Differential Diagnosis for Sudden Episode of Fatigue
- Single most likely diagnosis
- Dehydration or sleep deprivation: This is often the most common and straightforward cause of sudden fatigue, as it can be triggered by a lack of adequate rest or fluid intake, which are easily remedied.
- Other Likely diagnoses
- Viral illness (e.g., flu, common cold): Many viral infections can cause sudden onset of fatigue, which typically resolves on its own once the body recovers from the illness.
- Anemia: A condition characterized by a lack of enough healthy red blood cells to carry adequate oxygen to the body's tissues, making one feel tired and weak.
- Hypothyroidism: A condition where the thyroid gland doesn't produce enough thyroid hormone, which can lead to fatigue among other symptoms.
- Medication side effects: Certain medications can cause fatigue as a side effect, and this can be sudden if the medication is new or the dosage has been changed.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Myocardial infarction (heart attack) or cardiac arrhythmias: Although less common, sudden fatigue can be a symptom of a heart attack, especially in women, or arrhythmias, which require immediate medical attention.
- Pulmonary embolism: A blockage in one of the arteries in the lungs, which can cause sudden fatigue among other severe symptoms and is life-threatening.
- Sepsis: A life-threatening condition that arises when the body's response to infection causes injury to its own tissues and organs, which can initially present with non-specific symptoms like fatigue.
- Stroke: Similar to a heart attack, a stroke can present with sudden fatigue, especially if it affects areas of the brain involved in motor control and consciousness.
- Rare diagnoses
- Adrenal insufficiency: A condition where the adrenal glands do not produce adequate amounts of certain hormones, including cortisol, which can lead to fatigue among other symptoms.
- Sleep disorders (e.g., sleep apnea, narcolepsy): While not as common as other causes, sleep disorders can lead to sudden episodes of fatigue due to disrupted sleep patterns.
- Autoimmune disorders (e.g., lupus, rheumatoid arthritis): Certain autoimmune diseases can cause fatigue as one of their symptoms, though they are less common causes of sudden fatigue.
- Nutritional deficiencies (e.g., vitamin B12 deficiency): Deficiencies in certain nutrients can lead to fatigue, though these are typically identified through specific dietary habits or laboratory tests.