SECTION 8: NEUROLOGY
Up to half of people with PTHS have epilepsy with different types of seizures, which can vary in how severe they are. Someone with PTHS may have their first seizure before they are one year old, or not until early adulthood.
Seizures can easily be misdiagnosed when someone tends to experience pauses in their breathing (apnoea) since in both the lips and skin can go blue. Children with PTHS may have episodes of apnoea or hyperbreathing just before a seizure, but the abnormal breathing is not itself part of the seizure.
The drugs most commonly prescribed to control seizures are valproic acid, levetiracetam, lamotrigine, and carbamazepine. We don’t yet have enough data to say whether one drug is better than another.
Recordings of brain activity (electroencephalographic or EEG for short) in people with Pitt-Hopkins are usually abnormal, and the patterns will change over time.
If the EEG is normal doctors should be careful not to miss the possibility that there is no seizure, but a pause in breathing (apnoea). The EEG patterns are not usually so specific that they can show up a certain type of seizure.
As it is difficult to tell the difference between seizures and pauses in breath, doctors who are not sure should carry out an EEG and look at it while bearing this in mind. There is no need to make an EEG in everyone with PTHS.
Other neurological problems
Neurological problems relate to the brain, the nerves, and the nervous system. They are not very common in people with PTHS. Seven of the 47 people with PTHS who attended the PTHS World Conference were shown to have a tremor (shake) that did not get worse over time.
The wide standing position and movement that is common to children and adults with PTHS may be linked to problems with the nervous system, but there has not been enough study into it.
There is a noticeable difference in muscle tone in people with PTHS: three-quarters have weakness of the muscles in their torso (truncal hypotonia); less than 10% have a high muscle tone (hypertonia). One-third have this high muscle tone in arms and legs. It has been suggested the difference in muscle tone is due to the autonomic nervous system being disrupted.
Many parents say that their child sleeps extremely well, and sleep problems are seen in only a small number. Some parents mention that their child does not sleep through the night or has night terrors.
Melatonin, a natural hormone that controls sleep, had been used by 10 of the 51attendees who answered this question at the 2018 World Conference. In two it had worked well, in six it had no effect and in the remaining two the result was uncertain. Sleep has not been looked at in full detail yet and we need further studies.
Different brain scans (MRIs) have been done and smaller changes in the formation of the brain have been seen in some but in most the scans show normal results.
Almost invariably the results are not important in how a child with PTHS should be looked after. So it is suggested that an MRI is only needed when there are neurological signs and symptoms, such as repeated seizures. Nor is an MRI needed just because a child has a small head (microcephaly).
16/ EEG studies should only be carried out when there are clear seizures or when a doctor is unsure if someone with PTHS is showing seizures or pauses in breathing .
17/ Seizures can be treated just the same as in the general population; there is no evidence that one specific drug works better than others.
18/ MRI brain scans need only be carried out if there are neurological signs and symptoms and a scan would provide useful information to guide further management. A small head (microcephaly) alone does not mean a child should have an MRI.