Fatigue After Brain Injuries - Specialist Nutrition Rehab


07 Dec 2017

Fatigue After Brain Injuries

Fatigue after brain injury

 Fatigue After Brain Injuries

The 7 blood tests to ask for

The fatigue that affects 20-80% of people after a brain injury is different from “ordinary” fatigue because it is often unrelated to levels of exertion and doesn’t improve with rest.(1, 2)  The persistent nature of post-injury fatigue means it can negatively affect quality of life, reduce life satisfaction and pose a barrier to rehabilitation.(1, 2, 3)

Post-brain injury fatigue may be caused by a multitude of factors – such as damage to the brain cells, sleep problems, medication side effects and depression.(4) However, it is equally possible that one (or more) underlying medical issues are also contributing to the problem. Insufficient levels of certain vitamins and minerals, low thyroid function, high or low blood sugar levels, electrolyte imbalance and dehydration can all cause, or contribute to, feelings of fatigue.(1) Speak to the GP to see if your client needs any of the following blood tests to rule out an underlying medical problem. While the assumption may be that these have been done at various times during the person’s treatment and recovery, I frequently encounter clients where one or more of these tests have never been done. I would also recommend these be checked annual to monitor someone’s progress and detected any changes in vitamin/mineral levels.


1. Full blood count

A full blood count provides information about the red blood cells, the white blood cells and platelets in the body. When it comes to fatigue, I’m usually most interested in a person’s haemoglobin levels. Low haemoglobin levels suggest iron levels in the body are too low. Without adequate haemoglobin, the cells will not be getting enough oxygen and fatigue can be one of the symptoms for this.


2.  Ferritin

Reduced ferritin levels are an early sign that iron levels are becoming depleted. Ferritin is the storage form of iron. If someone is not getting enough iron (or losing more than they should), the body will start using up these iron stores in order to try and keep haemoglobin levels within a normal range. C-reactive protein (which measures inflammation) should be checked at the same time because ferritin levels are affected by inflammation — this will help interpret the results.(5) Some people start to experience fatigue when their ferritin levels drop, even if their haemoglobin is still within the normal range.(6) If left untreated, reduced ferritin levels will generally lead to reduced haemoglobin levels.


3.  Vitamin B12 & folate

A deficiency of vitamin B12 and/or folate can affect red blood cells and lead to fatigue. Vitamin B12 deficiency also damages the protective covering (myelin) on the peripheral nerves, spinal cord and brain which can affect brain functioning, balance, memory and motor functioning.(7) It can also cause numbness, pain and tingling in the hands and feet. Certain medications, such as proton pump inhibitors (eg. Omeprazole, Lansoprazole), H2 receptor antagonists (Ranitidine) and Metformin (among others), can increase the risk of B12 deficiency.(7) Proton pump inhibitors and anti-convulsant drugs can also increase the risk of folate deficiency.(8)


4.  Vitamin D

The symptoms of inadequate vitamin D levels include: fatigue, headache, musculoskeletal pain and weakness, depression and impaired cognitive performance, although the main concern with inadequate vitamin D is the risk to bone health.(9) After a traumatic brain injury, 80.2% of people were diagnosed with vitamin D that were either insufficient or deficient (<70 nmol/L) and these inadequate levels of vitamin D were associated with worse brain functioning and more severe depression.(10)

Vitamin D deficiency is caused by insufficient exposure to sunlight.(11) People who are hospitalised, in rehabilitation and/or in a care facility often get very little sunlight exposure. In the UK, it is only possible to produce sufficient amounts of vitamin D from the sun between late-March and October anyways, and even that is dependent on time of day, cloud cover, clothing and sunscreen use. Combine that with the fact that very few foods contain substantial amounts of vitamin D (oily fish is the main source), and it is no wonder so many people have low levels.(11) Certain anti-epileptic drugs can also actively break down vitamin D in the body.(11)


5.  Thyroid function

Thyroid hormones regulate the body’s metabolism. If one or more of these hormones is low, a person can feel fatigued, apathetic or experience muscle weakness.(12)  People with a brain injury need a more extensive set of thyroid tests than the general population. Both thyroid hormones, triiodothyronine (T3) and thyroxine (T4), need to be checked in addition to thyroid-stimulating hormone (TSH). Normally, TSH causes the body to produce T4 and then T4 is converted to the “active” form which is T3. However, due to various problems with the hypothalamus, pituitary gland and thyroid glands after a brain injury, this process doesn’t always happen like it should. T3 levels were found to be reduced in 66.7% of patients with brain injuries, and T4 levels were low in 22% — this won’t be picked up unless these are specifically checked.(13)


6.  Blood sugar levels

Blood sugar (glucose) is used by the cells to produce energy. Blood sugar levels which are too high (because the sugar can’t get from the blood into the cell) or too low (because there is a miss-match between food intake and insulin levels) can both cause feelings of fatigue.(14)


7.  Urea & electrolytes

The body requires sufficient amounts of fluid and electrolytes such as sodium, potassium and magnesium (among others) in order to function properly. Dehydration, or having electrolytes which are too low (due to loose stools, vomiting or other reasons), can contribute to feeling of fatigue.(1)   Magnesium and phosphate are not included in the general test for “electrolytes” so these blood tests will need to be requested separately.


Acting on the results

Any deficiencies identified by the above blood tests need to be managed by the GP and corrected with prescription strength supplements. Standard over-the-counter multivitamin and mineral supplements are  generally not strong enough to correct deficiencies. After the course of treatment, be sure to ask for another blood test to ensure the deficiency has been corrected and ask if anything can be done to prevent the deficiency from happening again in the future (eg. dietary changes).

As a dietitian, I can provide practical tips and advice that help people get sufficient levels of vitamins, mineral, electrolytes and fluid in their diet. I can help manage gut problems (which can prevent problems with electrolytes) and can also give advice on managing blood sugar levels. Please get in touch by emailing: info@specialistnutritionrehab.co.uk or calling 07787 603863 (UK) for a no-obligation discussion of what your needs are and how I can help.

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