I. Etiology
Upper respiratory tract infections are caused by viruses in 70% to 80% of cases. Including rhinovirus, coronavirus, adenovirus, influenza and parainfluenza virus, respiratory syncytial virus, echovirus, coxsackievirus, etc.. Another 20% to 30% of upper sensations are caused by bacteria. Bacterial infections can be direct or secondary to viral infections, with hemolytic streptococci being the most common, followed by Haemophilus influenzae, pneumococci, staphylococci, etc., or occasionally gram-negative bacteria.
Various causes that lead to the reduction of systemic or local defense function of the respiratory tract, such as cold, rain, sudden climate change, excessive fatigue, etc., can cause the virus or bacteria already present in the upper respiratory tract or invaded from outside to multiply rapidly, thus triggering the disease. Patients who are old, young, weak, immunocompromised or suffering from chronic respiratory diseases are susceptible.
Clinical manifestations
Depending on the cause and scope of the disease, there are different types of clinical manifestations.
1.Common cold
Commonly known as “cold”, also known as acute rhinitis or upper respiratory tract khat, mostly caused by rhinovirus, followed by coronavirus, parainfluenza virus, respiratory syncytial virus, echovirus, coxsackievirus, etc..
The incubation period varies from 1 to 3 days, depending on the virus, with enteroviruses being shorter and adenoviruses and respiratory syncytial viruses being longer. The main symptoms are nasal symptoms, such as sneezing, nasal congestion, and clear watery nose, or cough, dry throat, itching or burning sensation, or even postnasal drip. The symptoms of sneezing, nasal congestion and clear watery nose may occur at the same time or a few hours after the onset of the disease. 2 to 3 days later, the nasal discharge becomes thicker, often accompanied by sore throat, lacrimation, loss of taste, breathlessness and hoarseness. There is usually no fever and systemic symptoms, or only low fever, discomfort, mild chills and headache. Physical examination reveals congestion, edema, and secretions in the nasal mucosa and mild congestion in the pharynx.
Symptoms such as hearing loss may be present in case of coexisting pharyngotonsillitis. Purulent sputum or severe lower respiratory symptoms suggest a combination of viral infection other than rhinovirus or secondary bacterial infection. If there is no complication, it can be cured in 5 to 7 days.
2.Acute viral pharyngitis or laryngitis
(1) Acute viral pharyngitis is mostly caused by rhinovirus, adenovirus, influenza virus, parainfluenza virus, as well as enterovirus and respiratory syncytial virus. Clinical features are itching or burning sensation in the pharynx, coughing is rare, and sore throat is not obvious. When swallowing is painful, it often suggests a streptococcal infection. Fever and malaise may be present with influenza virus and adenovirus infections. Adenoviral pharyngitis may be associated with ocular conjunctivitis. On physical examination, the pharynx is visibly congested and edematous, and the submandibular lymph nodes are enlarged and painful to palpation.
(2) Acute viral laryngitis is mostly caused by rhinovirus, influenza A virus, parainfluenza virus and adenovirus. Clinical features include hoarseness, difficulty in speaking, pain on coughing, often with fever, sore throat or cough. Physical examination shows edema and congestion in the larynx, mild enlargement and tenderness of local lymph nodes, and wheezing sounds in the larynx can be heard.
3. Acute herpes pharyngitis
It is often caused by coxsackievirus A, manifesting as obvious sore throat and fever, with a duration of about 1 week, mostly in summer, and is common in children and occasionally in adults. Physical examination reveals a congested pharynx with grayish-white herpes and superficial ulcers on the soft palate, uvula, pharynx and tonsil surfaces, surrounded by a red halo and later forming a herpes.
4.Pharyngeal conjunctival fever
It is mainly caused by adenovirus, coxsackievirus and so on. Clinical manifestations include fever, sore throat, photophobia, lacrimation, and obvious congestion of the pharynx and conjunctiva on physical examination. The course of the disease is 4-6 days, often occurs in the summer, children are common, swimmers are easy to spread.
5.Bacterial pharyngeal-tonsillitis
Mostly caused by hemolytic streptococcus, followed by Haemophilus influenzae, pneumococcus, staphylococcus, etc.. The onset of the disease is rapid, obvious sore throat, chills, fever (body temperature can be 39 ℃ or more). Physical examination shows obvious congestion in the pharynx, enlarged and congested tonsils with yellow purulent secretions on the surface, enlarged and painful submandibular lymph nodes, and no abnormal signs in the lungs.
III. Examination
1.Blood count
In viral infection, the white blood cell count is normal or low, and the proportion of lymphocytes is increased; in bacterial infection, the white blood cell count often increases, and there is neutrophilia or left shift of nucleus.
2.Pathogenetic examination
Because there are many types of viruses, and it is not obvious that a clear type is helpful for treatment, there is generally no need for a clear pathogenic examination. If necessary, immunofluorescence, enzyme-linked immunosorbent assay, virus isolation and identification, and virus serological examination can be used to determine the type of virus. Bacterial culture can determine the type of bacteria and do drug sensitivity tests to guide clinical use.
IV. Diagnosis
Clinical diagnosis can be made based on history, epidemiology, nasopharyngeal symptoms and signs, combined with peripheral blood picture and negative chest imaging. In special cases, bacterial culture or virus isolation, or virus serological examination, etc. are feasible to determine the pathogen.
V. Differential diagnosis
The disease must be differentiated from other diseases that initially present with cold-like symptoms.
1.Allergic rhinitis
Clinically, it is very similar to “cold”, with the following differences.
(1) Rapid onset, itchy nasal passages, frequent sneezing, clear nasal discharge, no fever and less cough.
(2) Mostly caused by allergic factors such as mites, dust, animal fur, low temperature and other stimuli.
(3) If the allergen is removed, the symptoms disappear within a few minutes or 1 to 2 hours.
(4) Physical examination shows pale and edematous nasal mucosa.
(5) Eosinophilia can be seen in the smear of nasal secretions.
2.Influenza
Acute respiratory infectious disease caused by influenza virus, highly contagious, often with a large range of epidemic. Clinical features.
(1) rapid onset, systemic symptoms, chills, high fever, generalized aches and pains, conjunctival inflammation is obvious, some patients have nausea, vomiting, diarrhea and other gastrointestinal symptoms.
(2) Nasopharyngeal symptoms are mild.
(3) The virus is influenza virus, and the diagnosis can be clarified by virus isolation or serology if necessary.
(4) Early application of anti-influenza virus drugs such as amantadine and oseltamivir is effective.
(5) Influenza vaccination can be used for prevention.
3.Acute infectious diseases
Certain acute infectious diseases (such as measles, epidemic hemorrhagic fever, epidemic meningitis, poliomyelitis, typhoid fever, typhus) often have upper respiratory symptoms at the beginning of the disease, and should be closely observed during the epidemic season or in endemic areas, and necessary laboratory tests should be performed for identification.
(1) measles The symptoms of upper respiratory tract infection are prodromal symptoms, and about 90% of patients have small grayish-white spots on the buccal mucosa of the maxillary second molar area (Koch’s spots) visible 2 to 3 days after the onset of the disease, with no Koch’s spots on the upper senses.
(2) Epidemic hemorrhagic fever The main source of infection is rodents, and the epidemic is regional in nature. There may be headache, lumbago and orbital pain (commonly known as the three pains), fever, hemorrhage and kidney damage are the three main signs, and typical patients may have fever, hypotensive shock, oliguria, polyuria and recovery in five stages. The symptoms of systemic toxicity of epizootic are mild, mainly with nasopharyngeal cata symptoms.
(3) Epidemic encephalomyelitis Some patients have symptoms of sore throat and increased nasopharyngeal secretion at the initial stage, and soon enter the septic and meningitis stage, with chills, high fever, headache and rash. In the later stage, there may be severe headache and meningeal irritation signs. The main source of infection is the carrier, through droplet transmission.
(4) Poliomyelitis is an acute infectious disease caused by poliomyelitis virus, and children who have not been vaccinated are susceptible. Most of the prodromal period shows symptoms of upper sensation, and some of them enter the pre-paralysis period, showing neurological symptoms such as temperature rise, limb pain and sensory allergy, and the paralyzer shows asymmetric and flaccid paralysis of limbs, mostly in the unilateral lower limbs.
(5) Typhoid fever Fever is the earliest symptom and may be accompanied by upper sensory symptoms, but there is often a slow pulse, splenomegaly or rose rash, positive typhoid pathogenesis and serology, and a long duration of illness.
(6) typhus Epidemic typhus is most often seen in winter and spring, and endemic typhus is most often seen in summer and autumn. The onset of the disease is generally rapid, with a rapid pulse and a pronounced headache. The rash appears on the 5th to 6th day of the disease and is numerous and may have a hemorrhagic rash. The rash is positive.
VI. Treatment
1.Symptomatic treatment
(1) Rest Those who are seriously ill or old and frail should rest in bed, avoid smoking, drink more water, and keep indoor air circulation.
(2) Antipyretic and analgesic If you have fever, headache, muscle pain and other symptoms, you can use antipyretic and analgesic drugs, such as compound aspirin, acetaminophen, indomethacin (anti-inflammatory pain), pain relief tablets, ibuprofen, etc. For sore throat, various throat tablets such as lysozyme tablets, Jianmin Throat Tablets, or the Chinese herbal medicine Liushenwan can be taken orally.
(3) Decongestant nasal congestion, nasal mucous membrane congestion and edema, can use pseudoephedrine hydrochloride, can also be used 1% ephedrine nasal drops.
(4) Antihistamines For colds with increased sensitivity of the nasal mucosa, frequent sneezing and runny nose, antihistamines such as chlorpheniramine maleate or benadryl can be used.
(5) Cough suppressants For those with more obvious cough symptoms, cough suppressants such as dextromethorphan and pentoxifylline can be given.
2.Etiological treatment
（When there is evidence of bacterial infection such as elevated white blood cell count, pus moss in the throat and yellow sputum, penicillin, first-generation cephalosporins, macrolides or quinolones can be used as appropriate. It is rarely necessary to select sensitive antibacterial drugs according to the pathogenic bacteria.
(2) Antiviral drug treatment There are no specific antiviral drugs, and the abuse of antiviral drugs can cause the phenomenon of influenza virus resistance. Therefore, if there is no fever, normal immune function, and the onset of the disease is more than two days, generally do not need to apply. Patients with immunodeficiency can be used routinely at an early stage. Broad-spectrum antiviral drugs ribavirin and oseltamivir have strong inhibitory effect on influenza virus, parainfluenza virus and respiratory syncytial virus, etc., which can shorten the course of illness.
3.Chinese herbal medicine treatment
Chinese herbal medicine with the effect of clearing heat and detoxifying and antiviral can also be used to help improve the symptoms and shorten the course of the disease. Xiao Chai Hu punch and Pan Lan Gen punch are widely used.
VII. Prognosis
The disease is mild, short-lived and self-limiting, and most patients have a good prognosis. However, in a very small number of patients who are old, weak, or have more underlying diseases, especially in combination with severe chronic lung diseases such as chronic obstructive pulmonary disease (COPD), the prognosis may be poor due to serious complications.
Eight, prevention
1.Avoid triggers
Avoid cold, rain, overexertion; avoid contact with cold patients, avoid dirty hands touching the mouth, eyes and nose. Older and weaker susceptible people should pay more attention to protection, wear a mask when upper respiratory tract infection is prevalent, and avoid going in and out of public places with many people.
2.Enhance physical fitness
Adhere to moderate and regular outdoor exercise, improve the body’s immunity and cold tolerance is the main method to prevent this disease.
3.Immunomodulatory drugs and vaccines
For patients with frequent and repeated occurrence of the disease and those with low immunity in old age, immune boosters can be applied as appropriate. At present, there is no vaccine against viruses other than influenza virus.