Sunday 1 June 2008

Raphael's cranial nerves

The other "C" in CHARGE - Cranial nerves
The following are the details of what we know about Raphael's nerves in his head.

Medical Information
Raphael's notable cranial nerve conditions consist of the following:
  1. Nerve I - Olfactory nerve - cannot be tested satisfactorily at this age. No comments were made about this nerve on the MRI report.
  2. Nerve II - Optic nerve - Raphael's "left optic nerve appears smaller than the right, suggesting optic nerve hypoplasia" (MRI 18/12/2006).
  3. Nerve VII - Facial nerve - facial palsy evident. "I strongly suspect that infact the facial nerve on the left in congenitally absent." (MRI 18/12/2006). The CT scan (18/4/2007) identifies the facial nerve canals bilaterally.
  4. Nerve VIII - Vestibulocochlear nerve - There appears to be problems within Raphael's left IAM: "on the left side there appears to be one larger (vestibular) and one smaller (cochlear) nerve" (MRI 18/12/2006). The CT scan (18/4/2007) identifies a normal cochlea aqueduct but does not identify a vestibular aqueduct bilaterally.
  5. Nerve IX and X - Glossopharyngeal and vagus nerve - Uncoordinated swallow indicates some problems with these nerves. No comments were made about these nerves on the MRI report.
Explanation of the Medical Terms
The following is my simplified understanding of the terms and/or concepts listed above:
  1. The Olfactory nerve is used for olfaction (the sense of smell). CHARGE syndrome can result in this nerve not working properly. It is not known whether Raphael has a sense of smell and this probably cannot be reliably tested until he is about 8 years of age.
  2. The optic nerve is used for sight. I suspect that hypoplasia (incomplete development or underdevelopment) of Raphael's left optic nerve is related to the problem with his left eye.
  3. Raphael has a left facial palsy (paralysis) due to a possibly absent nerve. The canal through the bone can be seen on the CT scan suggesting that the nerve is actually present. Usually if the canal is there then the nerve is also there.
  4. Raphael's left IAM (internal acoustic meatus) canal (which carries the vestibulocochlea, autidory, or acoustic nerve and the facial nerve) appears to be small. This canal normally carries three nerves, the cochlea nerve, the vestibular nerve and the facial nerve. the cochlea nerve is responsible for transmitting sound information from the cochlea to the brain. The vestibular nerve transmits balance (or positional) information from the vestibule (part of the middle ear) to the brain and the facial nerve controls the muscles in the face. According to an MRI scan Raphael's left vestibular nerve appears to be the correct size but the cochlea nerve appears to be small and the left facial nerve appears to be absent. But according to the CT scan the cochlea and facial nerves appear normal and the vestibular nerve is absent.
  5. The glossopharyngeal and vagus nerves together, and amongst other things control the swallowing function. It is assumed that Raphael has problems with these nerves becuase of his inability to clear his own secretions in his pharynx (back of this throat).
Some interesting websites on cranial nerves:
http://en.wikipedia.org/wiki/Cranial_nerve
http://mywebpages.comcast.net/wnor/cranialnerves.htm
http://faculty.washington.edu/chudler/cranial.html


The Implications of These Conditions
  1. If Raphael has a lack of olfaction then this can result in different desires for food and potentially social problems later on in life.
  2. See Raphael's eyes and vision for comments on the optic nerve hypoplasia.
  3. It is unknown what effect Raphael's left facial palsy will have on him at this time. It is possible that this can result in difficulty eating (as food may escape the mouth), but this is usually only the case when the palsy is bilateral (on both sides). It is also possible that the palsy will effect his speech.
  4. The nerve problems with his cochlea can effect his hearing. I will be more thorough on this topic when and where I compile the information on his ears. Nerve problems with the vestibule effect his sense of balance.
  5. His dysfunctional swallow causes a few problems:
    • He is unable to properly swallow anything lumpier than puréed sweet potato. Even Mashed potato is too lumpy for him. non-smooth foods will cause him to start to cough which leads to vomiting.
    • He tires quickly and gets frustrated when eating, making it difficult to provide him with the necessary intake of food to make him grow. He has been fitted with an NGT (nasogastric tube) to provide supplemental feeding overnight to compensate for his poor intake during the day. An NGT is only a temporary measure, if he is unable to start to feed normally by himself then ultimately he will need to have a PEG (Percutaneous Endoscopic Gastrostomy) tube. This may also require a nissen fundoplication (fundo) to reduce the risk of gastroesophageal reflux (like vomiting).
    • He cannot swallow his own secretions properly. This results in gurgley breathing and a constant flow of mucus from his nose. Uninformed observers would think that he has a heavy cold because of the amount of mucus that comes from him. If he has eaten anything recently then the secretions are the colour of that food (can be very funny). Suctioning can remove the mucus but the mucus flow is back again within half an hour (closest web reference to suctioning I can find is here). He doesn't seem to be bothered by the mucus.
    • The mucus constantly makes his face damp. This used to moisten the tape that held his NGT (nasogastric tube) down and makes it more likely for him to be able to pull his NGT out. He has no tube now as weight gain is adequate without soon.
    • Increased risk of aspiration pneumonia. Aspiration pneumonia is an infection of the lung due to foreign material (which can include his own secretions) entering the lung. although antibiotics can be very effective in removing the infection, repeated aspiration pneumonia can result in scarring of the lung which permanently damages areas in the lungs functionality.
    • The secretions that are constantly in his throat prevent the fluid in his ears from draining properly through the eustachian tube and results in chronic glue ear. This directly causes conductive hearing loss because the build-up of fluid behind the eardrum prevents it from vibrating with sound waves normally. An operation, to insert grommets to drain this fluid, can be performed to rectify this problem; but grommets are self ejecting after 6-12 months and so the operation may need to be repeated a number of times.
Summary:
  • At this stage we don't know if Raphael has a sense of smell.
  • His left facial palsy does not seem to cause him any problems at this stage.
  • His left eye nerve probably does not provide him with useful vision.
  • His left ear nerve has decreased functionality but still provides some hearing ability.
  • His swallowing problems have previously resulted in the need for supplementing his feeding with an NGT. There were plans for a PEG, but a successful oral feeding trial has removed the need for any tube feeding.

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