Dive medicine: Scuba diving after a concussion

I got a concussion from a surfing accident last year and have just been cleared to dive.

It’s been a long (and at times, really frustrating) recovery as I learnt how to let myself rest. One of my biggest questions was “how would it affect my diving?” So I thought I would share my journey with you.
The first weekend out after Covid 19 restrictions eased last year an awesome east coast swell arrived and we headed north to catch some waves.

I will be the first to admit they were quite steep, bigger than I was used to. As I stood up on my first wave, I fell forward over my board and into the water. The water slammed my head into the seafloor below, catching the sandy bottom beneath my chin. At the same time the rail of the board hit the back of my head, breaking the fibreglass.

Despite this I was relaxed, knowing I could hold my breath for a couple of minutes. I thought ‘ouch that hurt’ then waited patiently for the wave to pass before coming to the surface. As I stood up I felt slightly dizzy but nothing to put me off. I signalled to my boyfriend to keep an eye on me and I went back out to catch the next wave. An hour later, we returned to the beach for a hot shower and headed home. It wasn’t until I woke the next morning I realised something was wrong.

It felt like the worst hangover. My head felt like it was in a clamp crushing my brain. The room was spinning around and I struggled to walk, using the walls for support. Later that day, one of my best friends, Marion, urged me to go to A&E where the doctors diagnosed a concussion.

After a week off work, the vertigo and the clamp crushing stopped, but I still had a constant headache and found my heart-rate was all over the place. I walked to the top of my driveway and my heart-rate peaked at 180bpm. I realised this wasn’t going to be an overnight fix.

What is a concussion?

A concussion is a type of traumatic brain injury caused by a bump, blow, or jolt to the head or a hit to the body that causes the head and brain to move rapidly back and forth.
The sudden movement can cause the brain to bounce around or twist in the skull, creating chemical changes in the brain and sometimes stretching and damaging brain cells.

The following months I felt like I had a constant hangover. The biggest shock was my initial assessment at the physio.

The first test, walk across the room and on your way, pick up a pen on the ground. Easy, right? As soon as I tried to pick up the pen, I instantly fell over. The second test has the patient follow the doctor’s pen with my eyes. Also easy, right? My physio said I was blinking constantly as I tried to follow the pen.

Practicing my eye tracking with a pen

I found I had lost all my balance, eye tracking was difficult, and the ability to process information decreased significantly. I couldn’t articulate my thoughts and had trouble speaking, my hearing was impacted as I couldn’t tolerate any loud sounds or multiple people speaking, and I wasn’t able to regulate my heart-rate. Being in a car at night when it was raining was my worst nightmare - moving bright lights and fast window wipers were not a good combination.

To assist my recovery, the team at APM gave me some fancy earplugs, blue light glasses and exercises to do. The hardest part was to get the balance right between rest and activity. I eased back into work starting with two hours, then four hours, slowly getting to half days in schools. Loud classrooms and VR headsets proved challenging. I also found afternoon naps to be amazing!

Four months after the injury I was able to work a full day and my headaches were by then intermittent, only increasing if I did too much exercise or didn’t get enough rest. So now I wanted to see if I was able to get back in the water. This had been the longest time out of the water since I learned to dive in 2013.

Implications of scuba diving after a concussion

I am no doctor and really had no idea about the risks associated with scuba diving after a concussion so I reached out to Simon Mitchell to hear his thoughts. Simon (a regular columnist for Dive Pacific) is an incredible physician specialising in occupational medicine, hyperbaric medicine and anaesthesiology as well as hugely respected in the diving community around the world. I felt so honoured that he emailed back and agreed to catch up. Trying not to be a fan girl, I was grateful for my facemask hiding my massive smile as I met Simon outside Auckland Hospital.

I had not lost consciousness or experienced any amnesia and therefore my concussion was classified as mild. Injuries with a loss of consciousness for 30mins to 24hours or a skull fracture are considered moderate; severe concussions include loss of consciousness or amnesia for more than 24hours, subdural hematoma or brain contusion.
Simon discussed one of the major risks for scuba diving after a concussion - an increased risk of seizures. The risk varies greatly according to the severity of the traumatic brain injury.

Though a mild concussion still increases the risk of a seizure to a small degree, Simon acknowledged no one can ever guarantee there will be no problems. I accepted this unknown degree of increased risk with Simon advising some cautions to help me ease back into diving.

The first was to understand which gas I was breathing. Increased partial pressures of oxygen can be known to increase the risk of seizures and therefore, instead of diving nitrox, diving with Air, 21% oxygen while I eased back into diving was highly recommended. Avoiding physical exertion and task loading on dives was also suggested, like avoid swimming into a strong current, or any activities that would raise my heart rate. Simon’s last piece of advice was not to push depth and for the first couple of months stick to open water dives (above 18m).

But this meant I could dive again! And I was very, very excited.

Back to basics

Being cleared to dive, I eagerly called up a couple of friends and asked if they would be happy to join me for my first dive back. We chose Goat Island, New Zealand’s first marine reserve and where my open water course was held.

We hit a maximum depth of 5m for an hour chasing fish, looking for crayfish and following Steph’s trusty navigation. It was so good to get back in the water, just in time for summer.

It has been several months since that first dive. The second week of my holidays was spent in my favourite place up north in sunny Tutukaka where I went diving as much as I could, sticking to Simon’s advice and slowly increasing my depth.

For the first couple of months I limited myself to a maximum depth of 18m avoiding physical exertion, then slowly increasing the depth limit to 30m. I have been making sure I drink plenty of water and allow for more rest and sleep than usual before and after diving.

Then, I completed four dives as a test to see how I would be after a full weekend of diving at the Mokohinau Islands. The longest was 71 mins. We had bronze whaler sharks, pilot whales, dolphins, a baby octopus, a little blue cod and hundreds of schooling koheru, a silver and yellow bait fish. My excitement and smile didn’t change the whole weekend. My next step is to start diving with nitrox then work towards more technical diving.

So here I wanted to share my experience and some of the cautions around scuba diving after a concussion. If you have had a traumatic brain injury, be sure to seek medical advice and clearance before returning back to diving. ‍

Annika Andresen is a BLAKE Senior Environmental Educator
www.annika.Andresen.com