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Nasopharyngeal Carcinoma
Published in R James A England, Eamon Shamil, Rajeev Mathew, Manohar Bance, Pavol Surda, Jemy Jose, Omar Hilmi, Adam J Donne, Scott-Brown's Essential Otorhinolaryngology, 2022
Early cancers of the nasopharynx produce minimal and trivial symptoms. Local features can be divided into nasal, otological, cervical, and neurological findings. Common nasal symptoms are blood-stained nasal discharge, post-nasal drip, obstruction, cacosmia, or a smell of blood.
Molecular Pathophysiology and the Clinical Presentation of COVID-19
Published in Srijan Goswami, Chiranjeeb Dey, COVID-19 and SARS-CoV-2, 2022
Srijan Goswami, Ushmita Gupta Bakshi
SARS-CoV-2 is the coronavirus known to cause a type of severe acute respiratory illness called COVID-19. There are basically two ways by which a pathogen gains entry inside the respiratory tract, one is through the nasopharyngeal route and the other is through the oropharyngeal route. When any respiratory pathogen, be it a bacteria, a fungus, or a virus (in this case, SARS-CoV-2) enters the upper respiratory tract, it first makes contact with the epithelial cells of the nasal mucosa. Anatomically, the nasopharynx is one of the routes that creates a connection between the outside environment and the host's respiratory system. The intelligence of the body knows that there is a good chance that pathogenic microorganisms may try to gain entry to the respiratory tract through this route. So, strong innate and adaptive immune components are present throughout this system. When a respiratory pathogen enters the nasopharynx, the cellular intelligence recognizes the threat and initiates protective responses like watery discharge from the nostrils, the sneezing reflex, increased secretion of mucus from the nose, and the swelling of nasal polyps giving rise to a collection of responses that cause discomfort in the upper respiratory tract.
Anatomy overview
Published in Stephanie Martin, Working with Voice Disorders, 2020
The respiratory tract has two parallel entrances, the nose and the mouth, through which air enters. These entrances merge into a common tract, known as the pharynx. The pharynx is a cone-shaped tube approximately 13–14 cm long, composed of muscular and membranous layers, wider at the top where it is continuous with the nasal cavity and opening laterally into the mouth. At its lower and narrower end it leads into the laryngeal inlet anteriorly and the oesophagus posteriorly. The area within the pharynx immediately behind the nose (the nasopharynx) and the area behind the mouth (the oropharynx) are separated by a muscular valve, the soft palate, which, when raised, closes off one section from the other, thus effectively preventing food or liquid escaping from the nose when swallowing. Along with the most inferior part of the pharynx, which contracts at rest and prevents any reflux of the stomach contents into the pharynx or air entering the oesophagus, the soft palate forms part of the involuntary protective mechanism in the respiratory tract. By far the most vigorous protective mechanisms, which are involuntary and reflexive, exist within the larynx. Some mechanisms attempt to ‘repel’ by closing off the airway and some attempt to ‘expel’ by forcing substances out of the respiratory tract.
In-silico investigation of airflow and micro-particle deposition in human nasal airway pre- and post-virtual transnasal sphenoidotomy surgery
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2022
Khashayar Moshksayan, Hojat Bahmanzadeh, Mohammad Faramarzi, Sasan Sadrizadeh, Goodarz Ahmadi, Omid Abouali
The present work has some possible limitations which are explained here. In our previous work, it was shown that the particle deposition patterns in the nasal cavity of a complete respiratory system, beginning from the nostrils to the end of the trachea, is slightly different from the results obtained from a nasal passage that is truncated at the nasopharynx (Naseri et al. 2017). During the inhalation phase of breathing, some micro-particles that pass the nasopharynx return to the nasal cavity, where they deposit. In the present study, in spite of using a truncated model, we used a denser mesh to increase the accuracy in comparison with the truncated model used by Naseri et al. (2017). Furthermore, it should be pointed out that the region of interest in this study is the targeted sphenoid sinus, which is located far from the nasopharynx. Hence, it is feasible to neglect reentering particles depositing in the sphenoid sinus during the exhalation phase.
COVID-19—from emerging global threat to ongoing pandemic crisis
Published in Baylor University Medical Center Proceedings, 2022
Karen B. Brust, Vinayika Papineni, Cristie Columbus, Alejandro C. Arroliga
The tools for diagnosis have expanded. The polymerase chain reaction (PCR) sampled from the nasopharynx still affords the highest sensitivity (80%) and specificity (99%).5 With increased viral shedding to ≥500 to 5000 copies/mL, the nasopharynx swab performs even better, nearing 100% accuracy. There has been consideration for the use of cycle threshold as a quantitative measure of the amount of SARS-CoV-2 in patients. However, its limitations include the lack of standardization across various PCR tests and laboratories, varying efficiency of nucleic acid extraction, and the lack of consistent correlation between cycle threshold values and viral culture.6 SARS-CoV-2 analysis has also been added to other established respiratory pathogen panels looking for concomitant illnesses, such as rhinovirus or influenza.
The relationship between Covid-19 and mucociliary clearance
Published in Acta Oto-Laryngologica, 2021
Mehmet Erkan Kahraman, Fatih Yüksel, Yaşar Özbuğday
Mucociliary clearance (MCC) is the main host defense mechanism that protects the nose, upper respiratory tract and lungs against the deleterious effects of inhaled toxic substances and pathogens [2]. This function ensures that inhaled small particles are delivered to the nasopharynx for cilia and mucus layer in healthy mucosa. Disruption of mucociliary activity, on the other hand, disrupts the nasal physiology and prepares the ground for infections. Various techniques are available to evaluate the MCC activity. Although stroboscopy, roentgenography and photoelectron techniques can evaluate the ciliary activity in the nasal mucosa, they are very expensive techniques unsuitable for routine studies. Apart from these, saccharin test and rhinoscintigraphy are the most widely used techniques in the measurement of nasal MCC. Although rhinoscintigraphy is a reliable and easily reproducible method, it has potential side effects related to radiopharmaceutical use [3]. So, we used the saccharin test to find the nasal MCC time in our study, because our patient group has a high contamination potential [3,4].