Diagnostic Frameworks Part 4: Checklist / Mnemonic Framework

In recent posts we explored the mechanism, systems, and anatomic frameworks to approach patient presentations. In this last part (for now!) on diagnostic frameworks, we talk about the checklist/mnemonic approach to differential diagnoses.

Case: You are resuscitating a patient with cardiac arrest who is asystolic. You use the “6 Hs” and “5 Ts” mnemonic to work through your differential: Hypovolemia, hypoxia, hydrogen ion (acidosis), hyper/hypokalemia, hypoglycemia, hypothermia, toxins, tamponade (cardiac), tension pneumothorax, thrombosis (pulmonary and coronary) and trauma.

What is the checklist/mnemonic framework? The use of a memorized mnemonic or pre-defined checklist to work through a differential diagnosis. This framework can easily be combined with your other frameworks. For example a recent post on diagnostic approach to headache highlighted the ‘5Ps’ and ‘SNOOP4’ mnemonics to rule out red flags of headache.

Using a mnemonic or checklist in your emergency scenario allowed for quick recall and you could efficiently work through the list of underlying causes of cardiac arrest/asystole. Also, in stressful situations where our system 2 thinking is not optimized, it can help make sure you aren’t missing important considerations. Checklists are also very valuable for rarer diseases or presentations when there are many different potential causes that are challenging to remember. Most of us have smart-phones in our pockets, checklists are always at our fingertips.

Stay tuned for my upcoming blog post on strategies to practice diagnostic thinking and using these frameworks in everyday clinical practice (without getting overwhelmed!)

Key Take Home Points:

1. Checklists are useful cognitive aids in acute situations to ensure important diagnoses are not missed.

2. Checklists are also useful for rarer presentations or for diseases whose cause can be from many different etiologies.

Make cheat sheets for your favourite checklists!

References/Readings:

1. Kämmer JE, Schauber SK, Hautz SC, Stroben F, Hautz WE. Differential diagnosis checklists reduce diagnostic error differentially: A randomised experiment. Medical education. 2021;55(10):1172-82.