My Kidneys Ate My Biceps.

How crossfit landed me an 8-day hospital stay.

I’ve been doing crossfit for 6 years, coach in my spare time, have a Fran time of 3:30; I didn’t think there was much I physically couldn’t do, so I didn’t expect push-ups and pull-ups to put me in the hospital. Rhabdo proved me wrong. Here’s the story.

After about a year off from crossfit, I came into the gym for a few workouts to ramp back up (red flag #1: I was deconditioned). The workout that was scheduled for Saturday morning, Murph, was more intense than a typical workout: 1 mile run, 100 pull-ups, 200 push-ups, 300 airsquats, another 1 mile run — and every bit of it — yes even the pullups- is done while wearing a 20-pound weight vest. (red flag #2: high repetition, body-weight exercises with eccentric contractions.) I was psyched.

I felt strong on the run and decent on the pull-ups, but halfway through the pushups, Murph got hard fast. My push-ups dropped to sets of 4–5, then sets of 3, then 2 at a time, which brings me to red flag #3: pushing through muscle failure. I was thrilled to do my last push-up and hit an adrenaline rush that carried me through 300 air squats before waddling off for the final mile. I finished exhausted and happy — my coach gave me a high five, and I biked home with that fully-applied sense of achievement that I came for.

Rhabdo Day 2–3: Something’s Wrong.

With rhabdo, intense physical exertion causes so much skeletal muscle damage that your muscles cells die en mass; they break open and sluff off into your circulatory system, where your kidneys have to filter them out. This puts you at risk for acute kidney failure, and in extreme circumstances, cardiac arrest. Your kidneys essentially choke on your own muscle detritus. The swelling muscle tissue also expands within the limits of your fascia and if there isn’t enough room in the fascia’s compartments to accomodate the swell, arteries and nerves get squeezed, causing cascading problems, including potential limb loss. If it gets bad enough, you will need a fasciotomy, where skin and fascia are sliced open to the air to accommodate the swelling tissue. Don’t google it — its not pretty.

Sunday morning I woke up with intensely sore arms and limited range of motion — I had heard of rhabdomyolysis and suspected something was off, so I did some reading and carried on with my day. Monday morning, soreness and range of motion were worse; I could barely bring a glass of water to my mouth. It is hard to know the line between normal delayed-onset muscle soreness and rhabdo, but online comments had a common warning: if your urine darkens, get to the ER. So I peed into an empty water bottle: what came out looked like Coca-cola.

At SF General triage, I started feeling nauseated and mentally off, maybe psychosomatic or maybe the result of toxins slowly accumulating in my bloodstream. I felt ready to barf when medical staff put me on IV fluids to protect my kidneys. Creatine-Kinase (CK) is an enzyme inside muscle cells, so blood CK levels show how much muscle detritus is choking up your kidneys. My bloodwork came back one thousand times the normal rate, ten times the rate the ER doctor expected, and twenty times the acute kidney failure threshold of 5,000. “I didn’t know CK levels could get that high,” my nurse said pointblank. Bloodwork showed my kidneys were working fine, but they could fail at any time. The docs ramped me up to the fastest fluid rate the IV machine would pump, 999 mL/hr, meaning that, at least initially, my 5 liters of human blood got diluted with a full liter of solution every hour. I started plumping up like a marshmallow man.

Rhabdo exists in a medical netherworld, outside any specialists particular domain. A sports medicine doctor could have told me if I had elevated risks, but it was too late for that. A renal specialist can treat a failing kidney, but it was too early for that: And ER docs stabilize — they aren’t trained to manage ongoing body chemistry. Turns out there aren’t really muscle doctors, so the ER gave me a general practitioner and sent me upstairs.

Rhabdo Day 4–6: Treatment.

To measure CK concentrations that are 1000x outside normal, the lab had to dilute the sample, which reduced significant figures and may have magnified errors. They sometimes reported back 100,000+ or 80,000+ rather than exact figures, so it is not clear whether the ups and downs observed in my early tests were signal or noise. I kept thinking I would go home, but each day the docs told me to wait.

Soreness and swelling peaked Wednesday, but as late as 1 week later, lingering swelling made it difficult for the nurse to find blood draw spots on my arms. My arms, which once drew compliments from phebotomists, became flubby swollen grandma arm-balloons. My blood pressure ran high, but my other lab results stayed in a safe range, and the docs played with my IV chemistry, switching me between NaCl, bicarbonate and p-lite with varying speeds to balance the risks to my heart, kidneys and lungs. With higher flow rates, I built up fluid edema in my lower back and arms — my skin became a playdough that retained finger imprints when pressed.

Rhabdo Day 7–11, Recovery.

7 days after my workout, my CK levels started to slowly drop. This morning, writing from the hospital on Day 11, they are at 11,000. For the past 4 days, I have felt almost perfectly normal, but the final remnants of my muscle cells in my bloodstream keep me here with plenty of time to sit, appreciate my kidneys, and contemplate the overall experience. Compared to kidney failure, cardiac arrest or a fasciotomy, being tethered to an IV bag for an eight day stay at the world’s shittiest $15,000-a-night motel is a low price to pay. I was lucky to get emergency care just as symptoms of nausea started to sink in. I benefited from having a very healthy organs and being hydrated: my kidneys were able to endure astronomical CK concentrations, and my heart and lungs were able to endure a massive high influx of fluid injected into my system to relieve my kidneys. Any weaknesses in these organs would have complicated my treatment significantly.

Takeaways.

Hopefully the most enduring aspects of this experience will be lessons and not injuries: not every challenge can be met at the moment you want to meet it, and willpower only goes so far. I simply was not sufficiently conditioned to safely complete Murph, and I misjudged my own strength and stamina. Crossfit haters will inevitably interpret this as an anti-crossfit message, but I’ll be back to crossfit and my take-home message is more nuanced: crossfit gives athletes a specific task, the tools to perform that task, and highly quantifiable and comparable performance metrics, leaving an athlete’s own effort and focus to be the chief variables driving success. This makes crossfit both effective and dangerous. Great crossfit coaches are responsible for the solid movement mechanics I developed over the last 6 years that have kept me virtually injury-free, and the sport deserves some of the credit for the physical stamina that enabled me to endure rhabdo. But crossfit is not some fitness magic bullet: if you consider it a substitute for good coaching, good mechanics, or awareness of personal limitations, you are going to get hurt.

I don’t know what’s next. Patients report varying long term effects from rhabdo —some recover fully and some have ongoing pain, weakness, and exhaustion. I have no fatigue or pain right now, so that makes me hopeful, but it is possible that I may never regain my former push-up or pullup strength, and it is certain that I will have greater awareness of my physical exertion limitations. My arms lack some of the definition I had last week — and that just sucks. If kidney failure is not enough reason for you to be careful out there, let permanent flubby grandma-arms ward you off from the impulse to push through pain.

Appendix: My bloodwork, charted

Appendix: Lessons Learned

Here are a few things I learned that I think are applicable for athletes and coaches:

• Know your limits. If you do so many deadlifts that you start flexing your thoracic spine under load, you will get hurt. It is no different if you push past your muscle’s limitations on bodyweight exercises.
• Watch out for time-off. Past athletes getting back into sport are particularly at risk, because our perception of our body’s limitations is not in sync with our physical preparedness.
• Watch out for eccentric contractions, or negatives, in which your muscles apply force as they lengthen. Your muscles can move more weight during the eccentric phase of a movement, and it comes with increased muscle tension, so its easier to over-exert. Pull-ups, pushups, dips, GHD sit-ups have significant negative components.
• Watch out for low-weight, high repetition movements. If you are too tired to backsquat a heavy weight, you are likely to fail and stop, but you are almost never too tired to do one or two more air-squats, so its easy to push past your body’s limit into danger zone.
• Watch out for heat and dehydration. These factors were not present in my scenario, but they can significantly increase risk.
• Be insured. From what I can tell, a week in the hospital cost my insurance more than $100,000 — I will absolutely hit my maximum out-of-pocket — money I could have spent on a month in Europe. No matter how young and strong you are, don’t go one day without health insurance, or you risk bankrupting yourself.

If you have symptoms:

• If you suspect you have over-exerted, hydrate with salts and sugars to keep your kidneys from experiencing unnecessary stress.
• If you experience swelling and limited range of motion after an intense workout, go to the doctor and get a blood test, elevated creatine-kinase, potassium, creatinine, BUN will help you know your kidney risk. Get treated before your pee turns brown.
• If your pee is a funny or dark color, go to the hospital immediately. Pack a bag and your insurance card and go to the ER. If you can capture a urine sample in a clear bottle, this will keep you from getting stuck in the administrative triage, waiting for a urine test to demonstrate emergency before they give you fluids.
• If possible, choose the right hospital. If you have a choice, go to a hospital your insurance covers, so there is minimal resistance to you staying or seeing a specialist or getting a test when you need it. I made the error of going to SF General, which is out of network for my insurance. I was covered because I was admitted for an emergency, but medical staff hesitated to find me a specialist and to order a urine test because they thought my insurance would resist paying — better to avoid this added stressor.
• Get ready for a shitty week — Rhabdo will not resolve in a couple days. Your kidneys are literally digesting your skeletal muscle, and depending on how much you need to pee out, it’s going to take some time.

Appendix: Basic Biochemistry

• Myoglobin — remnants of broken muscle fibers that are supposed to be pulled out by your kidneys. Too much Myoglobin is toxic to your kidneys, and is the chief chemical that can overwhelm them during rhabdo. Measuring your urine content for myo tells the doctors how much stress your kidneys are under.
• Creatine-Kinase (CK) is an enzyme present in muscle. When your muscles break down, like after a workout or from normal wear and tear, the CK is taken away by your bloodstream, so its an indicator of how much muscle tissue is seeping into your system. Normal levels of CK are 22–198 units per liter.
• Blood Urea Nitrogen (BUN) test measures the amount of nitrogen in your blood that comes from the waste product urea. This is a measure of how well your kidneys are performing at clearing waste out of your system. 10–20 mg/dL or 3.6–7.1 mmol/L is normal.
• Potassium — your body needs to maintain a delicate potassium balance to keep organs such as your heart functioning properly. Your kidneys regulate this concentration, so measuring potassium measures how well your kidneys are functioning, as well as your risks for other complications.
• Creatinine is a chemical waste product from all metabolism. Your kidney’s clear it out regularly, so the amount of it left in your blood should generally be below 1. Elevated levels indicate that your kidneys might not be processing waste out of your body effectively.
• Myoglobin — remnants of broken muscle fibers that are supposed to be pulled out by your kidneys. Too much Myoglobin is toxic to your kidneys, and is the chief chemical that can overwhelm them during rhabdo. Measuring your urine content for myo tells the doctors how much stress your kidneys are under.

If anyone has any corrections to my biochemistry explanations, or any guidance for post-rhabdo treatment or athletic re-introduction, please email me at rbaruffi@gmail.com.