patients with AFS will present with headaches and nasal obstruction. While most cases of AFS can be successfully managed with transnasal endoscopic techniques, orbitotomy and craniotomy represents an effective treatment for severe AFS cases with extensive intracranial and intraorbital involvement. This disease is found most commonly in young African American males and in the underinsured.

Diagnostic accuracy of double density sign on CT scan of para-nasal sinuses for fungal sinusitis taking microbiology culture as gold standard.

Objectives: To compare double-density sign on non-contrast computed tomography scan of paranasal sinuses with fungal sinusitis on histopathology. METHODS: This prospective study was conducted at the Shifa International Hospital, Islamabad, Pakistan, from July 1, 2021, to June 30, 2023, and comprised patients of either gender aged 20-60 years who were set to undergo functional endoscopic sinus surgery. Demographic characteristics and non-contrast computed tomography scan findings were recorded preoperatively, while microbiological and histopathology results were recorded post-operatively. The microbiological finding was taken as the gold standard. Data was analysed using SPSS 23. RESULTS: Of the 201 patients, 123(61.2%) were males and 78(38.8%) were females. The overall mean age was 41.62±8.52 years. The diagnostic accuracy of a double-density sign on computed tomography scan showed sensitivity 90%, specificity 90.8%, positive predictive value 84%, and negative predictive value 94.4%. CONCLUSIONS: A higher rate of sensitivity and specificity indicated that non-contrast computed tomography scan was an effective modality that could be used for the diagnosis of fungal sinusitis.

Characterising the allergic fungal rhinosinusitis microenvironment using full-length 16S rRNA gene amplicon sequencing and fungal ITS sequencing.

INTRODUCTION: Allergic fungal rhinosinusitis (AFRS) is a severe phenotype of chronic rhinosinusitis with nasal polyposis (CRSwNP), characterised by localised and exaggerated type 2 inflammation. While fungal antigenic stimulation of unregulated Th2-mediated inflammation is the core pathophysiological mechanism, the direct and synergistic role of bacteria in disease modification is a pervasive hypothesis. We set out to define the microenvironment of AFRS to elucidate virulent organisms that may be implicated in the pathophysiology of AFRS. METHODOLOGY: We undertook a cross-sectional study of AFRS patients and non-fungal CRSwNP patients. Demographics, disease severity, culture and microbiome sequences were analysed. Multimodality microbiome sequencing included short-read next-generation sequencing (NGS) on the Illumina Miseq (16S rRNA and ITS) and full-length 16S rRNA sequencing on the Oxford Nanopore Technologies GridION (ONT). RESULTS: Thirty-two AFRS and 29 non-fungal CRSwNP patients (NF) were included in this study. Staphylococcus aureus was the dominant organism cultured and sequenced in both AFRS and NF groups (AFRS 27.54%; NF 18.04%; p = .07). Streptococcus pneumoniae (AFRS 12.31%; NF 0.98%; p = .03) and Haemophilus influenzae (AFRS 15.03%; NF 0.24%; p = .005) were significantly more abundant in AFRS. Bacterial diversity (Shannon's index) was considerably lower in AFRS relative to NF (AFRS 0.6; NF 1.0, p = .008). Aspergillus was the most cultured fungus in AFRS (10/32, 31.3%). The AFRS sequenced mycobiome was predominantly represented by Malassezia (43.6%), Curvularia (18.5%) and Aspergillus (16.8%), while the NF mycobiome was nearly exclusively Malassezia (84.2%) with an absence of Aspergillus or dematiaceous fungi. CONCLUSION: A low diversity, dysbiotic microenvironment dominated by Staphylococcus aureus, Streptococcus pneumoniae and Haemophilus influenzae characterised the bacterial microbiome of AFRS, with a mycobiome abundant in Malassezia, Aspergillus and Curvularia. While Staphylococcus aureus has been previously implicated in AFRS through enterotoxin superantigen potential, Streptococcus pneumoniae and Haemophilus influenzae are novel findings that may represent alternate cross-kingdom pathophysiological mechanisms.

A Silent Threat Unveiled: Invasive Fungal Sinusitis in a High-Risk Hematologic Malignancy Patient.

Invasive fungal sinusitis (IFS) poses a fatal threat to patients with hematological malignancies or a history of allogeneic hematopoietic stem cell transplant (HSCT). While invasive aspergillosis, a subtype of IFS, remains rare in immunocompetent individuals, allogeneic HSCT recipients face a notable surge in incidence. Despite the rapid onset and progression of IFS, its clinical presentation is subtle, contributing to heightened mortality rates. Prompt surgical debridement and systemic antifungal therapy are required to yield positive results. Examining IFS cases in HSCT recipients is vital, providing insights into its clinical course, prevention strategies, and improved evaluation. We present a rare presentation of IFS with Aspergillus niger in a relapsed acute myeloid leukemia patient post-HSCT. Two weeks after chemotherapy, the patient developed headaches and blood-tinged sinus drainage in the setting of pancytopenia. Radiologic and pathological findings confirmed the diagnosis of IFS, necessitating weeks of intensive anti-fungal therapy. Despite the initial positive response, the disease ultimately progressed to a fatal outcome. This case emphasizes that early detection is required for a favorable treatment response. Furthermore, it underscores the importance of heightened clinical suspicion, risk stratification, multidisciplinary care, and ongoing research for optimal management of IFS in allogeneic HSCT recipients.

Facial Palsy in Post COVID-19 Invasive Fungal Sinusitis.

This study aimed to study the various presentations of post COVID-19 invasive fungal sinusitis with 7th cranial nerve palsy and to correlate topodiagnostic tests and radiological findings to identify the site of lesion. A retrospective study was conducted at a tertiary care hospital where 11 patients with post COVID-19 invasive fungal sinusitis with facial palsy presented to our institute. Detailed history, clinical examination, radiological imaging were done for all patients. A total of 11 patients with post COVID-19 invasive fungal sinusitis with facial palsy were included in this study. The mean age of the patients was 44.8, with a male to female ratio of 4.5:1. Diabetes Mellitus was a major factor contributing to immunosuppression in our study with 9 patients who were known cases of diabetes mellitus and 2 newly diagnosed cases. On MRI, 10 patients had involvement of the Pterygopalatine fossa and 4 patients had involvement of the petrous apex. Post COVID-19 invasive fungal sinusitis can present with facial palsy, and diabetes mellitus is a major contributing factor to immunosuppression in these patients. The involvement of the petrous apex is a possible site of involvement, and MRI can aid in localizing the site of the lesion. Further studies are required to identify the exact mechanism of facial nerve palsy in invasive fungal sinusitis.

Lacrimal sac Aspergillosis Masquerading as Malignancy: A Rare Case Report.

Invasive fungal infections are uncommon in an immunocompetent host and pose a real diagnostic dilemma. As they have a propensity for locoregional destruction, clinic-radiological findings can mislead to a faulty diagnosis of a malignancy. Here we present a case of Primary Aspergillus dacryocystitis in an immunocompetent individual initially thought to be an orbital malignancy until the histopathological examination.

Atypical headache by isolated sphenoid fungal sinusitis: A rare case.

INTRODUCTION: Fungal sphenoiditis is a rare case in clinical practice. Usually affecting just one sinus, Aspergillus is the most common cause of fungal sinusitis. Atypical headache with unresponsive to analgetics is one of symptom from Isolated Sphenoid sinusitis. CASE REPORT: This case report presents a 37 year old female with isolated sphenoiditis fungal. The patient came with atypical headache as the major symptom. CLINICAL DISCUSSION: Based on the morphology of the sphenoid sinus and its surrounding structures, diagnosis is often challenging. CONCLUSION: After some medicine, the chief complaint did not disappear. A functional endoscopic sinus surgery was performed to remove the fungal ball, and the patient get good result.

Impact of Zinc Oxide on the Development of Aspergillus-Induced Maxillary Sinusitis Rabbit Model.

Aspergillus fumigatus is commonly found in the airway and is associated with airway inflammatory diseases. Zinc oxide (ZO) is known to be an essential microelement that facilitates fungal survival, growth, and proliferation. This study aimed to investigate the impact of ZO on A. fumigatus-induced fungal sinusitis in rabbits. Twenty-eight New Zealand white rabbits were divided into four groups for this study. Group 1 (6 sides) was treated with intramaxillary phosphate buffer saline (PBS) served as the negative control, Group 2 (6 sides) received intramaxillary PBS and ZO, Group 3 (8 sides) was treated with intramaxillary A. fumigatus alone, and Group 4 (8 sides) treated with intramaxillary A. fumigatus with ZO. After 4 and 12 weeks, sinus mucosal cytokine and transcription factor expressions were determined. A histological analysis was performed to determine inflammatory cell infiltration, number of secretory cells, and mucosal thickness. Fungal biofilm formation was determined using confocal laser microscopy. The intramaxillary instillation of A. fumigatus conidia led to an increase in protein and mRNA expression of interleukin (IL)-1ß and IL-8 in the maxillary sinus mucosa. They were associated with mitogen-activated protein kinase and activator protein-1. Furthermore, intramaxillary instillation of fungal conidia resulted in significant enhancement of inflammatory cell infiltration, epithelial thickening, and fungal biofilm formation. However, intramaxillary ZO did not have a significant impact on A. fumigatus-induced cytokine protein and mRNA expression, and inflammatory cell infiltration and epithelial thickness in sinonasal mucosa. While intramaxillary instillation of A. fumigatus increased mucosal inflammation, cytokine production, and biofilm formation, the intramaxillary application of ZO did not have a significant influence on inflammation in the maxillary sinus mucosa.

Transcutaneous Retrobulbar Amphotericin B Injection for Invasive Fungal Sinusitis with Orbital Involvement: A Systematic Review.

BACKGROUND: Orbital involvement of invasive fungal sinusitis (IFS) is an ominous prognostic marker that should prompt rapid intervention. Transcutaneous retrobulbar administration of amphotericin B (TRAMB) is an off-label adjunctive treatment that can increase drug penetrance into diseased orbital tissue. To date, there is a lack of consensus regarding the use of TRAMB for treatment of IFS with orbital involvement. OBJECTIVE: This systematic review aims to synthesize the indications, efficacy, and potential complications of TRAMB. METHODS: PubMed, EMBASE, and Web of Science databases were probed for systematic review. Article search was conducted through June 2023 using the keywords "invasive fungal sinusitis," "invasive fungal rhinosinusitis," "rhino-orbital mucormycosis," "rhinosinusitis," "orbital," "retrobulbar," and "amphotericin." RESULTS: In suitable cases as determined by radiologic and clinical evaluation, TRAMB administration has the potential to improve orbital salvage rates and improve versus stabilize visual acuity. Treatment complications are more likely with deoxycholate than with liposomal amphotericin formulations. The existing literature describing use of TRAMB is limited due to its retrospective nature, but the increase in IFS cases since 2020 due to the COVID pandemic has broadened the literature. CONCLUSIONS: TRAMB is an effective adjunctive treatment in IFS with mild-to-moderate orbital involvement when used in combination with standard of care debridement, systemic antifungal therapy, and immunosuppression reversal. Prospective longitudinal studies and multi-institutional randomized trials are necessary to determine the definitive utility of TRAMB.

Persistent Severe Headache After Removal of Fungus Ball From the Sphenoid Sinus: A Case Report.

OBJECTIVE: Granulomatous invasive fungal sinusitis (GIFS) is a rare and life-threatening disease, whereas fungus ball (FB) is the most common form of noninvasive fungal sinusitis. Both GIFS and FB primarily develop in immunocompetent patients, with the former associated with higher mortality and morbidity. METHODS: A chart review and review of the literature. RESULTS: We present the case of a 77-year-old woman with mixed fungal sinusitis who was successfully treated with voriconazole. CONCLUSIONS: GIFS and FB can coexist in extremely rare cases, known as mixed fungal sinusitis; however, the diagnosis and subsequent treatment of mixed fungal sinusitis can be delayed because of a lack of awareness of the underlying concept. Therefore, it is crucial for clinicians to recognize the concept of mixed fungal sinusitis.

Clearing the Air: Acute Invasive Fungal Rhinosinusitis in Hematologic Cancer Patients.

OBJECTIVES: Air quality has been shown to impact the rates of fungal infection of the airway, causing diseases such as acute invasive fungal rhinosinusitis (AIFRS), particularly in immunocompromised patients. We theorize that patients with hematologic malignancies in units with aging air handling units (AHUs) have a higher attack rate of AIFRS. METHODS: Retrospective chart review identified patients with hematologic malignancy and AIFRS in two distinct and equal time periods between 2013 and 2022, representing the presence of aging AHUs and new AHUs, respectively. Cubic feet per minute (CFM) air flows, AIFRS attack rates, and clinical data were compared between the two groups and statistical analyses performed. RESULTS: The older AHUs produce air flow of 27,610 CFM and the newer AHUs produce air flow of 80,000 CFM. There were 18 patients with air supplied by older AHUs and 7 patients with air supplied by new AHUs who developed AIFRS. There was a significantly higher AIFRS attack rate for patients supplied by the older AHUs compared with patients supplied by newer AHUs (p = 0.033). The patients supplied by the older AHUs tended to be younger. The white blood cell counts, absolute neutrophil counts, and the mean time to diagnosis did not differ between the two groups. CONCLUSIONS: To our knowledge, this is the first study to examine AIFRS in immunocompromised patients' inpatient environment. Further research should explore whether higher CFM AHUs can decrease this disease among our most vulnerable patients. LEVEL OF EVIDENCE: 3 Laryngoscope, 2024.