#Megaloblastic #anemia #diseased #thyroid #recognize
Thyroid diseases such as hypofunction, Hashimoto’s diseaseand even hyperactivityaffect the functioning of the entire body – including the hematopoietic system. One complication that is rarely talked about is megaloblastic anemiai.e. anemia caused by vitamin b12 or folic acid deficiency.
In this article, we explain why this disease occurs more often in patients with thyroid disease, what symptoms it causes and how it is treated.
What is megaloblastic anemia?
Megaloblastic anemia is a type of anemia in which lesions appear in the bone marrow large, abnormal red blood cells – megaloblasts. They arise when the body has a problem with proper DNA synthesis, and the main cause is the lack of:
- vitamin B12,
- folic acid (vit. B9).
Without these ingredients, erythrocytes do not mature properly, making them larger, fragile and shorter-lived.
Why do thyroid diseases increase the risk of megaloblastic anemia?
1. Hashimoto’s disease and lack of vitamin B12
Hashimoto’s is an autoimmune disease. In patients with this disease, the immune system that often “attacks the thyroid” may also damage:
- stomach cells responsible for the secretion of intrinsic factor (IF),
- intestinal epithelium responsible for the absorption of vitamin B12.
This in turn leads to the so-called pernicious anemia (Addison-Biermer) – one of the forms of megaloblastic anemia. This is why people with Hashimoto’s thyroiditis very often suffer from vitamin B12 deficiency.
2. Hypothyroidism slows down your metabolism
Thyroid hormone deficiency causes:
- slower regeneration of blood cells,
- worse absorption of nutrients,
- gastrointestinal disorders (constipation, decreased peristalsis),
- chronic inflammation.
All of this increases the likelihood of B12 and folate deficiency.
3. Concomitant autoimmune disorders
Patients with Hashimoto’s thyroiditis are also more likely to suffer from:
- celiac disease,
- type A gastritis,
- SIBO,
- food intolerances.
Any of these conditions can impair the absorption of B12 and folic acid.
4. Gluten-free or elimination diet
Many people with Hashimoto’s thyroiditis decide to go on an elimination diet. If it is poorly balanced, it may lead to deficiencies.
Symptoms of megaloblastic anemia – they can be easily confused with hypothyroidism
Hypothyroidism and B12 deficiency anemia have very similar symptoms. This is why in many patients the problem remains undiagnosed for a long time.
The most common symptoms:
- chronic fatigue, lack of energy,
- pale skin and mucous membranes,
- dizziness, palpitations,
- shortness of breath on exertion,
- hair loss and brittle nails,
- memory and concentration disorders,
- low mood or depression,
- numbness and tingling in the arms or legs (neurological symptoms!),
- smooth, red “lacquered” tongue.
Neurological symptoms are characteristic mainly of vitamin B12 deficiency – and they can be irreversibleif the deficiency lasts for a long time.
How is megaloblastic anemia diagnosed in a patient with a thyroid disease?
The doctor most often orders:
1. Blood count (CBC)
Typical changes:
- increased MCV (blood cells are “too large”),
- decreased hemoglobin,
- decreased number of erythrocytes.
2. Vitamin B12 and folic acid levels
3. Homocysteine and methylmalonic acid (MMA) levels
An increase in these parameters confirms a functional B12 deficiency, even if the serum level appears “normal”.
4. Gastroscopy or antibodies against IF
Pernicious anemia is suspected.
5. Thyroid assessment
TSH, FT3, FT4, anti-TPO, anti-TG – to determine whether the problem is autoimmune.
How is megaloblastic anemia treated with thyroid disease?
Treatment depends on the cause.
1. Vitamin B12 supplementation
In the form:
- intramuscular injections (most effective in the case of pernicious anemia),
- sublingual tablets,
- oral capsules (if absorption is normal).
Doses are usually high initially and then progress to maintenance treatment.
2. Folic acid supplementation
Most often 400–800 µg per day,
but always after excluding B12 deficiency, because folate may mask the neurological symptoms of B12 deficiency.
3. Treatment of the underlying thyroid disease
Stabilizing the thyroid gland (e.g. appropriate dose of levothyroxine) also improves blood parameters.
4. Treatment of gastrointestinal disorders
SIBO, celiac disease, type A gastritis – require causal therapy to ensure proper absorption of vitamins.
The role of a pharmacist – when should a patient see a doctor?
In the pharmacy we often meet people:
- chronically tired,
- with Hashimoto,
- supplementing B12 “on your own”,
- with neurological symptoms,
- using elimination diets.
The pharmacist may suggest diagnostics if the patient reports:
- severe energy loss despite thyroid treatment,
- numbness in limbs,
- memory problems
- recurrent inflammation of the oral cavity,
- increased MCV in morphology.
It’s worth educating that B12 deficiency is not always caused by diet – it is often caused by thyroid and gastrointestinal disorders.
Summary
Megaloblastic anemia is a common but underestimated complication of thyroid diseases, especially autoimmune Hashimoto’s disease. Vitamin B12 and folic acid deficiency can significantly reduce the patient’s quality of life, and the symptoms can easily be confused with hypothyroidism.
Early diagnosis, appropriate supplementation and treatment of the underlying disease allow you to fully reverse blood changes and prevent neurological complications.
