Some cause for optimism

Near the start of the Dubbo Gully Run

As the early test results come back, I'm becoming more positive about a return to running.

So far, no evidence has been found of more sinister underlying conditions that could have led to a blood clot forming in my veins and migrating to my lungs.  However, I still need an Echocardiogram early next week to rule out any heart disease or other heart issues, so am not out of the woods.

On the other hand, an Ultrasound Doppler examination of my right leg yesterday, found a small clot just beneath my right knee and close to the site of severe knee pain I experienced following a 30km trail run on the Dubbo Gully course three weeks ago.  There is no pain there now, and there hasn't been for several weeks, so it seems reasonable to surmise that the clot may have been larger when the pain was greater.

Crossing Mangrove Creek on the Dubbo
Gully Run

What led to such a clot forming, and why didn't I pay more attention to it?

Firstly, I have had significant right knee pain for more than six years now (see Post titled "Adaptation"), so I expect it to be sore after a long run.  However, I recently switched from wearing Nike Pegasus shoes, a model I have worn for decades, to another brand that promised more cushioning.  I was wary about changing shoes because I know different brands and models can change the stresses and strains imposed on the legs making you potentially more vulnerable to injury.  However, I have also been struggling with a painful chronic right Achilles tendon injury and been stymied on several long runs, including the Melbourne Marathon, by lower back pain and associated sciatica.  A shoe offering a softer ride and different pressure on the heel was worth trying and I bought a pair.  After a couple of weeks and several long runs in the new shoes, positive signs were that my Achilles tendon was less painful and there had been no back trouble.  Offsetting this was a minor worsening of my knee pain, which seemed to have moved to just below the patella on the inside front of the leg.  Following the Dubbo Gully run, the pain was particularly intense, especially on the hour-long drive home, and was sufficiently painful to cause sleeplessness the next two nights.  It now seems likely this pain was associated with deep vein damage.

Part of the Dubbo Gully route

Three risk factors probably compounded the development of a clot in the vein.  I was dehydrated after the run, but drank sparingly in the next four or five hours, increasing the viscosity of my blood.  Unusually, I had a three hour nap (while still dehydrated) on my bed when I got home, during which my heart rate would have dropped to its usual low resting rate (~45 bpm).  Finally, I have low blood pressure anyway.

My guess is that the coincidence of the new shoes changing the stresses on an already damaged knee, dehydration, a post-run nap, and low blood pressure led to Deep Vein Thrombosis.  The next ten days saw parts of the clot break off and travel to my lungs and the development of Pulmonary Embolism.

Through gradually increasing the daily dosage of Warfarin, my International Normalized Ratio (INR), a measure of the clotting tendency of my blood, has reached 2.1 (the desirable range is 2.0 - 3.0) and the daily Clexane injections have ceased.  I'm still not allowed to run, but I played golf this morning and have been walking about 5km per day this week without ill-effects.  I haven't discussed it yet with the doctor, but I'm hoping I can resume unpressured jogging after a scheduled visit in a week's time, provided the Echocardiogram doesn't yield any concerns.  Fingers crossed!