Answer
Answer 21-12. Many medical conditions can produce headache, consider the possibility of problems with the temporomandibular joint, sinusitis, occipital neuralgia (greater occipital nerve),. Systemic illness (such as the flu) can produce headache as can diseases such as: malignant hypertension, various infections, inflammatory vasculitis, thyroid and parathyroid disease, cardiac disease, pulmonary disease, renal disorders, sleep disorders. Many medicines can trigger headaches.