How to formulate a functional diagnosis
By Nelson Gozah⚕️
A Medical diagnosis – shortened to Dx or Ds – is the process of figuring out the disease or condition causing someone’s symptoms and signs. Healthcare workers use this term frequently. To make a diagnosis, they typically get the patient’s medical history, do a physical exam, and sometimes run medical investigations.
A Functional diagnosis is a diagnostic approach that focuses on the patient’s functional status and the impact of the disease on the patient’s daily activities rather than just the disease itself. It involves identifying not only the disease or condition but also the underlying cause or etiology and any associated or potential complications.
A functional diagnosis goes beyond the disease itself and takes into account the patient’s functional status, such as their ability to perform activities of daily living, their social and emotional well-being, and their quality of life. This information is then used to develop a treatment plan that is tailored to the individual patient’s needs.
Functional diagnosis is a valuable tool in clinical practice because it helps to ensure that patients receive the most appropriate care. By taking into account the patient’s functional status, healthcare providers can develop treatment plans that are effective in improving the patient’s quality of life
In general, the process of making a medical diagnosis requires a systematic approach that encompasses a thorough history, physical examination, and diagnostic testing.
Remember, the process of making a diagnosis is not necessarily straightforward as it involves various clinical thought processes and dynamic in nature.
It’s about probability or mostly likely and pattern recognition, and sometimes it requires revisiting earlier steps as new information becomes available.
Also, certain classical signs and symptoms as well as key investigation outcomes serve as key diagnostic cues. Eg. Right iliac pain may be most likely of Acute appendicitis or ileal perforation, and a retrosternal pain that radiates to the shoulder,neck or jaw may also be mostly indicative of an MI, just to mention a few..
Here’s a step-by-step guide to understanding this process:
Step 1: Gather Information on the presenting complaints as stated in the case scenario.
Step 2: Consider the System(s)
Determine the system(s) affected based on the presenting symptoms and signs – cardiovascular, gastrointestinal, genitourinary, etc.
Thus, based on the patient’s symptoms and physical exam, consider which body system might be involved. For instance, chest pain might suggest a problem in the cardiovascular system or Respiratory system while frequent urination might point to the genitourinary system.
Also note the non specific or constitutional symptoms/signs and the disease-specific symptoms/signs when identifying the system(s) which might be involved.
Consider any physical exams findings stated in the case scenario..
This helps to identify any abnormalities that might provide clues about the patient’s condition.
Step 3: Formulate a Differential Diagnosis
Having identified the likely system(s), you can now formulate a differential diagnosis — a list of potential conditions that could explain the patient’s symptoms. This step involves a lot of critical clinical thinking and often VINDICATES mnemonic is considered when grouping various causes and categories of diseases:
-Vascular
– Inflammatory/Infectious
– Neoplastic
– Degenerative/Deficiency
– Idiopathic, Intoxication, Infiltrative
– Congenital
– Autoimmune/Allergic
– Traumatic
– Endocrine
– Something Else / Psychosocial
Thus, one will have to ascertain if the presenting clinical manifestations or group of symptoms and signs are pointing towards a vascular, inflammatory, infectious, traumatic etc condition as might be suggested in the case scenario.
Step 4: Narrow Down the Differentials
As you gather more information from the history, examination, and preliminary test results where given, you should start to narrow down your list of possible diagnoses. This involves ruling out certain conditions and moving others up the list based on the likelihood that they’re causing the patient’s symptoms. Thus, rule out important negatives.
To further narrow down the differential diagnoses, you may need to consider any test results if stated in the case scenario
Step 5: Reach a Final Diagnosis
After interpreting and integrating the history(including the personal data) and any other examination finding consider considering a full clinical picture, thus you should now be able to make a final diagnosis.
Adopting a model taught by Dr Awotwi a Physician Specialist ,the following triad dubbed “Awotwis Triad” can be of help when formulating a comprehensive functional diagnosis..;
The Format —
The Pathology,
Underlying Pathology and the
Functional State
The pathology(A)
Identify the primary diagnosis, the presenting pathology as indicated by the case study. Thus, the first step in formulation of a functional diagnosis is identifying the primary disease condition as suggested by the case scenario.
Underlying pathology(B)
Look out for the possible cause/etiology or precursor/precipitant from the scenario/hx
The functional state(C)
Look for any distress, imminent /attendant complications or sequelae indicated in the case scenario.
Thus having gone through the format, the sequence or pattern of the diagnosis could be expressed as follows;
“A” caused by “B”, and results to or complicated by “C”
For instance;
Assuming you’re presented with a case of a 45 year old man seen at the emergency complaining of colicky abdominal pain of 36 hours duration and absolute constipation. He had vomited repeatedly and on examination he was moderately dehydrated with abdominal distention, and tenderness and some guarding over a lower midline incisional scar in the abdomen.
~indicate the precise diagnosis
Analysis
From the above ,this is an obvious Intestinal Obstruction evidenced by the colicky abdominal pain and absolute constipation. However it will be too vague and won’t guide one enough to tailor an appropriate Rx
Thus, we could see that, Intestinal Obstruction is the primary diagnosis, but then, this could have different etiological factors . In this case it’s the Adhesions(from past surgery evidenced by the scar). Hence a mechanical obstruction (any obstruction caused by previous surgical adhesions is termed mechanical obstruction)
Also, the duration of onset, thus a 36hrs period makes it of an Acute onset.
Applying the format, ;
The Pathology itself is intestinal obstruction/bowel obstruction (Precisely Acute mechanical Intestinal obstruction)
Caused by or Secondary to ; Adhesions from previous surgery evidence by the midline incisional scar on the Abdomen
The patient’s functional state is ; fair, but moderately dehydrated, with an imminent viscus perforation, peritonitis as indicated by the abdominal distention, and tenderness and some guarding over a lower midline incisional scar in the abdomen.
Putting all together; we have
-Acute Mechanical Intestinal Obstruction secondary to Adhesion with peritonitis and moderate dehydration
Example 2
A 60 year old hypertensive presents at the OPD with complaints of bilateral leg swelling and difficulty in breathing which is worse when he sleeps. He usually uses 3 pillows to help alleviate breathlessness. Patient often wakes up at night gasping for air.
Blood pressure on presentation is 150/100. Patient pulse was irregularly irregular.
-Indicate a functional diagnosis for the above
Analysis
The pathology
from the scenario, the history of HPT, dyspnea, Paroxysmal nocturnal dyspnea, orthopnea and the bilateral pedal edema are suggestive of a heart failure (thus, both right and left heart failure) . With this, we have, Congestive Cardiac Failure (CCF).
Underlying pathology
from the the case, HPT remains the underlying etiology of the CCF— therefore can termed as Hypertensive Heart Disease or uncontrolled Hypertension.
The functional state
the patient’s condition is superimposed or complicated by Atrial Fibrillation evidence by the irregularly irregular pulse.
Putting all together;
We have:
“Congestive Cardiac Failure secondary to Hypertensive heart disease complicated by Atrial Fibrillation”
In the examples given above, the functional diagnosis for the first patient is “Acute Mechanical Intestinal Obstruction secondary to Adhesion with peritonitis and moderate dehydration.” This diagnosis not only identifies the mechanical obstruction of the intestine but also the underlying cause, which is adhesions from previous surgery, and the associated complications, which are peritonitis and moderate dehydration. This functional diagnosis allows for a more comprehensive understanding of the patient’s condition and guides appropriate management.
Similarly, the functional diagnosis for the second patient is “Congestive Cardiac Failure secondary to Hypertensive heart disease complicated by Atrial Fibrillation.” This diagnosis identifies the primary condition, which is congestive cardiac failure, the underlying cause, which is hypertensive heart disease, and the associated complication, which is atrial fibrillation. This functional diagnosis provides a more complete picture of the patient’s condition and helps to guide appropriate treatment and management.
Overall, functional diagnosis is a valuable tool in clinical practice as it helps to identify the impact of disease on the patient’s functional status and guides appropriate management.
It requires that one has a broad knowledge base on various medical conditions with their pathological underpinning