Uncovering the Causes of Fatigue

Rarely do we uncover a single etiology for the complaint of “fatigue”. Rather, medical detective work is required to get to the CAUSES of fatigue.

The work-up for fatigue begins with simple serology, or, blood-work.  The national standard of traditional medical care directs that we order a complete blood count (CBC), levels of the minerals that “run” the body including sodium, and potassium, screen kidney function with BUN and creatinine, and screen “thyroid function” with the pituitary test known as TSH (thyroid stimulating hormone).

If these tests are abnormal, further work-up is pursued. For example, depending on the type of anemia showing up in the CBC, we might then evaluate iron (ferritin level), vitamin B-12 (methylmalonic acid level), folate (homocysteine level), as well as check to see if new red blood cells are being formed (reticulocyte level).  We might order blood or fecal testing to detect viral, bacterial, fungal, parasitic, or spirochetal infections such as Borrelia.

Hypothyroidism frequently is identified as a cause of fatigue, as is autoimmune disease. These diseases are easy to diagnose with simple blood tests, and can be treated easily.

Please read the topics listed under Adrenal Function for more details.

Adrenal function must be evaluated in the presence of unexplained fatigue. The classic triad usually seen in adrenal failure (“Addison’s Disease”) is weight loss, dizziness, and fatigue.  While Addison’s Disease is relatively rare, we more commonly see suboptimal adrenal function.  Dysfunction of the adrenal cortex produces low cortisol, among other hormones, and is easy to diagnose by testing a 24-hour urinary level of cortisol (“free cortisol”) or by screening with salivary levels of free cortisol.  We usually give hydrocortisone only if there is Addison’s Disease, which we diagnose in our office by performing ACTH Stimulation Testing (adrenocorticotrophic hormone stimulation testing).

Infectious etiologies of fatigue must be evaluated.  In our country, 99% of us have had “mono” (i.e. been infected with the Epstein-Barr Virus) by the age of 1.  Frequently, in times of severe physical or emotional stress, the body loses its fight to suppress viruses such as this one, and the person will experience a reactivation of a distant infection. 

Many viral infections can now be delineated with blood testing, which can distinguish acute reactivation of infection versus chronic evidence of previous infection. Then we may opt to treat you with an antiviral prescription medication as well as to add nutritional support which biochemistry has proven boosts the body’s immune response to help fight off infection.

Many over-the-counter and prescription medications cause fatigue.  In addition, there are nutritional supplements which can promote fatigue.

Certainly, depression can worsen fatigue, also, and for many reasons.  The antidepressant medications are not addictive, and we don’t hesitate to utilize them. Many times, instead of prescribing such medication by trial and error, you might opt to perform testing which will measure your levels of the neurotransmitters serotonin, dopamine, norepinephrine, epinephrine, etc., which will then direct us to which antidepressant might work best for you.

Malabsorption is often seen, especially in people with undiagnosed food intolerances, or with Celiac Disease.  There are reports that many women have a small degree of dysfunction of the exocrine pancreas, and don’t produce enough digestive enzymes.  We can prescribe digestive enzymes such as Creon, or you might prefer a plant-based digestive aid from the health food store.  All folks whom have had their gallbladders removed are supposed to be on prescription digestive enzymes.

Allergies and chemical sensitivities are a frequent etiologic trigger for fatigue. We order comprehensive testing for allergies, even though at best some of the testing is less than perfect in detecting allergies. Many times we have our patients undergo elimination and provocation allergy testing to uncover hidden food sensitivities or true allergic reactions.  

Undetected inflammation is a key element in causing fatigue, and can be easily assessed utilizing simple blood testing, such as the “high-sensitivity (cardiac) C Reactive Protein” level, which gives more precise information than the older C-Reactive Protein, or the Erythrocyte Sedimentation Rate. Inflammation can be treated with NSAIDS (non steroidal anti-inflammatory drugs) as well as with the appropriate nutritional approach.  We prefer to utilize treatment which does not have deleterious side effects.  NSAIDS can cause ulcers and renal failure, so we try to stay away from utilizing these drugs.

Chronic “gut” infections can cause fatigue. We have learned that the majority of the body’s neurotransmitters (aka “brain chemicals”) are actually in the gut!  Hence there is a connection between food and mood, or mood/situation and bowel irritability.  We know how to diagnose this type of dysfunction, and how to teach you to correct the dysfunction.  Bacterial, viral, fungal and parasitic infections should be ruled out in anyone with “irritable bowel” or “spastic colon”, or with diarrhea, bloating, or unexplained abdominal symptoms such as chronic pain.

Frequently, and more frequently than many of us had realized, disorders of the cellular energy machinery, called “mitochondria”,  cause fatigue. One of the newest branches of medicine has been named “Mitochondrial Dysfunctional Medicine”.  This discipline studies defects in the cellular energy-producing apparatus known as the mitochondria.  Molecular testing now exists to evaluate mitochondrial energy systems to some extent.

Cardiopulmonary assessment is frequently used in our approach to unexplained fatigue.  Sometimes, a person might unknowingly have a lung condition such as Reactive Airways Disease (related to “asthma”) which can cause suboptimal oxygen levels which contribute to fatigue.  Asthma can be well controlled in this day and age once the etiologies are clarified.  Sleep apnea must also be ruled in or out in evaluating unexplained fatigue.

In summary, a whole-body approach is necessary to uncover the cause of any complaint, including fatigue.