Posts

Two common musculoskeletal problems frequently lead to fatigue are craniovenous drainage insufficiency and cranio-arterial hyperperfusion induced by thoracic outlet syndrome.

Firstly, arteries supply, whereas veins drain used blood back to the heart and lungs for reoxygenation.

When drainage is obstructed, cerebral intravenous pressures will increase and cause vascular congestion. The pressure itself is a common cause of headaches, fatigue, brainfog, etc. Moreover, as congestion worsens, mild to moderate degrees of tissue hypoxia can occur, seeing as capillary transitions will also congest and thus enough fresh blood will struggle to reach the tissues before the used blood can be properly drained. This also leads to fatigue, dizziness, brain fog, confusion, etc.

The most common cause of cerebral venous drainage insufficiency is internal jugular vein compression. Both of the internal jugular veins have a relatively high proclivity to compression at its transition between the styloid process of the skull and transverse process of the C1. This phenomenon is greatly influenced by posture, and is also influenced by the upper cervical muscles. Treating this would be the first step.

For diagnosis, a CT venogram is the best approach. If difficult to obtain, then a plain head mri can usually also determine the patency of the IJVs, at least good enough within the scope of conservative management. I also recommend a dynamic ultrasound exam of the IJVs, measuring blood flow volume in different positions.

If conservative management fails, then surgical management can be an option for patients with egregious symptoms. There is a general consensus that intravenous pressures should be measured through means of catheter measurement before surgery is deemed necessary. I like to compare central venous pressures to the pressures in the torcula and SSS rather than merely looking at the pressure gradients between the mid IJV and torcula or strict pre-post-stenotic gradients.

Surgical management will generally involve styloidectomy, but a careful anterior shaving of the C1 transverse process can also be feasible AS LONG AS the suboccipital muscles are not damaged in the process. It is better to omit the C1 shave if the suboccipitals cannot remain untouched.

Craniovascular congestion

img 2

As a continuation on my previous post on craniovascular congestion, let us continue with TOS CVH: Thoracic outlet syndrome-induced craniovascular hyperperfusion. This "fancy word" simply means that the brain is receiving more blood than it can consume.

The vertebral artery and TOS

Early in my practice I became increasingly aware, and frightened of the stated risks for vertebral artery compression in thoracic outlet syndrome. Truly, a few old papers from the 60s and 70s, most famously perhaps Powers' 1961 paper. This, and other similar papers have been cited over and over in the hundreds, making this problem seem like a common issue. It is, contrarily, extremely rare. Nonetheless, it is what incentivized me to start learning vascular ultrasonography in 2017. Quickly I realized that no post-stenotic waveforms could be identified in these patients despite very compelling clinical signs, also elicitation during rotatiaon of the neck. This perplexed me for some time, but at least I was able to ensure the absence of brain ischemic risk factors.

With time I realized that the strange waveforms seen in these patients were similar to some of the signs expected in pre-stenotic measurements. There would be a slow systolic upstroke, but normal flow velocity. There would be loss of the spectral window (turbulence). In early stages, an increased pulsatility would be seen (textbook "high pressure" waveforms), whereas in more advanced disease, then paradoxical blunting or even extreme blunting of the systolic upstroke. I later understood that this occurred due to distal hyper-congestion and vessel incompliance.

Why would this happen?

Saxton et al. 1997 documented an interesting case where a patient's lifelong history of migraine was also diagnosed with TOS, as she had developed brachial paresthesia and pain that triggered with arm abduction. An MRA showed subclavian stenosis at the interscalene triangle. TOS surgery not only resolved the brachial plexus symptoms, but to the authors' surprise, also the lifelong migraine. Why would decompression of the subclavian artery improve a migraine issue?

Because compression of the subclavian artery at its segments distal to the carotid and vertebral arteries, in simple terms, reduce flow to the arm and increase flow to the head. When the brain is supplied with greater amounts of blood than what it can consume, congestion happens, and can lead to anything from insignificant to very severe symptoms, ranging from mild headaches, fatigue and dizziness to seizures and syncopal events.

After examining hundreds if not thousands of these patients, I was convinced that 1., although vertebral artery compression can happen in these cases, it is a unicorn finding of extreme rarity and not what is instigating the craniological symptoms in the vast majority of TOS patients. 2., the CVH mechanism was the true instigating factor for these symptoms in the TOS group. This prompted me to write a paper on this topic, which I published in 2020.

How do you diagnose TOS CVH?

Firstly, you need extensive knowledge of this condition, its clinical presentation as well as imaging signs. You also need extensive understanding of diagnostic and clinical limitations.

In essence, you will be looking for a patient with a history of very high stress levels, or some kind of head or neck injury. To a smaller degree, perhaps 5% of patients or less, clavicular injuries and shoulder trauma. And, whose symptoms include (one or several) fatigue, brain fog, tinnitus or pulsatile tinnitus, dysopsia, light and sound sensitivities, headaches, migraines w/w.o. aura, syncopal events, vestibular problems. These issues tend to trigger with arm use, exertion, or sustained cervical extension.

This post is becoming too long so I will follow it up in a few days.

TOS-induced craniovascular hyperperfusion

img 3

Better late than never. I promised to write another post detailing the workup of TOS-induced craniovascular hyperperfusion. Let's continue with diagnostic signs.

Firstly, you will be looking for a patient with a history of very high stress levels, or some kind of head or neck injury. And, whose symptoms include (one or several) occipital headache or pain, fatigue, brain fog, tinnitus or pulsatile tinnitus, dysopsia, light and sound sensitivities, headaches, migraines w/w.o. aura, syncopal events, vestibular problems, or POTS. These issues tend to trigger with arm use, exertion, or sustained cervical extension.

There are six tests I generally perform with this patient group:

1. The Valsalva maneuver. Hold with high pressure for at least 15 seconds, or until failure. Look for triggering of symptoms during or after the test.

2. Queckenstedt's test. This is generally negative in TOS CVH, as it is a vein test, but sometimes positive due to capillary congestion. Hold manual pressure to the inferior parts of both internal jugular veins for 90-120 seconds. Look for triggering of symptoms. Head pressure would be expected, but pain or feeling as if the head will pop is ABNORMAL.

3. Cervical retraction test. I typically have the patient lie supine in bed with the head and shoulders leaning into extension outside of the bed's ledge. Hold for 90-120 seconds. Look for triggering of symptoms. They can occur during or AFTER the test, so be attentive.

4. Brain MRI: Look for narrowing OR dilatation of the lateral and third ventricles. Look for swelling of the ventricular wall tissue on FLAIR T2.

5. Carotid, vertebral and subclavian artery spectral doppler ultrasound. The most important signs here, are a delayed systolic upstroke, turbulence (filling of the spectral window), and an unclear transition between systole and diastole on the spectral graph. This is typically best visualized in the proximal part of the ICA.

6. Fundus exam. Pictures must be of high digital quality and well zoomed. Look for arteriolar sclerosis, tortuosity and arteriovenous nicking.

In some cases, cranioarterial hypertension can also be mediated through dysautonomia stemming from brachial plexus compression. I believe the author Pauliukas et al. has written some papers about this, and how inappropriate vasoconstriction of the vertebral artery can lead to occipital headaches and other symptoms. To build on this, I have found that brachial plexus compression can irritate the cervical sympathetic chain in its segmental entirety and thus also affect the carotid plexus. In these cases, the craniovascular symptoms will follow upper limb pain patterns much more closely than in a true CVH patient whose symptoms are of primary rather than secondary vascular compression.

In the first group, factors that reduce clamping of the subclavian artery is the first line of treatment. Neck and shoulder positioning is important, along with treatment of the scalene muscles, especially. Or resection of them. For the pectoralis minor, if applicable, then either botox or stretching, along with scapular movement and posture correctives will apply. However, for the group where dysautonomic vascular symptoms come secondary to plexus irritation, clearly, the plexus compression must be dealt with first. This is done through costoclavicular decompression (shoulder posture) and movement correctives predominantly, and secondarily via treatment of the muscles that can irritate the brachial and cervical plexi, ie., predominantly, the scalene and levator scapula muscles.

Medication wise, metoprolol taken right before bed, propranolol 2-4h before bed or candesartan once daily 6pm can be helpful. In fewer cases, acetazolamide taken either in the morning or right before bed. Talk to your physician first.

Now, let's talk about TOS CVH management. I will try to keep it simple:

1. Stress management and clenching mitigation is extremely important in all MSK-cases where chronic pain and maladies have onset without any concrete trauma, but less important in cases where a patient was normal, had a physical injury, and now is no longer normal.
2. Posture is important for TOS management, and for TOS CVH, especially the avoidance of habitual cervical extension. Retraction of the head tightens the scalene positionally and thus increases its clamping force onto the subclavian artery (which increases head pressure) and brachial plexus. It also raises the first rib and thus diminishes the space of the costoclavicular interval. Keeping the head a little (!) forward is generally helpful in TOS CVH management. The same applies to sleeping position.
3. Scapular mechanics are important in TOS management, especially in neurogenic TOS. This is a huge topic and a post of its own, but I have videos demonstrating proper scapular movements on my youtube channel. Beware that it is highly important to avoid scapular retraction in CVH management, as it will tighten the pectoralis minor and thus, just as the scalene with neck retraction, increase clamping on the subclavian artery and thus increase head pressure.
4. Strengthening of the scalenes and sternocleidomastoideus muscles. This is a difficult topic, because 1. it takes a long time to do successfully and 2. it is incredibly easy to mess up and get much worse. I recommend very careful strengthening once to twice per week, one single work set of X reps that yields very mild tissue fatigue. Ultimately, you are looking for 1 single day of mild symptom worsening after you've done the work. This is a slippery slope, and although it may sound relatively simple, it is not. It is the most common area where patients dramatically worsen their situation, get frustrated, give up, etc. Low effort and patience is the key. The videos are on my youtube channel.

There is more information that could be said, but if you get these 4 points right, you will be on the right track.