The classic symptom is a headache that becomes severe when the patient is upright and quickly disappears when the patient is lying flat. Thus, the headaches are typically absent first thing in the morning, and start or worsen shortly after getting out of bed. The pain is often worse at the back of the head, and may be accompanied by some neck discomfort and nausea. Rarely there are more serious neurological symptoms caused by stretching nerves or the downward displacement of the brain.