Diagnosis

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“In the fight which we have to wage incessantly against ignorance and quackery among the masses and follies of all sorts among the classes, diagnosis, not drugging, is our chief weapon of offence. Lack of systematic personal training in the methods of the recognition of disease leads to the misapplication of remedies, to long courses of treatment when treatment is useless, and so directly to that lack of confidence in our methods which is apt to place us in the eyes of the public on a level with empirics and quacks”

—William Osler 1904

Annemarie Jutel, medical sociologist at Victoria Unversity writes that "With few exceptions only the medical profession has the power to diagnose disease...Being able to diagnose is at the base of the social authority afford the doctor. It sets the doctor apart from the lay person and from other professionals, confirming the doctor’s greater knowledge and status"

There are some other professions in New Zealand who are afforded the status of being able to diagnose within their fields - physiotherapy, osteopathy, chiropractic, midwifery, nurse practitioners, pharmacy prescribers. There has also recently been the provision for self-diagnosis of COVID-19 through RAT testing.

Abbreviated History

Galen 129-216

Galen was a prodigy having written three books by the age of 13. He was reported to have been incredibly arrogant. He did anatomical studies on animals, some correct but many incorrect deductions. For example he described the rete mirabilis of the brain of a calf and assigned it to a vital physiological role in humans - but it doesn't exist in humans. He made incorrect deductions about the circulatory system. However he made correct deductions about spinal injuries and devised that the brain not the heart was in charge of the body.

Galenism became holy writ, and later part of Church dogma. He championed blood letting (laudable pus) and used the theory of opposites called Contraria Contrariis. A famous quote from the time is "Christ as a second and neglected Galen.”

Critics of “Galen’s grand plan” risked severe penalties. The grand plan was one that only he could recognise, and so after his death progress in medicine essentially stopped for 1,500 years.

Vesalius 1514-1564

Vesalius broke the dogma of Galenism. He studied anatomy through human dissections (previously disallowed). The human body rediscovered. He published a highly influential work called De Humani Corporis Fabrica Libri Septum.

He drew what he saw, not what Galen told him to see, but also made some errors. For example he hadn't fathomed the mechanism of circulation, he placed the lens in the centre of the eyeball, believed the vena cava came from the liver, and thought there only to be 7 cranial nerves.

Through Vesalius the anatomical view of body developed. This was the foundation of modern medicine. Others followed suit.

Sydenham 1624-1689

Sydenham brought about the classification of disease. He was committed to naming disease to enable communication between doctors and between doctors and students. The IASP Taxonomy can be traced back to this idea.

“All diseases then ought to be reduc’d to certain and determinate kinds, with the same exactness as we see it done by botanic writers in their treatises of plants”

—Sydenham

Morgagni 1682-1771

Morgagni founded the idea of patho-anatomical correlation through a publication of >500 autopsies in his book the sites and causes of disease in 1761. He compared diseased organs with normal ones and linked symptoms to abnormalities in the body. He made classic descriptions of angina, myocardial infarction, subacute bacterial endocarditis, strokes (lesion of cerebral blood vessels), hemiplegia due to a lesion on the opposite hemisphere of the brain.

Through morgagni we got the idea that physical diseases have physical causes, often in specific organs and tissues. The humoral theory was demolished.

Paris and German Schools of Medicine

“In 19th [the] century…symptoms [became] a window into otherwise hidden disease… no longer [were they] individual phenomena, [but the] external expression of disease”

—Annemarie Jutel

Through the Paris school we had physical examination (including percussion and mediate auscultation), psychological assessment, and autopsies became routine for clinico-pathological correlation.

In the German school we had the likes of Virchow who propounded the cellular theory pathology and Koch.

Medical Humanism Model

William Osler (1849 – 1919)

“The good physician treats the disease, the great physician treats the patient that has the disease”

—William Osler

The medical humanism model uses the reductionist biomedical approach as a base, but it is complemented by medical humanism. Humanism refers to the humanities rather than pyschological science. The model pays attention to the wishes, beliefs, fears of the patient. It is different to the Biopsychosocial model which is derived from psychoanalysis.

Biopsychosocial Model

Engel developed this influential model in the 70s derived from Psychoanalysis. It avoids biological reductionism and views all spheres as equally important. It has been criticized as being anti-humanistic and using psychological ideologies masquerading as science. It implies that the psychosocial is always relevant leading to stigma even in the face of evidence that a particular problem is rooted in a biomedical cause. This is contrasted to the medical humanism model where a humanistic approach is always relevant.

Physiological Diagnosis

In Musculoskeletal Medicine an important paradigm that developed was the idea of physiological diagnosis. This is captured by Bogduk’s Postulates – for diagnosing pain generators

Conflicts

There were huge debates in late 18th and 19th centuries. One group said it didn’t matter, just classify and treat. Another group (the etiologists) said it did matter. The etiologists mostly won this debate but there are still some clinicians who follow the "anti-reductionism" ideology. For example the ideology of classifying almost all chronic low back pain as "non-specific chronic low back pain" (despite copious evidence that most chronic low back pain has a biomedical source) is not a new ideology by any means, and is a vestige of the debates from 200-300 years ago. The different ideologies and how they all believe themselves to be "evidence based" is discussed further in Low Back Pain Treatment Strategies.

What is Knowledge?

The field of epistemology

Approximately =

Justified – diagnosis needs to be based on something real

True – pathophysiologically it has to be true

Belief – I have to believe it to be true

What is Diagnosis?

There is a difference between science and medicine. The doctor's epistemic task is to figure out how to help or cure

“Diagnosis is not knowledge for knowledge’s sake. It is knowledge for the sake of action. Medicine exists to cure, to care, to intervene, or in limiting cases, to know when not to intervene. Medicine is not a contemplative science”

—Mainetti 1992

It is important to remember that taxonomy is a social creation. For example dyslexia is not a disease in a non-literate society. To be a disease it needs to be visible, problematic, and perceived to be related to medicine. It is a cultural expression of what is accepted as normal (e.g. drapetomania). Consider such diagnoses as AIDS, depression, infertility, ADHD, alcohol use disorder, obesity, and fibromyalgia.

It is a classification tool by allowing segmentation and organisation. There are three types of diagnoses.

1. Patho-anatomical diagnoses (e.g. internal disc disruption)
2. Symptomatic diagnoses (e.g. non-specific chronic low back pain)
3. Medical unexplained symptoms (e.g. chronic primary pain)

The Benefits and Harms of Diagnosis

Benefits

“Diagnosis is both rudder and anchor”

—Annemarie Jutel

Rudder – the pursuit of diagnosis guides the individual to the doctor

Anchor – assignment of diagnosis positions identity and behaviour.

Annemarie Jutel

Personal diagnostic value to the patient

• Psychic value: patient given an explanation, clarifies, access to sick role
• Planning value: on patient life decisions e.g. work, retirement, financial plans, etc (prognosis
• Collective identity

Intrinsic diagnostic value to the broader system

• Research and Education value: More easily group with other similar patients to study the entity and develop treatments, CPD, quality outcomes
• Tool for political engagement and advocacy.
• Resource allocation: Which specialty should assume responsibility, access to physiotherapy, medications, prostheses, disability parking, WINZ, ACC, etc.

Impact on the doctor and doctor-patient decision making

• Knowledge Access: Allows the doctor to more effectively draw from their knowledge, do a literature review, or ask colleagues.
• Positive Therapeutic Utility: whether leads to improved outcome
• Negative Therapeutic Utility: whether prevents misadventure through inappropriate treatment, avoiding the harms associated with diagnostic error

The Value of the Explanation

Patients want a narrative for their pain. Delegitimisation is an experience or a series of negative consequences from not being seen to not being heard, to a sense of deficiency, and shame.

Patients have various expectations around diagnosis. Information needs are centred around a desire for a definitive diagnosis. Patients expect diagnosis through comprehensive physical examination and imaging. Accurate diagnoses are wanted for proving that their pain is real. Patients are not satisfied by “age-related wear and tear” explanations. Diagnostic satisfaction linked in with expectations of receiving a good physical examination.

“It is a psychological fact that if you tell a patient that you do not know what is the matter with them” he wrote, “he will immediately begin worrying. He will probably think that he has got some rare and awful disease, and will certainly think that you don’t know your job.” He advocated “Latinizing” symptoms to give a “diagnosis of sorts.” “To put into dog Latin the symptoms of which patient complains is not scientific, but it satisfies him every time . . . .”

—Sykes 1927

If tests confirm patient experience - Rhodes

“[T]hey ran some tests and that's when they realized my whole spinal column was kitty catty womper. I felt relieved. I felt like, well, here's proof. It's not just me going crazy or complaining. It's black and white and anybody can see it. [The doctor] showed me and... he showed me where it hurt. He said, your disc is kinda bulging out there, just kinda laying on this nerve.”

Q. So it sounds like you're happy with the diagnosis.

A. Yeah, I don't question it one bit. [All] anybody with a grain of sense would have to do is be shown the X-rays and it's right there, right in front of `em.

Intense Satisfaction with Diagnosis

I'm sure he thought that there was something wrong with the spine but nothing really serious. And they had done a CT scan which had turned up nothing. And they had done a normal X-ray which turned up nothing... And he kept telling me, we're just not finding anything. And I said, well, you can't hurt this bad and there not be something wrong... So finally, I think because I was insistent about it, he decided to do a myelogram... and I was laying on the table... and the technician said `Oh my gosh!' and I knew he had found it. And he called one of the doctors in.

“It was wonderful... he showed me on the X-ray the nerves that were pinched”

Collective Identity

Research and Education Value

Goitre Belt pre 1920s, 26-70% of children

Diagnosis in the 1944-1945 “Hunger Winter”

Schizophrenia in the 1960s and 1970s

1960s Psychologically oriented approach – due to harmful emotional experiences in childhood with primary caretakers (usually mothers)

1970s biological approach – genetic susceptibility, biological alterations present, twin studies showed family environment was irrelevant, no statistically significant psychosocial traumas

Psychoanalysts were proven wrong. The reductionist approach was more humane than the psychosocial approach.

Superior Semicircular Canal Dehiscence

Discovered in 1998

Seen on very small slice CT

Symptoms = pressure or sound induced vertigo, bone conduction hyperacusis, and pulsatile tinnitus

Previous to 1998 these patients were biopsychosocial

Harms

There are various potential harms of diagnosis

• Denial of insurance
• Denial of employment: e.g. military etc
• Negative internal appraisal: ?Lead to regard oneself as forever flawed and unable to “rise above” ones problem (hypothesis)
• External stigma: e.g. EDS, endometriosis, CFS, alcohol use disorder, depression, borderline personality disorder
• Commercial exploitation: Fertile ground for exploitation of patients and doctors (e.g. “social phobia” for shyness, endorses the use of medication)
• Marginalises unstudied populations (e.g. is endometriosis really more common in Pakeha women? Or are Pakeha women just more likely to seek care?)

Psychiatry Explains the Unexplainable

History of Hysteria

Multiple Sclerosis

Discovered in 1968 by Jean-Martin Charcot

Very challenging diagnosis

Diagnosis made easier by increased access to neurologists in the mid 20th century and then by MRI

Misdiagnosis as hysteria and neurosyphilis was common.

Hysteria and MS

“The diagnosis [of multiple sclerosis] from hysteria is of the greatest importance, and it is often very difficult and sometimes impossible.”

- Charles E. Beevor (1898)

“the frequent mistaking of this condition [MS] for hysteria . . . in this condition [MS] we make many mistakes. . . . [I] was often forced to revise [the] diagnosis of hysteria.The characteristic striking remissions after very grave symptoms are misleading”

- Dr Crafts, AMA (1917)

Diagnosis of hysteria reduced in mid 20th centuries with increased correct recognition of MS, but some diagnoses were changed to “epilepsy” “psychoses” “Freudian psychoneuroses”

Recognition of MS allowed treatments to be developed

Initially hypnotism, psychological framework

1951 – cortisone, effectively treated relapses but no long term effect

Currently more than 20 medications available for various types of MS

We have fancy new wastebasket terms for Hysteria

Previously

Wandering uterus

Hysteria

Sexual Frustration

Anxiety neuroses

Oedipus complex

Somatisation

Now

Medically unexplained symptoms

Central sensitisation

Somatic symptom disorder

Chronic primary pain

Conversion disorder

Biopsychosocial

Sociopsychobiomedical

Current Ideology in Medicine - Jutel

The prevalent assumption = if current technology can’t find the cause then it must be psychosomatic.

Medically unexplained is subsumed within psychiatry and used synonymously

The symptoms are “unjustified behaviours”

Based on assumptions linked to psychosomatic disorders

A psychiatric diagnosis implies that the patient might have the ability to control and reverse the symptoms

Leads to stigma and shame and encourages patient resistance

Current Ideology in Medicine

The psychiatric explanation relies on diagnosis by exclusion

It is a wastebasket diagnosis

This fails to acknowledge the limitations of knowledge

Presumes the infallibility of medicine

Shifts responsibility for cause and cure in a way that ignores sociohistorical realities

Current Ideology in Medicine - Jutel

Medically unexplained becomes ONE UNITARY LABEL

“there is a pervasive reference to them as an entity, or as a unified condition that could be considered under one light” – Jutel

The problem of medically unexplained symptoms

The diagnosis of medically unexplained symptoms

The treatment of medically unexplained symptoms

Assumption = all complaints without explanation can be viewed in the same way

“The greater the ignorance the greater the dogmatism” - Osler

All one treatment (intensive programme or day programme)

To me the ideology has a very alternative medicine flavour to it. E.g. everything treated with manipulation in vitalistic chiropractic

Also a quasi-religious flavour e.g. come back when you’ve accepted the pain as your lord as saviour.

Some are so deep in this ideology that there is an outright denial of a biomedical cause even when it is staring at them in the face.

Patient reactions to no diagnosis (Dumit, Nettleton, Malterud, ……)

Increased dissatisfaction.

Increased distress

Patients blame their healthcare provider for their inability to explain the cause of their pain

Feel that their pain isn’t legitimate and disconfirmed

Back pain is invisible, no diagnosis leads those close to them to question the legitimacy of their complaints.

Fear of being stigmatised by a psychogenic explanation

Patient reactions to no diagnosis

“I told my doctor once that I felt like, my back hurt so bad I felt like I had a large grapefruit down about the curve of the back... Course there's not a grapefruit there and they X-rayed me and there's nothing there.”

``The doctors... left me with the impression [my pain] was not real‘’

`Even though a psychologically minded physician may try to reassure the patient that he or she is not suggesting that `your pain is imaginary'... the patient will very likely see the physician as suggesting just that''

If pain is not `in' the body, where can it be but in the mind?

Back to the Intrinsic Value of Diagnosis

1998 study Mushlin et al

68 individuals had diagnostic workup for suspected MS

59/62 felt better off having received diagnostic information

Definitive diagnosis made: less anxious and expressed favourable feelings about the diagnostic workup even though they faced a lifelong chronic disease

No definitive diagnosis made: more anxious and less reassured by the “negative” workup

Restitution Narrative a Cultural Problem?

Patient’s expect:

I have pain ->

doctor will do imaging ->

source and cause of pain will be found through imaging ->

I will receive biomechanical treatment targeted at the source and cause ->

I will get better

There is a gross mismatch between patients information needs and clinician knowledge. (Lim, Hoffmann)

Psychosocial benefits from imaging - Lim

Despite strong desire for imaging to reach an accurate diagnosis

There are no measurable psychological benefits

The Contested Diagnosis (Dumit 2006)

The effect of diagnosing fibromyalgia (Jutel)

Initially a relief because it

validates their illness

provides reassurance

Provides credibility

But not uniformly welcome

Often felt need to keep a secret

Sense of stigmatisation because some health care professionals are quickly disinterested

Most “Fibromyalgia” is not “Fibromyalgia”

Wallit et al 2016 study of patients diagnosed as Fibromyalgia

73.5% did not meet the 2011 diagnostic criteria

Female = false positive OR of 8.81

Married = false positive OR of 3.27

White = false positive OR of 1.96

All three of white, married, female = true positive OR of 2.1

“The diagnosis of fibromyalgia is frequently applied to those with milder somatic complaints”

“Our data suggest that the term fibromyalgia has no clear valid or reliable clinical meaning or understanding, and is socially constructed”

“The term best reflects persons for whom fibromyalgia has become part of their health narrative”

Chronic Fatigue Syndrome (Deale and Wesely 2001)

2/3 felt they received an inappropriate psychiatric diagnosis

Patients believe strongly that their symptoms are due to a physical illness

Many doctors believe in the psychological origin

Biopsychosocial framework is not patient centred by being biased to the psychological

The model is contested by patient advocacy groups

Application of BPS leads to feelings of symptoms being trivialised

Model = initial viral illness, then symptoms perpetuated by dysfunctional illness beliefs and sickness behaviours.

Evidence for BPS model is lacking in terms of both validity and treatment approach

Applying the BPS model can cause harm

Psychology of Low Back Pain (Bogduk 2006)

No evidence that psychosocial factors are the cause of pain

Psychosocial findings are a perfectly reasonable consequence to persistent pain

Somatisation (pre-occupation) reflects that they feel they have pain

Depression is a natural consequence of any disabling disease that mercilessly persists

Hostility is provoked by doctors telling them there is nothing wrong

Obsessive compulsive traits because of dwelling on the pain that doesn’t remit

Psychotocism because they feel isolated in their suffering

Frustration because success is persistently thwarted

Uncertainty

Difference between non-diagnosis and uncertainty

10 minute episode of chest pain. Full work up for cardiac factors all clear. Non-diagnosis applied non-cardiac chest pain, sufficient

Vs. 6 months of recurrent daily chest pain, full work up gastro and cardiac all clear. Diagnostic uncertainty “medically unexplained”

Diagnostic Uncertainty

Aleotoric Uncertainty

Chance uncertainty

Disease variability

Disease incidence

Outcome variability

Epistemic Uncertainty

Limitations in knowledge

Doctors ability to access

Doctors ability to process

Translating population findings to individuals

Complex or poorly understood evidence

Three questions if a diagnosis can’t be made (Dhaliwal)

1.Have I reached the limit of my knowledge but not that of my colleagues?

2.Have I reached the limits of my local network’s knowledge but not that of another physician or team elsewhere?

3.Have I reached the limits of medical knowledge entirely (i.e., there is no known answer to the problem)?

Diagnostic Uncertainty

Open question = at what point do you “stop” and call it idiopathic?

Or at what point do you call it “psychosocial” or as some call it “sociopsychobiomedical”

Often ACC will decide when to stop.

What do you do?

Apply “we don’t know” “that part of the manual of the human body hasn’t been written yet”

Apply a psychosomatic label?

Apply the “functional” label?

Diagnostic Clinical Reasoning

Dual Process Theory is a key theory in the study of diagnosis.

System 1

• Reflexive, intuitive
• Efficient
• Pattern recognition
• E.g. 45 year old woman with a BMI of 40 with medial knee pain = knee OA
• Can lead to anchoring bias

System 2

• Analytical, cognitive
• Time intensive, deliberate
• Conscious, explicit application of analytical approach
• E.g. assessing the location of the lesion in foot drop.
• Can lead to putting undue emphasis on a clinical feature

Slow Thinking Example Framework

Individual Competencies

“Acute onset of a recurrent, monoarticular process in an otherwise healthy 40 year old man”

Diagnostic Error

The "big three" for diagnostic error are cancer, infection, and vascular Events. These account for three quarters of of serious misdiagnosis related harms. Rates of diagnostic error for these range from 2.2% (myocardial infarction) to 62% (spinal abscess), median of 13.6%. Misdiagnosis harms range from 1.2% (MI) to 35.6% (spinal abscess), median of 5.2%.

Most people will experience a diagnostic error in their lifetime. Most diagnostic errors occur through flaws in clinical reasoning skills. This is through deficiencies in data collection, data integration, data verification, leading to premature diagnostic closure.

Common cognitive biases include

• Overestimation - similar to expectations of high stock returns among investors.
• Base rate neglect - true base rates are usually lower than expected
• Anchoring bias - reflects experiences that represent improbable events.
• Confirmation bias - looking for evidence to fit original hypothesis while ignoring evidence that refutes it.

78% would treat cardiac ischaemia when a positive test result places their patient at 11% of less chance of disease.

Competencies in Diagnosis

Olson et al published an important paper on the foundational concepts and core competencies of modern diagnosis.

Foundational Concepts

1. .The primacy of medical knowledge
2. The dual-processing paradigm as a framework for understanding clinical reasoning
3. The value of rational thought and reflection
4. The value of experience and of feedback: learning from outcomes of decisions
5. The dynamic nature of diagnosis – the inevitable problems of uncertainty and complexity
6. The inherent power of teamwork, of patient engagement, and of health information technology
7. The relevancy of human factors and “the system” in determining diagnostic performance
8. The limits and biases of human cognition
9. The value of recognising high risk and “red flag” situations
10. The need to prioritise and triage appropriately
11. The need to focus on the needs of the patient
12. Assessment of diagnosis should include measures of skillful differential diagnosis and diagnostic efficiency

Desirable Attributes are Courage, Humility, Empathy, Flexibility, Integrity, Intellectual autonomy, Kindness, Persistence, Professionalism, Resilience and adaptability, Tolerance of uncertainty, Skepticism, Curiosity, Respect, Patience

Individual Competencies

1. Collect key clinical findings to inform hypotheses
2. Formulate problem representation
3. Correctly prioritise red flag diagnoses
4. Create and prioritise a differential diagnosis
5. Use support tools including checklists and second opinions  
6. Use strategies to mitigate cognitive bias.

Team-based Competencies

1. Engage with patient and family values and preferences, share uncertainty
2. Collaborate with other health care professionals
3. Safely transfer care, close loop on test result communication.

System-related Competencies

1. Mitigate system factors that detract from diagnostic quality and safety
2. Advance a culture of diagnostic safety with continuous learning about diagnostic performance
3. Disclose diagnostic errors and missed opportunities to patients and team members

Checklists

More than 40 biases but most lead to a single pathway where the doctor fails to generate an adequate differential diagnosis or even consider the correct one as a possibility.

Most common reason for diagnostic error is “I just didn’t think of it.” Using diagnostic checklists may improve diagnostic performance in difficult cases.

General Checklist

• Did I just accept the first diagnosis to mind?
• Did the patient come with a previous diagnosis?
• Should I review patient records before they leave?
• Is there anything that doesn’t fit with the diagnosis?
• Did I do the history, exam, and review the imaging myself?
• Where they seen recently for the same problem? What was done and what has changed?
• Any external pressures?

Clinically Oriented Checklist

This type of list has specific conditions to consider for different presenting complaints. The checklist may highlight "do not miss" and "commonly missed" conditions. See Portal:Differential diagnoses. For example, a checklist for neuropathic arm pain:

Differential Diagnoses for Neuropathic Arm Pain

• Spinal cord injury
• Cervical Radicular Pain
• Median Nerve
  • Carpal Tunnel Syndrome
  • Pronator Teres Syndrome
  • Anterior Interosseous Nerve Syndrome
  • Supracondylar Process Syndrome
• Ulnar Nerve
  • Cubital Tunnel Syndrome (Ulnar neuropathy at the elbow)
  • Guyon's Canal Syndrome
• Radial Nerve
  • Radial Neuropathy at the Spiral Groove (Saturday Night Palsy)
  • Posterior Interosseous Nerve Entrapment (at arcade of Frohse)
  • Wartenberg Syndrome (superficial radial nerve at the distal forearm)
  • Humeral Shaft Fracture
• Other Peripheral Nerve Lesions
  • Suprascapular Nerve Entrapment (at suprascapular notch or spinoglenoid notch)
  • Shoulder Dislocation (Axillary nerve)
  • Long Thoracic Nerve Injury
  • Lateral Antebrachial Cutaneous Nerve Entrapment
• Brachial Plexus Lesions
  • Neuralgic Amyotrophy (Parsonage-Turner syndrome)
  • Neurogenic Thoracic Outlet Syndrome
  • Erb-Duchenne Palsy
  • Klumpke's Palsy
  • Burner or stinger
  • Backpacker's palsy
  • Traumatic nerve root avulsion
  • Hereditary Neuralgic Amyotrophy
  • Neoplasms
  • Radiation-induced brachial plexopathy
  • Iatrogenic plexopathies (e.g. medial brachial fascial compartment syndrome)
  • Diabetic-related brachial plexopathy
• Systemic
  • Thalamic Pain Syndrome
  • Hemiplegic migraine
  • Focal sensory seizures
  • Multiple sclerosis
  • Axillary vein thrombosis or Paget-Schroetter disease
  • Fibromyalgia or Myofascial Pain Syndrome
  • Herpes Zoster
  • Mononeuritis Multiplex
  • Multifocal Motor Neuropathy