Is it Possible to Cough Up a Stone?

QUESTION: I couldn't believe it but apparently it's true. My husband had a
severe coughing spell and produced, instead of mucus, a little pebble. Is it
possible to cough up a stone? Where would it come from?
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ANSWER: Lithoptysis, or the spitting up of stones, has been documented since
ancient times and is the result of broncholithiasis, a disorder where
calcified material enters the tracheobronchial tree. Its often linked to lung
infections, such as tuberculosis, since the gravel-like stones, or
broncholiths, are believed to form when lymph nodes that surround the bronchi
(tubes that carry the oxygen to the lung tissue) become saturated with calcium
and calcify during the inflammatory stages of such an infection.
Though the exact biochemistry of tissue calcification is not completely
clear, we do know that once a lung infection develops, the necrotic or dead
tissue in the lung and surrounding lymph nodes become alkaline during the
healing process. This alkaline environment allows calcium phosphate and
carbonate to mass together and form deposits. Then, due to the constant
motion of the cardiopulmonary system, these calcified deposits enter the
bronchial tree by erosion and the stone is formed.
In many cases of broncholithiasis, no treatment is necessary because once
the stone is coughed up, the lung can usually clear itself. However,
broad-spectrum antibiotics may be prescribed for patients who are prone to
lung infections, and routine follow-ups should always be made to check for any
possible complications. I hope you have kept the "pebble" to show to your
physician, and will now seek the necessary professional care.