Recent media coverage surrounding the tragic death of 20-year-old law student Libby Instone has once again highlighted the dangers of diagnostic bias within urgent and emergency care settings.
Libby attended North Tees Hospital on multiple occasions over a 24-hour period suffering from severe abdominal pain, persistent vomiting and worsening symptoms. Despite repeated presentations, she was diagnosed with gastroenteritis and discharged. An inquest later heard that opportunities to investigate alternative causes were missed, with medical experts concluding that a scan could have identified a bowel obstruction and potentially saved her life. The Coroner found that neglect contributed to her death and criticised the hospital’s failure to move beyond the initial diagnosis.
How does a bowel become obstructed?
A bowel obstruction happens when the normal movement of food, fluid, gas and stool through the intestines is partly or completely blocked. It can affect either the small intestine or the large intestine, although small bowel obstructions are a common source of emergencies. When the bowel is blocked, material begins to build up behind the obstruction. This can cause cramping abdominal pain, bloating, nausea, vomiting and constipation, and as in Libby’s case, in a complete obstruction a person may be unable to pass stool or wind at all.
There are many possible causes. In some cases, the bowel is physically blocked by scar tissue from previous surgery, a hernia, a tumour, inflammation, narrowing from conditions such as Crohn’s disease, or a twist in the bowel known as a volvulus. Less commonly, one section of bowel can slide into another, which is called intussusception. Some obstructions are “partial”, meaning a small amount of fluid or gas may still pass through, while others are “complete”, meaning nothing can move beyond the blockage. A person with a partial obstruction may still have some bowel movements, which can sometimes make the diagnosis less obvious.
A bowel obstruction is dangerous because the bowel does not stop working in isolation. As pressure builds up, the bowel wall can become swollen and stretched. Vomiting can lead to dehydration and chemical imbalances in the blood. The bowel can also become increasingly inflamed and vulnerable to injury. In the most serious cases, the obstruction can cut off the blood supply to part of the intestine. This is known as a strangulated obstruction, and it can cause bowel tissue to die, a process sometimes described as infarction or necrosis.
Once bowel tissue has died, the risk becomes much more serious. The damaged section can perforate, meaning a hole forms in the bowel wall. If that happens, the contents of the bowel can leak into the abdomen and cause life-threatening infection, sepsis and shock. This is why persistent severe abdominal pain, repeated vomiting, abdominal swelling, inability to pass stool or wind, and signs of deterioration should be treated as red flags.
Diagnosis usually involves taking a careful history, examining the abdomen and arranging urgent imaging, often a CT scan, to look for the site and cause of the obstruction. Treatment depends on the type and severity of the blockage. Some patients may be treated with intravenous fluids, bowel rest and a nasogastric tube to drain fluid and gas from the stomach. However, complete obstructions, suspected strangulation, perforation, worsening pain or signs of reduced blood supply usually require urgent surgical assessment, and sometimes emergency surgery to remove the blockage or any damaged section of bowel.
What is diagnostic bias?
Diagnostic bias occurs when clinicians latch on to an initial diagnosis and so fail to adequately consider alternative explanations for a patient’s symptoms. One of the most common forms is “confirmation bias”, where subsequent assessments focus on evidence supporting the original diagnosis while discounting information that may point elsewhere.
In Libby’s case, an independent expert identified several warning signs that were inconsistent with gastroenteritis, including the absence of diarrhoea and her inability to open her bowels for several days. Nevertheless, the diagnosis remained unchanged throughout multiple assessments. The Trust’s Chief Medical Officer later acknowledged that “confirmation bias” played a role in the care provided.
Why does this matter?
Emergency departments operate under immense pressure, with clinicians often required to make rapid decisions based on limited information. However, patients who re-attend with worsening symptoms should trigger fresh clinical consideration rather than reinforcement of previous assumptions.
The consequences of diagnostic bias can be devastating:
- Delayed diagnosis and treatment;
- Progression of otherwise treatable conditions;
- Increased risk of serious injury or death;
- Loss of trust in healthcare services;
- Significant emotional trauma for patients and families.
When does a misdiagnosis become medical negligence?
Not every incorrect diagnosis amounts to negligence. Medicine is complex, and clinicians are not expected to be infallible.
However, a claim may arise where a healthcare professional fails to act in accordance with a reasonable standard of care. This may include:
- Failing to undertake appropriate examinations;
- Ignoring significant red-flag symptoms;
- Failing to arrange necessary investigations or imaging;
- Not considering alternative diagnoses;
- Inadequate monitoring of a deteriorating patient.
Where earlier diagnosis and treatment would have prevented harm, patients or their families may be entitled to pursue a clinical negligence claim.
Lessons for healthcare providers
The findings in Libby’s case serve as a powerful reminder of the importance of freshly considering the patient’s symptoms when treatment fails to help. Clinicians should be encouraged to challenge initial assumptions, particularly where patients return with persistent or worsening symptoms.
Robust safety-netting, effective handovers and a willingness to revisit working diagnoses are essential safeguards against diagnostic error.
How we can help
At Davies and Partners our medical negligence team regularly assists patients and families affected by delayed diagnosis and misdiagnosis. We understand the profound impact these cases can have and are committed to helping clients obtain answers, accountability and appropriate compensation.
If you believe that a failure to diagnose or treat a medical condition has caused avoidable harm, our specialist solicitors are available to provide confidential advice on your legal options.