Acute upper respiratory tract infection is the general term for acute inflammation of the nasal cavity, pharynx or larynx. It is the most common type of infectious disease of the respiratory tract. It is commonly caused by viruses and rarely by bacteria. Patients do not distinguish between age, gender, occupation and region. It is not only highly contagious, but can also cause serious complications and should be actively prevented and treated.
Etiology and pathogenesis
Acute upper respiratory tract infections are caused by viruses in about 70-80% of cases. The main ones are influenza virus (A, B, C), parainfluenza virus, respiratory syncytial virus, adenovirus, rhinovirus, echovirus, coxsackie virus, measles virus, rubella virus. Bacterial infections can occur directly or after viral infections, with hemolytic streptococci being the most common, followed by Haemophilus influenzae, pneumococci, and staphylococci. Gram-negative bacilli are occasionally seen. The main manifestation of the infection is rhinitis, pharyngitis or tonsillitis.
When there is cold, rain, overwork and other triggering factors, so that the systemic or local defense function of the respiratory tract is reduced, the viruses or bacteria already present in the upper respiratory tract or invaded from the outside can rapidly multiply and cause the disease, especially the old, young, weak or have chronic respiratory diseases such as paranasal sinusitis, tonsillitis, more susceptible to the disease.
Epidemiology
The disease can occur throughout the year, with a high incidence in winter and spring, and can be spread by virus-containing droplets or contaminated utensils, mostly sporadically, but often during sudden climatic changes. Because there are many types of viruses, human immunity to various viral infections is weak and short-lived, and there is no cross-immunity, and there are virus carriers in healthy people, so a person can have multiple attacks in a year.
Pathology
The nasal and pharyngeal mucosa is congested, edematous, with destruction of epithelial cells, a small number of mononuclear cell infiltrates, and plasmacytic and mucinous inflammatory exudates. Secondary to bacterial infection, there is neutrophil infiltration and a large amount of purulent secretions.
Clinical manifestations
Depending on the etiology, the clinical manifestations can be of different types.
I. Common cold
Commonly known as “cold”, also known as acute rhinitis or upper respiratory tract catarrh, with nasopharyngeal catarrh as the main manifestation. Most adults are caused by rhinovirus, followed by parainfluenza virus, respiratory syncytial virus, echovirus, coxsackievirus and so on. The onset of the disease is rapid, with a dry, itchy or burning sensation in the throat at the beginning, and sneezing, nasal congestion, and clear watery nasal discharge at the same time or a few hours after the onset, which thickens after 2-3 days. It may be accompanied by sore throat, sometimes hearing loss due to Eustachian tube inflammation, and also lacrimation, dull taste, breathlessness, hoarseness and small amount of cough. There is usually no fever or systemic symptoms, or only low fever, malaise, mild chills and headache. Examination reveals congestion, edema and secretion in the nasal mucosa and mild congestion in the pharynx. If there is no complication, it usually heals after 5-7 d.
Second, viral pharyngitis, laryngitis and bronchitis
Depending on the anatomical site of infection of the upper and lower respiratory tract caused by the virus, the inflammatory response can be clinically manifested as pharyngitis, laryngitis, and bronchitis.
Acute viral pharyngitis is mostly caused by rhinovirus, adenovirus, influenza virus, parainfluenza virus, as well as enterovirus and respiratory syncytial virus. It is characterized clinically by an itching and burning sensation in the pharynx, and the pain is not persistent or prominent. When there is pain in the throat, it often suggests a streptococcal infection. Cough is rare. Fever and malaise may be present with influenza virus and adenovirus infections. Physical examination of the pharynx is markedly congested and edematous. Submandibular lymph nodes are enlarged and painful to palpation. Adenoviral pharyngitis may be associated with ocular conjunctivitis.
Acute viral laryngitis is mostly caused by rhinovirus, influenza virus type A, parainfluenza virus and adenovirus. The clinical features are hoarseness, difficulty in speaking, pain on coughing, often fever, pharyngitis or cough, physical examination shows edema and congestion in the larynx, mild enlargement and tenderness of local lymph nodes, and wheezing can be heard.
Acute viral bronchitis is mostly caused by respiratory syncytial virus, influenza virus, coronavirus, parainfluenza virus, rhinovirus, and adenovirus. Clinical manifestations include cough, absence of sputum or mucus-like sputum, with fever and malaise. Other symptoms often include hoarseness and non-pleural subpleural pain. Dry or wet woven woven grass may be smelled. X-ray chest radiographs show increased and enhanced vascular shadowing but no pulmonary infiltrative shadowing. Influenza virus or coronavirus acute bronchitis often occurs as an acute exacerbation of chronic bronchitis.
III. Herpes pharyngitis
It is often caused by coxsackievirus A. It presents with marked sore throat and fever and lasts about a week. Examination reveals a congested pharynx, with superficial ulcers on the soft palate, palatal lobe, pharynx and tonsil surfaces with grayish-white herpes, surrounded by a red halo. Most attacks occur in summer, mostly in children, occasionally in adults.
Four, pharyngeal conjunctival fever
It is mainly caused by adenovirus and coxsackie virus. Clinical manifestations include fever, sore throat, photophobia, lacrimation, and marked congestion of the pharynx and conjunctiva. The course of the disease is 4-6 d. It often occurs in summer and is spread during swimming. It is common in children.
V. Bacterial pharyngeal – tonsillitis
Mostly caused by hemolytic streptococcus, followed by Haemophilus influenzae, pneumococcus, staphylococcus, etc.. The onset of the disease is rapid, with obvious sore throat, chills, fever, and a body temperature of 39°C or more. The examination shows obvious congestion in the pharynx, enlarged and congested tonsils with yellow dotted exudate on the surface, enlarged and painful sub-M lymph nodes, and no abnormal signs in the lungs.
Laboratory tests
I. Routine blood tests
Viral infections are seen with normal or low white blood cell count and elevated lymphocyte ratio. Bacterial infections have leukocyte count with neutrophilia and leftward nuclear shift.
Determination of viruses and viral antigens
Immunofluorescence, enzyme-linked immunosorbent assay, serological diagnosis and virus isolation and identification are available as needed to determine the type of virus and to distinguish between viral and bacterial infections. Bacterial culture to determine the type of bacteria and drug sensitivity test.
Complications
Acute sinusitis, otitis media, and tracheobronchitis can be complicated. Some patients may develop rheumatism, glomerulonephritis, myocarditis, etc.
Diagnosis and differential diagnosis
The clinical diagnosis can be made based on the history, prevalence, symptoms and signs of nasopharyngeal inflammation, combined with peripheral blood picture and chest x-ray. Bacterial culture and virus isolation, or virus serology, immunofluorescence, enzyme-linked immunosorbent assay, and hemagglutination inhibition test can be performed to determine the etiological diagnosis.
The disease needs to be differentiated from the following diseases
I. Allergic rhinitis
Clinically, it is very similar to “typhoid”, except that it has a rapid onset, itchy nasal cavity, frequent sneezing and clear water-like nasal discharge, and the attacks are related to sudden changes in environment or temperature. Examination: pale and edematous nasal mucosa, increased eosinophilia on smear of nasal secretions.
II. Influenza
There is often a clear epidemic. The onset of the disease is rapid, the systemic symptoms are heavy, high fever, generalized aches and pains, conjunctivitis symptoms are obvious, but the nasopharyngeal symptoms are light. Smear specimens of mucosal epithelial cells in the patient’s nasal washings are taken and stained with fluorescently labeled influenza virus immune serum and placed under a fluorescent microscope for early diagnosis, or virus isolation or serological diagnosis can be used for differentiation.
Third, acute infectious disease prodromal symptoms
Such as measles, poliomyelitis, encephalitis, etc. often have upper respiratory symptoms at the beginning of the disease, and should be closely observed during the epidemic season of these diseases or in endemic areas, and necessary laboratory tests should be performed to differentiate.
Treatment
There are no specific antiviral drugs for respiratory viruses, and symptomatic or traditional Chinese medicine treatment is commonly used.
I. Symptomatic treatment
1.Serious or febrile people or old and weak people should rest in bed, avoid smoking, drink more water, and keep indoor air circulation.
2.If there is fever and headache, use antipyretic and analgesic tablets such as compound aspirin and pain relief tablets for oral use.
3.Sore throat can be treated with anti-inflammatory throat tablets and local nebulization.
4, nasal congestion, runny nose can be treated with steroid hormone drug nasal spray.
Second, antibacterial drug treatment
If there is bacterial infection, suitable antibiotics can be used, such as penicillin, cephalosporin, erythromycin, spiramycin, ofloxacin, etc.. Simple viral infections can generally be treated without antibiotics.
Chinese medicine treatment
The use of proprietary Chinese medicine or the principle of evidence-based treatment has its own unique features for upper respiratory tract infections.
Prevention
1, enhance the body’s own resistance to disease is the best way to prevent acute upper respiratory tract infections.
2, adhere to regular and appropriate physical exercise, adhere to the cold water bath, improve the body’s ability to prevent disease and adapt to the cold.
3, do a good job of cold prevention, to avoid the onset of triggers.
4, regular life, avoid overwork, especially overwork at night, pay attention to the isolation of respiratory patients, to prevent cross-infection, etc.