Can lung ailments cause headache?
VALERIE GILBERT, MD, of Dartmouth, NS, asks, "Is there a lung-brain connection?" She explains, "I've recently had two patients presenting with headache as the primary symptom who were eventually diagnosed with pulmonary lesions. The first had chronic periorbital headache for almost two years before lung cancer was found. The second, who presented with acute-onset supraorbital neuralgia with associated migraine headache, turned out to have atypical pneumonia."
Lung conditions are often accompanied by headaches as a manifestation of systemic disease. As you've observed, two common associations are with lung cancer and atypical pneumonia. Metastatic lung carcinoma can present first with symptoms from brain tumours, so whenever these are diagnosed, it's important to look for a primary tumour in the lung, especially in smokers. Recently, there have been reports of successful surgery for both brain metastases and the lung tumour in patients with evidence of limited spread. Atypical pneumonia is frequently linked with headaches on initial presentation. Severe headache is classically seen with Chlamydia psittaci, Mycoplasma and Legionella pneumonia, but can also show up with pneumococcal pneumonia, often with fever, or later from associated rare meningitis. Headaches may be a symptom of other lung infections, including influenza and coccidiomycosis. Another common respiratory connection with headache is hypercapnia -- carbon dioxide retention is common in severe chronic obstructive pulmonary disease (COPD) and sleep apnea, typically early in the morning. As well, other diseases affecting the lungs, such as vasculitis, Wegener's granulomatosis, systemic lupus and even altitude sickness due to low oxygen, can cause headache. DB (See our neurologist's response to this question in the neurology category)