Causes of Sudden Extreme Fatigue

Causes of Sudden Extreme Fatigue
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Everyone feels tired now and then -- but fatigue is more than everyday tiredness. It's a state characterized by profound weariness that interferes with your ability to carry out the tasks of your daily life. Fatigue occurs with a wide variety of illnesses. Sudden, extreme fatigue suggests an acute rather than a chronic illness. Accompanying signs and symptoms help narrow the long list of possible causes.

Viral or Bacterial Infection

Severe fatigue occurs with many viral and bacterial infections. Examples of viral infections that frequently cause this symptom include influenza, infectious mononucleosis (mono), Lyme disease, cytomegalovirus (CMV) and acute hepatitis A or B. Fever is common with all of these illnesses but other signs and symptoms vary. For example, a severe sore throat might suggest mono while loss of appetite and nausea could signal acute viral hepatitis.


Sudden debilitating fatigue can also accompany serious bacterial infections of the lungs, kidneys, heart, bones or bloodstream. In addition to fever, signs and symptoms specific to the infected site are usually present.

Psychosocial Stress and Mental Health Disorders

Psychosocial stress often causes profound fatigue, especially if severe. Loss of a job, financial difficulties, separation or divorce, a serious illness in the family, or the death of a loved one are a few examples of situations that can trigger severe stress and fatigue. Mental health disorders, particularly depression, can also lead to sudden, disabling fatigue. A pooled analysis of 26 studies published in October 2016 in BMC Family Practice found that nearly 19 percent of people who went to their doctor with tiredness as their main symptom were diagnosed with major depressive disorder. The first episode of major depression most commonly occurs in early adulthood but can occur in middle-aged and senior adults.


Heart Disorders

Certain types of abnormal heart rhythms, or arrhythmias, can cause sudden, extreme fatigue. This symptom frequently occurs with arrhythmias that cause a slow heart rate, or bradycardia. Sick sinus syndrome and heart block are two examples. Fatigue might also occur with atrial fibrillation, a common arrhythmia characterized by rapid, disorganized electrical activity in the upper chambers of the heart.

Sudden fatigue might also signal an impending heart attack, especially in women. The authors of a study published in November 2003 in Circulation reported that among 515 women, 95 experienced new symptoms in the weeks to months before suffering a heart attack. The most common symptom was fatigue, which was experienced by 71 percent of those who reported heralding symptoms. Most women who experienced fatigue rated it as severe.


Other Considerations

There are many other possible culprits -- too numerous to list in a brief article -- that can potentially lead to sudden, extreme fatigue. Some of these other considerations include:

  • Medication side effect
  • Undiagnosed diabetes
  • Acute kidney injury
  • Early myalgic encephalomyelitis/chronic fatigue syndrome

Fatigue occurs with myriad other medical conditions although it tends to develop gradually or might wax and wane. Some examples of these conditions include:


  • Sleep disorders
  • Iron deficiency anemia
  • Celiac disease
  • Inflammatory bowel disease
  • Chronic renal failure
  • Congestive heart failure
  • Chronic obstructive pulmonary disease
  • Hypothyroidism
  • Systemic lupus erythematosus
  • Giant cell arteritis
  • Multiple sclerosis
  • Parkinson disease
  • Fibromyalgia
  • Solid organ cancer

Warnings and Precautions

See your healthcare provider as soon as possible if you experience sudden, extreme fatigue that lasts more than a few days. If it's flu season, be sure to tell the office about the symptoms you're experiencing. Seek immediate medical attention if your fatigue is accompanied by any warning signs and symptoms, including:

  • Shortness of breath or difficulty breathing
  • Persistent low-grade fever or fever higher than 102 F
  • Chest pain or pressure
  • Excessive sweating or cold, clammy skin
  • Sudden swelling of your feet, ankles or hands
  • Confusion, agitation, excessive drowsiness or other mental changes
  • Dizziness, lightheadedness or fainting
  • Severe nausea and vomiting
  • Yellow discoloration of the skin or whites of the eyes
  • Sudden severe or worsening bone pain
  • Suicidal thoughts or feelings


Is This an Emergency?

If you are experiencing serious medical symptoms, please see the National Library of Medicine’s list of signs you need emergency medical attention or call 911. If you think you may have COVID-19, use the CDC’s Coronavirus Self-Checker.