VIARTIS

PARKINSON'S DISEASE

The following symptoms can occur In Parkinson's disease. Which of these symptoms that do occur vary from person to person, over time, and in their severity

Muscular symptoms

Tremor : Tremor can occur in the fingers, hands, arms, legs, chin, tongue, lips, eyelids, and the head. It is most commonly in the hand and fingers because of the large size of the colony of pyramidal tract cells concerned with hand and finger movement. It often ceases during sleep only to return again on waking. As rigidity becomes increasingly severe, tremor may diminish because the sustained discharges of motor units which cause rigidity inhibit their rhythmical interruptions, which are the physiological basis for tremor. tremor: normally 4-7Hz tremor, maximal when the limb is at rest, and decreased with voluntary movement. It is typically unilateral at onset. This is the most apparent and well-known symptom. However, an estimated 30% of patients have little perceptible tremor as one of their symptoms. These are classified as akinetic-rigid.

Rigidity : Rigidity and stiffness occurs in the muscles as a primary symptom, because of their constant muscle contraction. This can lead to pain in rigid areas. Limbs can consequently resist passive movement. This may be exacerbated by mental concentration or active movement in another limb. It may be diminished by relaxation, which may completely abolish rigidity. In combination with a resting tremor, this produces a ratchety, "cogwheel" rigidity when the limb is passively moved.

Hypokinesia : Hypokinesia, which is a poverty of movement of muscles goes through three stages. Firstly, there is hypokinesia, which is impaired movement without any obvious disturbance of power or of coordination. Movement tends to be interrupted by pauses. There can also be difficulty with small movements. Secondly, there is bradykinesia, which is when voluntary movements can be performed, but slowly. Thirdly, there is akinesia, which is a loss of physical movement, which can begin with brief periods of complete immobility called akinetic attacks. Rapid, repetitive movements produce a dysrhythmic and decremental loss of amplitude.

Mouth : There is loss of control of the movements of the mouth and of the muscles of the larynx and pharynx. Speech demands precise control of these muscles, so the voice becomes softer and loses volume. This is called hypophonia. A loss of voice inflections can make the voice sound monotonous. A loss of articulation can lead to slurring. Festinating speech is a group of symptoms in which there is excessively rapid, soft, poorly-intelligible speech. Immobility of the mouth, tongue, palatal and pharyngeal musculature causes excessive salivation, leading to drooling, as there is no intermittent spontaneous and subconscious swallowing movements to dispose of saliva. This can lead to  drooling, which is most likely caused by weak, infrequent swallowing. Dysphagia is the impaired ability to swallow. This can lead to aspiration, pneumonia, and ultimately death.

Head and neck : There is a reduction and slowness of the emotional facial movements. This gives the appearance of a mask like face. There can also be a loss of movement and flexion of the neck. masked facies (a mask-like face also known as hypomimia), with infrequent blinking.

Eyes : A reduction in eye movement leads to the staring appearance of the eyes and a poverty of blinking. More sustained contraction of the orbicularis oculi firmly closes the eyes. Eye movements may be disturbed due to the weakness of their convergence. This causes defects in near vision such as seeing double because of the misalignment of the eyes. Vertical gaze is more affected than horizontal eye movements which are normally preserved. Loss of control of the eye muscles causes slow voluntary movements of the eyes to be Impaired, and fast voluntary movements of the eyes to be in small jumps. In severe cases there can be lengthy episodes of involuntary deviation of the eyes.

Trunk : A mild degree of flexion of the trunk Is common. Posture and balance are disturbed. There is an impairment of righting reflexes, and difficulty in moving the body. The muscles that control respiration are defective and lead to a reduction in breathing capacity. The muscles around the stomach, small gut and oesophagus are also affected so that there is reduced motility of them, and spasms in the oesophagus. The contraction of the muscles of the anal region leads to constipation. Contraction or loss of control of the muscles of the urogenital region can lead to urinary retention, incontinence and sexual incompetence. Stooped, forward-flexed posture. In severe forms, the head and upper shoulders may be bent at a right angle relative to the trunk (camptocormia). difficulty rolling in bed or rising from a seated position;Turning "en bloc": rather than the usual twisting of the neck and trunk and pivoting on the toes, PD patients keep their neck and trunk rigid, requiring multiple small steps to accomplish a turn.

Urinary symptoms : urinary incontinence, typically in later disease progression.

Alimentary symptoms : constipation and gastricdysmotility, severe enough to endanger comfort and even health.

Reproductive symptoms : altered sexual function: characterized by profound impairment of sexual arousal, behavior, orgasm, and drive is found in mid and late Parkinson disease. Current data addresses male sexual function almost exclusively.

Upper limb : Hypokinesia leads to a loss of arm movements, so that the arms do not swing whilst walking. There can be a flexion and loss of movement of the arms and wrists. The loss of hand movement can lead to the inability to carry out all normal manual functions. Decreased arm swing: a form of bradykinesia. micrographia (small, cramped handwriting); impaired fine motor dexterity and coordination. Poverty of movement: overall loss of accessory movements, such as decreased arm swing when walking, as well as spontaneous movement.

Lower limb : The rigidity and loss of movement in the legs causes difficulty in walking and running. This is especially difficult in the first few steps. At first walking is slower, steps become shorter, feet are often dragged. This can develop into shuffling, or a complete inability to walk or stand without assistance. Flexion can occur In the knees, toes, and also the ankles, which can become inverted. Gait and posture disturbances: Shuffling: gait is characterized by short steps, with feet barely leaving the ground, producing an audible shuffling noise. Small obstacles tend to trip the patient. Gait freezing: "freezing" is another word for akinesia, the inability to move. Gait freezing is characterized by inability to move the feet, especially in tight, cluttered spaces or when initiating gait. Postural instability : failure of postural reflexes, which leads to impaired balance and falls.

Festination : a combination of stooped posture, imbalance, and short steps. It leads to a gait that gets progressively faster and faster, often ending in a fall.

Visual symptoms : impaired visual contrast sensitivity, spatial reasoning, colour discrimination, convergence insufficiency (characterized by double vision) and oculomotor control.

Olfactory symptoms : loss of sense of smell (anosmia).

Cellular effects : L-Tyrosine and molecular oxygen do not completely form L-Dopa, so the toxic partial reduction product of oxygen, the superoxide anion O2 can be formed. This can destroy the dopaminergic neurons, which. makes the disorder even worse, as there would be fewer dopaminergic neurons available to produce dopamine. When L-Dopa is unable to form dopamine, it may Instead lead to the formation and accumulation of neuromelanin, which is similar to the'pignent melanin found in skin. It can do this via the enzyme peroxidase, instead of the enzyme tyrosinase, which Is usually responsible for melanin production, which does not occur in the dopaminergic neurons.


OTHER DISORDERS

There are other medical disorders that often occur simultaneously with Parkinson's Disease. However, they are not actually Parkinson's Disease itself :

Depression : Estimated prevalance rates of symptoms of depression vary widely according to the population sampled and methodology used. Reviews of depression estimate its occurrence in anywhere from 20-80% of cases. Seventy percent of individuals with Parkinson's disease diagnosed with pre-existing depression go on to develop anxiety. Ninety percent of Parkinson's disease patients with pre-existing anxiety subsequently develop depression, apathy or abulia.

Cognitive symptoms : slowed reaction time; both voluntary and involuntary motor responses are significantly slowed. executive dysfunction, characterized by difficulties in: differential allocation of attention, impulse control, set shifting, prioritizing, evaluating the salience of ambient data, interpreting social cues, and subjective time awareness.

Dementia : a later development in approximately 20-40% of all patients, typically starting with slowing of thought and progressing to difficulties with abstract thought, memory, and behavioural regulation. Procedural memory is more impaired than declarative memory. Prompting elicits improved recall.

Sleep disturbances : Excessive daytime somnolence. Initial, intermediate, and terminal insomnia. Disturbances in REM sleep: disturbingly vivid dreams, and REM Sleep Disorder, characterized by acting out of dream content.

Autonomic disturbances : oily skin and seborrheic dermatitis;dizziness and fainting; usually attributable orthostatic hypotension, a failure of the autonomous nervous system to adjust blood pressure in response to changes in body position.

Dystonia : abnormal, sustained, painful twisting muscle contractions, usually affecting the foot and ankle in Parkinson's Disease patients. This causes toe flexion and foot inversion, interfering with gait.

Pain : neuropathic, muscle, joints, and tendons, attributable to tension, dystonia, rigidity, joint stiffness, and injuries associated with attempts at accommodation .

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