What are the limitations of the physical examination in practice?

 

The ideal innovation is inexpensive, readily incorporated into practice and has substantial patient benefits. In this context the humble physical examination is a strong candidate. However it is reported that in practice laboratory and or radiological tests are requested more often than not. Here is a quote from an editorial in the British Medical Journal (2009):

In the first camp are those who pine for the old days, bemoan the loss of clinical bedside diagnostic skills, and complain that no one knows Traube’s space or Kronig’s isthmus. In the second camp are those who say good riddance and point out that evidence based studies show that many physical signs are useless; some might even argue that examining the patient is just a waste of time. Verghese and Horwitz

Research suggests that most diagnoses are based on the history and examination:

In this prospective study of 80 medical outpatients ….in 61 patients (76%), the history led to the final diagnosis. The physical examination led to the diagnosis in 10 patients (12%), and the laboratory investigation led to the diagnosis in 9 patients (11%). The internists’ confidence in the correct diagnosis increased from 7.1 on a scale of 1 to 10 after the history to 8.2 after the physical examination and 9.3 after the laboratory investigation. These data support the concept that most diagnoses are made from the medical history. The results of physical examination and the laboratory investigation led to fewer diagnoses, but they were instrumental in excluding certain diagnostic possibilities and in increasing the physicians’ confidence in their diagnoses. Peterson et al

In only one of six patients in whom the physician was unable to make any diagnosis after taking the history and examining the patient did laboratory investigations lead to a positive diagnosis. BMJ 1975

Also the value of tests is contested in some cases:

Information from the history, physical examination, and routine procedures should be used in assessing the yield of a new test. As an example, the method is applied to the use of the treadmill exercise test in evaluating the prognosis of patients with suspected coronary artery disease. The treadmill test is shown to provide surprisingly little prognostic information beyond that obtained from basic clinical measurements. The JAMA network

A considerable number of plain abdominal films taken for patients with acute abdominal pain could be avoided by focusing on clinical variables relevant to the diagnosis of bowel obstruction. European Journal of Surgery

However the predictive value of the physical examination appears to depend on the clinical scenario. If the patient appears ill it is far more likely that they will have clinical signs:

In order to study the occurrence and positive predictive value of history and physical examination findings suggestive of serious illness in ill-appearing and well-appearing febrile children, 103 consecutive children aged ≤24 months with fever ≥38.3°C were evaluated from July 1, 1982 to Nov 24, 1982….The positive predictive values of abnormal physical examination findings for serious illness in ill-appearing (11 of 14, 79%) and well-appearing children (3 of 12, 25%) were significantly different (P = .02 by Fisher’s exact test). The trends for abnormal history findings in ill-appearing and well-appearing children were similar to those for abnormal physical examination findings but did not achieve statistical significance. The results, indicating an important interaction between a febrile child’s appearance and physical examination findings, are discussed in terms of probability reasoning in clinical decision making. McCarthy et al

In some common clinical scenarios it is difficult to find objective evidence in support of a diagnosis and tests are necessary. There are many examples including:

Irritable bowel syndrome

Individual symptoms have limited accuracy for diagnosing IBS in patients referred with lower gastrointestinal tract symptoms. The accuracy of the Manning criteria and Kruis scoring system were only modest. Despite strong advocacy for use of the Rome criteria, only the Rome I classification has been validated. Future research should concentrate on validating existing diagnostic criteria or developing more accurate ways of predicting a diagnosis of IBS without the need for investigation of the lower gastrointestinal tract. Ford et al

Heart Failure

Differences in clinical parameters in heart failure patients with decreased versus normal systolic function cannot predict systolic function in these patients, supporting recommendations that heart failure patients should undergo specialized testing to measure ventricular function. Thomas et al

Painful shoulder

Thirty one consecutive patients with a first flare of shoulder pain were prospectively included in the study. All had a physical examination performed by two blinded rheumatologists. Ultrasonographic examination was carried out within one week of the physical examination by a third rheumatologist experienced in this technique who had no knowledge of the clinical findings. Ultrasonography was considered the optimal diagnostic technique. Naredo et al

Also relevant are the physician’s skill in eliciting and interpreting signs:

Agreement between 24 physicians on the presence or absence of respiratory signs was investigated. The physicians were divided into six sets of 4; each set examined 4 patients with well-defined chest signs. There was generally poor agreement about particular signs. Overall, the 4 physicians in a set were in complete agreement only 55% of the time. Some signs such as wheezing seemed to be more reliably elicited than others such as whispering pectoriloquy. Comparison of diagnoses based on the clinical findings with the correct diagnoses supported by investigations showed that 28% of physicians’ diagnoses were incorrect. The more often the examiners differed from the majority on the presence or absence of a sign, the more likely they were to make an incorrect diagnosis.  The Lancet

In some cases physical signs are unreliable:

A review of published studies of patients suspected of having pneumonia reveals that there are no individual clinical findings, or combinations of findings, that can rule in the diagnosis of pneumonia for a patient suspected of having this illness. However, some studies have shown that the absence of any vital sign abnormalities or any abnormalities on chest auscultation substantially reduces the likelihood of pneumonia to a point where further diagnostic evaluation may be unnecessary. JAMA

Therefore always relying on physical signs without conducting tests is unsafe. However the value of the clinical examination as an integral part of the patient experience was eloquently articulated in the BMJ editorial:

A third view of the bedside examination, and one that we advocate, is that it is not just a means of data gathering and hypothesis generation and testing, but is a vital ritual, perhaps the ritual that defines the internist. Rituals are all about transformation. The elaborate rituals of weddings, funerals, or inaugurations of presidents are associated with visible transformation. When viewed in that fashion, the ritual of the bedside examination involves two people meeting in a special place (the hospital or clinic), wearing ritualised garments (patient gowns and white coats for the doctors) and with ritualised instruments, and most importantly, the patient undresses and allows the doctor to touch them. Disrobing and touching in any other context would be assault, but not as part of this ritual, which dates back to antiquity. Verghese and Horwitz

Common sense dictates that where the patient appears unwell the physical examination will have a higher yield. In those circumstances clinical examination is crucial:

Misdiagnosis of acute appendicitis is more likely to occur with patients who present atypically, are not thoroughly examined (as indexed by documentation of a rectal examination), are given IM narcotic pain medication and then discharged from the ED, are diagnosed as having gastroenteritis (despite the absence of the typical diagnostic criteria), and with patients who do not receive appropriate discharge or follow-up instructions. Rusnak et al

Therefore the physical examination has an incalculable value not necessarily obviating the need for tests but increasing patient satisfaction and reducing the risk of litigation. Click the link for an excellent video on examination.

 

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