感冒不仅仅是上呼吸道感染演示课件

1、1,感冒-不仅仅是上呼吸道感染,2,Definition,The common cold (acute viral rhinopharyngitis, , acute coryza, viral upper respiratory tract infection, or a cold) is a contagious, viral infectious disease of the upper respiratory system, primarily caused by rhinoviruses, (picornaviruses小核糖核酸病毒 ) or coronaviruses. It i

2、s the most common infectious disease in humans；there is no known cure, but it is very rarely fatal.,3,Definition,Collectively, colds, influenza, and other infections with similar symptoms are included in the diagnosis of influenza-like illness. Often, influenza and the common cold are mistaken for e

3、ach other, even by professional healthcare workers, but most of the recommended home treatments (drinking plenty of warm fluids, keeping warm, etc.) are similar if not the same. The symptoms of influenza often include a fever and are more severe than the cold.,4,SYMPTOM,cough, sore throat, runny nos

4、e, nasal congestion, and sneezing; sometimes accompanied by pink eye, muscle aches, fatigue, malaise, headaches, muscle weakness, uncontrollable shivering, loss of appetite, and rarely extreme exhaustion. Fever is more commonly a symptom of influenza, another viral upper respiratory tract infection

5、(URTI) whose symptoms broadly overlap with the cold, but are more severe. Symptoms may be more severe in infants and young children (due to their immune system not being fully developed) as well as the elderly (due to their immune system often being weakened).,5,SYMPTOM,A sensation of chilliness eve

6、n though the cold is not generally accompanied by fever, and although chills are generally associated with fever, the sensation may not always be caused by actual fever. In one study, 60% of those suffering from a sore throat and upper respiratory tract infection reported headaches, often due to nas

7、al congestion. The symptoms of a cold usually resolve after about one week; however, it is not rare that symptoms last up to three weeks.,6,What is the Difference Between Influenza and the Common Cold?,7,complications,opportunistic coinfections or superinfections such as acute bronchitis, bronchioli

8、tis, croup, pneumonia, sinusitis, otitis media, or strep throat.（脓毒性咽喉炎） People with chronic lung diseases such as asthma and COPD are especially vulnerable. Colds may cause acute exacerbations of asthma, emphysema or chronic bronchitis,8,Cause and susceptibility,one of the 99 known serotypes of rhi

9、novirus, a type of picornavirus. Around 30-50% of colds are caused by rhinoviruses. Other viruses causing colds are coronavirus (causing 10-15%), human parainfluenza viruses, human respiratory syncytial virus, adenoviruses, enteroviruses, or metapneumovirus. 5-15% are caused by influenza viruses. In

10、 total over 200 serologically different viral types cause colds. Coronaviruses are particularly implicated in adult colds. Due to the many different types of viruses and their tendency for continuous mutation, it is impossible to gain complete immunity to the common cold.,9,Cause and susceptibility,

11、Sleep Lack of sleep has been associated with the common cold. Those who sleep fewer than 7 hours per night were three times more likely to develop an infection when exposed to a rhinovirus when compared to those who sleep more than 8 hours per night. Vitamin D A 2009 study found that low blood serum

12、 levels of vitamin D were associated with increased rates of the common cold. A randomized controlled trial found that 104 post-menopausal African American women living in New York given vitamin D were three times less likely to report cold and flu symptoms than 104 placebo controls. A low dose (800

13、 IU/day) not only reduced reported incidence, it abolished the seasonality of reported colds and flu. A higher dose (2000 IU/day), given during the last year of the trial, virtually eradicated all reports of colds or flu.,10,Cause and susceptibility,Exposure to cold weather prolonged exposure to col

14、d weather such as rain or winter conditions Cold No evidence that short-term exposure to cold weather or direct chilling increases susceptibility to infection, implying that the seasonal variation is instead due to a change in behaviors such as increased time spent indoors at close proximity to othe

15、rs test the hypothesis that acute cooling of the feet causes the onset of common cold symptoms. Constriction of blood vessels of the nasal passages which might lead to reduced immunity Decreased temperature may result in a drop in tissue permeability and, as a result, may lead to reduced plasma leak

16、age. -complement proteins,11,Pathophysiology,saliva or nasal secretions of an infected person; in aerosol form generated by coughing and sneezing; or from contaminated surfaces.,12,Pathophysiology,Major entry point for the virus is normally the nose, - back of the nose and the adenoid area. The viru

17、s then attaches to a receptor, ICAM-1, which is located on the surface of cells of the lining of the nasopharynx. The receptor fits into a docking port on the surface of the virus. Large amounts of virus receptor are present on cells of the adenoid.,13,Pathophysiology,Rhinovirus colds do not general

18、ly cause damage to the nasal epithelium. Macrophages trigger the production of cytokines, which in combination with mediators cause the symptoms. Cytokines cause the systemic effects. The mediator bradykinin(缓激肽） plays a major role in causing the local symptoms such as sore throat and nasal irritati

19、on,14,Pathophysiology,The common cold is self-limiting, and the hosts immune system effectively deals with the infection. Within a few days, the bodys humoral immune response begins producing specific antibodies that can prevent the virus from infecting cells. Additionally, as part of the cell-media

20、ted immune response, leukocytes destroy the virus through phagocytosis and destroy infected cells to prevent further viral replication. In healthy, immunocompetent individuals, the common cold resolves in seven days on average,15,Incubation period and progression of disease,The upper respiratory vir

21、al replication cycle begins 8 to 12 hours after initial infection. Symptoms usually begin 2 to 5 days after initial infection but occasionally occur in as little as 10 hours after. Symptoms peak 23 days after symptom onset, whereas influenza symptom onset is constant and immediate. The symptoms usua

22、lly resolve spontaneously in 7 to 10 days but some can last for up to three weeks,16,Prevention,The best way to avoid a cold is to wash hands thoroughly and regularly; and to avoid touching the eyes, nose, mouth, and face. Anti-bacterial soaps have no extraordinary effect on the cold virus; it is th

23、e mechanical action of hand washing with the soap that removes the virus particles. Rhinoviruses can live up to 3 hours outside the body on the skin or objects. In 2002, the Centers for Disease Control and Prevention recommended alcohol-based hand gels as an effective method for reducing infectious

24、viruses on the hands of health care workers. The common cold is caused by a large variety of viruses, which mutate quite frequently during reproduction, resulting in constantly changing virus strains. Thus, successful immunization is highly improbable.,17,Lung disease and Influenza,Get vaccinated fo

25、r both seasonal flu and H1N1 flu 接种疫苗，包括季节性流感和H1N1流感 Cover your nose and mouth with your arm when you cough or sneeze 打喷嚏时用胳膊挡住口鼻 Wash your hands frequently with soap and water勤洗手 Alcohol-based hand cleaners are also effective when washing isnt possible酒精消毒 Avoid touching your eyes, nose or mouth避免接

26、触眼睛及口鼻 Try to avoid close contact with sick people避免与患病者近距离接触 Avoid large crowds不去人群密集处 Ask family and friends to be mindful of your higher risk and not expose you to their sickness if they are ill 避免和高危人群接触 Stay home if you are sick: 患病后勿外出 For 7 days after symptoms begin; or 症状出现后7天或症状消失后24消失内 Unt

27、il clear of symptoms for 24 hours Watch for public health advisories, as these recommendations may change健康咨询 For those with asthma, please remember to refer to and maintain your Asthma Action Plan as necessary.哮喘患者必要时仍需行哮喘治疗,18,Treatment,Conservative management The National Institute of Allergy and

28、 Infectious Diseases suggests getting plenty of rest, drinking fluids to maintain hydration, gargling with warm salt water, using cough drops, throat sprays, or over-the-counter pain or cold medicines. Saline nasal drops may help alleviate congestion. Treatments that may help alleviate symptoms incl

29、ude analgesics, decongestants, and cough suppressants, first-generation antihistamines such as brompheniramine, chlorpheniramine, diphenhydramine and clemastine (which reduce mucus gland secretion and thus combat blocked/runny noses but also may make the user drowsy). Second-generation antihistamine

30、s do not have a useful effect on colds.,19,Treatment,Conservative management Vitamin C in normal or mega doses has not been shown to be beneficial in a normal population for the prevention or treatment of the common cold. It however might be beneficial in people exposed to periods of severe physical

31、 exercise or cold environments. Various cold medicines exist however little evidence suggest they are any more effective than simple analgesics. They include antitussives, antihistamines and decongestants usually in combination with an analgesic. They are not recommended for use in children because

32、evidence does not support their effectiveness and there are concerns of harm.,20,Treatment,Antibiotics Antibiotics only target bacteria and thus do not have any beneficial effect against the common cold. Antivirals There are no approved antiviral drugs for the common cold. Nasal steroid still in trial Alternative treatments alternative treatments which similarly lack solid scientific evidence include calendula, ginger, garlic and vitamin C supplements.,21,惠菲宁的主要成分及药理作用,马来酸氯苯那敏（扑尔敏）（A）：抑制腺体分泌，减少鼻液后流对咽喉部的刺激以及抗胆碱能活性 盐酸伪麻