It was a Saturday morning. Michael (43) popped in to get the results of his test as requested by the message left on his phone. He was told that the doctor who ordered the test wasn’t on duty that day so he asked to see whoever was available. That’s how I came to be involved.
From the records it wasn’t clear why the cortisol assay had been requested along with a battery of other tests all of which were normal. All the man could tell me is that he had asked for the test because:
It might explain a lot.
We had to start again. He was tired. He was stressed. He was working long hours at two jobs to pay a mortgage and service his debts. He had three young children and had been on antidepressants on and off for years. He wasn’t taking any tablets at the time. Didn’t smoke or drink. He was attending a counsellor.
There must be a reason I’m feeling so tired.
There was no obvious explanation for the borderline low result. Physical examination was entirely normal. No recent change in weight, normal blood pressure and no hint of major depression. No history of tuberculosis. No evidence of Addison’s disease.
I thought the ‘cortisol’ levels would be high I’m under a lot of stress.
We could now be on the way to more tests to determine what I suspected would be the final outcome that there would be no explanation. Life can cause people to feel this way with multiple physical symptoms including dysphoria, fatigue, insomnia, sexual dysfunction, weight changes and anxiety. Reasons may include poor choice of occupation, poor choice of partner, poor money management, poor time management, poor parenting. All of these can be associated with unfulfilling social interactions and or job dissatisfaction. Poor coping mechanisms then lead to physical sequela. People can be trapped in a spiral of increasing adverse consequences until lessons are learned and either alternative choices are forced upon them or circumstances conspire to offer the opportunity to start again.
People may not be ready to face their demons and that means they will ask to go searching for something more palatable than a need for a education, honesty, economy or help.
As for doctors ordering tests could add to the complexity of the situation. Rare causes of fatigue are legion. However typically people will ask if their fatigue is caused by some malfunction of their ‘hormones’ or if they are anaemic or diabetic.
In the case above there was no hint in the records what the patient had been told to expect after the test. His understanding of hormones was not recorded. He had read that cortisol is related to stress but not what the results might mean.
Because of the very low prevalence of pathology the Positive Predictive Value of ‘abnormal’ tests for middle aged patient without any positive history or examination findings is low for example:
- Random capillary blood sugar (Diabetes- assuming a prevalence of 8.5%):( PPV 42%)
- Thyroid stimulating hormone ( Thyroid disease- assuming a prevalence of 2%): (PPV 20%)
- Full Blood count ( Iron deficiency anaemia- relying on Red cell distribution width, assuming a prevalence of 5%): (PPV 8.38%)
- Synacthen test (primary adrenal insufficiency-assuming a prevalence of 0.00005%) (PPV 0.01%)
Therefore the probability that one simple test will make the diagnosis is unlikely. People will need multiple tests and possibly a referral to a specialist once we embark on the hunt for the elusive physical cause. The likelihood of finding one when the patient doesn’t have any physical signs is vanishingly low. In sporting terms what’s needed is a set play. The question can be anticipated and the response to the initial request for tests needs to be crafted in advance. There is no better start then taking a full history and examining the patient before looking for the needle in the haystack.
Picture by Henti Smith