Hemicrania Continua: Diagnosis and Treatment. The Role of Sphenopalatine Ganglion in Diagnosis and Treatment of all Types of Headaches.

Hemicrania Continua is discussed in a new article in Neurology Advisor (NA).

According to NA Hemicrania continua (HC), one of the trigeminal primary headaches, causes intense unilateral pain for several months, as well as autonomic symptoms.  MY COMMENTS WILL BE IN ALL CAPITAL LETTERS.   ALL HEADACHES ARE TRIGEMINAL HEADACHES.  THE TRIGEMINAL NEERVE, OFTEN CALLED THE DENTIST’S NERVE IS THE LARGEST INPUT TO THE BRAIN AFTER AMPLIFICATION IN THE RETIICULAR ACTIVATING SYSTEM.  THERE ARE AUTONOMIC NERVES THAT TRAVEL FROM THE SPHENOPALATINE GANGLION ALONG ALL BRANCHES OF THE TRIGEMINAL NERVE.

Updated classification of headache type is intended to help clinicians better understand and diagnose this headache syndrome.  Common brain structures are involved in HC and other types of headache (eg, cluster headache and short-acting neuralgiform headache attacks), resulting in autonomic symptoms and disinhibition of the trigeminal autonomic reflex.    THE AUTONOMIC NERVES ARE KEY TO ALL AUTONOMIC CEPHALGIAS, THE  THE SPHENOPALATINE GANGLION IIS THE LARGEST PARASYMPATHETIC GANGLION OF THE HEAD BUT SYMPATHETIC NEERVES FROM THE SUPERIOR CERVICAL SYMPATHETIC CHAIN PASS THRU THE GANGLION AS DO SOMATOSENSORY NERVES.

Diagnosing HC Based on the New Classification

Previously, HC was classified in the “other primary “HEADACHES” category, but as it is associated with autonomic symptoms, it is now considered a trigeminal autonomic cephalgIa, according to the International Classification of Headache Disorders (ICHD) third edition.  In addition to unilateral headache, THE HEMICRANIA CONTINUA IS LARGELY DEFIINED BY THE HC’s autonomic symptoms include ipsilateral facial sweating, nasal congestion, rhinorrhea, tearing, conjunctival injection, eyelid edema, and miosis or ptosis. The new definition of HC also recognizes the relapsing-remitting nature of the attacks.

One of the hallmarks of HC is resolution with either an oral dose or intramuscular injection of the nonsteroidal anti-inflammatory drug (NSAID), indomethacin.  THIS IS ACTUALLY A PRIMARY DIIAGNOSTIC FACTOR THOUGH SOME HEADACHES ARE CONSIDERED TO BE HEMICRANIA CONTINUA EVEN THOUGH THEY DO NOT RESPOND TO INDOMETHACIN.   In countries where indomethacin is available by injection, the “Indotest” is a 50-mg to 100-mg injection of indomethacin that is used both for diagnosis and treatment of HC. Although pain subsides within 24 hours for most patients treated with indomethacin, some individuals may not respond for as long as 10 days. Experts recommend that indomethacin be co-administered with a gastrointestinal protectant, as it may irritate this system.  INDOMETHACIN IS WELL KNOWN TO CAUSE GASTRIIC ISSUES, OFTEN SEVERE.

 The new definition of HC, however, is not without controversy. “The presence of cranial autonomic symptoms was a must before the current ICHD-3 β criteria,” said Sanjay Prakash, MD, professor and head of the neurology department at Sumandeep Vidyapeeth University in Vadodara, Gujarat, India. “Now, it is not a must if exacerbations are associated with agitation. We believe that an alternative should also be given for the indomethacin response to HC in the criteria. There is a need of more accommodating type alternative criteria in the appendix section of ICHD-3 β, as clinical features, therapeutic measures, and many other aspects are still to be determined for HC.”  THE CATEGORIZATION OF HEADACHE TYPES OFTEN IS A DIIAGNOSIS OF EXCLUSION OR MUST CONTROL A CERTAIN ASPECT.  INDOMETHACIN RESPONSE WAS ONCE CONSIDERED THE DIAGNOSTIC KEY TO THE DIAGNOSIS OF HEMICRANIA CONTINUA.

When Patients With HC Are Unresponsive to Indomethacin

Although most HC cases resolve with INDOMETHACIN  some patients may require adjuvant therapies for adequate pain relief.  Label warnings for indomethacin state that the drug may be associated with an increased risk for myocardial infarction and stroke in patients with cardiovascular disease.    Long-term use of indomethacin may also be associated with hypertension, gastrointestinal pain, vascular events, and bronchial spasms.   BASED ON HIGH RISKS ASSOCIATEED WIIITH INDOMETHACIN OTHER APPROACHES TO TREATMENT ARE OFTEN CONSIDERED.

Indomethacin is one of the cyclooxygenase 1 inhibitors with the highest penetration rate in the blood-brain barrier.  Indomethacin, but not other NSAIDs (ie, naproxen and ibuprofen), was found to inhibit nitrous oxide-dependent vasodilation.  Other medications that could be considered for HC include topiramate, lamotrigine, naproxen, lithium, onabotulinumtoxinA, and melatonin.  THEERE IS OFTEN A SHOTGUN APPROACH TO TREATMENT OF HEADACHES EVEN THOUGH THAT SHOULD MAKE THE INITIAL DIAGNOSIIS BE QUESTIONED.

“If indomethacin does not show the expected effect, first step would be to rethink the diagnosis,  AS I DISCUSSED PREVIOUSLY afterward if every other condition is ruled out, start with the prophylactic medications described in the literature to be effective (eg, cyclooxygenase-2, topiramate, gabapentine, verapamil),” advised neurologist Ozan Eren, MD, from the German Center for Vertigo and Balance Disorders in Munich, Germany. “And of course, the use of neuromodulation is a great option, as the side effects are usually negligible.”

Nonpharmacologic Therapies for HC

Borrowing from the migraine armamentarium, some clinicians have leveraged invasive techniques to relieve HC pain, including deep brain stimulation, occipital nerve stimulation, and sphenopalatine ganglion stimulation.   Transcutaneous vagus nerve stimulation and supraorbital nerve stimulation are among the noninvasive methods that have shown promise in patients with chronic migraine and chronic cluster headaches. 

THE USE OF MINIMALLY INVASIVE SPHENOPALATINE GANGLION BLOCKS (PTERYGOPALATINE GANGLION BLOCKS) SHOULD BE CONSIDERED TO EVALUATE  THE EFFECTS OF BLOCKING THE SYMPATHETIC AND PARASYMPATHETIC NERVE.  THE BLOCKING OF THE SPHENOPALATINE GANGLION WAS ORIGINALLY DESCRIBED BY DR GREENFELD SLUDER IN 1908 IN THE ANNALS OF INTERNAL MEDICINE.  He described sluder’s neeuralgia which is now thought to be either a Cluster Headache  (a TAC) or a TMJ Disorder.

These blocks can often turn off the pain of any type of migraine, cluster or tension headache, often almost instantly.  The side effects of decreased anxiety or agitation is believed to be the turning off of the Sympathetic “Fight or Flight” reflex and turning on the Parasympathetic “Feed and Breed” or “Eat and Digestt” reflex.   These blocks can treat about one third of essential hypeertension.

A new diagnostic category of headache based on response to blocks or neuromodulation of autonomic nerves is probably long past due.

The Myomonitor is an Ultra Low Frequency TENS unit that is used to relax the Trigeminally Innervated Muscles via a single synapse reflex.  This same unit also acts as  neuromodulation of the Sphenopalatine Ganglion which sits with the maxillary division of the trigeminal nerve iin the Pterygopalatine Fossa.  The unit is a three wire unit with bilateral electrodes over the coronoid notch allows it access to the maxillary nerve after it leaves the pterygopalatine fossa and provide anti-dromic stimulation that also affects the Sphenopalatine Ganglion.  The input is a common electrode on the neck and the path of current wiill actually pass over the bilateral Occipital nerves as well as over thee greater and lesser occipital nerves.  Addiitionally it also stimulated the facial nerves.

Diagnostic value of  neuromodulation has only been minimally explored but it has been highly effective in treating a wide variety of crainial pain syndromes and headaches.  The use of the Myomonitor is minimally invasive and has an impressive 50  year safety record.  The use of the Myomonitor is part of the enormous effectiveness of neuromuscular dentistry in treating and eliminating both TMJ Pain, TMD, Myofascial Pain Syndromes, a wide variety of facial pain, ear pain, sinus pain and eye pain.  Interesting , Sphenopalatine Ganglion Blocks have similar effectiveness and the blocks and neuromuscular orthotics appear to have additive benefits.

While these blocks can be given via intra-oral or extra-oral injections as well by se of nasal catheteers, the Sphenocath, the Allevio or the TX360.  Even more effective is the practice of Self-Administered SPG Blocks with lidocaine allowing the patient freedom to use
SPG Blocks to treat and prevent headaches and migraines including Cluster headaches, SUNCT, SUNA, and Hemiicrania Continua.

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