Injuries and Diseases
This page provides an overview of a few injuries and diseases which can occur in the human leg.
This is an injury where the foot can no longer be raised at the ankle joint (a movement known as dorsiflexion). The foot becomes weak and walking is difficult causing a condition called steppage gait. A person with this has to lifft the foot which is affected higher than normal so that their toes do not scrape along the floor and then the foot "slaps" back down to the floor. Numbness and tingling is often found in patients with foot drop.
Foot drop is commonly associated mainly with peroneal nerve palsy; an injury of the femoral (peroneal) nerve (see nerves and blood vessels page). This can be the result of physical trauma. There are also numerous other causes of foot drop including:
- Diseases (including multiple sclerosis, parkinson's disease and muscular dystrophy).
- Abnormal anatomy.
- Cauda equine (nerve bundles in the lower spinal cord become too compressed).
- Drug toxicity.
- Muscle damage.
A patient with foot drop will not be able to walk on their heel, so this is often a good indication of the disorder. This indication is often one of the first signs picked up during a routine physical examination, as well as the general look of the foot. Blood tests are also done to analyse whether the cause is metabolic (such as drug toxicity, diabetes, etc). An MRI (magnetic resonance image) may be done to try to visualise any nerve damage causing the injury. If nerve damage is the cause, an electromyelogram can be used to find out what type of nerve damage is responsible for the foot drop.
Foot drop can range in severity between cases. Different severity levels of foot drop have different treatments.
The simplest treatment is a foot-ankle support cuff which mimics the normal range of motion in the ankle. When worn over a period of time this can correct the injury.
If the foot drop is caused by nerve damage then the affected nerve can be stimulated to eventually treat the condition. The nerve is stimulated as the foot is lifted in the same way as if to take a stride and then dropped.
The most major and effective treatment is surgery. This is done to relieve pressure on nerves or repair muscle. However, surgery is not always a possible treatment option.
Becker's Muscular Dystrophy
In this type of muscular dystrophy there is a gradual weakening of the leg and pelvic muscles. This muscle weakening is due to wasting, meaning that muscle mass is lost. Muscle wasting also occurs in other areas of the body but is most severe in and mainly affects the muscles of the leg and pelvis. As individuals with this disease age they also experience pain whilst muscles are contracting. This is because over time the muscle fibers shorten and fibrosis of the connective tissue occurs, resulting in the muscle not being able to be used.
People with this disorder often experience their leg muscles becoming larger during teenage years to try and compensate for the weakness of muscles, as mentioned above. This enlargement of muscles eventually leads to the extra tissue, which has been created to balance out the effects of the disease, being replaced by non muscle tissues such as fat and connective tissue.
All of the above means that the sufferer finds it progressively harder to perform even simple movements such as walking.
Other symptoms may include:
- Equinus (walking on the toes).
- Difficulty breathing (in some cases).
- Heart disease.
- Falling over alot.
- Deformities in bones (due to muscle wasting occuring before bones are fully formed).
- Deformities in muscles.
- Higher levels in creatine phosphokinase (linked to muscle degeneration).
The cause of this disease is genetic. It in an X-linked recessive disorder. This means that the condition is only found in boys, although girls can be carriers. If a woman is a carrier then there is a 25% chance that a son of hers will have the condition and a 25% chance that a daughter of hers will be a carrier.
In sufferers of this condition the gene encoding dystrophin is mutated. Dystrophin is a protein that stabalises the muscle cell membrane structure. The result of this mutation is that there is not enough dystrophin produced to stabalise muscle cells, causing weakening and wasting of muscles.
The first signs of a person having this disorder are calf muscle enlargement, muscle weakness and muscle wasting.
There are several tests a doctor will do to confirm that a patient has this disease.
First they must make sure that the cause of the symptoms is due to muscle tissue wasting and is not because of nerve damage in the area. This is done by electromyography.
When it has been confirmed that the patient's condition is due to muscle deterioration then 2 other methods are commonly used to find out the cause of the muscle deterioration. The first is a biopsy of the muscle. This is used to see what the physiological cause of the muscle destruction is. It is done by immunohistochemistry and immunoblotting. The second method used to diagnose the disease is a genetic test. This is done by taking a sample of the patients blood and analysing it in a lab to see whether the mutation is present.
At the present time there is no known treatment to completely cure becker's muscular dystrophy.
There are however some treatment which are used to slow the onset of the condition. These include:
- Steriods which are immunosuppresants.
- Leg braces to help with mobility.
- Debio-025 (a hepatitis C drug).
- Physical therapy which encourages as much movement as possible to build muscle strength.
There is also genetic counselling available for carriers of the disease.