Cluster Headache (Episodic)

Patient Summary

Is this FDA-cleared for this use?

Not FDA-cleared for cluster headache. FDA cleared medicinal leeches only for venous congestion in microsurgical reconstruction (K040187, 2004). Use here is investigational.

What evidence exists?

Tier C (investigational). There are no published controlled trials. Cluster headache is one of the most painful conditions known and requires aggressive evidence-based therapy: acute attacks with high-flow oxygen via non-rebreather mask, subcutaneous sumatriptan, or intranasal zolmitriptan (the highest-evidence acute therapies); transitional prevention with corticosteroid taper or occipital nerve block; preventive therapy with verapamil (first-line), lithium, topiramate, or galcanezumab; non-invasive vagal nerve stimulation (FDA-cleared for episodic cluster); and sphenopalatine ganglion stimulation or occipital nerve stimulation for refractory cases. Onset of an acute attack is a medical emergency for symptom control.

Main risks

• Bleeding from each bite site for 6 to 24 hours after detachment
• Bruising over the temporal or periorbital region for 5 to 10 days
• Local skin or, rarely, Aeromonas hydrophila infection
• Allergic reaction to leech saliva (uncommon)
• TRIGGER RISK: any stimulus can trigger a cluster attack during a cluster period
• Delay of high-flow oxygen, sumatriptan, verapamil, and other proven therapies (a delay in cluster is intolerable pain)
• Misdiagnosis - clusters are sometimes confused with secondary causes (pituitary tumor, carotid dissection) that need urgent workup
• Placement near temporal artery in age over 50 risks giant cell arteritis being missed

Who should not consider this

• Patients in an active cluster period who have not optimized acute (oxygen, triptans) and preventive (verapamil) therapy
• Patients with red-flag features (focal neurological signs, autonomic features outside attacks, age over 50 new-onset)
• Patients with suspected secondary causes (pituitary tumor, AVM, carotid dissection)
• Patients on anticoagulants, with hemophilia, or with severe anemia
• Patients with active dermatitis or broken skin at planned placement sites
• Patients on monoamine oxidase inhibitors or with cardiovascular contraindications to triptans (different issue, but triptan optimization first)

What to ask your clinician

• Am I receiving high-flow oxygen (12 to 15 L/min via non-rebreather) for acute attacks?
• Have I tried subcutaneous sumatriptan or intranasal zolmitriptan?
• Am I on verapamil titrated to adequate dose for prevention?
• Have I had MRI brain to rule out secondary causes (pituitary tumor, AVM, carotid dissection)?
• Am I a candidate for occipital nerve block, sphenopalatine ganglion stimulation, or non-invasive vagal nerve stimulation?
• Why is leech therapy being considered given the highly effective evidence-based options for cluster?
• What is the practitioner's plan if I have a cluster attack during or after a session?

When to seek urgent care

• Thunderclap (worst-of-life) headache, sudden severe headache (possible subarachnoid hemorrhage - 911)
• Headache with fever, stiff neck, photophobia, or altered mental status (possible meningitis)
• Headache with focal neurological deficit, vision change, speech difficulty, or seizure
• Sudden severe pain with neck stiffness and Horner syndrome features (possible carotid dissection)
• Cluster attacks that do not respond to oxygen or triptans
• Bleeding from a bite site lasting more than 24 hours
• Hives, facial or throat swelling, or breathing difficulty