Anatomy overview
Stephanie Martin in Working with Voice Disorders, 2020
Oxygen enters the bloodstream and excess carbon dioxide moves out through the capillaries surrounding the alveoli within the lungs. The respiratory system can be said to begin at the nose and the mouth, and end with the alveoli in the lungs. Within this system two distinctive respiratory tracts are identified. The upper respiratory tract is composed of the nasal and oral cavities, the pharynx and the larynx. In addition to its role in respiration, the upper respiratory tract has multiple functions, such as the processes of chewing, swallowing, articulation, resonance and phonation. The lower respiratory tract refers to the trachea, the bronchi and lungs, which are housed within the bony thoracic skeleton or ribcage, and in contrast to the upper respiratory tract, functions exclusively for the process of breathing for life and for phonation.
Avian Influenza Virus
Dongyou Liu in Handbook of Foodborne Diseases, 2018
One of the most common presentations is self-resolving conjunctivitis. Upper respiratory tract infections are also very common and often occur early in cases where the disease progresses to a lower respiratory tract infection. Upper respiratory tract infections cause the ubiquitous “influenza-like illness,” symptoms of which can include coughing, sore throat, aches, reduced appetite, and fever.23,39,41–46 In severe cases, pneumonia, acute respiratory disease syndrome, renal failure, and multiple organ dysfunction are typically seen.21,23,39,42,43,47–50 Vomiting and diarrhea are uncommon but can occur alone or in combination with respiratory symptoms.23 Encephalitis and central nervous system involvement in AIV infection in humans is very rare but has been reported with the H5N1 lineage.51
Commensal Flora
Firza Alexander Gronthoud in Practical Clinical Microbiology and Infectious Diseases, 2020
Streptococci, staphylococci, Corynebacterium spp., Moraxella spp., Neisseria spp. (including Neisseria meningitidis) and Haemophilus spp. can be found in the respiratory tract. The lower in the respiratory tract, the lower the bioburden. Common causes of upper and lower respiratory tract infections are S. pneumoniae and H. influenzae. Atypical pneumonia is caused by bacteria which don't have a cell wall and are not considered to be true members of the commensal flora: Mycoplasma pneumoniae, Legionella pneumophila and Chlamydia pneumophila (see Chapter 4.4 for diagnosis and treatment of atypical pneumonia). Candida spp. and Aspergillus niger can also be found in the ear canal and are common causes of otomycosis.
Can the immunological system of the upper respiratory tract, improved by physical exercise, act as a first immunological barrier against SARS-CoV-2?
Published in Expert Review of Anti-infective Therapy, 2022
Jairo Azócar-Gallardo, Alex Ojeda-Aravena, Jorge Carrizo Largo, Claudio Hernández-Mosqueira
In anatomical terms, the respiratory tract is divided into two segments: upper (nose, nasal cavity, mouth, pharynx, and larynx) and lower (trachea, lungs, and bronchi) [21]. The upper respiratory tract, in particular, is the main site of attacks by invasive microorganisms such as viruses and bacteria, causing upper respiratory tract infections such as acute bronchitis, common cold, influenza, and respiratory distress syndromes [22–24]. To defend itself, the upper respiratory tract releases lymphocytes (B cells) which in turn allow the synthesis of immunoglobulins – specialized antibodies for the humoral immune response to toxins and extracellular pathogens [25,26]. The immunoglobulin family consists basically of three types: immunoglobulin A (IgA; IgA1 and IgA2), immunoglobulin G (IgG), and immunoglobulin M (IgM). They act by inhibiting microorganisms from adhering to the mucosa, thus neutralizing the virus [27,28]. IgA is the predominant antibody, secreted by the mucosas of the organism including nasal and pulmonary secretions, saliva, tears, milk and secretions of the urogenital and intestinal tracts; it is a fundamental ‘first line of defense’ against the vast majority of infections that try to invade the respiratory tract of the human body [23,25,26,29]. Therefore, IgA is an important resistance effector against the pathogenic micro-organisms that cause upper respiratory tract infections [23,25,30,31]; it also acts as a bridge between innate and adaptive immunity [17].
Value of combined detection of serum amyloid A, C-reactive protein and procalcitonin in differential diagnosis of respiratory tract infection in children of China
Published in Annals of Medicine, 2022
Hailun Yin, Songming Mo
Respiratory tract infections are a common respiratory illness, occurring at the turn of the season, especially in children. The clinical features of respiratory infections in children often include cough, runny nose and fever, which if left untreated may prone to develop into lower respiratory tract infection, even causing nephritis, myocarditis, sepsis, rheumatic fever, etc [8]. If the disease cannot be a timely and effective control, the continuous progress of the disease may lead to sepsis, multiple organ failure and septic shock, and even endanger the lives of children [9]. Therefore, timely diagnosis and appropriate treatment are essential for the management of respiratory tract infections. However, conventional culture tests for respiratory tract infections are long, have a low positive diagnosis rate and are of low clinical value. Hence, the search for more accurate and specific tests is of great clinical importance for early and accurate and effective treatment of the disease. In addition, in China, antibiotics are the mainstay of treatment for respiratory tract infections in children. However, antibiotic therapy is not effective for non-bacterial infections and respiratory infections caused by viruses. If antibiotic treatment is applied blindly without a clear diagnosis of the pathogen, it is more likely to increase the risk of dual infection. Therefore, early diagnosis of the disease also plays an important role in determining the type of infection, avoiding the misuse of antibiotics and reducing the incidence of drug resistance.
New drugs under investigation for the treatment of alopecias
Published in Expert Opinion on Investigational Drugs, 2019
Jorge Ocampo-Garza, Jacob Griggs, Antonella Tosti
In patients with alopecia areata, viral infections, including herpes zoster, were the most frequent cutaneous side effects. Upper respiratory tract infections, urinary infections, and gastrointestinal complaints were the most frequent non-cutaneous effects [20–25]. Treatment with tofacitinib and ruxolitinib might increase total cholesterol, low-density lipoprotein, and high-density lipoprotein [23]. The majority of patients treated for alopecia areata had no or minor side effects; however, cases of serious infections have been reported in patients treated with tofacitinib for rheumatoid arthritis. The risk of lymphoproliferative disorders or other cancers was not increased in patients treated with these drugs, but long-term safety data are limited [26,27].