Bronchial hyperresponsiveness after cervical spinal cord injury

Cervical spinal cord injury results in interruption of sympathetic airway innervation, which originates from the upper thoracic spine, whereas parasympathetic nerve supply, arising in the vagal nuclei of the brainstem, remains intact. To assess the effect of such an altered neural environment on airway reactivity, bronchoprovocation testing was performed on eight subjects with nonacute traumatic lesions of the cervical spine, all of whom were lifetime nonsmokers without history of respiratory symptoms prior to their injury. Bronchial challenge was subsequently repeated after pretreatment with the anticholinergic agent, ipratropium bromide, an inhibitor of airway muscarinic receptors. All subjects demonstrated hyperresponsiveness to methacholine (the concentration of methacholine producing a fall in FEV1 of 20 percent from baseline [PC20] = 1.42 +/- 1.61 [SD] mg/ml). Airway hyperreactivity was completely blocked by pretreatment with inhaled ipratropium bromide (mean PC20 > 25 mg/ml [p < 0.0001]). The bronchial hyperresponsiveness observed in this population most likely reflects the loss of sympathetic airway innervation and resultant unopposed cholinergic bronchoconstrictor tone which results from transection of the cervical spine. Blockade of methacholine hyperresponsiveness with ipratropium bromide suggests a muscarinic receptor-mediated phenomenon.

Baclofen-induced bronchoconstriction

OBJECTIVE

To report the occurrence of acute bronchospasm in one asthmatic patient and increased bronchial reactivity in another following the administration of a single dose of oral baclofen.

CASE SUMMARY

On two separate occasions, a 46-year-old asymptomatic asthmatic man developed dyspnea and chest tightness one hour after the ingestion of baclofen 40 mg. Pulmonary function studies revealed a significant decrease in airflow relative to baseline. A 33-year-old asymptomatic woman with a history of exercise-induced dyspnea and wheezing displayed bronchial hyperresponsiveness to inhaled metacholine 2 hours after ingesting 40 mg of baclofen. The patient had had a negative methacholine challenge test 72 hours earlier.

DISCUSSION

The gamma-aminobutyric acid-agonist baclofen has been shown to reduce airway responsiveness to various bronchoconstricting agents in animal studies. The etiology of this seemingly paradoxical response in two patients is unclear, but may offer insight into the neurally mediated airway constriction that occurs in asthma.

CONCLUSIONS

Clinicians should be aware of the possibility of baclofen-induced bronchospasm, especially in asthmatic patients.

Pulmonary obstruction in individuals with cervical spinal cord lesions unmasked by bronchodilator administration

In subjects with spinal cord injury (SCI) a restrictive ventilatory impairment has been well described. Despite numerous studies of pulmonary function in patients with SCI, evidence of an obstructive component of respiratory dysfunction as a result of paralysis has not been observed in this population. We performed spirometry in 34 patients with cervical SCI before and after administration of an inhaled bronchodilator. Significant improvement in flow rate was demonstrated in 14 (41%) subjects. Our results suggest that transection of the cervical spine may result in obstruction to air flow, possibly due to interruption of the sympathetic innervation of the lung with resultant unopposed parasympathetic tone producing bronchoconstriction.

Primary endobronchial actinomycosis in association with foreign body aspiration

A 66-year-old diabetic man presented with a bilobar pneumonia two months after aspiration of a chicken bone. Flexible fiberoptic bronchoscopy demonstrated a mass in the bronchus intermedius. Histologic examination of endobronchial biopsy specimens revealed bone fragments, vegetable matter, and sulfur granules containing Actinomyces organisms. The patient responded to bronchoscopic removal of the foreign body and penicillin therapy. To our knowledge, the association of actinomycotic infection with an aspirated endobronchial foreign body has not previously been reported.