Watson’s colleague’s associate is eagerly waiting for Watson and his colleague’s arrival, having shouted coffee and croissants. “I am keen to hear your experience with the behaviour of head pain and what it means for me.”
“I understand you know it’s your neck, but despite that, the behaviour of your head pain rules out musculoskeletal misbehaviour in your upper neck as being responsible,” explains Watson. “I think before I relate to your head pain behaviour, it is important to recognise that, in essence, there are three forms of head pain – stationary, alternating (side-shift) and transitory and that with any head pain behaviour, there is always a possibility that the neck is involved.”
“Okay,” interjects Watson’s colleague. “I am a little confused with ‘alternating, side-shift, radiating’ etc.”
Stationary Head Pain
Watson continues, “Within this group, there are three forms: Side-locked Unilaterality, Symmetrical Bilaterality, and Side-locked Asymmetrical Bilaterality. Whilst Side-locked Unilaterality has been a foundational criterion from the birth of CGH – a hallmark of Cervicogenic Headache (CGH), it can manifest from an underlying medical condition, such as temporal or giant cell arteritis.”
“What about bilateral presentations? I understand these presentations rule out CGH, but you disagree?” enquires Watson’s colleague.
“Yes,” comes Watson’s unequivocal reply. “However, in my experience, whilst both Symmetrical Bilaterality and Side-locked Asymmetrical Bilaterality can be manifestations of CGH, underlying medical conditions, for example, Pseudotumor Cerebri (Idiopathic Intracranial Hypertension) or space-occupying lesions respectively.”
“So what you are saying is that stationary head pain alone does not confirm upper neck involvement,” surmises Watson’s colleague. “Correct.”
Alternating Head Pain
“There are two forms in this group – Alternating Unilaterality and Alternating Asymmetrical Bilaterality.”
Alternating Unilaterality refers to unilateral head pain that alternates or swaps sides to occur exclusively on one side at a time – never on both sides simultaneously. This can happen between episodes or within the same episode. For example, this could start on one side and then, within a variable time frame, swap to the other side, leaving the original side. I have seen patients whose migraine episodes consistently last three days; on Day 1, it might be left; on Day 2, it swaps to the right; and finally, it switches back to the left before the end of the episode. This is characteristic of a musculoskeletal misbehaviour – CGH.”
“That is clear,” comes the united reply.
“Yes, and what’s more is that this behaviour occurs in over 80 per cent of those with unilateral migraine,” emphasises Watson. “Conversely, Alternating Asymmetrical Bilaterality is relatively rare but also confirms CGH.
“What does Alternating Asymmetrical Bilaterality mean?” enquires Watson’s colleague’s associate. “This refers to bilateral head pain in which the pain is more intense on one side, but the side of increased intensity alternates or side-shifts,” explains Watson. “That’s mine!” exclaims Watson’s colleague’s associate, almost choking on his croissant.
“So, alternating?” clarifies Watson. “Yes,” comes the unambiguous reply.
“So that leaves Transitory,” concludes Watson’s colleague. “What’s that!” comes his associate’s slightly irritated reply.
Transitory Head Pain
“I describe head pain as Transitory (an impermanent state) when it begins as one kind of head pain and then transforms into another kind of head pain. For some patients, a headache might begin as one-sided and then become bilateral; for others, it’s the reverse. Or pain might start as stronger on one side but then become evenly distributed, or vice versa. For science nerds curious about naming conventions, here is the logic behind the names of transitory head pain behaviours: the term that follows ‘transitory’ describes how the head pain starts. Therefore, ‘transitory unilateral’ means a headache starts as unilateral; ‘transitory symmetrical’ means a headache starts as symmetrical; and so on,” Watson carefully explains.
“There are four types of transitory behaviours:
Transitory Unilaterality refers to unilateral head pain that spreads to include the other side within a variable, relatively short period (within hours) without leaving the original side. This behaviour also represents a musculoskeletal event – CGH. Interestingly, over the past few decades, acquiescence has slowly developed around the side-locked unilaterality CGH diagnostic criterion to allow a ‘soft’ bilaterality, i.e., with a side-locked unilateral predominance.”
Watson, realising his colleague’s associate is becoming frustrated, continues deliberately, “Transitory Symmetrical Bilaterality refers to bilateral symmetrical head which transforms to adopt a unilateral predominance.
Conversely, Transitory Asymmetrical Bilaterality refers to morphing from one side being stronger than the other to be symmetrical.”
“And finally,” Watson, taking a subtle deep breath, continues, “there is Transitory Symmetrical Alternating Bilaterality, i.e. pain starts evenly but becomes stronger on one side, but the side of increased intensity alternates – this is extremely rare.”
Aha!
Watson, relying on his colleague’s understanding, is relieved when… “Okay, I think I have got it. So, whilst Stationary Headache can be a manifestation of CGH, it doesn’t define CGH. However, the ‘mobility’ of head pain, i.e. alternating or transitory behaviours, is a crucial characteristic of upper cervical musculoskeletal driven head pain,” comes Watson’s colleague’s realisation. “Therefore, these presentations are not reliant on a physical examination for cervical relevancy.”
“Correct,” replies Watson. “Yes, the side and behaviour of head pain, which I ascertain within three minutes into my initial consultation, in the vast majority of patients with episodic headache, confirm cervical relevancy – typically, these ‘mobile’ presentations have been recurring and are well known to my patients.”
Turning to his colleague’s associate, “Your bilateral headache, in which there is increased intensity unilaterally that switches sides, is characteristic of CGH.”
“So, my headache is from my neck,” rejoices Watson’s colleague’s associate.
“It seems that way,” chimes in Watson’s colleague.
“Aha, come to think about it, my neck discomfort mirrors the side of increased headache intensity,” Watson’s colleague’s associate realises.
“Why am I not surprised,” comes Watson’s satisfied reply.
