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Respiratory infections and chronic lung diseases are among the most common reasons that patients consult primary care physicians. Most of the respiratory problems encountered by primary care physicians are acute, with the majority comprising respiratory infections, exacerbations of asthma, chronic obstructive pulmonary diseases (COPDs), and pulmonary embolism (PE).

Common Colds/Upper Respiratory Tract Infections

Essentials of Diagnosis

  • Sore throat, congestion, low-grade fever, mild myalgias, and fatigue.
  • Symptoms lasting for 12-14 days.

General Considerations

Although colds are mild, tend to get better on their own, and are of short duration, they are a leading cause of sickness and of industrial and school absenteeism. Each year, colds account for 170 million days of restricted activity, 23 million days of school absence, and 18 million days of work absence.

Most colds are caused by viruses. Rhinoviruses are the most common type of virus and are found in slightly more than half of all patients. Coronaviruses are the second most common cause. In rare instances (0.05% of all cases), bacteria can be cultured from individuals with cold symptoms. It is not clear if these bacteria cause the cold, are secondary infectious agents, or are simply colonizers. Bacterial pathogens that have been identified include Chlamydia pneumoniae, Haemophilus influenzae, Streptococcus pneumoniae, and Mycoplasma pneumoniae.


The mechanisms of transmission suggest that colds can be spread through contact with inanimate surfaces, but the primary transmission appears to be via hand-to-hand contact. The beneficial effects of removing viruses from the hands are supported by observations that absences due to colds among children in day-care or school settings have been reduced through the use of antiseptic hand wipes throughout the day.

Clinical Findings

Colds generally last 12-14 days. Telling patients that colds last no longer than a week underestimates the actual natural history of an uncomplicated viral respiratory tract infection and leads patients to believe that symptoms that persist beyond a week are not normal. When the symptoms of congestion persist longer than 2 weeks, consideration should be given to other causes of chronic congestion (Table 27-1).

Table 27-1. Differential Diagnosis for Congestion and Rhinorrhea.

Symptoms of colds include sore throat, congestion, low-grade fever, and mild myalgias and fatigue. In general, early in the development of a cold the discharge is clear. As more inflammation develops, the discharge takes on some coloration. A yellow, green, or brown-tinted nasal discharge is an indicator of inflammation, not secondary bacterial infection. Discolored nasal discharge raises the likelihood of sinusitis, but ...

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