Page 12 - Problem-Based Feline Medicine

4 HOW TO MAKE A PROBLEM-BASED DIAGNOSIS

● Prioritizing, ruling in or out the most likely update the problem list, differential diagnoses,
diseases diagnostic plan and treatment plan.
● Choose tests initially that are least invasive,
and to some extent easiest and/or cheapest to
perform
● Choose the tests that have the best Summary of the steps in making a
combination of specificity and sensitivity. problem-based diagnosis
Remember that each negative or normal test result 1. Obtain data from a detailed history and
makes the list shorter. physical examination.
For example, for the problem “liver mass” that was
2. List the problems identified based on the
identified based on ultrasound, radiology and biochem-
history and physical examination.
istry profile, the following is an example of a diagnos-
tic plan. 3. List the differential diagnoses for the
● Following ultrasound identification of the mass, major and most organ-specific problems.
fine-needle biopsy and cytological examination will Use your answers to “WHERE?” and
be performed, with culture requested if no neoplastic “WHAT?” to formulate a logical list of
cells are obvious. Although the sensitivity and speci- differential diagnoses. Cross-match the
ficity are not as high as with a wedge biopsy or patient and disease characteristics to
laparotomy, it is balanced by the less-invasive identify the most likely diseases.
nature, ease and cost. These diagnostic decisions 4. Formulate a diagnostic plan to rule-in or
need to be made in conjunction with the owner. rule-out the likely differential diagnoses.
● If a definitive diagnosis is not possible from the results
5. Formulate a treatment plan.
of the fine-needle biopsy, the next diagnostic tests that
could be considered would be a needle biopsy suitable 6. Update points 2–5 as diagnostic data
for histological examination, or laparotomy and become available and the response to
wedge biopsy. The decision will require balanced therapy is observed.
consideration of many factors including input from
the owner regarding cost, invasiveness, etc.

5. Formulate a rational treatment plan based on
the diagnoses identified.
USING THE BOOK
● Treatment may either be specific for a disease process,
This book is set out to facilitate making a problem-
such as antibiotics and drainage of an abscess, or be
based diagnosis. At the start of each chapter there is
non-specific, for example, IV fluids for dehydration.
a summary of the answers to the questions
Initial treatment plans will often be formulated in par-
‘Mechanism?’, ‘Where?’, and ‘What?’ for each prob-
allel with diagnostic plans, because some problems
lem. A quick reference summary lists the diseases that
such as dehydration or cyanosis need addressing early.
can be associated with that problem. Stars after each
6. As diagnostic data are received and the response disease denote the importance of the disease as a cause
to initial therapy is observed, it is important to of the problem.