1Department of Anesthesiology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA; 2LAC‐USC Neurology Residency Program, Keck School of Medicine, University of Southern California, Glendale, CA, USA; 3Department of Neurology, Keck Medical Center of USC, Los Angeles, CA, USA; 4Keck School of Medicine, University of Southern California, Los Angeles, CA, USA

Background: 1. Post‐dural puncture headache (PDPH) following neuraxial anaesthesia is a well ‐known complication which can be particularly debilitating and significantly interferes with patient's ADLs.

2. Incidence is 3.1% by atraumatic spinal needle 25G Whitacre and 17.3% by spinal needle 25G Quincke (4)

3. PDPH was the second most common reason for patient claiming financial compensation following anaesthesia.

4. According to IHS, typical presentation of PDPH is a headache that worsens within 15 min after sitting or standing and improves with 15 min of lying down, with at least photophobia and nausea. Alternatively it may show delayed response to postural change, worsening after minutes or hours of being upright and improving, but not necessarily resolving, after minutes or hours of being horizontal. (5)

5. The positional feature of headache is considered the hallmark to the diagnosis of PDPH.

6. Some patients with dural perforation associated with intracranial hypotension may also present with non‐postural headache. The incidence of atypical PDPH has been described as 5.6%. (1)

7. The main risk factor for developing non‐orthostatic PDPH described are a past medical history of migraine, a more cephalad level of epidural insertion and identification of dural puncture by aspiration of CSF (cerbrospinal fluid) from the epidural catheter.

8. Atypical PDPH is a rare event and published literature occasionally reported atypical PDPH with musculoskeletal symptoms and/or intracranial nerve impairment.

9. Prophylactic use of indomethacin used rectally had no significant effect on the frequency of PDPH. (3)

10. Paroxysmal Hemicrania has been defined as attacks of severe, strictly unilateral pain which is orbital, supraorbital, temporal or in any combination, lasting 2–30 minutes and occurring several or many times a day. The attacks are associated with ipsilateral conjunctival injection, lacrimation, nasal congestion, rhinorrhoea, forehead and facial sweating, miosis, ptosis and/or eyelid oedema. They respond absolutely to indomethacin. (5)

11. Paroxysmal Hemicrania has not been described previously as an atypical presentation of PDPH

Methods: This is a case report and review of literature. 30 years old male, with BMI of 41, originally presented about 4 years ago for low back pain, underwent s/p L5‐1 interlaminar epidural steroid injection. Epidural injections about 4 months apart gave him initially longer relief followed by pain relief, lasting for few weeks. Patient returned to orthopedic clinics for recurrence of lumbar pain about 4 months ago. Multiple repeat MRI Lumbar spine showed small central/right paracentral disc protrusion at L5‐S1 and mild L4‐L5 and L5‐S1 facet arthropathy. He was taken to fluoroscopy suite and using an 18G Tuohy epidural needle and loss of resistance technique under fluoroscopic guidance, epidural space access was attempted. CSF was seen coming out due to inadvertent entrance into the spinal space. It was positive aspiration of CSF in the glass syringe for about 3 ml. At that time, it was decided to abort the procedure and Tuohy needle was pulled out. Patient developed headache while he was in the recovery area. Opioid pain medications were given and patient was sent home. When returned to clinic after 20 days for follow‐up, patient described having side locked headache in the left retro‐orbital area. This new onset headache was different from his previous history of migraine headache which affected his right occipital/sub occipital area. With this new onset left retro orbital headache, he experienced phonophobia, photophobia but no nausea. This left side headache occurring multiple times throughout the day and could last from an hour to entire day. This was always associated with left sided unilateral rhinorrhea and tearing of the left eye. His lumbar pain score was 2/10. He denied having any numbness, tingling or burning except in lower back. He was given Gabapentin as a scheduled dose at night, with PRN Gabapentin throughout the day for headache and back pain. He was also started on Indomethacin protocol as described in Cleveland Clinic Headache Manual 2015. Patient had complete resolution of his left sided retro orbital headache. Unfortunately, while he was finishing his indomethacin, he had Motor vehacle accident where he got rearended and started having bilateral neck and suboccipital pain. But he did not have recurrence of his left retro‐orbital pain with autonomic features, worsening with postural changes at least on 3 months followup mark after indomethacin was started. He definitely did not need any epidural blood patch for his postdural puncture headache.

Results: Paroxysmal hemicrania is one of the trigeminal autonomic cephalalgias, characterized by unilateral trigeminal distribution pain that occurs in association with ipsilateral cranial autonomic features. Paroxysmal hemicrania may begin at any age, although onset usually occurs during adulthood. The clinical phenotype of paroxysmal hemicrania is highly characteristic, typically brief, severe attacks of pain, strictly unilateral, most often in the ophthalmic trigeminal distribution, associated with cranial autonomic features that recur several times per day. The headache usually lasts 2 to 30 minutes, but may go on for up to two hours. Ipsilateral cranial autonomic features, such as lacrimation, conjunctival injection, nasal congestion, or rhinorrhea, frequently accompany the headache; eyelid edema, ptosis, miosis, and facial sweating are less frequent. The mean attack frequency is 11 to 14 daily. The Paroxysmal Hemicranias (PH) are defined by an absolute response to indomethacin. The headaches are similar in quality to cluster pain, but the pain is shorter lasting and more frequent during any given day. Attacks of PH can be less severe than CH (cluster headzches), but in the same location, as it is in V1, more than half of the time. Patients are less frequently agitated in PH than with CH. Agitation is not a diagnostic criterion for PH. There is no circadian or circannual periodicity. PH attacks occur at random. The diagnosis of paroxysmal hemicrania is based upon a compatible clinical history in the setting of a normal neurologic examination. The diagnosis is confirmed by an optimum therapeutic trial of indomethacin. Complete resolution of the headache is usually prompt, occurring within one to two days of initiating the effective dose. All primary headaches differ in extent of response to indomethacin, just as they differ in clinical features. Those include trigeminal autonomic cephalalgias (paroxysmal hemicrania and hemicrania continua), Valsalva‐induced headaches (cough headache, exercise headache, and sex headache), primary stabbing headache, and hypnic headache. Case reports describing indomethacin responsive cluster headache, nummular headache, and ophthalmoplegic migraine but post dural puncture paroxysmal hemicrania phenotype have not been described. An MRI scan of the brain should be routinely performed in all patients with paroxysmal hemicrania to exclude a structural brain lesion as secondary paroxysmal hemicrania is relatively common and can be associated with diverse pathologic processes at various sites, including the following: Post coil embolization of a supraclinoid carotid artery aneurysm, Cerebral arterio‐venous malformation, middle cerebral artery infarction, Occipital infarction, Pituitary adenoma, Frontal lobe tumor, Gangliocytoma of sella turcica, Cavernous sinus meningioma, Petrous ridge meningioma, Intracranial parotid carcinoma metastases, Pancoast tumor, Tuber cinereum hamartoma, Collagen vascular disease, Essential thrombocythemia, Intracranial hypertension, Maxillary cyst, Ophthalmic herpes zoster and Post‐traumatic.

Conclusion: As migraine and other Trigeminal Autonomic Cephalgias can have autonomic features as described above, our patient's presentation of having paroxysmal hemicrania after iatrogenic dural puncture was unique, not only in clinical diagnosis but also its response to indomethacin. He was referred to us by the spine surgeon, who saw the patient after patient developed postdural puncture headaches. Spine surgeon recommended epidural blood patch as it's the well‐known treatment for postdural puncture headache. But with our evalution and talking to the patient about the nature of his headache, it turned out to be a paroxysmal headache phenotype. We started him on indomethacin and his headache resolved completely. This sould be looked in greater detail in other headache patients presented with similar phenotype.

References

1. Loures V et al. Atypical headache following dural puncture in obstetrics. Int J Obstet Anesth. 2014 Aug;23(3):246‐52.

2. Basurto Ona X et al. Drug therapy for preventing post‐dural puncture headache. Cochrane Database Syst Rev. 2013 Feb 28;2:CD001792

3. Flaatten H et al. Postoperative headache in young patients after spinal anaesthesia. Anaesthesia. 1987 Feb;42(2):202‐5

4. Jabbari A et al. Post spinal puncture headache, an old problem and new concepts: review of articles about predisposing factors. Caspian J Intern Med. 2013 Winter;4(1):595‐602

5. Headache Classification Committee of the International Headache Society (IHS), The International Classification of Headache Disorders, 3rd edition (beta version), Cephalalgia 33(9) 629–808, 2013 cep.sagepub.com

6. VanderPluym J. Indomethacin‐responsive headaches. Curr Neurol Neurosci Rep. 2015;15(2):516.

7. Cleveland Clinic Manual of Headache

8. Paroxysmal Hemicrania. UpToDate.com