What is Orthostatic Headache?
Orthostatic headache, also known as positional headache, is a condition where a person experiences headache when standing up or being in a vertical position and the headache subsides or gets relieved when the patient lies down or is in a horizontal position. Orthostatic headache used to be wrongly diagnosed as different primary headache disorders, such as tension headaches or migraine. However, due to the increasing awareness of this condition and its causes, it has now become possible to prevent a misdiagnosis or delayed diagnosis.
Causes of Orthostatic Headache
Decrease in cerebrospinal fluid pressure is the commonest cause of orthostatic headache. Decrease in cerebrospinal fluid pressure occurs from a a post-dural puncture leak, spontaneous cerebrospinal fluid leak or a traumatic cerebrospinal fluid leak. This is also often the primary symptom of POTS or postural orthostatic tachycardia syndrome, which is a type of dysautonomia. POTS is diagnosed using autonomic testing; whereas, imaging tests are done to diagnose a CSF leak.
It is difficult to differentiate between POTS and a cerebrospinal fluid leak as the defining symptom of POTS is positional tachycardia, which is also experienced by people who have cerebrospinal fluid leaks. Additionally both these conditions can also be present in the same patient, particularly in those people who have Ehlers–Danlos syndrome.
Other causes of Orthostatic Headache include colloid cysts and also connective tissue disorders. Orthostatic headache can also result as a complication of some surgeries, such as decompressive craniectomy for cerebral edema or decompressive surgery for chiari malformation.
Symptoms of Orthostatic Headache
If the cause of Orthostatic Headache is CSF leak, then patient usually starts to experience the headache within 15 minutes of standing up or sitting and it improves 20-30 minutes after lying down. In some cases, there may be many hours before the orthostatic headaches improve or worsen with any change of position. The location of orthostatic headaches in case of CSF leak is at base of the skull or posterior side of the head. However, it can also occur in the sides, front or all throughout the head. Orthostatic headache is rarely felt on one side of the head. Orthostatic headache is usually described as a pulling type of sensation extending from the head to the neck. The intensity of the orthostatic headache ranges from mild to very severe and can also become quite disabling for the patient.
Some of the other symptoms, which accompany orthostatic headache, include neck stiffness, neck pain, nausea, vomiting, sensitivity to sound/light, lack of coordination, tinnitus, hearing changes, visual changes, facial numbness or pain, dizziness or vertigo and changes in taste. The pain of orthostatic headache can also radiate to the center of the shoulder blades and into the upper arms. In rare cases, pain can also be felt at the site of CSF leak.
Pathophysiology of Orthostatic Headache
As mentioned previously, the most common cause of orthostatic headache is cerebrospinal fluid Leak. CSF leak causes decrease in the volume of CSF around the brain, which leads to loss of buoyancy of the brain resulting in increased pressure on regions, which are pain-sensitive such as dura mater and the blood vessels. This produces the pain which is known as Orthostatic Headache. As the brain is dependent on its buoyancy, which is present in a vertical or upright position, switching to a horizontal position by lying down relieves the orthostatic headache.
Epidemiology of Orthostatic Headaches
Different types of patients suffer from orthostatic headaches. This condition is more dominant in females than males. Females around the age of 40 usually start to experience orthostatic headache. However, patients of all ages can also suffer from orthostatic headache. CSF leak, which is the common cause of orthostatic headaches, occur more in patients suffering from connective tissue diseases, such as Ehlers-Danlos syndrome.
Diagnosis of Orthostatic Headache
Different tests are done to diagnose the cause of Orthostatic Headaches including cerebrospinal fluid leaks. A diagnostic dural puncture is generally used, as it easily shows the presence of a CSF leak. Other types of tests which are done include cranial CT, spinal MRI, cranial MRI and CT myelography. Diagnosis can be easy with a cranial MRI, as it shows the primary findings of CSF leak, which include engorgement of venous structures, enhancement of the meninges, subdural fluid collections, sagging of the brain and pituitary hyperemia.
Treatment of Orthostatic Headache
Orthostatic Headache occurring due to cerebrospinal fluid leaks are treated with bed rest and by giving the patient lots of hydration. Treatment then is done with an epidural blood patch (EBP) using autologous blood. If this is not effective, then surgery is done. The type of surgery done depends on the size of the leak and on the location of the leak.
If the cause of orthostatic headache is POTS or postural orthostatic tachycardia syndrome, then the treatment is done by managing the symptoms with diet, medication and preventative behaviors. Medicines which are used comprise of fludrocortisone, midodrine, pyridostigmine and droxidopa. These medicines help in stabilizing the blood pressure. Changes in diet help in ensuring that the patients are getting the necessary amount of fluid intake along with increase in the salt intake. Dietary changes also help in preventing recurrence of orthostatic headache.
Abdominal binder can also be used to alleviate the symptoms, as this helps in increasing the pressure of the fluid in the head. Water-bolus treatment helps in cases where there is increased orthostatic stress. This treatment comprises of rapid drinking of two 8 ounce glasses of cold water. This helps in increasing the standing blood pressure for some amount of time.
Prognosis of Orthostatic Headaches
The prognosis of orthostatic headaches is good. Patients suffering from POTS can manage their orthostatic headaches by identifying when the symptoms are occurring and can try to prevent orthostatic headaches by making the necessary changes and hence maintain their daily life.
Orthostatic headaches occurring from CSF leaks can be managed by repairing the CSF leaks and only a minor percentage of patients experience recurrence of orthostatic headaches.