It's funny (slash annoying) the way that, if you're a superhero, people feel they can ask you anything. Would you go up to the guy behind the milk bar counter and ask ‘So, do you have parents?' Or quiz the office worker sitting on the train next to you with, ‘What sort of food do you eat?' I think not.

I'll leave you to ponder that for a bit, and while you do, let's talk about something different: work causation.

I was called out recently (slicking back my hair as I stepped out of the triple bypass W32 DocMobile) to see a 30-year-old with carpal tunnel syndrome and assess whether her work was a contributing factor to her condition. She had it in both hands, though it was worse in her right. Her normal job was as a nanny for twins, which involved some house cleaning, caring for the four-month-old babies, cooking some meals, washing nappies and hanging them out on the line, and lifting the children reasonably regularly.

When she saw her doctor about the numbness in her wrists, he sent her for nerve conduction tests and carpal tunnel was diagnosed.

Carpal tunnel is a condition where the nerve to the hand becomes squashed as it travels through the tunnel at the wrist called the carpal tunnel. This tunnel can't expand so if there's any swelling inside, it squishes the other structures including the median nerve. This results in numbness and tingling, and sometimes weakness.
 
The problem in this situation is that the nanny's GP suggested that the condition was probably a result of her job. He couldn't identify other risk factors. She told the GP that hanging out the nappies and repeatedly using the clothes pegs stirred her symptoms.

Now we have a considerable amount of evidence about what causes or leads to carpal tunnel syndrome, and the way this young lady was using her hands did not put her at an increased risk of developing the condition. We know that highly repetitive movements, such as those carried out by a meat worker in an abattoir, do put the person at increased risk, but not the type of work carried out by the nanny.

The issue is that people commonly comment on work contribution to a condition, without having a good understanding of the facts. In this situation the woman is left with expectations (relating to her – now set – belief that her work caused the condition), and reversing those expectations now carries a series of implications. Her claim is contested by a workplace with medical evidence contradicting the nanny's doctor, and the whole process of her treatment is delayed. Secondly, she feels as though she is being questioned and thirdly, the process of assessing such a situation will often cost a few thousand dollars; there might be an independent medical review and a circumstance investigation, as well as the time and energy of those involved.

It's not easy to access all the information – called ‘occupational epidemiology' – needed to make an accurate judgment call in a situation such as the nanny's.

Epidemiology is the study of the health of populations of people. Occupational epidemiology is the study of work health issues of populations of people.

It's a complex area, some countries such as the Netherlands have done a good job of bringing the information together, and trying to assist all those involved with an adequate and evidence-based assessment of the situation. Other countries such as Australia and the US are languishing far behind.

It takes an individual practitioner tens or even hundreds of hours to find the research, study the issues and provide an educated opinion. Considering the amount of controversy involved, the consequences for people and the negative financial impact, it's surprising we don't spend more time and energy trying to understand this. Some researchers have endeavoured to do so, but it needs a coordinated and sustained effort to not only provide the information, but to foster the information being used. It would be great to see a government initiative take this on, such as the workers' compensation authorities, a university research group or the Commonwealth.

Failing that, it would be helpful to have general practitioners or those caring for patients in similar circumstances, say, ‘Well, I don't know the answer to that, but we should try to find out'. There's nothing to stop the person lodging a claim and their situation being assessed, but at least if they go into the assessment with open expectations, rather than a belief based on misinformation, the outcome for the patient will be better. 

[Maybe that's why people ask me so many questions, so they don't jump to wrong conclusions, like, 'You must be a protein-shake drinking immaculate conception, because aren't all superheros?' What question would you ask a (superdoc) superhero? Let me know, I might just answer…]