of disease processes and treatments.
However, when an animal or group of animals becomes unwell, the clinical signs they exhibit can be caused by a number of disorders of a range of different body systems – the list may seem endless. They do not present to the veterinarian with labels on their heads stating the disease they have (more’s the pity!). Therefore, for veterinarians to fully access their knowledge bank about disorders and their treatment, they need to have a robust method of clinical reasoning they can rely on. This method allows them to consolidate and relate their knowledge to the clinical case and progress to a rational assessment of the likely differential diagnoses. This makes it easier to determine appropriate diagnostic and/or management options for the patient. Because you have a clear path, communication with the client becomes easier.
The next part of the journey to becoming an experienced clinician is that clinical judgement and decision‐making processes become unconscious or intuitive. The rapid, unconscious process of clinical decision‐making by experienced clinicians is referred to in medical literature as intuition or the ‘art’ of medicine. The conscious thinking process is often referred to as ‘science’ (evidence based) or analytic. Intuition is context‐sensitive, influenced by the level of the clinician’s experience, context‐dependent and has no obvious cause‐and‐effect logic. Why is this important? We have all thought ‘I just know that the animal has …’ The unconscious mind will pretend to the conscious mind that the clinical decision was based on logical assumptions or causal relationships. This is not a problem as long the intuition or ‘pattern recognition’ has resulted in a correct diagnosis. However, when it does not, we need to understand why it failed and have a system in place to rationally progress our clinical decision‐making.
This book will provide you with the tools and thinking framework needed to unravel any clinical riddle, unleashing the potential of your unconscious mind rather than blocking your working memory as you try to recall all of the facts you may have once known.
Why are some cases frustrating instead of fun?
Reflect on a medical case that you have recently dealt with that frustrated you or seemed difficult to diagnose and manage. Can you identify why the case was difficult?
There can be a multitude of reasons why complex medical cases are frustrating instead of fun.
Was it due to the client (e.g. having unreal expectations that you could fix the problem at no cost to themselves? Unwilling or unable to pay for the diagnostic tests needed to reach a diagnosis? Unable to give a coherent history?)
Was the case complex and didn’t seem to fit any recognisable pattern?
Were you unable to recall all of the facts about a disease, and this biased your thinking?
Did the signalment, especially breed and age, cloud your clinical reasoning, resulting in an incorrect differential list?
Did the case seem to fit a pattern, but subsequent testing proved your initial diagnosis wrong?
Did you seem to spend a lot of the client’s money on tests that weren’t particularly illuminating?
Can you add any other factors that have contributed to frustrations and difficulties you may have experienced with medical cases?
Apart from the client issues (and as discussed later, we may be able to help a little bit here as well), we hope that by the end of this book, we will have gone some way towards removing the common barriers to correct, quick and efficient diagnosis of medical cases and have made unravelling medical riddles fun rather than frustrating.
Solving clinical cases
When a patient presents with one or more clinical problems, there are various methods we can use to solve the case and formulate a list of differential diagnoses. One method involves pattern recognition – looking at the pattern of clinical signs and trying to match that pattern to known diagnoses. This is also referred to as developing an illness script. Another method can involve relying on blood tests to tell us what is wrong with the patient – also referred to as the minimum database. Or we can use problem‐based clinical reasoning. Often, we may use all three methods.
Let’s consider three cases. Each of these will trigger thoughts and ideas about possible diagnoses depending on your knowledge and experience.
Case 1: ‘Sundance’
Sundance is a 17‐year‐old female (neutered) domestic short‐haired cat with a 1‐month history of increased appetite (polyphagia) and increased drinking (polydipsia). Obvious weight loss had been noted by owner over this period of time. Sundance has seemed more agitated and demanding of food and attention.
On physical examination she was obviously thin with a body condition score (BCS) 3/9 and an elevated heart rate (tachycardia) of 240 beats per minute (bpm). There were no other significant findings.
Case 2: ‘Brutus’
Brutus is a 10‐year‐old male neutered Dalmatian with a 3‐day history of vomiting bile and excessive urinating and drinking (polyuria/polydipsia) for 10 days. His appetite has been much reduced for about 10 days as well. On physical examination he was found to be depressed and dehydrated with no other significant abnormalities noted.
Case 3: ‘Erroll’
Erroll is a 4‐year‐old neutered male Burmese cat. He has a 2‐week history of intermittently vomiting bile‐stained material. Over the last 4–5 days he has become progressively anorexic and depressed. 24 hours prior to presentation he had started straining to urinate, and the urine was blood stained. No diarrhoea had been noted by the owners. His water intake was normal until the past 24 hours, when it may have been reduced.
On physical examination he was noted to be very depressed and dehydrated. His rectal temperature was normal (38.1°C). Heart rate was elevated at 220 bpm. Mucous membrane colour was poor and the capillary refill time (CRT) was greater than 3 seconds. Abdominal palpation was unremarkable – the kidneys felt normal and were not painful. The bladder contained some urine but felt normal and could be easily expressed.
So – can we solve all of these cases in the same way? Do we need to? What are the challenges? Let’s consider the tools we use to clinically reason.
Pattern recognition
Pattern recognition involves trying to remember all diseases that fit the ‘pattern’ of clinical signs/pathological abnormalities that the animal presents with. This may be relatively simple (but can also lead to errors of omission) and works best:
For common disorders with typical presentations
If a disorder has a unique pattern of clinical signs
When all clinical signs have been recognised and considered, and the differential list is not just based on one cardinal clinical sign and the signalment of the patient presented
If there are only a few diagnostic possibilities that areeasily remembered orcan easily be ruled in or out by routine tests
If
