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Mary, my registrar, had been consulted by Jake, a quarryman in his mid-thirties, who was complaining of feeling unaccountably weak. As presenting symptoms go that’s pretty non-specific, and could have been a feature of innumerable conditions. His vague tummy aches, occasional nausea, and unintentional weight loss didn’t help narrow it down, either. But the whole picture had been sufficiently concerning for Mary to have arranged some blood tests.
“Look what’s come back on his electrolytes,” she told me.
Sodium level well below normal; potassium level a touch high.
“I wondered about Addison’s. It can’t be, can it?”
I understood her disbelief. Addison’s disease – which sees destruction of the adrenal glands, where the steroid hormone cortisol is made – is so rare that a UK GP will encounter a new case only once in their entire career, if at all. And if they do come across one, they’ll likely miss it.
Addison’s is notorious for giving rise to vague, non-specific symptoms which get put down to virtually anything else. The majority of Addison’s patients end up seeing a succession of doctors before someone twigs what’s going on. The average delay between first presentation and eventual diagnosis is two years. For Mary to have sorted a case in one consultation would be quite something.
“Check his cortisol,” I said. “That’ll settle it.”
A couple of days later Jake’s cortisol level came back from the lab, abnormally low.
Mary is a very modest person, and made some noises about it having been a textbook case. Most Addison’s in the UK is caused by an aberrant immune system, which mistakenly attacks the adrenal gland tissue. As such, it is often associated with other autoimmune conditions, and Mary mentioned that Jake had also proved to have vitiligo – scattered patches of lily-white skin where the pigment cells have been destroyed by an abnormal immune response. “Textbook or not, you’ve done Jake a huge service,” I said.
Addison’s is infamous for causing disasters. Cortisol plays a vital role in the body’s response to infection, and undiagnosed Addison’s patients can quickly die from what in anyone else would be a trivial illness such as gastroenteritis. The medical literature – and not infrequently the law courts – periodically deal with cases where Addison’s has only been discovered at post-mortem. Devastating for the patient and their family, and awful for the doctors who realise what they’d been missing. Jake will be able to live a normal life now, his energy restored by hormone tablets, and his cupboard stocked with a cortisone injection to give himself in the event that he becomes acutely unwell.
Mary’s triumph set me thinking about Iain, a printer in his late twenties who’d been consulting me for six months with baffling leg weakness. His symptoms had progressed such that he was now unable to stand for more than a couple of hours. Among innumerable tests, I’d checked his electrolytes and they’d come back normal. Then again, the characteristic pattern of derangement that Mary had picked up in Jake is absent in at least a fifth of Addison’s cases, so I hadn’t ruled it out. And Iain had both vitiligo and autoimmune thyroid disease. But. Mary diagnosing Addison’s was a rare enough event – surely two doctors in one practice could never pull off the same feat in the space of a week?
My instinctive doubtfulness reminded me of Mary’s initial reaction when faced with Jake’s results – and everything about Iain’s case now seemed to scream “Addison’s!” at me. I called him and arranged a cortisol test, excited that I might soon have the answer to his mysterious illness.
The result came back plumb normal, completely ruling out Addison’s. I’m back to square one with Iain’s failing limbs. Sometimes medicine goes according to the textbooks. Many more times, it does not.