Common medical problems in Morquio syndrome involve the skeleton. All children with Morquio disease should be referred to an orthopaedic surgeon as soon as the diagnosis is made and a close watch should be kept on the condition of the cervical spine.
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The spine tends to be severely affected and its bones or vertebrae are abnormally flattened. Sometimes one or more of the vertebrae will slip back in position, narrowing the spinal canal. The spine may be curved to one side (scoliosis), hump-backed (kyphosiis) or a mixture of the two (kyphoscholiosis).
Difficulties can arise from a structural defect in the upper vertebrae of the spine (the cervical spine or the neck). There should be a piece of bone called the odontoid sticking up between the second and first vertebrae and giving support as the head moves. In individuals with Morquio syndrome this may fail to develop with the result that the spinal cord in insufficiently protected. The spinal cord is a bundle of nerves which carries messages between the brain and the rest of the body. Compression or squeezing of the spinal cord (cervical myelopathy) has very serious effects. In rare cases it can lead to sudden death or paralysis after a fall, but more often chronic damage leads to a gradual loss of power in arms and legs. In some cases it may be necessary to fuse some vertebrae in the spine to prevent damage to the spinal cord. This will involve one or two operations and some months in a plaster cast or jacket to support the spine while the fusion takes place.
As the child grows older, the knees gradually become more "knocked''. It is sometimes possible for the legs to be straightened but it is best to wait until the child has stopped growing.
Occasionally heart disease develops in late childhood but it does not cause problems until much later in life. It is usually the heart valves that are affected by the storage of mucopolysaccharides.
The enamel covering the teeth is typically abnormally thin which allows the bonelike substance underneath (dentin) to show through, giving the teeth a greyish yellow colour. The teeth are more liable to decay and should be cleaned regularly. You must tell your dentist if your child has a heart problem and you will probably be advised that he or she should be given antibiotics before and after any dental treatment. This is because bacteria in the mouth might get into the bloodstream during treatment and cause an infection which could damage the heart valve further.
Anaesthesia should not be undertaken lightly in MPS IV. There can be difficulties anaesthetising someone suffering from the disease and an experienced anaesthetist should always be involved. If the cervical spine is unstable the child would be at risk if the neck is flexed while he or she in unconscious and special precautions must be taken. Adult sufferers should ideally wear some sort of identification bracelet with a contact medical person in case of emergency. With children, parents should inform their child's school and any person who looks after the child in case they cannot be contacted in an emergency. If you have to go to a different hospital in an emergency you should tell the anaesthetist that there might be problems with intubation. The MPS Society has more information on this important subject.
Some degree of hearing loss is common. It may be conductive or nerve deafness or both (mixed deafness) and may be made worse by frequent ear infections. It is important for all MPS IV children to have their hearing monitored regularly and for problems to be treated early to maximise the child's ability to learn and communicate. Nerve deafness is managed by the fitting of a hearing aid or aids. There are also adaptations to enable the hearing aid wearer to hear the class teacher, the television or telephone conversations more clearly. Details are available from the Australian Hearing Service.