INTRODUCTION:Chronic cough is a common pediatric medical complaint defined as daily symptoms lasting more than 4 weeks. The cough is usually associated with asthma, gastroesophageal reflux disease, post-nasal drip syndrome, environmental irritants, or recurrent aspiration. We report an unusual case of persistent cough as the primary manifestation of a Chiari I malformation.
CASE PRESENTATION:The patient’s birth and past medical history were uneventful until he was 9 months of age when he developed a chronic, non-productive cough. The cough was present throughout the daytime and nighttime, both during and between feedings. It was refractory to inhaled corticosteroids, bronchodilators, and antibiotics. On examination, he appeared content without obvious distress. His physical exam, including his cranial nerve exam, did not reveal significant abnormalities. Sweat chloride test, chest radiograph and chest CT were unremarkable. Upper gastrointestinal series was negative for reflux or anatomic abnormality. Bronchoscopy revealed normal vocal cords and airway anatomy. Cytology from the bronchoalveolar lavage revealed numerous neutrophils and moderate lipid laden macrophages. Tracheal ciliary biopsy was normal. Swallow evaluation with videofluoroscopy showed silent aspiration when the patient became agitated. A magnetic resonance imaging of the brain and cervical spine demonstrated caudal descent of the cerebellar tonsils to C2 consistent with a Chiari I malformation and syringohydromyelia through most of the spinal cord.He underwent posterior fossa decompression, and within one month of surgery his cough had almost completely disappeared. Five months later, a swallow evaluation still revealed the presence of aspiration, but his cough remained absent.
DISCUSSIONS:In Chiari I malformation, the cerebellar tonsils herniate through the foramen magnum into the upper cervical spine, which may produce symptoms of occipital or posterior cervical pain. Brainstem compression may manifest as laryngeal sensory loss, vocal cord paralysis, dysphagia and recurrent aspiration pneumonia; therefore, chronic aspiration due to diminished laryngeal sensation is one possible etiology of our patient’s persistent cough. Surprisingly, he had persistent aspiration during a swallow assessment five months post-decompression, but his cough had resolved soon after his surgery, suggesting that there may have been a neurologic cause for our patient’s intractable cough. The brainstem is thought to be the integration center that transmits impulses to the effector muscles for cough. We propose that the brainstem compression in our patient may have been directly linked to his persistent cough.
CONCLUSION:This case shows that decompression of the Chiari malformation treated our patient’s chronic cough. One likely explanation is that his swallow function improved, decreasing the frequency of aspiration events and subsequently his cough. However, the persistent aspiration on an objective swallow study months after resolution of cough suggests that brainstem compression from the Chiari I malformation may have a direct association with our patient’s persistent cough. To our knowledge, this phenomenon has not been reported in the medical literature.
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