Rhino-Orbital mucormycosis in an immunocompetent pediatric patient with hyperglycemia of the hospitalized patient

Introduction: Acute invasive rhino-orbital mucormycosis usually affects diabetic or neutropenic patients, and only exceptionally develops in immunocompetent adults and children. Methodology: A 12-years-old immunocompetent female, presented with complicated rhinosinusitis with a subperiosteal orbital abscess, without improvement after initial medical and surgical management, the patient also developed hyperglycemia of the hospitalized patient that represented a challenging and potentially lethal clinical scenario. Results: Diagnosed with an unsuspected rhino-orbital mucormycosis by direct microscopy and PCR, she survived after amphotericin B and surgical treatment. Conclusions: In cases with torpid clinical evolution, even in apparently immunocompetent patients, appropriate multidisciplinary workup must be performed to rule out opportunistic etiologies including mucormycosis to improve survival.


Introduction
Mucormycosis is a rare and frequently fatal opportunistic invasive fungal disease [1].
In adults, it usually affects immunocompromised diabetic patients, particularly in developing countries; most of the children with mucormycosis have an underlying hematological malignancy, but also uncontrolled diabetes type I has been reported. Mucormycosis exceptionally develops in immunocompetent adults and children [1].
Fungal invasive rhinosinusitis is caused by some species that belong to the order Mucorales (the most frequent Rhizopus spp but also by Mucor spp, Lichtheimia spp, Cunninghamella spp, Apophysomyces elegans among others) and by some species of Aspergillus (reported mainly in adult hematologic patients), with a tendency for vascular invasion causing thrombosis that leads to tissue necrosis [1][2][3].
In children, the paranasal sinus/sino-orbital region is the third site of infection; cutaneous, pulmonary, gastrointestinal, and disseminated infection have also been reported [1,2,4,5].
Diagnosis requires a high index of suspicion and the identification of the fungus with histopathology, culture, direct microscopy, and molecular tests; image studies as magnetic resonance imaging help to determine the extension in the rhino-orbit-cerebral forms [3].
Antifungals and surgery, along with correction of the underlying medical condition, are the cornerstone of treatment [3,6].
The reported mortality ranges between 33-67% depending on the underlying condition, the site and dissemination of the infection, and the treatment administered; to be noted, even in immunocompetent patients, death can occur. [1,7]

Case Report
A 12-years-old eutrophic female, with a history of introducing a hairpin in her left nose that was extracted several hours later by a physician who also recommended an unspecified oral antibiotic. Five days later, she noted nasal obstruction, left purulent rhinorrhea, ocular pain, diplopia, and an increase of volume of her left eyelid.
A computed tomography showed ethmoidal sinusitis and left orbital cellulitis with proptosis.
Consultation with the otolaryngology and ophthalmology departments was obtained; the nasal endoscopy showed normochromic nasal mucosa and purulent secretion at the left middle meatus. A diagnosis of complicated bacterial rhinosinusitis with orbital cellulitis was considered.
Antibiotic treatment with i.v. clindamycin (30 mg/kg/ per day) and ceftriaxone (75 mg/kg/ per day) were initiated, and she was surgically treated with endoscopic left ethmoidectomy, draining scarce purulent secretion, also, debridement of palpebral fasciitis was performed. Negative bacterial cultures were reported. Pathology of the ethmoidal sinus tissue reported mucosa with acute inflammation and bone with acute osteitis.
Postoperatively, she persisted with orbital swelling, ophthalmoplegia, and low-grade fever (38.2 °C maximum); headache and papilledema were detected leading to suspicion of endocranial hypertension, a cerebral magnetic resonance imaging reported an abscess in the upper left orbital region, bifrontal meningeal thickening, and left frontoethmoidal and maxillary sinusitis (Figure 1).
Vancomycin and dexamethasone were initiated, and orbital surgery performed through an external supra-ciliary approach, draining a subperiosteal abscess.
Direct microscopic examination with potassium hydroxide preparation (KOH mount) and light microscopy of the secretion revealed broad, nonseptated hyphae, compatible with Mucormycosis ( Figure 2).
PCR was carried out in the research laboratory, with a positive result for Rhizopus oryzae. Genomic DNA was isolated from paraffin-embedded tissue sample using a DNeasy blood and tissue kit (Qiagen, Ventura, CA, USA) according to the manufacturer's instructions. The molecular identification was achieved by 18S-ITS1-5.8S-ITS2-25S rRNA gene amplification using a set of primers previously reported to identify fungi species (5'-TCCGTAGGTGAACCTTGCGG-3') and ITS4 (5'-TCCTCCGCTTATTGATATGC-3') [8].
A PCR product of 630 bp was amplified, purified, and sequenced in both directions; nucleotide sequence was determined with Taq FS Dye Terminator Cycle Sequencing Fluorescence-Based Sequencing and analyzed on an Applied Biosystems 3730 DNA sequencing system (Foster City, CA, USA) ( Figure 3).
The sequence was edited with the Vector NTI program, and a homology search was performed in the  GenBank database (Nucleotide Blast), finding a 100% identity with Rhizopus oryzae NB31, BAB-4277, CMH004, and 1231D17 strains, among others. The sequence obtained for Rhizopus oryzae GEA 616 was deposited in the GenBank under accession number MW345817.
Negative bacterial cultures were reported. Histopathology study showed ischemic necrosis and acute inflammation from the upper left eyelid tissue.
The patient was transferred to the pediatric intensive care unit where Amphotericin B (1 mg/kg/ per day) was initiated. No liposomal amphotericin was available at our institution.
Although her glucose on admission was within normal ranges, during her hospital stay she developed hyperglycemia up to 307 mg/dL that required insulin management. The requested glycosylated hemoglobin was 6.1%, integrating the diagnosis of hyperglycemia of the hospitalized patient by the endocrinology service.
She gradually improved, her glucose level returned to normal, and she was discharged from the hospital. After 6 months of follow-up, she is asymptomatic and without any treatment.

Discussion
In only about 9.5-14% of children with mucormycosis, as this case report, no apparent underlying medical conditions are found, predominantly when located at sinus and sino-orbital sites, therefore, a high clinical suspicion is required for its diagnosis [1,2].
Although no consistent correlation has been found between the clinical form and the etiological agent, not infrequently, species different than Rhizopus, like Apophysomyces elegans, Cunninghamella spp, Actinomucor elegans, and Conidiobollus spp have been reported in the immunocompetent cases [6,7,9,10].
This case presented with some confounding risk factors that maybe have interacted for the development of mucormycosis: the foreign body introduced at her nose that may harbor fungal elements, the instrumentation for its removal that can have disrupted the mucosal lining, and the prescribed antibiotics that may cause dysbiosis, a known predisposing factor for superinfections [11].
Hyperglycemia of the hospitalized patient is a recognized clinical entity that can impact the mortality and morbidity in diabetics and non-diabetics who need to be managed at the emergency room and may predispose to metabolic and immunologic complications associated with its pathophysiology. As reported by Palacio et al. [12], hyperglycemia was present in one-fourth of the children admitted in the hospital, most of them without a history of diabetes before admission and was associated with a greater need for intensive care unit (ICU) care and longer ICU stay but not with increased in-hospital mortality, like the case we report. In patients with mucormycosis, glycemic control including cases with hyperglycemia of the hospitalized patient and correction of the underlying medical conditions, are key factors in their management [6,9].
The clinical presentation of complicated rhinosinusitis with an orbit abscess in this immunocompetent patient delayed the diagnosis of mucormycosis [13,14].
In this case, the histopathological report of ischemic necrosis, and the lack of clinical improvement, raise the clinical suspicion of an atypical cause of rhinosinusitis; until repeated surgical drainage and debridement, and after many differential diagnoses were ruled out, the diagnosis was achieved by a multidisciplinary team.
The limitations of this report are that it is an isolated case, and although we diagnosed the mycotic infection by PCR and direct microscopy, we were unable to culture the pathogenic fungus.

Conclusions
Even in immunocompetent pediatric patients, one must consider mucormycosis in the differential diagnoses and carry out the appropriate microbiological, pathological, and serological studies to make the correct diagnosis.