MonitorEmergency Guide
Fatigue: Red Flags & Emergency Signs
Severe or rapidly progressive fatigue with dyspnoea, pallor, or haemodynamic instability can indicate severe anaemia, cardiac failure, or malignancy requiring urgent assessment.
🚨 Call 999 / 112 Immediately
- ⚠Severe fatigue with breathlessness at rest and haemoglobin <7 g/dL — symptomatic severe anaemia
- ⚠Fatigue with new confusion and low blood pressure — septic shock
⚡ See a Doctor Today
- •Fatigue with dyspnoea on minimal exertion and ankle oedema — cardiac failure
- •Fatigue with pallor, bruising, and recurrent infections — bone marrow failure
- •Fatigue with weight loss, night sweats, and lymphadenopathy — malignancy
- •Fatigue with excessive thirst, polyuria, and weight loss — undiagnosed diabetes
High-Risk Combinations
When fatigue occurs together with any of these symptoms, urgency increases significantly:
Conditions to Rule Out Urgently
Severe Anaemia (Hb <8)urgent
FBC + reticulocytes; blood film; iron/B12/folate; transfusion threshold
Leukaemia / Lymphomaurgent
FBC + blood film; bone marrow if blasts present
BNP + echo; ECG; Holter
Condition Authority Pages
Differential diagnosis analyses:
When to Call Emergency Services
- →Fatigue with breathlessness at rest and known severe anaemia