Differential Diagnosis: Endometriosis

Similarly to Multiple Sclerosis (MS), the vast majority of patients classified under Functional Neurological Disorder (FND) are women, with percentages ranging anywhere between 60% and 80% of cases.There is a striking female preponderance of 60-80%

Some attribute these high percentages to sexism, particularly given historical perspectives where symptoms were dismissed as hysteria, a term literally derived from the Greek word for uterus. Historically, this reflected the ancient belief (notably in Hippocratic and later Freudian theories) that certain psychological disturbances in women were caused by a "wandering womb."

While claims of sexism are plausible, we should avoid being distracted by what might be ideological bias and instead focus on what the statistics themselves suggest. Functional disorders and gender bias

This opens another avenue of exploration beyond philosophy, encouraging investigation into possible underlying causes.

Even though ancient understanding was crude and often linked unexplained symptoms in women to female-specific issues, it raises a valid point: the female endocrine system (which includes the uterus) is far more complex than that of men. The female endocrine system has additional organs (ovaries, uterus, placenta during pregnancy) and cycles (menstrual, reproductive, menopausal) that men do not, making hormonal interactions more intricate and providing more points where things can go wrong. The endocrine system as a whole might not always be the cause, but in some cases it can be, depending on what thorough investigations reveal.

Symptoms interpreted as neurological could be endocrinological. A Review of Neurological Disorders Caused by Hormonal Abnormalities Insulinoma misdiagnosed as neurologic disease While doctors may focus on abnormalities in the central nervous system, they might overlook other contributing factors. As is often observed, specialists tend to interpret findings narrowly within their own field. (if you only have a hammer, everything looks like a nail).

Ironically, although doctors present the FND framework as a more evolved replacement for outdated concepts like hysteria, conditions such as endometriosis may still be wrongly attributed to FND, echoing the same historical misattributions that labelled unexplained female symptoms as psychological rather than physiological.

Endometriosis affects about 10% of women of reproductive age worldwide, roughly 1 in 10. Prevalence is higher (up to 30–50%) in women with chronic pelvic pain or infertility.

In my wife's case, her confirmed diagnosis of endometriosis (including the removal of nodules) should be considered in the differential diagnosis, yet endometriosis is rarely included in that list.

Peripheral nerve-related:

• Sciatica-like leg pain (if affecting the lumbosacral plexus)
• Numbness or tingling in the legs
• Shooting pelvic or lower back pain

Central / referred symptoms:

• Pelvic pain radiating to the lower spine or hips
• Chronic fatigue
• Dizziness (secondary to pain or hormonal changes)

Autonomic-like symptoms:

• Bowel or bladder dysfunction (nerve compression or irritation)
• Abnormal sweating or flushing in the lower limbs

Other mimics:

• Gait disturbances (pain-related or nerve irritation)
• Muscle spasms or cramps

Central nervous system:
Cerebral endometriosis or via secondary inflammatory or immune effects:

• Seizures (catamenial epilepsy)
• Focal neurological deficits (weakness, numbness) during menstruation
• Headaches or migraines (hormonal/inflammatory triggers)
• Visual disturbances (rare, if occipital involvement)
• Cognitive fog or concentration issues (secondary to pain/inflammation)
• Vertigo or balance problems (rare, case reports of cerebellar involvement)

Cerebral endometriosis is extremely rare; only a few dozen confirmed cases are reported worldwide in medical literature, mostly as isolated case reports. No reliable prevalence data exists because of how uncommon it is.

Source: Healthline – Endometriosis in the brain

Doctors usually suspect it when neurological symptoms flare up with the menstrual cycle. MRI can sometimes show cyst‑like or bleeding spots, and if surgery is done, a biopsy can confirm the diagnosis. In my wife’s case, we don’t see this kind of cycle‑linked flare‑up, but the general effects of endometriosis could still contribute to the symptoms she’s experiencing.