What Causes Headache?

1 Answer

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Headache is usually referring to the pain in the upper part of the head, including the upper part of the eyebrow arch, the upper edge of the helix, and the joint above the occipital protuberance. In many cases headaches are caused by neuralgia, intracranial infections, intracranial lesions, cerebrovascular disease, and systemic diseases such as acute infection and poisoning.  It's common in all adult age groups.
Headache can be classified into three types:
1 The primary headaches: including migraine, tension headaches, cluster headaches, etc.
2 secondary headaches: including head and neck trauma, cranial and cervical vascular factors, intracranial Non-vascular diseases, infections, drug withdrawal, mental factors and other causes of headaches.
3 Cranial neuralgia, central and primary facial pain, and other facial and facial structure caused by headaches and other types headache.
Causes
  • Infection
Craniocerebral infections, such as meningitis, meningoencephalitis, encephalitis, brain abscess, and intracranial parasite infections, such as cysticercosis, hydatid infection, often cause headaches.
Acute infections such as influenza, pneumonia and other diseases may also cause headache.
  • Vascular disease
Subarachnoid hemorrhage, cerebral hemorrhage, cerebral thrombosis, cerebral embolism, hypertensive encephalopathy, cerebral insufficiency, cerebral vascular malformation, these can all lead to headache.
  • Occupational lesions
Brain tumors, intracranial metastases, and inflammatory demyelinating pseudotumors can cause headaches, it's because of the increased intracranial pressure.
  • Head and neck neuropathy
Head and face dominating neuralgia: such as trigeminal nerve, glossopharyngeal nerve and occipital neuralgia. Head facial ENT disorders such as eye, ear, nose, and teeth diseases. Cervical spondylosis and other neck diseases cause head and neck pain.
  • Systemic disease
Hypertension, anemia, pulmonary encephalopathy, and heat stroke all can cause headaches.
  • Brain trauma
Such as concussion, brain contusion, subdural hematoma, intracranial hematoma, sequelae of traumatic brain injury.
  • Poison and drug poisoning
Such as alcohol, carbon monoxide, organic phosphorus, drugs (such as belladonna, salicylic acid) and other poisoning.
  • Internal disorders and mental factors
Menstrual period and menopause headache are good examples. Neurotic somatization disorders and snoring headaches are also common. 
Diagnosis
The area of pain is the first clue for diagnosis. It's important to determine it's a primary or secondary headache. Most primary headaches are benign and secondary headaches are caused by organic lesions. The diagnosis of any primary headache should be based on the exclusion of secondary headaches.
The cause of headache is complicated. During physical exam, a doctor needs to collect intensive information including the history of headache, the way of headache, frequency, duration, location, pain level, presence or absence of prodromal symptoms, and presence or absence of predisposing factors, age and gender, trauma history, medication history, poisoning history, family history... 
Usually a comprehensive and detailed physical examination, especially the examination of the nervous system and head and facial features, helps to find where the headache is. Doctors will ask for imaging exam or Lumbar cerebrospinal fluid test when necessary. 
Treatment
Common treatment to headache is medication and physical therapy.
Medication mainly means pain reliever in this case. Patients need to follow the prescription.
Physical therapy include cold dressing, heat dressing, inhaling oxygen.
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