Tired all the time — fatigue, weight gain and low mood history
PLAB 2 & PRES 3 · endocrine · medium · 8 minutes
Candidate brief
You are an FY2 doctor in a GP surgery. Ms Priya Kaur, 45, has come in because she feels tired all the time and has been putting on weight over the past six months. Take a focused history, explore possible causes, and discuss your assessment and management plan with her.
What examiners look for
Fatigue is a presentation, not a diagnosis. The stations reward breadth with structure: endocrine (thyroid, diabetes), haematological (anaemia, B12 and iron deficiency), sleep (apnoea), mood (depression), and red-flag pathology all sit in one differential. Hypothyroidism and depression mimic and coexist with each other. Weight gain, cold intolerance, constipation, dry skin, hair loss and menorrhagia point to thyroid; anhedonia and poor concentration sit in both. The correct behaviour is to test, not to guess. Heavier periods plus a vegetarian diet makes iron-deficiency anaemia a live candidate. Note that her pharmacy "iron tonic" failing proves nothing — dose, duration and absorption all matter, and the cause still needs finding. Family history is diagnostic data here: a mother on levothyroxine raises the prior probability of autoimmune thyroid disease materially. Always ask directly about self-harm when a patient describes low mood — calmly, in the same tone as any other question. Asking does not plant the idea, and a clear denial with protective factors is a finding worth documenting, not a box ticked. Sleep apnoea earns a question even in patients who do not fit the stereotype: snoring, witnessed apnoeas, morning headache and unrefreshing sleep. A negative screen here still belongs in the summary. Avoid premature closure in both directions: "it's depression" without bloods and "it's your thyroid" without a mood assessment are mirror-image errors, and the marking scheme treats them as such. Close with a mechanism, not a mood: what tests, when the results come, when she will be seen again, and exactly what should make her seek help sooner. Vague reassurance is the station's named failure.
Guideline references
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