In the latest in our monthly series, Dr Nicolas Alexander asks readers to suggest what’s causing persistent diarrhoea in this otherwise well woman. Put your answers in the comments.
You see a 34-year-old female patient with a two-week history of diarrhoea, which she explains started suddenly a few days after returning from holiday in Switzerland. She volunteers no other symptoms, and denies any nausea, vomiting or abdominal pain. She also denies any recent stressors or change in diet. She hasn’t lost any weight or had any reduced appetite. No one else is unwell at home. She has no other past medical history and takes no regular medication.
She has been doing some internet research and is concerned about a possible ‘nasty bug’ causing her diarrhoea, as she drank water from a stream whilst hiking on holiday. Being the diligent GP you are, you furiously Google the cleanliness of water in Switzerland, and any known bugs in its waters or forests, and are relieved you can’t find anything.
Two weeks seems somewhat prolonged for a standard gastroenteritis. You reason it is likely to settle down in the near future but, given her concern, you agree to do a stool microscopy and culture and check for ova, cysts and parasites. You suspect it will be normal and might be a bit of IBS, so you discuss lifestyle, mindfulness and over the counter treatment options. She politely listens but you can sense she’s unconvinced.
Three weeks later the patient returns to see you with ongoing diarrhoea. Things have not changed much; she still does not have any other symptoms and feels well diarrhoea aside. Her weight has not changed, nor has her appetite and the diarrhoea continues though it still isn’t bloody. Her faecal tests were all normal and she has been trying to be mindful about managing her stress levels and has even tried some over the counter IBS tablets which haven’t helped. You scratch your head.
‘Given things are ongoing, let’s get some bloods done to see if there is an underlying cause for this,’ you reason. You work through the possible differentials (though you still think this is probably IBS and bloods will be normal) and settle on: FBC; U+E; LFT; CRP; coeliac screen. This seems a short list and since you’ve been doing some reading, you decide to check TFTs and bone profile too. You wonder about cancer, though it’s still early days. You decide to err on the side of caution and order a FIT test and faecal calprotectin in case you’re missing IBD. These don’t seem likely given her age and lack of weight loss, family history and the symptoms she describes.
Several days later you are reviewing her bloods and see that most have come back normal… except for one. Which do you think it is?
Put your answers in the comments below. Answer to be revealed in the coming weeks…
Dr Nicolas Alexander is a GP and GP trainer in North East London
