Occipital Neuralgia

THE CLINICAL SYNDROME

• Occipital neuralgia is typically brought on by a direct blow to the greater or lesser occipital nerves.

• Fibers of the dorsal primary ramus of the second cervical nerve and, to a lesser extent, fibers of the third cervical nerve give rise to the greater occipital nerve.

  • This nerve is located in the back of the head. Along with the occipital artery, the greater occipital nerve penetrates the fascia immediately below the superior nuchal ridge. This is the location of the superior nuchal ridge.
  • It nourishes the medial part of the posterior scalp all the way up to the vertex, which is located farther anteriorly.
  • The ventral major rami of the second and third cervical nerves give birth to the lesser occipital nerve, which is located in the back of the head.
  • The lesser occipital nerve travels superiorly along the posterior border of the sternocleidomastoid muscle before it divides into cutaneous branches that innervate the lateral portion of the posterior scalp and the cranial surface of the pinna of the ear. This portion of the sternocleidomastoid muscle is also innervated by these cutaneous branches.

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SIGNS AND SYMPTOMS

• When the greater and lesser occipital nerves are palpated at the level of the nuchal ridge, a patient suffering from occipital neuralgia experiences neuritic pain in the distribution of these nerves.
• A certain number of patients experience pain when they rotate their neck or bend laterally at the cervical spine.

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TESTING

• No specific test exists for occipital neuralgia.
• The primary goal of the testing is to uncover a hidden pathologic process or another disease that may cause symptoms similar to those of occipital neuralgia.
• It is recommended that magnetic resonance imaging (MRI) of the brain and cervical spine be performed on all individuals who have recently begun experiencing headaches that may be due to occipital neuralgia.
• In patients who had previously stable occipital neuralgia but who have recently noticed a shift in the severity of their headache symptoms, an MRI examination is also recommended.
• An intracranial condition that may mimic the symptoms of occipital neuralgia can also be identified with the help of computed tomography scanning of the brain and cervical spine.
• If the diagnosis of occipital neuralgia is uncertain, screening laboratory tests, which include a complete blood count, erythrocyte sedimentation rate, and automated blood chemistry, should be conducted.
• Occipital neuralgia can be differentiated from tension-type headaches by using a technique called neural blockade, which involves cutting off the greater and lesser occipital nerves. At the nuchal ridge, it is possible to readily obstruct both the larger and the lesser occipital nerves.

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DIFFERENTIAL DIAGNOSIS

• Occipital neuralgia is a rare cause of headaches that almost never manifests itself in the absence of direct trauma to either the larger or the lesser occipital nerve.
• Tension headaches are the most common type experienced by patients whose headaches involve the occipital area.
• Although occipital nerve blocks are ineffective for treating tension headaches, cervical epidural nerve blocks, in conjunction with antidepressant medication like amitriptyline, have been shown to be effective treatments for the condition.
• Therefore, the clinician should reassess the diagnosis of occipital neuralgia in patients whose symptoms are compatible with occipital neuralgia but who fail to respond to greater and lesser occipital nerve blocks.

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TREATMENT

• Neural blockade with a local anesthetic and steroid is the primary component of the treatment for occipital neuralgia. In addition to this, judicious use of nonsteroidal anti-inflammatory drugs, muscle relaxants, tricyclic antidepressants, and physical therapy are also essential components of the treatment.
• The patient is positioned in a sitting position with the cervical spine flexed and the forehead resting on a padded bedside table in order to perform a neural blockade of the greater and lesser occipital nerves.
  When used on certain patients, ultrasound needle guiding has the potential to increase the accuracy of needle placement. If the patient has a return of their symptoms after first finding relief following a trial of occipital nerve blocks, it is reasonable to proceed with radiofrequency lesioning of the afflicted occipital nerves as the next stage in their treatment.

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COMPLICATIONS AND PITFALLS

• The scalp has a dense network of blood vessels.
• Due to the vascularity of the area as well as its close proximity to the arteries that supply the greater and lesser occipital nerves, the clinician needs to perform careful calculations in order to determine the maximum amount of local anesthetic that can be administered without risk to the patient, particularly when performing bilateral nerve blocks.
• Both postblock ecchymosis and hematoma formation are more likely to occur as a result of the vascularity of the area as well as its close proximity to the arterial supply.
• When manual pressure is administered to the area of the block shortly after the injection, the risk of these problems can be significantly reduced.
• A reduction in the amount of discomfort and bleeding can also be achieved by applying cold packs to the area for twenty minutes following the block.
• Because the subarachnoid administration of local anesthetic in this location results in instantaneous total spinal anesthesia, care must be taken to avoid accidentally inserting the needle into the foramen magnum.

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