Numbness in hands and arms

Hi
I'm a fit 46 year old male, 6ft tall and 161 pounds (73kg) and have never had any medical problems until recently.
A few months ago I had a minor hernia repair operation, which healed well after 4 weeks, with no issues.
A month ago I went to a friend's house garden party, and spent the night sleeping on an old mattress on the floor. The next day I had a very sore and tender scalp, which I assumed was due to sun burn (in the garden all day). My scalp was still painful for a week, and I noticed a slight numbness in my skin of my upper legs (top of thighs and bottom). The next day, the numbness had spread to my torso area. Over the weekend, this numbness had spread to my fingers, hands and arms. My doctor checked out my reflexes (ok) and booked me for a blood test, to check for vitamin B12 deficiency, etc. 2 weeks later, the blood test results were normal. I am now waiting for a Neurologist appointment, which may take a while.
My symptoms now are: Loss of sensation in fingers and hands, and arms. All other body areas feel ok now, but it may just be that my hands / arms are very tingly. I wake up with sharp head pain tinges to the temple areas, but this goes away after I get up and about. I have no other pain at all. My handwriting is suffering, and my guitar playing is not so good, as I can't feel the strings very well. I have no rashes, or other visible skin signs. My strength is very good (60 press-ups ok), and I have no dizziness or vision problems.
My questioins are: Could I have been bitten on the scalp by a cat flea (at the house party) which could have affected my nervous system? If so, what should I do? Could it be anything to do with the hernia operation? Infection? Does this sound like it could be a trapped nerve, and should I try a Chiropractor? I want to be pro-active, to avoid any possible long term nerve damage.
Any advice would be greatly appreciated.
Thanks.

[Christopher R Newey, DO]

Thanks for using the forum. I am happy to address your questions, and my answer will be based on the information you provided here. Please make sure you recognize that this forum is for educational purposes only, and it does not substitute for a formal office visit with a doctor.

Without the ability to examine and obtain a history, I can not tell you what the exact cause of the symptoms is. However I will try to provide you with some useful information.

I am not sure if the scalp tenderness is related to the anterior leg numbness. Since you are having symptoms of bilateral upper extremity numbness and tenderness, I would suggest you get an MRI of the neck to evaluate the vertebral discs, which can herniate and cause numbness/pain. In most people these symptoms may resolve within 4-6 weeks. A minority of patients do not respond to medical/conservative management and require surgery.  Symptoms suggesting the need for urgent surgery include muscle weakness, loss of bowel or bladder control, loss of sensation, and progressive pain.
A test called EMG/NCS can be performed to determine the extent a nerve is being compressed or damaged by a herniated disc. This test is performed by neurologist at most local offices.

I highly doubt a flea could have caused your symptoms and current symptoms. An infection is possible, but lower on the differential as well. I would avoid going to a chiropractor until you are evaluated by a neurologist. He/she will do a thorough neurological examination that will lead him/her to a differential diagnosis. The exam will consist of sensory and motor components, reflexes, cranial nerves, and cerebellar/gait. Depending on what is found, he/she may order an MRI or additional blood tests. There are many causes of numbness, such as diabetes, autoimmune processes, vitamin deficiencies, and demyelinating processes to name a few.

I encourage you to follow up with the neurologist and be evaluated by him/her first before obtaining alternative treatments, such as chiropractor.

Thank you for this opportunity to answer your questions, I hope you find the information I have provided useful, good luck.