What is the cause of fatigue?

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Differential Diagnosis for Feeling Tired

The symptom of feeling tired is a common complaint that can have numerous causes. Here's a categorized differential diagnosis:

  • Single Most Likely Diagnosis

    • Anemia or Iron Deficiency: This is often a common cause of tiredness due to the lack of red blood cells or hemoglobin that carry oxygen to different parts of the body.
    • Depression: Fatigue is a key symptom of depression, which can also include feelings of sadness, hopelessness, and a lack of interest in activities.
    • Hypothyroidism: An underactive thyroid gland can lead to fatigue, weight gain, and dry skin among other symptoms.
  • Other Likely Diagnoses

    • Sleep Apnea: This condition, characterized by pauses in breathing during sleep, can lead to poor sleep quality and daytime tiredness.
    • Diabetes: High blood sugar levels can cause fatigue, among other symptoms like increased thirst and urination.
    • Chronic Fatigue Syndrome: A condition characterized by extreme fatigue that cannot be explained by any underlying medical condition.
    • Medication Side Effects: Certain medications, such as sedatives and antidepressants, can cause drowsiness and fatigue as a side effect.
  • Do Not Miss Diagnoses

    • Heart Failure: Fatigue can be a symptom of heart failure, where the heart is unable to pump enough blood to meet the body's needs.
    • Cancer: Certain types of cancer, such as leukemia or lymphoma, can cause fatigue due to the disease itself or its treatment.
    • Adrenal Insufficiency: A condition where the adrenal glands do not produce enough hormones, leading to fatigue, weight loss, and low blood pressure.
    • Sleep Disorders: Conditions like insomnia, restless leg syndrome, or narcolepsy can significantly impact sleep quality and lead to daytime tiredness.
  • Rare Diagnoses

    • Mitochondrial Myopathies: A group of disorders that affect the mitochondria, leading to muscle weakness and fatigue.
    • Myasthenia Gravis: An autoimmune disorder that causes muscle weakness and fatigue, particularly after periods of activity.
    • Pernicious Anemia: A rare condition caused by a lack of vitamin B12, leading to fatigue, weakness, and shortness of breath.
    • Wilson's Disease: A genetic disorder that leads to copper accumulation in the body, causing fatigue, liver disease, and neurological symptoms.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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