Cerebral palsy (CP) – causes, symptoms, diagnosis, treatment & pathology


It’s pretty well-established that your brain’s
really important. It’s like, if your body was a computer, your brain’s the mainframe.
It controls everything, whether you’re aware of it or not. Cerebral palsy means “brain
disease causing paralysis”; so essentially, cerebral palsy refers to damage to the brain
that causes loss of muscle control, like for example if the cerebellum was damaged, patients
might have issues with fine motor skills like using writing or typing. That being said,
though, cerebral palsy’s a broad umbrella term to basically cover a wide variety of
issues, since ultimately the muscles affected and severity depends on which part of the
mainframe’s been affected, right? Cerebral palsy’s considered a neurodevelopmental
disease, meaning that something happens to an area of the brain during its initial development,
which is an extremely sensitive period. If that area doesn’t develop right, then it
can’t carry out whatever function it’s supposed to control. What’s this vague “something” that can
happen, though? Well, I said “something” because there’s such a wide variety of causes.
The majority of cerebral palsy cases are thought to happen before birth, or prenatally, which
typically means the underlying cause is really hard to pin down. Exposure to radiation and
infection during fetal development can cause cerebral palsy. Hypoxia to the developing
fetus been linked as well, in this case the developing brain doesn’t get enough oxygen,
potentially from problems like the placenta not being able to supply enough oxygen and
nutrients. Cerebral palsy doesn’t have to happen prenatally, though, and some postnatal
causes are things like head trauma, or again an infection or a period of oxygen deprivation.
Although most cases are likely are due to some trauma or injury, a very small proportion
of cases are due to a genetic mutation. Even though the brain damage or injury or abnormality
is permanent, one super important point about cerebral palsy is that it doesn’t get worse
over time, and for that reason it’s considered a non-progressive disease. Cerebral palsy is classified by the type of
muscle movements that result from the brain injury and how that affects what activities
the patient can perform. The first type is called spastic cerebral palsy, which accounts
for about 70% of cases, and this is characterized by having really tight or stiff muscles, which
can make patients’ movements seem jerky. This tightness results from a lesion in an
upper motor neuron. So with a lesion, which just means some kind of abnormality, the ability
of some of these neurons to receive GABA might be impaired. GABA’s the main inhibitory
neurotransmitter, so if nerve impulses can’t be inhibited which is a double negative, then
those nerves are basically over-excited, leading to hypertonia, which is an abnormal increase
in muscle activity, basically like if the muscles were constantly flexed. This is why
some people with spastic cerebral palsy have a scissor gait. Think about how hard it’d
be to walk when your adductor muscles were always partly flexed, which causes your knees
and thighs to constantly touch. Similarly, sometimes patients have a “toe-walk”,
because their calves are always flexed, which pulls the achilles tendon up and causes someone
to go up on their toes. A second type of cerebral palsy is Athetoid
or dyskinetic cerebral palsy, and this one involves damage or injury to the basal ganglia.
The basal ganglia is this structure here which essentially helps us initiate and prevent
certain movements. If the basal ganglia becomes damaged, patients can lose the ability to
prevent movements, and therefore they can have involuntary movements, meaning out of
their control. So dyskinetic cerebral palsy is characterized by dystonia and/or chorea—dystonia
is random, slow, and uncontrolled movements in the limbs and trunk. Chorea is random “dance-like”
movements, since the small uncontrolled movements seem to move from muscle to muscle. Finally there’s ataxic cerebral palsy. Taxis
refers to an order or arrangement, so ataxic essentially means without order, which is
in reference to patients with this type being shaky or uncoordinated, and this is caused
by damage to the cerebellum, which helps with coordination and fine or precise movements.
These patients often have clumsy or unstable movements and poor balance when doing things
like walking or picking something up. Although different from patient to patient,
many patients with muscle control issues have other symptoms as well. Patients often experience
pain from tightened muscles or abnormal posture and stiff joints. Also, abnormal movements
might make it difficult to sleep at night and patients can develop sleep disorders.
Eating can become difficult as well, which can range from the preparation of food to
the action of chewing and swallowing food. Other brain-related issues are also associated,
like difficulties with speaking and communication, vision problems, and learning disabilities. Since cerebral palsy involves a permanent
abnormality to the brain’s structure, it’s not curable, but that doesn’t mean it’s
not treatable. Treatment for cerebral palsy usually involves a multidisciplinary approach,
pulling from a number of clinical specialties like neurologists, rehabilitation specialists,
occupational therapists, speech therapists, and others—hopefully to find a unique approach
for each patient, ultimately improving their quality of life. Physical therapy can be used
to build strength and improve walking ability, along with stretching to reduce contracture,
which is a permanent shortening of muscle tissue from being hypertonic or contracted
for so long. Sometimes muscle relaxants are given or botulinum toxin is injected into
certain muscles to reduce hypertonicity and relax the muscles, which can both help reduce
pain associated with hypertonus and also help fit patients with specific orthotic braces.
Sometimes surgery might also be performed to help with a variety of issues, like loosening
tight muscles, straightening out bones that have been subject to abnormal muscle forces
over time, and cutting certain nerves to reduce their associated movements
or spasms.