Chronic Neurological Problems

Now we're moving from more acute neurological problems to the chronic ones! Specifically, we will be covering cerebral palsy and seizure disorders (a.k.a. epilepsy), both of which are of particular interest to me because one of my cousins is unfortunate enough to have both.

Cerebral Palsy

Cerebral palsy is a non-progressive disorder in which there are issues with motor skills and persistence of infant reflexes, such as the Moro reflex (where a baby that thinks it's falling will stretch out its arms and legs). Some other symptoms include dysarthria (a problem with verbal articulation due to motor issues), seizures and vision defects.

The cause of cerebral palsy is unfortunately unknown, but some factors that may contribute include genetic mutations, abnormal problems and infection or damage in the perinatal period (i.e. at the time of birth). For example, a difficult delivery may cause haemorrhages or hypoxia. Other potential factors include kernicterus (a lot of bilirubin crossing the blood-brain barrier), which can occur due to Rh factor incompatibility or prematurity (premature babies have more red blood cells containing foetal haemoglobin that they have to get rid of). Hypoglycaemia may also be a factor.

Cerebral palsy can be categorised in several ways. Firstly, it can be categorised according to the area affected. If all four limbs are affected, this is quadriplegia. If one side of the body is affected, this is hemiplegia (the most common form). If both arms or both legs are affected, this is diplegia. Secondly, cerebral palsy can be categorised according to the area of the brain that has been affected. In spastic CP, which is the most common, the pyramidal tract is affected, resulting in "scissors gait" (walking with crossed legs) and hyperreflexia. In dyskinetic CP, the basal nuclei and cranial nerves are affected, resulting in choreiform (jerky) involuntary movements and loss of gross motor movements. Finally, in ataxic CP, the cerebellum is affected, resulting in loss of balance and difficulty controlling gait.

Seizure Disorders (a.k.a. Epilepsy)

In seizure disorders, there is uncontrolled excessive neuron activity in the brain which spreads before ending spontaneously. Many seizures are idiopathic- that is, they have no known cause, but may have a genetic component. Some seizures are as a result of head injury. Individuals prone to seizures may have them in response to flashing lights, alkalosis, hypoglycaemia or fever. Seizures as a result of fever ("febrile seizures") are more common in babies and young children, who usually grow out of them.

Generalised Seizures

Generalised seizures are seizures affecting most parts of the brain. There are two main types: petit mal and grand mal.

Petit mal, or absence seizures, are the less severe of the two. These involve a brief loss of awareness, eyelid twitching and staring. Although they generally do not involve a loss of consciousness, patients will generally have no awareness of the event. These usually occur in children.

Grand mal, or tonic/clonic seizures, are quite severe and occur in stages. In the prodromal phase, where no clear signs appear on an ECG, a patient may experience symptoms like irritability or an aura (seeing or smelling strange things). Loss of consciousness may then occur. In the ictal phase, patients have tonic muscle contraction, which is essentially flexion of muscles followed by rigidity. This results in forced expiration, a clenched jaw and so on. Clonic contraction may also occur, in which there is jerky contraction and relaxation that occurs so quickly that it looks like a tremor. These contractions may result in incontinence and vomiting. Finally, in the post-ictal phase, which follows the main part of the seizure, the patient is limp and sleepy.

One complication of generalised seizures is status epilepticus, which occurs when there are many recurrent seizures with loss of consciousness. These seizures can be so frequent that they interfere with normal bodily functions, such as breathing. This can result in hypoxia, hypoglycaemia and acidosis.

Partial Seizures

Partial seizures affect only a small area of the brain. These cause symptoms such as repeated motor activity and/or unusual sensations such as tingling or ringing in the ears. There is no loss of consciousness in a partial seizure, though there may be reduced consciousness. One type of partial seizure is a Jacksonian seizure, in which there is a progressive spread of clonic contractions.

Seizure Treatment

Seizures can be treated with anti-convulsive drugs such as Dilantin, or even sedatives. Unfortunately they don't always have the nicest side effects- they can result in a low white blood cell count, or gingival hyperplasia, which is excessive growth of gum tissue. As with nearly everything in medicine, treating epilepsy requires evaluating the benefits and the risks.