SUMMARY: Acute appendicitis is a common condition, and a frequent cause of medical malpractice enquiry. Plaintiff counsel can learn to medically screen out some cases as having fatal flaws. When the symptoms, clinical signs or results of tests are very atypical, the missed diagnosis may not be considered substandard. Acute appendicitis is a common condition, and a frequent cause of medical malpractice enquiry.
Misdiagnosis of acute appendicitis is among the top 5 emergency department causes of medical malpractice action1.
Usually, the client is seen by one or more medical practitioners, who do not recommend appendectomy.
The client later seeks further medical advice and the appendicitis is found to have perforated.
A central problem is that a third to a half of cases have features that differ, sometimes considerably, from the classical clinical presentation2:
Practice PointClassical symptoms:
1. Abdominal pain
Plaintiff counsel can learn to medically screen out some cases as having fatal flaws.
Pain may instead be localised in the right flank, middle back, or testicle, or in the pelvis, rectum or left lower abdomen.
Anorexia, nausea and vomiting may be entirely absent3.
Common confusing symptoms are persistent vomiting, diarrhea, constipation, urinary and respiratory complaints.
Types of patients who frequently have atypical presentations are children4, the elderly5, pregnant women6 and patients who are immunocompromised (AIDS, cancer, chemotherapy)7.
Typical clinical signs
Classical clinical signs may similarly be absent:
Practice PointClassical signs:
1. VITAL SIGNS NORMAL or mildly raised: pulse, blood pressure, temperature
2. Abdomen soft with LOCALISED right lower TENDERNESS
Mildly raised pulse-rate and blood pressure probably reflect apprehension. Temperature is rarely raised more than 1oC.
Muscle guarding that is involuntary (not under conscious control) generally denotes perforation with peritonitis (irritation of the inner lining of the abdomen), as do board-like rigidity of the abdomen and absent bowel sounds.
Atypical clinical signs
Absence of Rovsing's, psoas, or obturator signs should not be accepted as defensive evidence against the diagnosis of acute appendicitis, as these occur in only 10% of cases3.
Unusual anatomical location of the appendix, particularly retrocecal (behind the cecum), and unusual location of the cecum to which it is attached, Cause atypical symptoms and atypical clinical signs8.
Although C-Reactive Protein has not been adopted as a routine in suspected acute appendicitis, it is a highly sensitive test in combination with White Blood Cell Count (WBC) and neutrophil count9.
That is to say, acute appendicitis is highly unlikely if all three tests are normal10,11.
Typical Laboratory tests:
If urinalysis is abnormal, particularly in showing microscopic evidence of small amounts of WBC, bacteria and blood, defence may try to argue that the diagnostic error was therefore not substandard.
However, these abnormalities should not be accepted as mitigating evidence because they occur in a significant minority of cases of acute appendicitis, in women more than in men12.
Graded compression ultrasonography (US), if available and technically satisfactory, is highly specific and sensitive in acute appendicitis.
It has become the diagnostic imaging test of first choice in the presence of suggestive symptoms and equivocal clinical findings13.
When the symptoms, clinical signs or results of tests are very atypical, the missed diagnosis may not be considered substandard.
As previously noted, substandard alternative diagnosis such as gastroenteritis may form the basis of plaintiff success in an atypical case.
If such misdiagnosis is made with faulty or inadequate evidence, the client may have been negligently advised to be unconcerned about continuation or worsening of symptoms.
By contrast, a careful assessment that results in the conclusion "abdominal pain, N[ot] Y[et] D[iagnosed]" encourages the medical practitioner to admit, "I don't know" and recommend early reassessment.
The timing of perforation of acute appendicitis may make or break an action for medical malpractice.
Once perforation has occurred, the hour or day of the event is largely irrelevant clinically, but may require careful analysis for medicolegal purposes.
The major complications, and therefore the main source of Quantum of Damages, are usually Caused by the perforation itself, and any further delay in diagnosis and treatment usually have little effect.
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