Endometriosis
Tissue similar to the uterine lining growing where it shouldn't: on the peritoneum, ovaries, bowel, bladder, ureters, diaphragm and nerves.
Endometriosis is not simply 'bad periods'. It is a whole-body inflammatory disease that can affect the bowel, the bladder, the ureters and the diaphragm, and it is frequently missed because it does not reliably show on a scan. Diagnosis is usually clinical, made from a careful history rather than from imaging or an exploratory operation.
What it actually is
The traditional description is that endometriosis is the lining of the uterus growing outside the uterus. There is an element of truth in it, and the tissue is very similar. But we know it is a little different, and that it does different things.
Endometriosis makes connections to the body around it. It grows blood vessels to feed itself. It forms connections to local nerves. And it produces its own hormones to feed itself, in particular estrogen, through an enzyme called aromatase. That last part is what makes it insidious: it is not simply living off the hormones your ovaries produce, it makes its own supply.
It responds to some hormones in ways similar to the lining of the uterus, but not always, and it works in subtly different ways. Those differences are a large part of why you cannot simply switch periods off with birth control and expect the endometriosis symptoms to stop with them, at least not without side effects.
Why it causes so many different symptoms
What the disease does to the tissue immediately around it is inflammatory. It irritates whatever it is sitting against, and the symptom you get depends on which tissue that is.
A nerve. An irritated nerve does what a nerve does. It fires, and it tells the brain there is pain, not only at the lesion but anywhere that nerve travels.
The bladder. The bladder is a muscle. Irritate a muscle and it does the one thing it knows how to do, which is squeeze. That is why patients rush to the bathroom, go more often, and have all the classic symptoms of an irritated bladder.
The bowel. What you get depends on where along the bowel the irritation sits. It is why so many patients with endometriosis have bloating, nausea, food intolerance, diarrhea, constipation, pain with bowel movements, and sometimes blood with them.
The rest of the body. The estrogen the disease produces does not stay local. It affects the hormonal changes you go through across a cycle. It commonly makes headaches and migraines worse, produces mood changes with periods and mood changes on birth control, and contributes to fatigue, palpitations and inflammatory symptoms like swelling in the hands and feet.
Those are the most common ones. There is a much wider range that patients recognize in themselves, subtle and inconsistent from one person to the next, because different organs respond differently depending on where the disease happens to be. That variation is a large part of why it is so hard to diagnose.
Why you may have collected several diagnoses
Very little of this sounds like a gynecological problem, and that is the heart of the delay.
You feel one kind of symptom, so you see the doctor who deals with that kind of symptom. Most people with bloating and diarrhea end up with a gastroenterologist, and those doctors will try their best to give them answers. So diagnoses accumulate: irritable bowel syndrome, inflammatory bowel disease, gastroparesis, something involving the bladder, something involving nerves or muscles. Each one is reasonable on its own, and each one fits the symptom in front of it.
Step back and something else becomes visible. One person has collected diagnoses across so many organ systems that it can feel as though their body is falling apart in several directions at once. Put the whole picture together and it is usually one disease affecting several organs, rather than several unrelated things going wrong at the same time.
How it is diagnosed
When patients describe these symptoms, the pattern itself is the information. The combination points to where the disease is, because that constellation does not occur in anything else. No other disease behaves like this.
Having heard enough of these histories, you learn that particular symptoms described in particular ways tell you which structure is involved: which nerve, which segment of bowel. Much of that is ordinary medical school anatomy and physiology applied to what the patient is telling you.
This is why a careful history usually reaches the diagnosis without a diagnostic operation, and why the consult is sixty minutes rather than fifteen.
How it changes over time
Endometriosis changes as people get older. It goes on producing its own estrogen and feeding itself, and the problems mature. Symptoms that were confined to periods in a teenager start appearing outside periods as well.
Other patterns are common. Some people manage reasonably until a trauma to the body, another operation or a pregnancy, and then symptoms appear apparently out of nowhere. Sometimes the disease builds quietly for years and it takes an event to make it obvious.
Pregnancy and menopause
There is a long-standing teaching that pregnancy improves endometriosis, and there is a grain of truth in it. During pregnancy you are not cycling, so the symptoms tied to periods ease. Not always completely, but noticeably. For generations of women who spent much of their adult lives pregnant or breastfeeding, it genuinely felt as though the disease had gone away.
Menopause can feel the same. The symptoms that were tied to periods do stop. Others carry on, because the picture was never only about periods, and that part was not being recognized.
What an assessment is for
Most of what we are doing when we assess someone is working out the larger picture. Where you are now, how things are likely to change, what you can expect and what you should expect, what can be changed and what needs to be changed.
Then, for each of those parts separately, what medication, surgery or other treatment would realistically do about it.