9 Integrated Case Practice

Use a repeating reasoning cycle

Clinical reasoning is a repeating cycle: recognize immediate threats, build and rank a differential, act on the highest-priority problems, then reassess and revise. A working diagnosis should be treated as a testable explanation rather than a commitment.

These cases are illustrative educational examples, not individual treatment instructions. Use current local protocols and stay within your scope of practice. When a patient is unstable, seek senior or emergency support early.

Recognize urgency first

Begin with the patient’s appearance, vital signs, symptoms, and trajectory before naming a disease. If the patient is critically ill or deteriorating, use ABCDE—Airway, Breathing, Circulation, Disability, Exposure—to identify and address life-threatening problems in order.

Call for appropriate help early, work in parallel with the team, and reassess after interventions. Do not delay escalation for a complete differential when the patient is unstable.

Define the problem and compare causes

Summarize the presentation in one sentence, including age and relevant context, time course, key symptoms, major findings, and stability. Then build a short, prioritized differential diagnosis.

Compare possibilities by asking what is most likely, what is most dangerous to miss even if less likely, and what time-sensitive or reversible cause needs prompt action. Consider what evidence supports or weakens each possibility and what finding would change the plan.

Avoid anchoring on the first plausible explanation. Include relevant history, medicines, allergies, baseline function, and the patient’s perspective. Seek additional information when it could change the assessment.

Match actions to risk

Stabilization and diagnostic work can happen together. Choose focused tests and interventions that address immediate threats or distinguish leading alternatives. State the working diagnosis and its uncertainty clearly, identify what you expect to change, and set a time to review the response.

Monitoring frequency should reflect the patient’s condition. Worsening observations or clinical concern should prompt a response, and every intervention should be followed by an assessment of its effect. If the patient worsens, escalate rather than continuing a plan without review.

Case: Breathlessness with a reassuring first look

A 28-year-old reports episodic breathlessness and wheeze after a respiratory infection. They are speaking comfortably, have stable observations, and have no obvious signs of poor perfusion.

Airway reactivity is plausible, but infection, pulmonary embolism, pneumothorax, and cardiac causes may matter depending on the history, examination, risk factors, and course. Wheeze alone does not settle the diagnosis.

Establish the time course and severity; check vital signs, oxygenation, work of breathing, chest findings, relevant risks, and prior episodes. Use focused investigations when findings or risk justify them. If the patient worsens, move immediately to an ABCDE assessment and escalate care.

On review, ask whether breathing is easier and whether oxygenation, work of breathing, and vital signs are stable or improving. If the expected improvement does not occur, reconsider the diagnosis and need for further evaluation instead of simply repeating the initial assumption.

Case: Chest discomfort with instability

A 68-year-old has new chest pressure, sweating, and light-headedness. Blood pressure is low, the patient looks unwell, and symptoms are ongoing.

Acute coronary syndrome is a major concern. Other dangerous possibilities include aortic disease, pulmonary embolism, and pericardial tamponade; arrhythmia and non-cardiac causes may also be relevant. The immediate priority is to recognize instability and act safely, not to identify the final diagnosis from one symptom.

Call for urgent help, assess ABCDE, monitor closely, and obtain an ECG and other urgent assessment according to local protocol. Pursue stabilization while evaluating the cause; do not postpone escalation to complete a lengthy history or broad testing.

Repeat the clinical assessment and vital signs after each intervention and when the condition changes. Persistent hypotension, altered mental status, worsening pain, or new respiratory distress calls for prompt review of the plan and level of care.

Case: Fever and confusion with an unexpected course

A 74-year-old presents with fever and new confusion. Initial assessment raises concern for infection, but the patient is also hypotensive. After initial actions, blood pressure remains low and focal abdominal tenderness develops.

Infection remains possible, but the new findings require reconsideration of the source and of non-infectious causes of shock, including bleeding or another abdominal emergency. Do not use a plausible initial diagnosis to explain away contradictory evidence.

Escalate urgently and continue a structured assessment. Investigate likely infection and other time-critical causes in parallel, selecting further tests and treatment with the responsible clinical team and according to local protocols. Sepsis guidance emphasizes rapid evaluation and treatment while accounting for evolving physiology and possible alternative causes.

State what changed, which diagnoses rose or fell in priority, and what must happen next. Set a clear monitoring and reassessment plan. A diagnostic timeout—a deliberate review of the working diagnosis when uncertainty or an unexpected trajectory arises—can help expose missed alternatives.

Reassess and learn from the course

At each review, consider what has changed in symptoms, examination, observations, test results, or baseline function. Ask whether the patient responded as expected. If not, consider whether the intervention was ineffective, insufficient, or based on the wrong working diagnosis.

Then reconsider which alternatives matter more and whether a dangerous possibility remains unaddressed. Identify the next action, who is responsible, and when the patient will be reviewed again. Decide whether a higher level of care or additional expertise is needed.

Document the reasoning, uncertainty, response, and plan. When learning from a case afterward, judge decisions using the information available at the time, not only the eventual diagnosis.