3 interesting clinical cases from a nutrition consultation

In a gastrointestinal nutrition clinic, it is common to encounter patients with very similar symptoms: abdominal distension, flatulence, indigestion or changes in the frequency and consistency of stools, amongst others.

But the reality is that similar symptoms do not always have the same cause. Sometimes, behind an apparently common set of digestive symptoms, there may be very different conditions requiring different approaches.

In this article, we present three clinical cases in nutrition that began with similar digestive manifestations and ultimately led to very different diagnoses: coeliac disease, Giardia intestinalis infection and bacterial overgrowth in the context of Crohn’s disease.

Clinical case 1: iron-deficiency anaemia and severe folic acid deficiency

The first case concerns a 20-year-old woman who presented for consultation with non-specific digestive symptoms: abdominal distension, flatulence, indigestion and discomfort following the consumption of foods such as bread, pasta or other cereals.

Given this combination of digestive symptoms, malabsorption and anaemia, it was deemed necessary to rule out coeliac disease.

Specific serological tests were requested, along with other nutritional and autoimmune parameters. The results showed IgA levels within the normal range and elevated IgA anti-tissue transglutaminase type 2 antibodies. Vitamin D deficiency and vitamin B12 levels in the lower-normal range were also detected.

Based on these findings, the patient was diagnosed with coeliac disease.

The nutritional approach focused on starting a gluten-free diet and, initially, reducing foods high in FODMAPs to improve digestive tolerance. The outcome was very favourable: the nutritional deficiencies improved, as did the intestinal discomfort.

In subsequent consultations, the focus shifted to gradually reintroducing foods rich in fermentable sugars, reinforcing nutritional education, improving the ability to read food labels, and preventing exposure to traces of gluten, particularly when eating out.

This first case demonstrates how iron-deficiency anaemia associated with folic acid deficiency and persistent digestive symptoms can be a key clue in suspecting coeliac disease.

Clinical case 2: non-coeliac gluten sensitivity (NCGS)

The second case concerns a 39-year-old man following a vegetarian diet who presented for consultation with symptoms such as abdominal distension, diarrhoea and poor tolerance to various foods.

According to the patient, the symptoms mainly occurred after consuming foods that typically contain gluten, as well as certain fruits, vegetables and pulses. He also presented with mild to moderate secondary fructose malabsorption.

He had previously undergone an endoscopy with gastric and duodenal biopsies, which revealed no significant findings. Serological tests for coeliac disease had also been normal. Given this situation, the patient himself suspected that he might have non-coeliac gluten sensitivity.

However, before attributing the symptoms to gluten, it was important to assess whether the problem might be related to other food components, such as the fructans present in wheat, or to another underlying digestive cause.

A controlled dietary intervention involving fructose and oligosaccharides was then initiated. Although the digestive symptoms improved to some extent, the patient did not tolerate food reintroductions well.

A subsequent laboratory test changed the course of the case: elevated eosinophil counts were observed. This led to a request for a parasitological stool examination. Two of the three samples tested positive for Giardia intestinalis, an intestinal protozoan capable of causing diarrhoea, malabsorption and symptoms consistent with those presented by the patient.

Following the treatment prescribed by the gastroenterologist-a one-week course of metronidazole-digestive tolerance improved progressively. Although recovery was not immediate, tolerance to various foods increased markedly in the following weeks.

This second case reminds us that not all symptoms associated with the consumption of wheat or foods containing gluten should be directly attributed to non-coeliac gluten sensitivity. Before confirming this diagnosis, it is essential to rule out other causes, such as intestinal infections, fructose malabsorption or fructan intolerance.

Clinical case 3: small intestinal bacterial overgrowth (SIBO) in Crohn’s disease

The third case concerns a 42-year-old woman with ileocolic Crohn’s disease.

The patient appeared to be stable from an inflammatory perspective, with no acute abdominal pain or fever, but reported a heavy feeling after meals, progressive abdominal distension throughout the day and steatorrhoea.

During the medical history, she explained that, during a previous flare-up, she had undergone an intestinal resection that included the ileocecal valve.

This information was highly relevant. The ileocecal valve acts as an anatomical barrier between the small intestine and the colon. When it is resected or does not function correctly, there is an increased risk of bacteria from the colon ascending into the small intestine, promoting the development of small intestinal bacterial overgrowth (SIBO).

Given this suspicion, a lactulose breath test was recommended. Whilst awaiting the test results, a low-FODMAP, gluten-free diet was prescribed at the patient’s request.

Although bloating and flatulence improved to some extent, steatorrhoea persisted, probably also related to the ileal resection.

At follow-up, the patient remained free of clinical activity of her Crohn’s disease, with no evidence of active SIBO, and was following an adapted dietary regimen: a low-to-moderate-fat diet to control steatorrhoea, a gluten-free diet by personal preference, and occasional use of a low-FODMAP diet when significant bloating recurred.

This last case highlights the importance of taking surgical history into account in patients with inflammatory bowel disease. In the presence of abdominal distension, flatulence and digestive changes, bacterial overgrowth should form part of the differential diagnosis, particularly if an ileocecal resection has been performed.