Symptoms & Signs

What are the signs and symptoms of the infection?

Many of the signs and symptoms depend on the type of upper respiratory infection. Common symptoms of URIs include:

 a runny nose or stuffy nose

 sore throat
 fever
 headache
 cough
 malaise, or vague feeling of illness
 muscle aches
 loss of appetite
 ear pain

Thereare many different types of upper respiratory infections, including:

 the common cold, usually due to a virus

 the flu, or influenza virus infection, which causes more severe symptoms than a cold
 acute sinusitis or chronic sinusitis, which involve the nasal sinuses
 otitis externa, or infection of the outer ear
 acute otitis media, or infection of the middle ear behind the eardrum
 pharyngitis, or sore throat
 acute bronchitis, an infection in the lower windpipes
 croup, which is a viral infection of the main windpipe that is usually only seen in children
 epiglottitis, a bacterial infection of the main windpipe that is more commonly seen in children

Definition and causes

Upper respiratory tract infection (URI) is a nonspecific term used to describe acute infections involving the nose, paranasal
sinuses, pharynx, larynx, trachea, and bronchi. The prototype is the illness known as the common cold, which is discussed here,
in addition to pharyngitis, sinusitis, and tracheobronchitis. Influenza is a systemic illness that involves the upper respiratory tract
and should be differentiated from other URIs.

Viruses cause most URIs, with rhinovirus, parainfluenza virus, coronavirus, adenovirus, respiratory syncytial virus,
coxsackievirus, and influenza virus accounting for most cases. 1 Human metapneumovirus is a newly discovered agent causing
URIs. Group A beta-hemolytic streptococci (GABHS) cause 5% to 10% of cases of pharyngitis in adults. 2 Other less common
causes of bacterial pharyngitis include group C beta-hemolytic streptococci, Corynebacterium diphtheriae, Neisseria
gonorrhoeae, Arcanobacterium haemolyticum, Chlamydia pneumoniae, Mycoplasma pneumoniae, and herpes simplex virus.
Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis are the most common organisms that cause the
bacterial superinfection of viral acute sinusitis. 3 Less than 10% of cases of acute tracheobronchitis are caused by Bordetella
pertussis, B. parapertussis, M. pneumoniae, or C. pneumoniae.4

Prevalence and risk factors

Most URIs occur more frequently during the cold winter months, because of overcrowding. Adults develop an average of two to
four colds annually. Antigenic variation of hundreds of respiratory viruses result in repeated circulation in the community. A
coryza syndrome is by far the most common cause of physician visits in the United States. 1 Acute pharyngitis accounts for 1% to
2% of all visits to outpatient and emergency departments, resulting in 7 million annual visits by adults alone. 1 Acute bacterial
sinusitis develops in 0.5% to 2% of cases of viral URIs.3 Approximately 20 million cases of acute sinusitis occur annually in the
United States. About 12 million cases of acute tracheobronchitis are diagnosed annually, accounting for one third of patients
presenting with acute cough.4 The estimated economic impact of non–influenza-related URIs is $40 billion annually. 1

Influenza epidemics occur every year between November and March in the Northern Hemisphere. Approximately two thirds of
those infected with influenza virus exhibit clinical illness, 25 million seek health care, 100,000 to 200,000 require hospitalization,
and 40,000 to 60,000 die each year as a result of related complications. 5 The average cost of each influenza epidemic is $12
million, including the direct cost of medical care and indirect cost resulting from lost work days. Pandemics in the 20th century
claimed the lives of more than 21 million people. A widespread H5N1 pandemic in birds is ongoing, with threats of a human
pandemic. It is projected that such a pandemic would cost the United States $70 to $160 billion. 6

Pathophysiology and natural history

Transmission of organisms causing URIs occurs by aerosol, droplet, or direct hand-to-hand contact with infected secretions, with
subsequent passage to the nares or eyes.7 Thus, transmission occurs more commonly in crowded conditions. Direct invasion of
the respiratory epithelium results in symptoms corresponding to the area(s) involved.

Sinusitis and acute bronchitis are frequently preceded by a common cold. Sinonasal allergies, anatomic abnormalities such as a
deviated nasal septum, sinus ostial blockade caused by mucosal edema, immunodeficiency disorders such as
hypogammaglobulinemia and human immunodeficiency virus infection, and cocaine abuse predispose to the development of
acute sinusitis.3

Most influenza epidemics in the 20th century were caused by the influenza A virus, but a few were caused by the influenza B
virus. Most epidemics are believed to spread from schoolchildren to their families. Annual influenza epidemics result from the
transmission of a mutated influenza virus for which most humans do not have immunity (antigenic drift). Pandemics, on the other
hand, occur when a totally new influenza virus is transmitted to humans from other species, most commonly swine and birds
(antigenic shift). People older than 65 years and those with comorbidities are at higher risk than healthy people for hospitalization
and death because of exacerbation of their underlying medical conditions as a result of influenza.

Signs and symptoms

Significant overlap exists in the clinical manifestations of the different forms of URIs. Onset of symptoms occurs 1 to 3 days
after exposure to the infectious agent. Nasal congestion, sneezing, and sore throat are the hallmarks of the common cold. A
predictive index score for the diagnosis of picornavirus infections has been developed, but is not of practical use. 8 Conjunctivitis
is characteristically seen with adenovirus infections. Sudden onset of sore throat, fever, absence of cough, and exposure to a
person with known streptococcal pharyngitis in the preceding 2 weeks suggest the diagnosis of GABHS-related pharyngitis. 9
Patients with acute sinusitis experience symptoms for more than 1 to 2 weeks after a common cold, including unilateral facial
pain, maxillary toothache, headache, and excessive purulent nasal discharge. 10,11 Acute tracheobronchitis is an illness
characterized by cough, with or without sputum production, or wheezing, lasting 1 to 3 weeks. 4 Pertussis in adults with waning
immunity caused by previous illness or immunization may not manifest with the typical whooping cough seen in children with
primary infection. Influenza is a sudden illness characterized by high fever, severe headache, myalgia, and dry cough, followed
by significant fatigue and malaise.12 The constellation of these symptoms during influenza epidemics is 70% to 80% sensitive for
making the diagnosis. Older patients with influenza may also present with confusion and somnolence. The presence of sneezing
among adults older than 60 years reduces the likelihood of influenza. 12

On physical examination, patients with common colds may have a low-grade fever, nasal vocal tone, macerated skin over the
nostrils, and inflamed nasal mucosa.8 Patients with GABHS-related pharyngitis may have pharyngeal erythema and exudate,
palatal petechiae (doughnut lesions), tender anterior cervical lymphadenopathy, and occasionally a scarlatiniform rash. 9
Pharyngeal or palatal vesicles and ulcers (herpangina) should suggest enteroviral or herpetic pharyngitis. Pharyngeal exudates
occur most commonly with GABHS-related pharyngitis, but can also be seen with infectious mononucleosis caused by Epstein-
Barr virus, acute retroviral syndrome, candidal infections, and diphtheria. Swelling, redness, and tenderness overlying the
affected sinuses and abnormal transillumination are specific for, but not commonly seen, in patients with acute sinusitis. 10
Generalized lymphadenopathy associated with sore throat, fever, and rash should raise the possibility of a systemic viral
infection, such as Epstein-Barr virus, cytomegalovirus, or human immunodeficiency virus. Patients with acute tracheobronchitis
may also have audible respiratory wheezes. Patients with influenza appear toxic and may have pulmonary rhonchi and diffuse
muscle tenderness.