Alternating Unilateral Head Pain: The Elephant in the Room


Indeed, this is the elephant in the room!

A key diagnostic criterion for CGH is side-locked unilateral head pain, i.e. head pain always occurs exclusively on the same side, never the other.  This has been established by the medical model of headache, respectfully not fully au fait with musculoskeletal medicine. In my experience, whilst side-locked unilateral head pain can be characteristic of CGH, unilateral head pain occurring exclusively on one side, and on other occasions exclusively on the other side confirms CGH.

However, according to the medical model of headache, this behaviour rules out CGH.

This presents a conundrum, as the mechanisms behind the alternating or side-shifting nature of unilateral head pain remain unexplored, and an explanation from the medical model is conspicuously absent. To the best of my knowledge, despite this omnipresent characteristic of migraine, only one hypothesis has been proposed; essentially the silence is deafening.

The alternating behaviour of unilateral head pain within the context of spinal dysfunction mimics conditions of alternating unilateral pain in the neck, shoulder, arm, leg, and lower back.  Whilst the underlying pathophysiology of this phenomenon is pending, compelling research in relation to low back pain supports alternating aberrant spinal intra-discal pressure as the underlying issue in these presentations.  As manual therapists, most of us would have experienced patients with alternating lumbar lists; alternating unilateral head pain is the C2-3 equivalent of an alternating lumbar list.

A seminal clinical phenomenon experienced by myself and colleagues is patients experiencing a shift in the side of head pain within a single treatment session following an unambiguous examination of the C2-3 intervertebral segment. This pragmatic experience demonstrates a spinal origin for the behaviour of alternating unilateral head pain and challenges side-locked unilaterality as a diagnostic criterion.

Alternating or side-shift behaviour of unilateral head pain characterises an upper cervical musculoskeletal phenomenon – this requires a significant paradigm shift – one which is not likely to happen because surveys and clinical observations indicate that 83 per cent of unilateral migraine manifestations exhibit the tendency to alternate sides or shift during or between episodes.

This erroneous diagnostic criterion denies many with migraine and other unilateral primary headache conditions in which alternating behaviour occurs, a skilled examination and treatment of the upper cervical spine…

… before I leave you, there is another pattern of unilateral head pain characteristic of musculoskeletal misbehaviour, i.e. head pain starting on one side (and typically it always starts on the same side), which, as the headache progresses, spreads to include the other side without leaving the original side, becoming bilateral.  This is what I call ‘Transitory Unilaterality’.

Until next time

If you are new to Watson Headache®, welcome to the Watson Headache® Approach, an evidence-informed practice when considering the role of the neck in Cervicogenic and Primary Headache.

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