Diagnosis

Author: Lisa Sanders

Synopsis

What does it take to make accurate and timely diagnoses when the stakes are very high? How do doctors get the job done when they are ‘confronted with a patient who has a problem that just might kill him’ (page xxix). This book is all about a process the author depicts as ‘often the most difficult and most important component of what physicians do’ (page xxiv). It accurately conveys ‘the feeling of uncertainty and intrigue‘ that accompanies the diagnostic process, describing it as ‘messy‘ and ‘filled with red herrings, false leads, and dead ends‘ (pages xiii and xxiv). The author, a journalist and doctor, describes herself as ‘a collector of diagnostic stories’, and she deployed many illustrative anecdotes to demonstrate her arguments (page xxviii). These accounts reveal how doctors frequently get it right, but more importantly, they demonstrate how doctors also make diagnostic errors, with the tragic consequences that ensue.

The book does a brilliant job of describing the different stages of making a correct diagnosis. In doing this, the author stressed the primacy of a detailed history, asserting that this is often the best and most reliable source for the clues that unlock the diagnosis (page 7). Arguing that ‘the patient’s story contained the diagnostic tip-off 70 per cent of the time’, she expressed misgivings that doctors frequently deny patients the opportunity to tell their personal stories, preferring to focus on the limited ‘medical story’ (pages 7, 44, and 69).

A properly performed physical examination is the second stage in the diagnostic process, and the book describes this as ‘the hallmark of the physician’, and a fundamental bulwark against diagnostic mistakes (page 49, 57, and 64). The book illustrated the different stages of the physical examination with appropriate anecdotes. She referred, for example, to the Scottish surgeon Joseph Bell, the person on whom Arthur Conan Doyle modelled his fictional detective Sherlock Holmes, whose ‘keen eye for detail‘ and ‘remarkable deductive powers‘ demonstrated the significance of clinical observation in the diagnostic process (page 115). She however noted that doctors frequently neglect this critical skill, rather relying on laboratory tests which are not always accurate, and which may even ‘slow or sidetrack the diagnostic process’ (page 216). The book made many interesting recommendations to help medical students ‘hone their powers of observation’, such as the study paintings (pages 116-117). 

A running theme throughout the book is the uncertainty that pervades the whole diagnostic process. Describing medical uncertainty as ‘the water we swim in’, the author illustrated how ‘the fear of getting it wrong is always present for both doctors and patients’ (pages xxvi). She touchingly portrayed the emotional turmoil doctors go through in making difficult diagnoses, worrying ‘that they’d missed some clue that could mean the difference between life and death‘ (page xii). The fear of getting it wrong is however justified as the author cites evidence showing that diagnostic errors ‘make up a large chunk of the errors made in medicine’ (page xxv). Citing clinical errors expert Pat Croskerry, the author reviewed the diverse causes of diagnostic mistakes, emphasising common types such as cognitive error (sick thinking) and premature closure (pages 252-255).

The book advocates a very pragmatic and philosophical approach to managing diagnostic errors, acknowledging that ‘we are regularly wrong in the pursuit of being right‘. It explores the strategies that may prevent diagnostic error, illustrating these with appropriate examples such as the repeated misdiagnosis of a case of pernicious anaemia, just because nobody asked ‘that most fundamental question in diagnosis: what else could it be?’ (page 254). The book reviewed several other precautionary measures against diagnostic mistakes such as looking again at the data with fresh eyes, questioning every assumption, double-checking test results, and making a list of differential diagnoses (pages 268-269 and xxvii). When things do go wrong however, she advocates a policy of openness, honestly acknowledging and discussing the error (page ix).

The book is crammed with striking clinical diagnoses, and the brilliant ways they were made. Such diagnoses include cannabinoid hyperemesis, Lemierre’s disease, West Nile virus infection, ischaemic colitis, and Rocky Mountain spotted fever (pages 14, 39, 79, 147 and 297). The author discussed many helpful clinical diagnostic pearls and tools such as the Alvarado score for diagnosing appendicitis (page 141). She also revealed the poor evidence-base for many popular clinical signs such as Spurling’s test of cervical disc disease, Tinel’s test of carpal tunnel syndrome, and Adson’s test of thoracic outlet syndrome (pages 151-157).

Opinion

Whilst this book is anchored on stories, these are not just interesting anecdotes but highly instructive narratives. It is a deceptively well-researched work full of lessons on the value of good medical practice. It weaves diligent practice and empathic care with evidence-based medicine. The author’s examples cut across the different medical specialties, and they all illustrate how keen observation, brilliant thinking, and deep knowledge often reveal the mystery behind complex diagnoses.

Overall assessment

This book admirably projects the fundamental importance of the medical history and physical examination in the diagnostic process. By a delicate application of relevant stories, the author has done an excellent job of depicting the key elements of making accurate clinical diagnoses, and I highly recommend it to all doctors.

Book Details