Weird symptoms, positive for anti smooth muscle antibodies, tumor in neck?

[Blissfulboredom]

What can cause a positive result on an ASMA test other than autoimmune hepatitis? None of my blood tests for liver function were abnormal, so I'm confused.

I began seeing doctors for neuromuscular symptoms, vision problems, fatigue and shooting pains (among other things). I've had numerous tests looking at possibilities of MS and even ALS, now the thought is myasthenia gravis... but some things just don't fit.

Here's some info that may or may not be pertinent:

I tested negative for AChR and MuSK antibodies (usually present in MG). But positive for ASMA (usually indicative of autoimmune hepatitis).

There was an MRI finding of a 1.5cm tumor on my carotid artery above where it splits into two. Possibly a schwannoma, but more tests have yet to be done.

MRIs show no lesions in my brain or spinal chord. (So not MS)

Normal standard EMG (So not ALS)
(I'm referred now for a more specialized EMG to test repetitive movements)

Dozens of other blood tests were done, with only a couple of abnormalities. Low creatinine and high MCH.

Neurological exam was abnormal; hyperreflexia, clonus, babinski reflex and pronounced weakness in arms and legs.

Anyone have a clue what could be going on? I just want to figure this out so I can get appropriate treatment.
I see a different neurologist next week, but until then (and possibly after) I'm left speculating.

Any suggestions are appreciated.

[Red_Star]

GP Notebook -  Anti-smooth muscle antibodies -

"High titres are found in approximately 97% of autoimmune active hepatitis. Transient low titre antibodies may occur in other hepatic disorders, alopecia, primary pulmonary hypertension and in viral infections."

Low blood creatinine levels can mean lower muscle mass caused by a disease (eg: muscular dystrophy) or by aging. Other causes include severe liver disease, a diet very low in protein and water loss (pregnancy,  excess water intake, and certain medications).

High MCH can be a sign of macrocytic anaemia (red blood cells are larger than normal.  Enlarged blood cells are often associated with a deficiency or malabsorption of vitamin B12 and folate. Underlying causes can include liver problems, autoimmune diseases, severe hypothyroidism, bone-marrow diseases, use of certain medications and alcohol abuse.

I have malabsorption of vitamin B12 due to autoimmune pernicious anaemia and in my case my blood cells never enlarged even with B12 serum finally dropped below the reference range (a range that is far too low). I had plenty of neurological symptoms and I have permanent nerve damage.

Excerpt from MS Signs vs. Symptoms: What is the Babinski Sign?...

“Is MS the only disease which causes damage along the corticospinal tract?  If I experience Babinski sign, does that mean I have MS?”

No. The abnormal Babinski reflex can be caused by several conditions including spinal cord injury or tumor, meningitis, stroke, amyotrophic lateral sclerosis (ALS), pernicious anemia, Friedreich’s ataxia, syringomyelia, poliomyelitis, rabies, brain tumor or head injury involving the corticospinal tract, or following a generalized tonic-clonic seizure."