Fatigue, Irritable mood: 31 Possible Causes
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What causes fatigue and irritable mood? 31 possible conditions

See a list of possible causes in order from the most common to the least.


CFS (Chronic Fatigue Syndrome)

Chronic fatigue syndrome (CFS) is a debilitating disorder characterized by extreme tiredness that can't be explained by an underlying medical condition.

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There are many symptoms of HIV/AIDS, including persistent skin rashes, night sweats, and mouth sores.

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Low Blood Sugar (Hypoglycemia)

This condition is considered a medical emergency. Urgent care may be required.

Hypoglycemia, or low blood sugar, is a potentially dangerous condition that's most common in people with diabetes. Learn what causes it and how to prevent it.

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Bipolar Disorder

Bipolar disorder is a mental illness marked by extreme shifts in mood ranging from mania to depression. It is also called bipolar disease or manic depression.

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Low Blood Sodium (Hyponatremia)

Low blood sodium, or hyponatremia, occurs when water and sodium are out of balance in your body. A quick drop in sodium levels can cause weakness, headache, nausea, and muscle cramps.

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Sleeplessness, or insomnia, is a serious sleep disorder. It can mean the inability to fall asleep or stay asleep throughout the night, or the tendency to wake too early before having gotten enough sleep.

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Learn more about anxiety with this overview of anxiety disorders.

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Iron Deficiency Anemia

Iron-deficiency anemia is the most common type of anemia, which occurs when the body does not have enough of the mineral iron. The body needs iron to produce hemoglobin.

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Sinus Infections (Sinusitis)

A sinus infection, or sinusitis, is a common condition that affects 30 million people in the United States each year, according to the National Institute of Allergy and Infectious Diseases. The infection occurs whe...

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Diabetes Overview

Diabetes is a group of chronic metabolic diseases caused by defects in insulin production or function. Advanced diabetes may cause stomach pain, nausea, dizziness, and cramps.

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PMS (Premenstrual Syndrome)

Premenstrual syndrome causes a wide variety of emotional and physical symptoms. Learn more about it.

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This condition is considered a medical emergency. Urgent care may be required.

Meningococcemia is a bacterial infection that can lead to meningitis. Learn more about the symptoms.

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Generalized Anxiety Disorder

People who suffer from generalized anxiety disorder, or GAD, worry uncontrollably about common occurrences and situations. The condition may also be called chronic anxiety neurosis.GAD is different than normal feeling...

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Tension Headaches

A tension headache is the most common type of headache. It can cause mild, moderate, or intense pain in your head, neck, and behind your eyes.

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This condition is considered a medical emergency. Urgent care may be required.

A concussion is a mild traumatic brain injury. Usually it occurs after an impact to your head or after a whiplash-type injury. A concussion can cause many severe symptoms that affect brain function.

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Cocaine and related disorders

According to the National Institute on Drug Abuse, about 15 percent of people in the U.S. have tried cocaine. Find out more about the effects of addiction.

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Graves' Disease

Graves' disease is an autoimmune disorder that causes your thyroid gland to create too much thyroid hormone. Learn the symptoms and your treatment options.

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Whiplash occurs when a person's head moves backward and then forward very suddenly with great force. This injury is most common following a car collision.

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Migraine with Aura

Migraine is a disorder characterized by repeated attacks of severe headache. Symptoms include throbbing or pulsating pain, usually on only one side of the head, and can last between four hours and three days.

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Alcohol Withdrawal Syndrome

This condition is considered a medical emergency. Urgent care may be required.

Alcohol withdrawal syndrome (AWS) is the name for the symptoms that occur when a heavy drinker suddenly stops or significantly reduces their alcohol intake. With AWS, you may feel mild anxiety and fatigue. You may als...

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This feature is for informational purposes only and should not be used to diagnose.
Please consult a healthcare professional if you have health concerns.