Is Hashimoto's the same as hypothyroidism?

Short answer: No. The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) describes Hashimoto's disease as an autoimmune disorder that can cause hypothyroidism, and hypothyroidism as when your thyroid gland doesn't make enough thyroid hormones to meet your body's needs. One is a cause. The other is a state. The American Thyroid Association says Hashimoto's is the most common cause of hypothyroidism in the United States, and Cleveland Clinic says not everyone with Hashimoto's disease develops hypothyroidism. Hypothyroidism has other causes too.

If your portal says hypothyroidism, a doctor said Hashimoto's, and nobody told you whether that's one problem or two, this is for you.

It's a fair thing to be unsure about. The two words travel together so often that they start to sound like the same thing. They answer two different questions. Hashimoto's answers why. Hypothyroidism answers how much.

Think of the kitchen tap. Low water pressure is the state. A kinked pipe under the sink is one reason for it. A plumber can find the kink before the pressure drops, and the pressure can drop for reasons that have nothing to do with that pipe.

If you keep your results in Osmi's lab album, both halves already have a place: TSH, Free T4, Free T3 and TPO antibodies each hold their own card in your Thyroid set. Photograph the paper, upload the PDF, or type one number.

What each word means, in NIDDK's terms

The NIDDK page on Hashimoto's disease says that in people with it, the immune system makes antibodies that attack the thyroid gland, and the thyroid becomes damaged and can't make enough thyroid hormones. NIDDK says it's also called Hashimoto's thyroiditis, chronic lymphocytic thyroiditis, or autoimmune thyroiditis. Rarely, it says, the disease can cause an overactive thyroid instead.

The NIDDK page on hypothyroidism describes it as an underactive thyroid: your thyroid gland doesn't make enough thyroid hormones to meet your body's needs, and without enough of them, many of your body's functions slow down.

So one word names what the immune system is doing to your thyroid. The other names how much hormone your thyroid puts out. NIDDK, the ATA, Cleveland Clinic and MedlinePlus all describe Hashimoto's as the most common cause of hypothyroidism.

Hashimoto's vs hypothyroidism, side by side

Hashimoto's without hypothyroidism

NIDDK says most people with Hashimoto's disease develop hypothyroidism. Most, not all: Cleveland Clinic says you might not notice any symptoms if you have Hashimoto's disease without hypothyroidism.

The ATA says Hashimoto's often progresses very slowly over many years, and that you may not have any symptoms early on, even if thyroid antibodies are detected in your blood tests. It goes further: Hashimoto's can be diagnosed even though you have no symptoms. In the ATA's words, "Your thyroid antibody levels are high, but your thyroid hormone levels are normal."

That's the first way the two words come apart. A diagnosis of Hashimoto's can sit on your record before hypothyroidism does, or without it.

In that case, NIDDK and Cleveland Clinic both describe a watching phase. NIDDK says that if you don't have hypothyroidism, your doctor may choose to simply check your symptoms and thyroid hormone levels regularly. Cleveland Clinic says that with high antibody levels but no hypothyroidism, your provider will likely monitor your thyroid levels instead of starting treatment.

Hypothyroidism without Hashimoto's

The second way runs in the other direction. NIDDK says hypothyroidism has several causes. Hashimoto's is one. Others on its list include thyroiditis, which is inflammation of your thyroid, congenital hypothyroidism that's present at birth, surgery to remove part or all of your thyroid, and radiation treatment of your thyroid. One type of thyroiditis, NIDDK says, is postpartum thyroiditis, which develops after a woman gives birth.

The ATA's hypothyroidism page adds one more name. Its list of reasons starts with autoimmune disease, and it gives two examples: Hashimoto's thyroiditis and atrophic thyroiditis. So the ATA names more than one autoimmune kind.

That's why a record can carry one word and not the other. Hypothyroidism describes how much hormone your thyroid makes. Hashimoto's names one reason it might not make enough. NIDDK says doctors may use several thyroid blood tests and imaging tests to confirm the diagnosis and find its cause.

Which tests US bodies describe for each

For hypothyroidism, the ATA says a blood test is the only way to know for sure. It names two:

• TSH. The ATA calls it a hormone from the pituitary gland that tells your thyroid to work.
• Free T4. The ATA says it checks the amount of thyroid hormone in your blood that your body can actually use. It adds that testing for T3 is not often needed.

NIDDK says a diagnosis can't be based on symptoms alone, because many of its symptoms are the same as those of other diseases.

For Hashimoto's, NIDDK says your doctor will order one or more blood tests to check for hypothyroidism and its causes. Its examples are T4 and T3, TSH, and thyroid peroxidase antibodies (TPO), which it says are present in most people with Hashimoto's disease. Cleveland Clinic lists TSH, free T4 and an antithyroid antibody test, which looks for antibodies that attack your thyroid. NIDDK says you probably won't need other tests to confirm Hashimoto's, and that an ultrasound may come in if your doctor suspects it but you don't have antithyroid antibodies in your blood.

The ATA lists when a Hashimoto's diagnosis may be made: when you have symptoms of hypothyroidism and a blood test shows an underactive thyroid gland, when you have an enlarged thyroid gland (goiter), or when you have elevated thyroid antibody levels, if measured. Note the ATA's last two words: if measured. Thyroid antibodies, explained covers what each one tests.

Put plainly: TSH and free T4 are the tests the ATA names for the state, and the antibody test is the one NIDDK, Cleveland Clinic and the ATA tie to Hashimoto's.

Taking it to your doctor

Which word applies to you, which tests sit behind it, and what your own results show, is a conversation for your doctor. Please talk to your doctor about your results and what they mean for you.

Keeping both halves on one record

Osmi doesn't diagnose. It shows each value against the range your own lab printed and what's changed since the last draw. Osmi files every result with its unit, date, lab and printed range, and a re-draw stacks on the same card and shows what moved.

The daily check-in sits on the same record. Answer seven questions or speak with Rose, your thyroid mascot. About a minute, and every answer lands on the same record as your labs, cycle, and sleep.

If the Hashimoto's diagnosis is new, what to do after a Hashimoto's diagnosis picks up from here.

One small thing for this week: find your most recent thyroid report and check whether an antibody result is on it.

Two words, two questions. Why, and how much.

Questions women ask about Hashimoto's and hypothyroidism

Can you have hypothyroidism without Hashimoto's? Yes. NIDDK says hypothyroidism has several causes, and Hashimoto's is only one. Others on its list include thyroiditis, congenital hypothyroidism, surgery to remove part or all of your thyroid, and radiation treatment of your thyroid. The ATA also names atrophic thyroiditis as a second autoimmune example.

Is Hashimoto's worse than hypothyroidism? They aren't two conditions to rank against each other. NIDDK describes Hashimoto's as an autoimmune disorder that can cause hypothyroidism, and says most people with it develop hypothyroidism. Cleveland Clinic calls Hashimoto's a lifelong condition. How either affects you is a question for your doctor.

What test confirms Hashimoto's disease? NIDDK names thyroid peroxidase antibodies (TPO), alongside TSH, T4 and T3, and says TPO antibodies are present in most people with Hashimoto's disease. It says you probably won't need other tests to confirm it, and that an ultrasound may be used if your doctor suspects it but you don't have antithyroid antibodies.

Is Hashimoto's treated differently from hypothyroidism? NIDDK says how doctors treat Hashimoto's disease usually depends on whether your thyroid is damaged enough to cause hypothyroidism. If it isn't, NIDDK says your doctor may choose to simply check your symptoms and thyroid hormone levels regularly. What applies to you is your doctor's call.

Is Hashimoto's thyroiditis the same as Hashimoto's disease? Yes. NIDDK says Hashimoto's disease is also called Hashimoto's thyroiditis, chronic lymphocytic thyroiditis, or autoimmune thyroiditis. The ATA uses Hashimoto's thyroiditis and lists the same two other names. Both call it an autoimmune disorder, and the ATA says that in the United States, Hashimoto's thyroiditis is the most common cause of hypothyroidism.

Why does my chart say hypothyroidism but not Hashimoto's? Hypothyroidism names a state, and NIDDK lists several causes for it. The ATA says a Hashimoto's diagnosis may rest on elevated thyroid antibody levels, if measured. Ask your doctor which cause, if any, was found, and whether an antibody test was part of your workup.

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Educational, not medical advice.