From the Guidelines
No, trigeminal neuralgia and hemicrania continua are not in the same diagnostic group. Trigeminal neuralgia is a neuropathic pain disorder characterized by brief, severe, electric shock-like pains along the distribution of the trigeminal nerve, typically triggered by innocuous stimuli like touching the face, eating, or brushing teeth [ 1 ]. It's classified as a cranial neuralgia. In contrast, hemicrania continua is a primary headache disorder characterized by continuous, unilateral head pain with periodic exacerbations and autonomic symptoms like tearing, nasal congestion, or ptosis.
Key Differences
- Trigeminal neuralgia is typically treated with anticonvulsants like carbamazepine (200-1200 mg/day) or oxcarbazepine (600-1800 mg/day) [ 1 ].
- The key distinguishing feature of hemicrania continua is its absolute responsiveness to indomethacin, which is diagnostic.
- These conditions differ in their underlying pathophysiology, with trigeminal neuralgia often involving neurovascular compression of the trigeminal nerve [ 1 ], while hemicrania continua likely involves dysfunction in pain processing pathways and the trigeminal autonomic reflex.
Diagnostic Considerations
- A diagnosis of trigeminal neuralgia is based on the presence of paroxysmal attacks of pain in the distribution of the trigeminal nerve, with or without triggers [ 1 ].
- A diagnosis of hemicrania continua is based on the presence of continuous, unilateral head pain with periodic exacerbations and autonomic symptoms, and a positive response to indomethacin.
Treatment Implications
- Treatment of trigeminal neuralgia typically involves anticonvulsants, with carbamazepine and oxcarbazepine being first-line options [ 1 ].
- Treatment of hemicrania continua typically involves indomethacin, with a positive response being diagnostic.
From the Research
Diagnostic Classification
- Trigeminal neuralgia (TN) and hemicrania continua (HC) are two distinct headache disorders with different diagnostic criteria 2, 3.
- HC is currently classified under the heading of trigeminal autonomic cephalalgias (TACs), which also includes other primary headache disorders 3.
- TN has been described in association with various primary headache disorders, including HC, suggesting a possible link between the two conditions 2.
Clinical Presentation
- TN is characterized by unilateral, paroxysmal, stabbing facial pain, originating from the trigeminal nerve 4.
- HC is characterized by a continuous and strictly unilateral headache, with possible cranial autonomic symptoms during episodes of pain exacerbation 3, 5.
- Both disorders can present with similar symptoms, making diagnosis and differentiation challenging 2, 6.
Treatment Options
- TN is typically treated with carbamazepine and oxcarbazepine as first-line therapy, while HC is treated with indomethacin 2, 4, 3.
- Alternative treatment options, such as non-invasive vagus nerve stimulation and onabotulinumtoxinA injections, have been explored for HC, particularly in patients who are intolerant to indomethacin 5, 6.
- The identification of TN and HC as separate entities is important, as both disorders may require different treatment approaches 2.