Wednesday, January 7, 2015

A short update, and new issue- Hypoventilation in Neurologic diseases

By the way, since it has been a while since I have done anything here, this is a short update. . .

Overall, my strength is still a problem. I can do 3 push-ups, barely. One further issue with the push-ups is that my right wrist is not up to the challenge even if my shoulders were. That wrist has been a weak point all along, and seems worse now.

My legs tend to go through weak times as mentioned earlier. Currently, they are not too bad, and I can walk further and faster now than at other times recently.

Hypoventilation in Neurological diseases

One issue that seems to be a rare thing for HNA, but can occur, is an issue with breathing. In general, this is only a problem at night when I sleep, or at least try to. Since the last updates, I have had a pretty severe problem getting good sleep. I had an initial O2 saturation study done as I slept, which determined that I had several periods of desaturation during the night. A very expensive full sleep study followed, which was inconclusive, except for a suggestion that my periods of REM sleep were shorter and less frequent than normal. I think I had trained myself to avoid REM sleep because I sensed I could not breath as well during it. I think the doctors were looking for standard obstructive sleep apnea, and my case did not suggest that, so they stopped looking into it. My sleep returned to normal right after the study. Go figure. It is like research into electrical problems in cars. They are a problem for you because you drive your car all the time. When you are at a mechanic to get it fixed, the problem can't be reproduced for them to diagnose the cause, or to fix it.  

See this link for more on breathing issues and neuromuscular diseases

http://emedicine.medscape.com/article/304381-overview

“Neuromuscular disorders

Neuromuscular diseases that can cause alveolar hypoventilation include myasthenia gravis, amyotrophic lateral sclerosis, Guillain-Barré syndrome, and muscular dystrophy. Patients with neuromuscular disorders have rapid, shallow breathing secondary to severe muscle weakness or abnormal motor neuron function.

The central respiratory drive is maintained in patients with neuromuscular disorders. Thus, hypoventilation is secondary to respiratory muscle weakness. Patients with neuromuscular disorders have nocturnal desaturations that are most prevalent in the REM stage of sleep. The degree of nocturnal desaturation is correlated with the degree of diaphragm dysfunction. The nocturnal desaturations may precede the onset of daytime hypoventilation and gas exchange abnormalities.”




Hereditary Neuropathies of the Charcot-Marie-Tooth Disease Type

Since I had been curious about a link between HNA and CMT Disease, here is one other site that discusses what that link entails. This article is over multiple pages on the site, and is a bit too technical for me to understand fully. But, this and other things I have discovered do suggest that HNA is at least related to CMT disease. It may not matter in the long run to most of us, but things like this are of interest to me, as a curiosity at least.

http://emedicine.medscape.com/article/1173484-overview

“In some hereditary neuropathies discussed below, focal asymmetric features (eg, hereditary neuropathy with liability to pressure palsy [HNPP]) predominate; in others (eg, certain cases of Charcot-Marie-Tooth disease type 1A (CMT1A) and inherited brachial plexus neuropathy [IBPN]/hereditary neuralgic amyotrophy [HNA]), proximal weakness predominates. Typically, a predilection exists for distal limbs as the site of disease onset and more severe symptoms and signs. Furthermore, while significant variation in nerve conduction velocities exists between and within families, this parameter does not predict severity, with the exception of the very low (ie, < 5 m/s) velocities observed in Dejerine-Sottas syndrome (DSS) and congenital hypomyelination neuropathy (CHN).”