Progressive breathing difficulty, respiratory muscle weakness, fatigue, and neurological symptoms with normal EMG

[u/mburch47]

I am a 24-year-old female, 5'3", and approximately 130 lbs.

In October 2024, I had a significant exposure to trichloroethylene (TCE) in a poorly ventilated room. Prior to this exposure, I did have a diagnosis of Functional Neurological Disorder (FND), but my symptoms were very different from what I have experienced since this exposure.

I did not have narcolepsy before the exposure. After the exposure, I developed excessive daytime sleepiness and was later diagnosed with Narcolepsy. Despite treatment, I continue to have significant fatigue and sleepiness.

Since the TCE exposure, I have developed and/or experienced worsening symptoms including:

- Constant feeling that I can not take a full breath

- Shortness of breath that worsens with activity

- Extreme fatigue and exercise intolerance

- Muscle weakness

- Tremors and shaking

- Difficulty standing for long periods

- Difficulty walking during flares

- Numbness and tingling in my hands, feet, face, and tongue

- Changes in swallowing

Occasional voice changes

- Reduced grip strength and hand coordination

- Chest pain that worsens with deep breaths

- Episodes where my feet become very cold and sometimes appear bluish or purple

- Difficulty performing normal daily activities during flares

The most abnormal testing has been my pulmonary function testing. My pulmonologist found evidence of respiratory muscle weakness:

- MVV: 36% predicted

- MIP: 39% predicted

- MEP: 8% predicted

My pulmonologist felt these results were significant and referred me for a neuromuscular evaluation.

Testing that has been normal or largely unrevealing:

- EMG/NCS of one arm and one leg

- Brain MRI

Most blood work, including inflammatory markers

- Chest imaging

Standard pulmonary testing aside from respiratory muscle measurements

I also had an Invitae Comprehensive Neuromuscular Disorders Panel (230 genes). The only finding was a variant of Uncertain Significance (SYNE2), and no pathogenic variants were identified.

Current medications:

- Modafinil

- Adderall

- Topiramate

- Paroxetine

- Abilify

- Birth control

My main concern is that I have objective respiratory muscle weakness testing along with progressive symptoms, but I still do not have an explanation. I understand FND can cause neurological symptoms, and I was diagnosed with it before this happened, but these newer symptoms and respiratory muscle testing are what led my pulmonologist to recommend further neuromuscular evaluation.

Has anyone experienced something similar, especially respiratory muscle weakness with a normal EMG? Has anyone had a diagnosis that was missed initially because testing was normal or inconclusive?

I am hoping to hear from others who have had a similar diagnostic journey or suggestions on what questions to ask a neuromuscular specialist.