Complications of acute bronchitis

Mechanical complications of cough syndrome

The evolution of cough is a key marker of the course of acute bronchitis. At the onset of the disease (the first days), it is dry and unproductive, and during the peak period, it becomes moist with the discharge of mucous or mucopurulent sputum. Intense cough syndrome can cause a number of unpleasant mechanical consequences:

• Vomiting. It is triggered both by hacking coughing paroxysms themselves and by heavy swallowing of discharging sputum (which is especially typical in pediatric practice).
• Pain syndrome. Patients often complain of burning, soreness, and marked discomfort behind the sternum, which is associated with overstrain of the respiratory muscles and mechanical irritation of the trachea.

Bronchial obstruction syndrome

When the small bronchi are involved in the pathological process, an obstructive variant of acute bronchitis develops. The pathogenetic triad of obstruction includes smooth muscle spasm, mucosal edema, and hypersecretion of viscous mucus.

Clinically, this manifests as expiratory dyspnea (labored, prolonged expiration) and wheezing, which can be heard even at a distance. The consequence of impaired respiratory mechanics is lung hyperinflation, and in moderate-to-severe cases, hypoxia inevitably joins. Atypical microflora (Mycoplasma, Chlamydia, Legionella) is particularly prone to developing bronchial obstruction.

Downward infection and development of pneumonia

The logic of the development of complications is directly related to the etiology and spread of the pathogen down the respiratory tract. Isolated acute bronchitis is accompanied only by scattered dry or moist (coarse- and medium-bubbling) rales. The appearance of "red flags" (red flags) requires an immediate in-depth examination and chest radiography to rule out focal pneumonia. These signs include:

1. Fever above 38 °C.
2. Tachycardia (HR > 100 beats per minute).
3. Tachypnea (RR > 24 breaths per minute).
4. Appearance of local physical findings: dull percussion sound and persistent asymmetric crackles.

Specific complications of viral infections

The disease extremely rarely occurs in isolation; more often it is combined with nasopharyngeal lesions, sinusitis, and conjunctivitis (which is especially typical for adenovirus infection).

The most formidable specific complications are characteristic of respiratory syncytial (RS) infection. The death and desquamation of the epithelium combined with impaired mucociliary clearance lead to bronchiolar occlusion. As a result, atelectasis, acute perifocal emphysema, and focal serous pneumonia are formed. The development of interstitial pneumonitis with infiltration of the interalveolar septa is also possible. Outside the lungs, the RSV virus can cause interstitial inflammation of internal organs (kidneys, liver, pancreas, intestines) and even meningoencephalitis. In young children, such systemic lesions and the addition of secondary flora can lead to death.

Class and exam questions

What else to study on this topic

• Etiology and mechanisms of development of community-acquired pneumonia (role of Streptococcus pneumoniae and staphylococci)
• Clinical features of lung damage by atypical pathogens (Mycoplasma, Chlamydia, Legionella)
• Pathogenesis and complications of staphylococcal destructive bronchopneumonia
• Scoring systems for the severity of broncho-obstructive syndrome in pediatrics
• Morphology of symplasts and pathological anatomy of RSV infection

Other topics in the "Additional Topics" section

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