Comparison of COVID-19 and common cold chemosensory dysfunction.

Anosmia constitutes a prominent symptom of COVID-19. However, anosmia is also a common symptom of acute colds of various origins. In contrast to an acute cold, it appears from several questionnaire-based studies that in the context of COVID-19 infection, anosmia is the main rhinological symptom and is usually not associated with other rhinological symptoms such as rhinorrhoea or nasal obstruction. Until now, no study has directly compared smell and taste function between COVID-19 patients and patients with other causes of upper respiratory tract infection (URTI) using valid and reliable psychophysical tests. In this study, we aimed to objectively assess and compare olfactory and gustatory functions in 10 COVID-19 patients (PCR diagnosed, assessed on average 2 weeks after infection), 10 acute cold (AC) patients (assessed before the COVID-19 outbreak) and 10 healthy controls, matched for age and sex. Smell performance was assessed using the extended "Sniffin' Sticks" test battery (4), while taste function was assessed using "taste strips" (5). Receiver Operating Characteristic (ROC) curves were built to probe olfactory and gustatory scores in terms of their discrimination between COVID-19 and AC patients. Our results suggest that mechanisms of COVID-19 related olfactory dysfunction are different from those seen in an AC and may reflect, at least to some extent, a specific involvement at the level of central nervous system in some COVID-19 patients. In the future, studies to assess the prevalence of persistent anosmia and neuroanatomical changes on MRI correlated to chemosensory function, will be useful to understand these mechanisms.

Neural plasticity in developing and adult olfactory pathways - focus on the human olfactory bulb.

The topic of human adult neural plasticity and neurogenesis is of great interest for medical and scientific community, but it is also largely debated. In the last years, an increasing interest has been paid to the olfactory system, and particularly to the plasticity of the olfactory bulb (OB). While the molecular/cellular mechanisms underlying OB plasticity remain a matter of debate, measurements of the OB using magnetic resonance imaging clearly indicate that it is a highly plastic structure. In this review, we present results regarding the plasticity of the human adult olfactory system.

Nationwide survey on immunotherapy practice by ENT specialists.

BACKGROUND: According to the Federal Institution of Health Insurance, ENT doctors perform more skin prick tests for the diagnosis of allergic rhinitis (AR) than other medical specialties in Belgium. However, immunotherapy (IT) is not practiced by all. This study aims to obtain insight into IT practice by ENT doctors, the type of IT performed and the reasons not to perform IT. METHODOLOGY: A questionnaire was sent to all registered ENT doctors of Belgium (n=648), involving questions on type and duration of ENT practice, geography and gender. In addition, the questionnaire informed about diagnosis of AR, indication for IT, type of IT performed, and reasons not to perform IT and referral pattern. RESULTS: The response rate among ENT doctors was 54%, with 7% of responders being excluded as they do not diagnose AR. 81% of Belgian ENT doctors make the indication for IT in AR patients, with 19% neglecting the indication for IT in AR patients. The two main reasons for not indicating IT are lack of expertise and the perception of high costs associated with IT. 70% of ENT specialists are practicing IT themselves, with sublingual IT being mostly performed. Interestingly, IT is mostly frequently performed by those ENT doctors with long-standing ENT practice, in private practice and in Wallonia. CONCLUSION: Despite the high prevalence of AR in ENT practice, IT is most frequently performed by ENT doctors with longstanding practice, working in private practice and/or in the French speaking part of Belgium. Among the different types of IT, sublingual IT is the most frequently performed means of IT by ENT doctors.

Clinical usefulness and feasibility of time-frequency analysis of chemosensory event-related potentials.

BACKGROUND: The clinical usefulness of olfactory event-related brain potentials (OERPs) to assess olfactory function is limited by the relatively low signal-to-noise ratio of the responses identified using conventional time-domain averaging. Recently, it was shown that time-frequency analysis of the obtained EEG signals can markedly improve the signal-to-noise ratio of OERPs in healthy controls, because it enhances both phase-locked and non phase-locked EEG responses. The aim of the present study was to investigate the clinical usefulness of this approach and evaluate its feasibility in a clinical setting. METHODOLOGY: We retrospectively analysed EEG recordings obtained from 45 patients (15 anosmic, 15 hyposmic and 15 normos- mic). The responses to olfactory stimulation were analysed using conventional time-domain analysis and joint time-frequency analysis. The ability of the two methods to discriminate between anosmic, hyposmic and normosmic patients was assessed using a Receiver Operating Characteristic analysis. RESULTS: The discrimination performance of OERPs identified using conventional time-domain averaging was poor. In contrast, the discrimination performance of the EEG response identified in the time-frequency domain was relatively high. Furthermore, we found a significant correlation between the magnitude of this response and the psychophysical olfactory score. CONCLUSION: Time-frequency analysis of the EEG responses to olfactory stimulation could be used as an effective and reliable diagnostic tool for the objective clinical evaluation of olfactory function in patients.

Sphenoid sinus fungall ball: a retrospective study over a 10- year period.

A fungal ball consists of a dense conglomerate of fungal hyphae growing at the surface of the sinus mucosa without tissue infiltration. The maxillary sinus is by far the most commonly involved paranasal sinus cavity followed by the sphenoid sinus. The present study is a retrospective study of 25 consecutive cases treated during the last 10 years in the two hospitals be- longing to the Catholic University of Louvain (CHU Mont-Godinne and UCL Saint Luc). We report the symptomatology, the imaging and discuss the different surgical managements. We conclude that the clinician must have a high index of suspicion when dealing with a unilateral rhinosinusitis persisting despite a maximal and well conducted medical treatment. This is particularly so in elderly women when associated with facial pain and post nasal drip, particularly when the computed tomography shows an unilateral opacity of the sphenoid sinus with or without a sclerosis or an erosion of the bony walls, a polyp in the sphenoethmoidal recess or a hyperdensity mimicking a foreign body. An endonasal endoscopic sphenoidotomy is the treatment of choice in most cases, allowing good ventilation of the sinus and radical removal of all the fungal concretion. A biopsy of the sinus mucosa adjacent to fungal elements is of upmost important to confirm the non- invasiveness of the fungi within the tissue. Antifungal medication is not required in uncomplicated forms. All host factors producing some degree of immunosuppression must be corrected when present and must alert the clinician to rule out any forms of invasive disease.

Chemosensory function assessed with psychophysical testing and event-related potentials in patients with atrophic rhinitis.

Atrophic rhinitis (AR) is a chronic inflammation of the nose characterized by an atrophy of the nasal mucosa. This is typically associated with an impaired sense of smell and a subjective sensation of poor nasal breathing. The aim of this study is to assess chemosensory function in patients suffering from AR using psychophysical testings and event-related potentials (ERP) responses. A cohort of nine patients was extensively studied. Eight out of nine had secondary AR sequela of a bilateral total inferior turbinectomy whereas one patient had a primary AR. All the patients had a clinical evaluation using Sniffin' Sticks test and a retro-olfaction test and an electrophysiological evaluation based upon ERPs obtained after both olfactory and trigeminal stimuli. All the patients complained of a poor nasal breathing and presented a distortion of the chemosensory function. Actually, the orthonasal psychophysical testing showed that four patients out of nine had anosmia, three out of nine had hyposmia and two out of nine were normosmic. All the patients demonstrated retro-olfaction scores inferior to the normal values. The chemosensory ERP showed that seven patients had no olfactory response whereas six had no trigeminal response. Four patients had neither olfactory nor trigeminal ERP response. In conclusion, this study demonstrates that most patients with AR secondary to a total bilateral inferior turbinectomy have a reduction of the chemosensory function measured objectively by psychophysical testings and ERP [corrected].

Assessment of chemosensory function using electroencephalographic techniques.

Electroencephalographic techniques are widely used to provide an objective evaluation of the chemosensory function and to explore neural mechanisms related to the processing of chemosensory events. The most popular technique to evaluate brain responses to chemosensory stimuli is across trial time-domain averaging to reveal chemosensory event-related potentials (CSERP) embedded within the ongoing EEG. Nevertheless, this technique has a poor signal-to-noise ratio and cancels out stimulus-induced changes in the EEG signal that are not strictly phased-locked to stimulus onset. The fact that consistent CSERP are not systematically identifiable in healthy subjects currently constitutes a major limitation to the use of this technique for the diagnosis of chemosensory dysfunction. In this review, we will review the different techniques related to the recording and identification of CSERP, discuss some of their limitations, and propose some novel signal processing methods which could be used to enhance the signal-to-noise ratio of chemosensory event-related brain responses.

Functional Imaging in Olfactory Disorders.

Purpose of Review: The aim was to synthesize key findings regarding the use of functional MRI (fMRI) to assess olfactory dysfunction (OD), and thus, to evaluate whether fMRI could be a reliable clinical diagnostic tool. Recent Findings: In response to olfactory stimulation, patients with quantitative OD display reduced activation in olfactory-related brain regions but also stronger activation in non-olfactory brain areas. Parosmic patients also seem to show both weaker and higher brain signals. As to trigeminal chemosensory system, fMRI suggests that central processing may be declined in patients with OD. Functional connectivity studies report a possible correlation between altered neuronal connections within brain networks and olfactory performances. Summary: fMRI emerges as a valuable and promising objective method in OD evaluation. Yet, its high inter-individual variability still precludes its routine clinical use for diagnostic purpose. Future research should focus on optimizing stimulation paradigms and analysis methods.

Olfactory bulb volume and depth of olfactory sulcus in patients with idiopathic olfactory loss.

Olfactory loss is considered as idiopathic (IOL) when no cause can be found, neither on the basis of a standardized history nor a thorough clinical evaluation. Olfactory bulb volume (OB) has been shown to be decreased in patients with olfactory loss due to trauma, infections, or sinonasal disease. However, OB volume has not yet been investigated in IOL patients. Twenty-two patients with IOL were compared with 22 controls in terms of olfactory performance and of OB volume assessed with magnetic resonance imaging (MRI). Psychophysical testing confirmed that patients had lower scores than controls: P < 0.001 for threshold (T), discrimination (D), identification (I) and global TDI score. Mean right, left and total OB volumes were significantly smaller for IOL patients as compared to controls. Both for IOL and controls, there was a significant correlation between odor thresholds and total OB volume, respectively. In conclusion, patients with IOL have decreased olfactory function and decreased OB volume when compared with controls. This was previously demonstrated for patients with postinfectious or posttraumatic olfactory dysfunction, but not for patients with uneventful conditions possibly damaging their olfactory apparatus.

Lymphoepithelial cyst of the nasogenian sulcus: a case report.

A rare case of lymphoepithelial cyst formed in the nasogenian sulcus is reported. Lymphoepithelial cysts are comprised of a stratified squamous epithelial lining above dense lymphoid tissue. They are uncommon in the oral region and, to our knowledge, have never been reported in the nasogenian sulcus. Surgical excision was performed and no recurrence was noted after 6 months. In this report, we describe the etiopathogenesis of lymphoepithelial cysts, as well as the differential diagnosis of nasogenian sulcus swellings.

A Pott's puffy tumour as a late complication of a frontal sinus reconstruction: case report and literature review.

A Pott's Puffy Tumour (PPT) is a rare clinical entity, which, traditionally has been described as an acute abscess with periosteitis secondary to osteomyelitis of the external table of the frontal bone of the skull, complicating an acute frontal sinusitis. The aim of this article is to present a case of progressively evolving PPT, which emerged during the course of a common rhinitis, in a patient who, thirty years previously, had undergone a reconstruction of the frontal sinus involving osteosynthesis. The patient was treated with antibiotic therapy coupled with external access surgery using the Cairn Unterberger approach. This allowed the drainage of pus, the removal of infected osteosynthetic material and a complete debridement of osteomyelitic bone from the affected area. Frontal sinus obliteration was undertaken using methyl methacrylate, preferable in this case to hydroxyapatite, due to the direct communication with the neighbouring sinus cavities and the presence of defective bone in the superior orbit. A review of literature available on Medline up to January 2008 reveals that this is the third published case of PPT complicating a frontal reconstruction.

Trigeminal event-related potentials in patients with olfactory dysfunction.

OBJECTIVE: There are mutual interactions between the olfactory and trigeminal systems. The purpose of this study was (1) to assess trigeminal sensitivity using chemosensory event-related potentials (CSERPs) in patients with olfactory dysfunction and (2) to evaluate whether trigeminal ERPs were different with regard to the presence or absence of olfactory ERPs. MATERIALS AND METHODS: Prospective study of 60 patients who presented with olfactory dysfunction (postinfectious olfactory loss: n = 19, posttraumatic olfactory loss: n = 28, and olfactory loss due to idiopathic, or toxic causes: n = 13). All patients were extensively evaluated with an orthonasal olfactory test based on the "Sniffin' Sticks". In addition, chemosensory ERPs were recorded in response to olfactory and trigeminal stimulation. RESULTS: Olfactory/trigeminal ERPs were recorded in 25/60 patients, respectively. Patients with no detectable olfactory ERPs, considered as severely affected, demonstrated an altered trigeminal sensitivity as indicated by an increase in P2 latencies and a decrease in both, P2 and N1-P2 amplitudes compared to patients with detectable olfactory ERPs. A regression analysis showed a negative relation between P2 latencies and the "Sniffin' Sticks"score (r = -0.46, p < 0.001). CONCLUSIONS: Patients with severe olfactory dysfunction demonstrated decreased trigeminal sensitivity as indicated by electrophysiological measures. This study supports the idea of interactions between the chemical senses. Whether altered responses to trigeminal stimulation may be used as a prognostic measure related to recovery from olfactory loss remains to be demonstrated.

Congenital dacryocystocele: five clinical cases.

Congenital dacryocystocele (CDC) is recognised as a cause of nasal airway obstruction or respiratory distress in newborns. CDC is caused by the distal obstruction of the lachrymal duct and presents as a cystic formation in the inferior meatus. We discuss five cases of dacryocystocele, together with surgical management and outcome. Endoscopic endonasal marsupialisation and appropriate postoperative care resulted in definitive recovery for all patients. In newborns or infants with nasal obstruction, CDC should be considered in the differential diagnosis, and prompt endoscopic endonasal marsupialisation is mandatory.

The role of nasal cavity disinfection in the bacteriology of chronic sinusitis.

OBJECTIVES: Several factors may influence the results of bacteriological studies in chronic rhinosinusitis. We investigated the potential role of nasal cavity disinfection in the bacteriology of the bulla ethmoidalis in patients suffering from chronic sinusitis. MATERIAL AND METHODS: Bacteriology of the bulla ethmoidalis was studied in 176 consecutive adult patients presenting a chronic sinusitis refractory to standard medical treatment who underwent functional endoscopic sinus surgery. Two different techniques were used: (A) a technique with nasal vestibule and facial disinfection with chlorhexedin (N = 89 patients and 165 samples) vs. (B) a technique with facial, nasal vestibule and nasal cavity disinfection with a povidone-iodine solution followed by a cleansing of the nasal cavity (N = 87 patients and 166 samples). RESULTS: Culture rate was 89.6% (183 bacterial isolates) for technique (A) vs 76.5% (164 bacterial isolates) for technique (B) (p < 0.001). Major bacteria encountered in the (A) group and in the (B) group were respectively: Coagulase Negative Staphylococcus: 77 vs 40 isolates (p < 0.001); Coagulase positive Staphylococcus: 44 vs 30 isolates (p = 0.061); Streptococcus pneumoniae: 4 vs 5 isolates; Others: Streptococcus sp.: 12 vs 16 isolates; Haemophilus influenzae: 8 vs 6 isolates; Enterobacteriacea: 33 vs 53 isolates (p = 0.013) and others Gram Negative Bacilli: 3 vs 7 isolates. CONCLUSIONS: The standard (A) technique to study the bacteriology of the bulla ethmoidalis in patients with chronic sinusitis yielded a higher percentage of positive culture and of bacterial isolates than a more advanced (B) technique. This is mainly due to the higher percentage of contaminant bacteria such as Coagulase Negative Staphylococcus recovered with the standard technique. Enterobacteriacea and others Gram Negative Bacilli were more often encountered into the bulla ethmoidalis with the technique where disinfection of the nasal cavity was performed.

Nasal obstruction and its impact on sleep-related breathing disorders.

Upper airway patency is essential during sleep in order to avoid sleep-related breathing disorders (SRBD). Nasal obstruction may have a negative impact on sleep quality and must be considered to be a co-factor in the pathophysiology of SRBD. In this paper we will discuss the relation between nasal physiology at night and sleep quality and the possible mechanisms between nasal obstruction and obstructive sleep apnea-hypopnea syndrome (OSAS). We will review the effect of the relief of nasal obstruction (with nasal dilators, medication and/or surgery) on SRBD. Also an algorithm on the management of OSAS patients when nasal surgery is indicated will be proposed.

Post-transplant lymphoproliferative disorder with supraglottic involvement.

OBJECTIVE: Transplant patients with primary Epstein-Barr virus (EBV) infection may develop post-transplant lymphoproliferative disorder (PTLD). Since many infants are seronegative at the time of transplantation, PTLD is a major concern for paediatric transplant centres. First manifestations of PTLD are frequently observed in the ENT area with adenoidal and/or tonsillar involvement. DESIGN: Retrospective study of two cases of PTLD with confirmed supraglottic involvement, their management and outcome. Only patients with pathologically and immunologically demonstrated B-cell proliferation were diagnosed as PTLD. RESULT: Two infants developed an acute stridor during PTLD respectively 8 and 10 months after orthotopic liver transplantation (OLT). These infants were seronegative for EBV at the time of transplantation. IgM anti-EBV and/or detection of EBV genome by polymerase chain reaction were positive. Laryngeal examination revealed hypopharyngeal and/or supraglottic mucosal hyperplasia. Immunostaining of laryngeal biopsy was positive for latent membrane protein-1 (LMP1). Patients were treated by a reduction in immunosuppression as far as tolerated with the intent to recover natural immune response by the patient over the proliferation of EBV-infected cells. Complete remission of PTLD was observed in these two cases. CONCLUSION: Tonsillar hypertrophy and adenoid enlargement are the most encountered features of PTLD in OLT occurring in the ENT area. Acute stridor with supraglottic involvement may also be observed in PTLD and must be promptly diagnosed as the prognosis of this disorder is related to rapid reduction in immunosuppression and consequently to the recovering of a natural immune response against the EBV infection.

Fungus-like sinusitis.

Fungus-like sinusitis is also called eosinophilic mucin rhinosinusitis (EMRS). This terminology is purely descriptive and refers to a rhinosinusitis, whose clinical presentation and imaging are similar to those of a noninvasive fungal sinusitis but in which fungus could not be demonstrated pathologically using the conventional silver staining technique or on culture. The authors report 2 clinical cases and recall the diagnostic criteria for the different forms of fungal sinusitis in immunocompetent patients.

Metastasis of a small cell carcinoma from undetected origin to the pituitary gland--the otolaryngologist's view.

Tumour metastasis to the anterior pituitary-hypothalamic area is rare. We present a patient who had severe headache, bitemporal quadrant hemianopsia and an expanding mass in the sella turcica as revealed by MRI. Partial resection via a transsphenoidal approach was performed and postoperative radiation therapy was initiated. Immunohistochemical investigation identified the tumour as a metastatic small cell carcinoma whose primary site remained undetected for more than 12 months despite repeated oncological evaluations. We reviewed the literature on metastatic disease of the pituitary gland.

Bacteriology of chronic sinusitis: the bulla ethmoidalis content.

OBJECTIVE: To study the microbiology of the bulla ethmoidalis of patients who suffered from chronic sinusitis. DESIGN: A prospective study performed at the Saint-Luc universitary clinic (University of Louvain) from June 1999 to December 2000. MATERIAL AND METHODS: Seventy seven patients underwent functional endoscopic endonasal surgery during this period for chronic sinusitis refractory to standard medical treatment. All the patients presented symptoms for more than 3 months. After Povidone-Iodine disinfection, samples were taken into the bulla ethmoidalis after its opening with an endoscopic endonasal control. Samples were transferred to the microbiology laboratory using a thioglycolate medium for aerobic and anaerobic cultures. RESULTS: One hundred forty eight samples were studied. Culture rate was 73.6%. Thirty nine samples remained sterile. In the 109 culture positive specimens, 135 bacterial isolates were recovered. The main results are: Staphylococcus coagulase negative: 31, Staphylococcus aureus: 22, Streptococcus sp: 20, other Gram positive Cocci: 5, Haemophilus influenzae: 4, non-fermentative Gram negative bacilli: 6, Enterobacteriaceae: 45, anaerobic bacteria: 2. CONCLUSION: Enterobacteriaceae or enteric gram negative bacilli were frequently encountered in the bulla ethmoidalis of patients suffering from chronic sinusitis. This report suggests that endoscopically guided culture obtained from the ethmoid sinus may accurate our understanding of the microbiology of chronic ethmoidal sinusitis and underline the importance of Enterobacteriaceae in this disease.

Transnasal repair of unilateral choanal atresia.

OBJECTIVES: To evaluate the outcomes of the surgical correction of unilateral choanal atresia using a transnasal approach. PATIENTS AND METHOD: Over a 36-months period (from 1999 to 2001), seven children underwent endoscopic endonasal repair of an unilateral choanal atresia using the microdebrider (powered instrumentation). At the end of the procedure, topical application of Mitomycin-C was performed. No postoperative nasal stenting was inserted. Clinical characteristics of these patients, CT scan examination, complications of the procedure and outcomes were analysed and compared to historical cases treated in the same institution from 1990 to 1998. RESULTS: Seven patients (2 M/5F) (age 6 to 46 months) presented with primary unilateral choanal atresia and were operated during the period from 1999 to 2001. All the patients were symptomatic before surgical correction. No patients showed other facial anomaly. Of the 7 patients procedures, 6 (85.7%) remained patent (follow-up range 12 to 36 months). Mean surgical repair per patient before obtaining patent choana was 1.14. One patient required surgical transnasal revision nine months after the initial procedure with a patent choanal after this second procedure (follow-up 9 months). Minor turbinoseptal synechiae diagnosed 6 months after the surgical correction occurred in one patient and was the only postoperative complication. When compared to historical cases of unilateral choanal atresia (19 patients from 1990 to 1998) repaired without endoscopic control and without Mitomycin-C, it was shown that this current method provided better results; mean surgical repair per patient; 1.14 vs 1.89 and 85.7% of patent choanae at twelve months vs 47.3%. CONCLUSION: An endoscopic endonasal approach without postoperative stenting, using the microdebrider seems to us the treatment of choice for unilateral choanal atresia. The exact role of the topical application of Mitomycin-C needs to be further investigated.