Generality
Sclerosis is the name that doctors give to any process of hardening of an organ, or of a considerable part of it, as a result of an increase in connective-fibrous tissue at the expense of normal parenchymal tissue.
Several organs and tissues of the human body can be victims of a sclerosis process.
The most known types of human sclerosis are: multiple sclerosis, amyotrophic lateral sclerosis (ALS), arteriosclerosis, atherosclerosis, otosclerosis and tuberous sclerosis.
What is Sclerosis
Sclerosis is the medical term that indicates a process of hardening of an organ, or of a considerable part of it, due to the "increase in" scar tissue "(connective-fibrous) and the regression of normal parenchymal tissue.
In other words, when undergoing sclerosis, an organ or tissue sees its normal parenchymal component decrease and the connective-fibrous component increase.
Depending on the causes, the regression of the parenchyma may precede the increase of the connective-fibrous tissue or vice versa (ie the increase of the connective-fibrous component may precede the decrease of the normal parenchymal tissue).
SCLEROSIS, FIBROSIS AND CIRRUSIS: THE DIFFERENCES
Sclerosis, fibrosis and cirrhosis are three different processes, which however, due to some similar characteristics, are often confused with each other.
By the term fibrosis, doctors mean an increase in connective-fibrous tissue in an organ, or in a portion of it, without any reference to the behavior of the parenchyma.
With the term cirrhosis, on the other hand, they mean an increase in the connective-fibrous component in an organ or in a part of it, associated with a decrease in parenchymal tissue and attempts by this same tissue to regenerate.
MASSIVE SCLEROSIS
The term massive sclerosis refers to a generalized sclerotic process, which involves an organ in its entirety.
Often, the process of massive sclerosis involves a decrease in the volume of the organ, consequent not only to a reduction of the parenchymal component, but also to a scar contraction of the newly formed connective-fibrous tissue.
Types of Scleroderma
Several organs and tissues of the human body can be victims of a sclerosis process.
The best known types of human sclerosis are:
- Multiple sclerosis;
- Amyotrophic lateral sclerosis;
- Arteriosclerosis and atherosclerosis;
- Tuberous sclerosis;
- The "otosclerosis;
- L "osteosclerosis;
- Progressive systemic sclerosis;
- Hippocampal sclerosis;
- Segmental and focal glomerulosclerosis;
- The lichen sclerosus genital.
MULTIPLE SCLEROSIS
Multiple sclerosis is a chronic and disabling disease, which arises as a result of a progressive sclerotic degradation of myelin belonging to the neurons of the central nervous system (N.B: the central nervous system, or CNS, includes the brain and spinal cord).
The symptoms of multiple sclerosis can be mild or severe. Clinical manifestations that are considered mild are, for example, numbness of the limbs and tremors; conversely, examples of serious disorders are paralysis of the limbs or loss of vision.
Despite the numerous studies conducted to date, the precise causes of multiple sclerosis remain a mystery. According to the most reliable hypotheses, the disease could be the result of a combination of immunological, environmental, genetic and infectious factors.
The lack of knowledge of the precise triggering causes is one of the main reasons why multiple sclerosis is an incurable condition. Currently, in fact, the only treatments available to patients consist of symptomatic therapies, that is, treatments whose only effect is to mitigate the severity of the symptoms.
AMYOTROPHIC LATERAL SCLEROSIS
Amyotrophic lateral sclerosis, also known as ALS, Gehrig's disease or motor neuron disease, is a degenerative disease of the central nervous system, which specifically affects motor neurons, the nerve cells responsible for controlling muscles and muscle movement.
As a consequence of motor neuron degeneration, the ALS patient gradually loses the ability to: walk, breathe, swallow, speak and hold objects.
ALS always has a dramatic course and a fatal outcome: the patient dies (usually from severe respiratory insufficiency) after about 3-5 years from the onset of the disease and, in this period of time, is first forced to a chair. wheels (because paralyzed) and then to breathe through a support for mechanical ventilation.
The causes that trigger the degenerative process of motor neurons - which is then a process of sclerosis - are unknown.
As long as the triggers of ALS remain unknown, the chances of developing a specific cure (and not just aimed at relieving symptoms) are practically nil.
ARTERIOSCLEROSIS AND ATHEROSCLEROSIS
In medicine, the term arteriosclerosis identifies all those forms of hardening, thickening and loss of elasticity of the artery wall, ie the blood vessels that carry blood from the heart to the periphery.
Atherosclerosis is the best known and most widespread form of atherosclerosis.
According to the most recent definitions, it is a degenerative disease of the arteries of medium and large caliber, characterized by the presence of atheromas on the inner wall of the arterial vessels.
Atheromas are plaques of lipid (mostly cholesterol), protein and fibrous material, which, in addition to obstructing the lumen of the arteries and preventing blood flow, can also become inflamed and fragmented. The fragmentation of an atheroma is responsible for the dispersion, in the bloodstream, of mobile bodies, which can occlude small arteries located even very far from the site of origin of the same atheroma.
A progressive morbid condition, atherosclerosis represents an important risk factor for serious diseases, such as: angina pectoris, myocardial infarction and stroke.
Various factors can contribute to the formation of atheromas on the artery wall, some not modifiable and others modifiable.
Among the non-modifiable favoring factors are: old age, male sex, familiarity and population to which they belong (eg: Caucasian, African, etc.).
The modifiable favoring factors, on the other hand, include: cigarette smoking, hypercholesterolemia, hypertension, obesity, sedentary lifestyle and diabetes mellitus.
Arteriosclerosis is a subtle condition, as it often remains silent until the worst consequences appear.
- Atherosclerosis
- Arteriolosclerosis
- Calcific sclerosis of Mönckeberg
SCLEROSIS TUBEROSA
Tuberous sclerosis is a genetic disease characterized by the formation of hamartomas in different organs and tissues of the human body.
The result of a very intense cellular multiplication process, a hamartoma is an obvious cluster of cells, similar to a lump or tuber. Hamartomas are not tumors, but sometimes they could become one, assuming the connotations of benign neoplasms comparable to fibroids and angiofibromas.
Tuberous sclerosis, with its hamartomas, mainly affects the brain, skin, kidneys, heart and lungs. Given the multiplicity of organs and tissues that it can involve, it is one of the multisystemic genetic diseases.
The genes, the mutation of which is responsible for the appearance of tuberous sclerosis, are known as TSC1 (chromosome 9) and TSC2 (chromosome 19). According to various statistical surveys, most patients with tuberous sclerosis (about 80%) would have a TSC2 mutation and only a small part (about 20%) a TSC1 mutation.
Mutations of TSC1 and TSC2 can arise spontaneously, during embryonic development, or have a hereditary origin.
- Skin manifestations. They typically consist of depigmented spots on the body, areas of thickened skin, growth of layers of skin under or around the nails, and red-tinged spots on the face.
- Neurological manifestations. Hamartomas in the brain can cause: episodes of epilepsy, the appearance of subependymal nodules or subependymal giant cell astrocytomas and, finally, mental deficits in behavior and learning.
- Renal manifestations. They can be the result of the rupture of hamartomas located in the kidneys or the consequence of alterations in the renal anatomy.
In the first case, they generally consist of: haemorrhage, hematuria and abdominal pain; in the second case, they can consist of: horseshoe kidney, polycystic kidney, renal agenesis and double ureter. - Cardiovascular manifestations. Due to hamartomas located on the walls of the cavities of the heart, they consist of arrhythmias and alterations in the cardiac flow.
In severe cases, hamartomas located in the heart can lead to heart failure. - Pulmonary manifestations. They are mainly due to two conditions, whose specific name is: lymphangioleiomyomatosis (AML) and micronodular multifocal hyperplasia.
AML is responsible for cysts in the lungs, mainly affects female patients and causes symptoms such as dyspnoea, cough and spontaneous pneumothorax.
Multifocal micronodular hyperplasia causes nodules in the lungs, affects both sexes equally and is often asymptomatic.
OTOSCLEROSIS
Otosclerosis is a pathology of the ear, characterized by a sclerotic process affecting the stapes, one of the three ossicles of the middle ear (the other two are the hammer and the anvil).
The sclerosis process that distinguishes otosclerosis induces the formation, all around the stapes, of an abnormal bone mass; this bone mass stiffens and blocks the movements of the stirrup itself, thus altering the transmission of sound waves entering the ear and directed towards the brain. An incorrect transmission of the sound waves, along the chain of the three bones of the middle ear, affects the hearing ability, and therefore the perception of sounds.
The presence of otosclerosis in an individual coincides with a gradual loss of hearing. Failure to treat otosclerosis can lead to complete deafness.
The precise causes of otosclerosis are unknown. However, there is a "fairly reliable hypothesis, which recognizes the reasons for the disease in the interaction between genetic and environmental factors."
Otosclerosis is usually a bilateral problem; unilateral otosclerosis is very rare.
Currently, the therapies available to patients consist of the use of external hearing aids and surgical practice aimed at removing / remodeling the stapes.
If the treatment is done in time, the prognosis is generally positive.
OSTEOSCLEROSIS
Osteosclerosis, or bone sclerosis, is a pathological process that causes an abnormal hardening and an equally abnormal thickening of a bone.
In most cases, osteosclerosis is due to an osteoarthritis condition, "osteitis ossifying," reactive osteitis, or osteoid osteoma.
A fair number of patients with osteosclerosis suffer from this disorder for no recognizable reason (idiopathic osteosclerosis).
As a result of the sclerosis process, the affected bone is denser and more compact than normal. In fact, what happens in the case of osteosclerosis is the opposite of what happens in the case of osteoporosis.
PROGRESSIVE SYSTEMIC SCLEROSIS
Progressive systemic sclerosis, better known as scleroderma, is a skin disease characterized by abnormal hardening and an equally abnormal thickening of the skin.
In most cases, scleroderma affects the skin on the arms and legs and the skin area around the mouth. More rarely, it also affects the capillaries, arterioles and internal organs of the heart, kidneys, intestines and lungs.
When progressive systemic sclerosis also involves internal organs, it can have very serious consequences, including death of the patient.
Despite numerous studies on the subject, the precise causes of scleroderma are unknown. According to some researchers, the condition is linked to some genetic factor.
Currently, there is still no cure for scleroderma, but only a symptomatic treatment, which relieves the ailments and improves the quality of life of patients.
HIPPOCAMPAL SCLEROSIS
Hippocampal sclerosis is a neurological condition characterized by a severe loss of nerve cells (or neurons) and a process of gliosis in a specific section of the temporal lobe of the brain, known as the hippocampus.
Currently, the precise causes of hippocampal sclerosis are unclear. According to some theories, factors such as old age, vascular problems (hypertension and stroke in particular) and belonging to the lower socio-economic classes would favor the appearance of the condition.
The most characteristic consequence of hippocampal sclerosis is a form of epilepsy, known as temporal lobe epilepsy.
According to statistics, hippocampal sclerosis has a notable mortality.
What is gliosis?
In medicine, the term gliosis indicates a pathological proliferation of glia cells.
SEGMENTAL AND FOCAL GLOMERULOSCLEROSIS
Segmental and focal glomerulosclerosis is a condition that alters the normal anatomy of the renal glomeruli and causes nephrotic syndrome.
Following the onset of segmental and focal glomerulosclerosis, the renal glomeruli of the affected person have a higher than normal connective-fibrous component and a reduced healthy parenchymal component.
The precise causes of segmental and focal glomerulosclerosis are unknown. For reasons still unknown, the condition in question is more common in the male population.
The most important complication is renal failure.
The only therapies available to patients are symptomatic: their purpose is to alleviate the symptoms and avoid (or at least delay) the onset of renal insufficiency.
