Clinical Methods. the Diagnostic Process Pp1t

8/9/2019 Clinical Methods. the Diagnostic Process Pp1t

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Clinical methods

The diagnostic process

Dr. Khaled D. Al-Harby

MBBS, ABFM, SBFMConsultant Family Physician

Dr. Khaled Dhaifullah


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Inductive and hypotheticodeductive

methods of problem-solving

Inductive method: full history + fullexamination + investigation = diagnosis

In reality, most clinicians reach diagnosisby a process ofhypotheticodeductivereasoning, i.e. by educated guessing andtesting .

HD method enables doctors to solveproblems with maximum time- and cost-effectiveness and minimal disturbance topatients Dr. Khaled Dhaifullah


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Some practical tips to assist in

generating diagnosis Make use of the stage ofPDI Clarify the presenting symptoms or the pivotal

symptoms

Diverse symptoms and signs are commonly causedby a single disease or entity

Remember:

- uncommon manifestations of common conditions

are more common than common manifestations ofuncommon conditions

- Simple conditions are caused by simple problems

Use checklists to trigger your memory, 5 : 2 ratio(most likely: less likely but important to consider)Dr. Khaled Dhaifullah


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Checklists

Surgical sieve

Congenital

Acquired:

Traumatic

Infective

Inflammatory

Metabolic

HematologicalDegenerative

Psychological

IatrogenicDr. Khaled Dhaifullah


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Checklists

systemic approach

Cardiovascular

Respiratory

Gastrointestinal Genitourinary

Musculoskeletal

Neurological

Hemopoietic



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Checklists

anatomic approach

Skin

Muscle

Bones Pleura

Lungs

Heart

Esophagus \ stomach



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Relative contribution of H\O, P\E,

Investigations in the diagnostic process.

In medical OPD:

history alone determine the diagnosis in 56

% of all referral made (27-56%) Physical examination : 17 % (0-24%)

Routine investigation: 5% (0-17%)

Special investigations: 18% (6-58%)

Routine CBC & urinalysis: 1%



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Generating and ranking appropriate

diagnostic possibilities

Probability: (the most likely)

Seriousness: (the average GP is likely toencounter a malignant melanoma only once or

twice in a professional lifetime, so suspicionshould be genius.

Treatability: hypothyroidism is an uncommoncause of tiredness but it should not be overlooked

as it is readily corrected by replacement therapy Novelty: e.g pheochromocytoma as a cause of

hypertension



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Common errors in diagnostic

process

Unwarranted fixation on a hypothesis:

twisting all data in an attempt to fit it)

Premature closure of hypothesis generation Rule-out syndrome: (due to poorly focused

history-taking)

Generation of very unlikely hypothesis(novelty)



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The triple diagnosis

In generating diagnostic hypothesis, it is also

essential to think in physical, social, and

psychological terms (as appropriate)

Example: acne vulgaris in a teenage girl:

- physical: dermatological problem

- Social: social withdrawal due to poor self- image

and self- confidence- Psychological: trauma (which may lead to

anxiety and depression)



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Use of time as a diagnostic aid

Wait and see approach

About 72 % of patients who had originally beenundiagnosed did not need to return to their doctor

mainly because ofspontaneous remission ofsymptoms

The doctor must be able to control in himself andin his patient the almost inevitable feelings of

uncertainty Use safety net properly

It allows doctor to have a course between theover-reaction and the under-reactionDr. Khaled Dhaifullah


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By using time as a deliberate diagnostic

strategy in appropriate circumstances, the

doctor can avoid the following problems: Devoting too much time to minor or self-limiting

conditions

Unnecessarily subjecting his patients toinconvenient, painful or costly investigations

Increasing his patients anxiety

Referring to other specialties too frequently orwith an inappropriate degree of urgency


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Clinical Methods. the Diagnostic Process Pp1t