Episodic headaches affect the overwhelming majority of the population. While inconvenient, episodic headaches are rarely consequential from a medical or personal perspective. In contrast, chronic headaches may substantially interfere with daily activities and quality of life. Constant or chronic headaches may occur due to abnormalities of the brain or its associated structures. More commonly, chronic headaches occur in reaction to an illness elsewhere in the body that manifests with headache as a persistent symptom.
Chronic Tension Headaches
Tension headaches affect nearly 80 percent of the general population, according to information provided by the University of Maryland Medical Center. The pain of tension headaches typically begins toward the back of the head and may encompass much of the head, sometimes extending into the neck. Chronic tension headaches occur at least 15 days per month for several successive months. Certain foods, excessive stress, smoking, chronic overwork, sleep deprivation, alcohol and drug use, skipping meals and inadequate exercise may contribute to chronic tension headaches. Antidepressants or antiseizure medications may be helpful in preventing chronic tension headaches.
Brain Tumors
Noncancerous and cancerous brain tumors may cause constant headaches, according to the National Institute of Neurological Disorders and Stroke. Although other causes of persistent headaches prove far more common, consideration of brain tumor merits attention due to the progressive and potentially life-threatening nature of this disorder. Brain tumor-associated headaches typically cause non-throbbing, deep pain, frequently near the site of the tumor. The peak level pain characteristically occurs upon awakening and eases gradually throughout the day. Relief of pain after vomiting is a hallmark characteristic of brain-tumor associated headaches. New onset seizures, changes in personality or behavior, and localized sensory or movement abnormalities increase suspicion for a possible brain tumor. The Central Brain Tumor Registry of the United States reports that approximately 62,950 newly diagnosed cases of brain or spinal tumor occur annually among American adults and children.
Hypoxemia
Abnormally low oxygen levels in the brain can lead to persistent headaches. When the blood oxygen content decreases, the blood vessels that supply the brain typically dilate to permit maximal blood flow. Brain swelling may occur with severe oxygen deprivation. Hypoxemia-induced headaches typically cause generalized throbbing pain. Information provided by the Mayo Clinic states that possible causes of chronically low oxygen levels include emphysema, chronic obstructive pulmonary disease, anemia, pulmonary fibrosis, cystic fibrosis, sleep apnea, heart failure, high altitude sickness and chronic low-level carbon monoxide exposure. Headaches associated with sleep apnea and chronic obstructive pulmonary disease are typically worst upon awakening. Treatment of the underlying condition with improvement in the blood and brain oxygen levels typically reduces or eliminates associated headache symptoms.
