Basal ganglia disorders- أ.د.عمرو حسن الحسني أستاذ المخ و الأعصاب

The basal ganglia are a cluster of subcortical nuclei deep to cerebral hemispheres. The largest component of the basal ganglia is the corpus striatum which contains the caudate and lenticular nuclei (the putamen, globus pallidus externus, and internus), the subthalamic nucleus (STN), and the substantia nigra (SN).

Symptoms

Parkinson's disease symptoms can be different for everyone. Early symptoms may be mild and go unnoticed. Symptoms often begin on one side of the body and usually remain worse on that side, even after symptoms begin to affect the limbs on both sides.

Parkinson's symptoms may include:

Tremor. Rhythmic shaking, called tremor, usually begins in a limb, often your hand or fingers. You may rub your thumb and forefinger back and forth. This is known as a pill-rolling tremor. Your hand may tremble when it's at rest. The shaking may decrease when you are performing tasks.
Slowed movement, known as bradykinesia. Over time, Parkinson's disease may slow your movement, making simple tasks difficult and time-consuming. Your steps may become shorter when you walk. It may be difficult to get out of a chair. You may drag or shuffle your feet as you try to walk.
Rigid muscles. Muscle stiffness may occur in any part of your body. The stiff muscles can be painful and limit your range of motion.
Impaired posture and balance. Your posture may become stooped. Or you may fall or have balance problems as a result of Parkinson's disease.
Loss of automatic movements. You may have a decreased ability to perform unconscious movements, including blinking, smiling or swinging your arms when you walk.
Speech changes. You may speak softly or quickly, slur, or hesitate before talking. Your speech may be more of a monotone rather than have the usual speech patterns.
Writing changes. It may become hard to write, and your writing may appear small.

Types:
Parkinsonian syndromes can be divided into four subtypes according to their origin:
Primary or idiopathic (Parkinson’s disease).
Secondary or acquired.
Hereditary parkinsonism.
Parkinson plus syndromes.

dystonia is characterized by one or more repeated postures.
Causes:
Primary or idiopathic dystonia: dystonia occurs as a solitary symptom and is not associated with an underlying disorder e.g. Early-onset primary dystonia are due to a mutation in the dyt-1 gene.

Secondary or symptomatic dystonia: dystonia occurs because of another underlying disease process e.g. Wilson disease, stroke, brain trauma or medications.

Classification: Dystonia may also be classified as follows, according to the bodily distribution of symptoms:
Focal dystonia: limited to one region of the body e.g. neck or an arm or a leg.
Segmental dystonia: affecting two adjacent areas of the body e.g. the head and neck.
Multifocal dystonia: affecting two areas of the body that are not next to each other, such as the two arms, or an arm and a leg.
Generalized dystonia: symptoms begin in an arm or a leg and advance, becoming more widespread. Eventually, the trunk and the rest of the body are involved.

2ry dystonia: treatment of the cause
Treatment of dystonia:
Oral medications e.g. benzodiazepine.
Botulinum toxin injection (Botox)
Surgery.
Deep brain stimulation.

Botulinum toxin injection (Botox):
Botulinum toxin is a toxic protein that is produced by the bacterium Clostridium botulinum. This toxin is known to cause botulism, a deadly form of food poisoning that is contracted through the ingestion of contaminated food products.
However, when a minute amount of commercially prepared Botulinum toxin (Botox) is injected directly into an overactive muscle  block the release of acetylcholine  relaxes that muscle  decreases inappropriate or excessive muscle contractions allowing the affected area (e.g., arm, neck, leg, eyelid, etc.) to assume a more normal position or posture.



Chorea is characterized by multiple repeated but not rhythmic movements.

Athetosis is characterized by non-rhythmic movements without intervening postures.