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Practice 10-minute consultation


BMJ 2007; 334 doi: (Published 07 June 2007) Cite this as: BMJ 2007;334:1221

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The myth of Chronic Fatgue Syndrome

It pains me to see the concept of Chronic Fatigue Syndrome (CFS)
promoted by individuals and organizations alike, including a prestigious
US Government Agency such as CDC (Center for Disease Control).
I do not recall using CFS as a diagnosis. The reason is simple, I go
beyond the CDC criteria in investigating chronic fatigue.
In their 10-minute consultation "Tiredness", Drs Moncrieff and Fletcher
jump to a speedy conclusion that the patient under discussion has
depression. That is exactly what patients dislike about our diagnostic
acumen, attributing major symptoms in their life to mental diseases
without first exhausting all the underlying physical ailments.

I have yet to see a diagnostic criteria list for fatigue that is
complete. This unfortunately includes the diagnostic criteria for Chronic
Fatigue Syndrome issued by CDC.
No wonder we keep citing CFS as a cause for fatigue when we ourselves fail
to pinpoint the diagnosis.
In my endocrine practice after ruling out the obvious causes of fatigue
(mentioned in this 10-minute consultation, I will also add adrenal
insufficiency which is an autoimmune disease not mentioned by name in the
mini consultation), I will do the following tests and I almost always find
the cause for fatigue:
1. True biological reference range of TSH should be 0.3-2.5.
If TSH is > 2.5, especially when Thyroid Peroxidase titer is > 10,
the patient might have evolving hypothyroidism. If you go by your
laboratory's reference range of 0.5-5, of course you will miss the boat,
and resort to the waste basket diagnosis of CFS.

2. Check glucose tolerance test on people who are obese, have family
history of diabetes, and have nocturia, or polyuria. The fasting plasma
glucose should be <100 mg/dl (5.5 mmol/l).Postprandial plasma glucose
should be <140 mg/dl (7.7 mmol/l)at 30-minute, 60-minute, 90-minute,
and 120-minute.
If you do not use these diagnostic thresholds, you will miss the diagnosis
of diabetes, or impaired fasting glucose, or impaired glucose tolerance.
The latter 2 are also called pre-diabetes. Pre-diabetes and diabetes both
can cause severe fatigue if remained undiagnosed. The mechanism is through
loss of glucose (body's fuel) in the urine (Glycosuria>

Check vitamin B12 level. The cutoff reference range is >300 pg/mL
(>221 pmol/L), or even higher. Most laboratories in the US have the
reference range at 160 or 180, erroneously low. If in doubt, check
homocysteine level, the reference range of homocysteine should be between
5 and 15 µmol/L (some authorities use 10 as cutoff).
If you rely on outdated reference range, you miss the boat and fall in the
trap of CFS.

3. In the Northern regions of the United States and Europe, vitamin D
deficiency is rampant. In some cities in the United States 70% of the
population in the winter might have vitamin D deficiency (such as Boston).
Vitamin D deficiency is responsible for calcium and phosphorus absorption
(among other host of other functions).
Lack of phosphorus means lack of ATP in the body, which means that you
feel tired.
I have helped thousands of victims of this type of chronic fatigue through
vigorous vitamin D supplementation. Not to mention that vitamin D
deficiency causes also severe myalgia and bone pains (osteomalacia), often
missed since vitamin D deficiency is not on the list of differential
diagnosis of fatigue, including (tragically) the CDC list. Failure to
recognize vitamin D deficiency leads you to misdiagnosing patients as CFS
and/ or fibromyalgia. Nearly 70% of patients with fibromyalgia have
vitamin D deficiency, i.e. misdiagnosed.
The true reference range of 25 hydroxy vitamin D is 32-100 ng/ml.

4. Sleep deprivation is a very common cause of fatigue. This was
mentioned in the 10-minute consult.

5. Celiac disease is relatively common (~1% of Caucasians have it,
most of them undiagnosed). If you don't think of Celiac, you will be an easy
victim in the trap of CFS.
Celiac can cause pan-malabsorption of iron, vitamin D, B12 (mentioned
above) in addition to other nutrients and minerals.

6. If iron saturation is high, perform genetic testing for
hemochromatosis. This is another relatively common genetic disease in the

Any list that does not address the above diagnoses (with the
reference ranges that I mentioned), would lead to missing the root causes
of fatigue. CFS is not a diagnosis; it is merely re-labeling fatigue with
a fancier name.
It is the time that CDC revisited the criteria of CFS, and included the
causes I cited above.
I can say with confidence, backed up with data of hundreds, or even
thousands of patients with fatigue who I have helped over years, that
patients with chronic fatigue syndrome are patients who have not been
adequately worked up in accordance with the criteria mentioned above.
It is for this reason that CFS is not in my medical vocabulary.

Competing interests:
None declared

Competing interests: No competing interests

09 June 2007
Shirwan A. Mirza, MD, FACP, FACE
Pivate Ptactice
Auburn, NY 13021 USA