Mönckeberg's arteriosclerosis, or Mönckeberg's sclerosis, is a form of arteriosclerosis or vessel hardening, where calcium deposits are found in the muscular middle layer of the walls of
arteries (the
tunica media
The tunica media (New Latin "middle coat"), or media for short, is the middle tunica (layer) of an artery or vein. It lies between the tunica intima on the inside and the tunica externa on the outside.
Artery
Tunica media is made up of smooth m ...
). It is an example of
dystrophic calcification
Dystrophic calcification (DC) is the calcification occurring in degenerated or necrotic tissue, as in hyalinized scars, degenerated foci in leiomyomas, and caseous nodules. This occurs as a reaction to tissue damage, including as a consequence o ...
. This condition occurs as an age-related degenerative process. However, it can occur in pseudoxanthoma elasticum and idiopathic arterial calcification of infancy as a pathological condition, as well. Its clinical significance and cause are not well understood and its relationship to
atherosclerosis and other forms of vascular
calcification
Calcification is the accumulation of calcium salts in a body tissue. It normally occurs in the formation of bone, but calcium can be deposited abnormally in soft tissue,Miller, J. D. Cardiovascular calcification: Orbicular origins. ''Nature Mat ...
are the subject of disagreement.
Mönckeberg's arteriosclerosis is named after
Johann Georg Mönckeberg, who first described it in 1903.
Signs and symptoms
Typically, Mönckeberg's arteriosclerosis is not associated with symptoms unless complicated by
atherosclerosis,
calciphylaxis
Calciphylaxis, also known as calcific uremic arteriolopathy (CUA) or “Grey Scale”, is a rare syndrome characterized by painful skin lesions. The pathogenesis of calciphylaxis is unclear but believed to involve calcification of the small blood ...
, or accompanied by some other disease.
However, the presence of Mönckeberg's arteriosclerosis is associated with poorer prognosis. This is probably due to vascular calcification causing increased
arterial stiffness
Arterial stiffness occurs as a consequence of biological aging and arteriosclerosis. Inflammation plays a major role in arteriosclerosis development, and consequently it is a major contributor in large arteries stiffening. Increased arterial stiff ...
, increased
pulse pressure and resulting in exaggerated damage to the
heart
The heart is a muscular organ in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as carbon dioxide t ...
and
kidneys.
Cause
Minor degrees of calcification of the cardiovascular system are common in elderly people,
and the prevalence of vascular calcification is increased by some diseases (see
Epidemiology section).
Vascular calcification results from the deposition of calcium phosphate crystals (
hydroxyapatite
Hydroxyapatite, also called hydroxylapatite (HA), is a naturally occurring mineral form of calcium apatite with the formula Ca5(PO4)3(OH), but it is usually written Ca10(PO4)6(OH)2 to denote that the crystal unit cell comprises two entities. ...
) as a consequence of disordered calcium phosphate regulation in the blood vessel. Hydroxyapatite is secreted in vesicles that bleb out from vascular smooth muscle cells or pericytes in the arterial wall.
The mechanism of vascular calcification is not fully understood, but probably involves a phenotypic change in the vascular smooth muscle cells in the wall with activation of bone-forming programs. Numerous regulators of calcification such as
osteopontin,
osteoprotegerin, matrix gla protein and
fetuin-A
alpha-2-HS-glycoprotein (AHSG, Alpha-2-Heremans-Schmid Glycoprotein) also known as fetuin-A is a protein that in humans is encoded by the ''AHSG'' gene. Fetuin-A belongs to the fetuin class of plasma binding proteins and is more abundant in feta ...
, receptor activator of
NF-kappa-B, receptor activator of NF-kappa-B ligand and
tumor necrosis factor (TNF)-related apoptosis-inducing ligand protein have been implicated in this process.
It is unclear whether Mönckeberg's arteriosclerosis is a distinct entity or forms part of a spectrum of vascular calcification that includes atherosclerosis and calcification in the inner layer of the artery wall (
tunica intima
The tunica intima (New Latin "inner coat"), or intima for short, is the innermost tunica (layer) of an artery or vein. It is made up of one layer of endothelial cells and is supported by an internal elastic lamina. The endothelial cells are in ...
), calcification of the internal elastic lamina, calcification of
cardiac valves and widespread soft tissue calcification. The existence of Mönckeberg's arteriosclerosis has been disputed and it has been proposed that it is a part of a continuum of atherosclerotic disease:
the majority of atherosclerotic plaques contain some calcium deposits and calcification of the internal elastic lamina is common in pathological specimens labelled as Mönckeberg's arteriosclerosis.
However studies in animals suggest that a predominantly medial pattern of vascular calcification reflects different underlying mechanisms of disease,
and despite involvement of the internal elastic lamina, evidence of
inflammation
Inflammation (from la, wikt:en:inflammatio#Latin, inflammatio) is part of the complex biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or Irritation, irritants, and is a protective response involving im ...
is rare in Mönckeberg's arteriosclerosis.
Diagnosis
Often Mönckeberg's arteriosclerosis is discovered as an incidental finding in an
X-ray
An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 picometers to 10 nanometers, corresponding to frequencies in the range 30&nb ...
radiograph, on
mammogram
Mammography (also called mastography) is the process of using low-energy X-rays (usually around 30 kVp) to examine the human breast for diagnosis and screening. The goal of mammography is the early detection of breast cancer, typically through d ...
s, in
autopsy
An autopsy (post-mortem examination, obduction, necropsy, or autopsia cadaverum) is a surgical procedure that consists of a thorough examination of a corpse by dissection to determine the cause, mode, and manner of death or to evaluate any di ...
, or in association with investigation of some other disease, such as
diabetes mellitus
Diabetes, also known as diabetes mellitus, is a group of metabolic disorders characterized by a high blood sugar level ( hyperglycemia) over a prolonged period of time. Symptoms often include frequent urination, increased thirst and increased ap ...
or
chronic kidney disease
Chronic kidney disease (CKD) is a type of kidney disease in which a gradual loss of kidney function occurs over a period of months to years. Initially generally no symptoms are seen, but later symptoms may include leg swelling, feeling tired, vo ...
. Typically calcification is observed in the arteries of the upper and lower limb although it has been seen in numerous other medium size arteries.
In the radial or ulnar arteries it can cause "pipestem" arteries, which present as a bounding pulse at the end of the calcific zone. It may also result in "pulselessness." Epidemiological studies have used the ratio of ankle to brachial blood pressure (
ankle brachial pressure index
The ankle, or the talocrural region, or the jumping bone (informal) is the area where the foot and the leg meet. The ankle includes three joints: the ankle joint proper or talocrural joint, the subtalar joint, and the inferior tibiofibular joint ...
, ABPI or ABI) as an indicator of arterial calcification with ABPI >1.3 to >1.5 being used as a diagnostic criterion depending on the study.
Management
Epidemiology
The prevalence of Mönckeberg's arteriosclerosis increases with age and is more frequent in diabetes mellitus, chronic kidney disease,
systemic lupus erythematosus
Lupus, technically known as systemic lupus erythematosus (SLE), is an autoimmune disease in which the body's immune system mistakenly attacks healthy tissue in many parts of the body. Symptoms vary among people and may be mild to severe. Comm ...
, chronic inflammatory conditions,
hypervitaminosis D
Vitamin D toxicity, or hypervitaminosis D is the toxic state of an excess of vitamin D. The normal range for blood concentration is 20 to 50 nanograms per milliliter (ng/mL). However, the toxic state is known to be a value of 100 ng/ml or more in ...
and rare genetic disorders, such as
Keutel syndrome
Keutel syndrome (KS) is a rare autosomal recessive genetic disorder characterized by abnormal diffuse cartilage calcification, hypoplasia of the mid-face, peripheral pulmonary stenosis, hearing loss, short distal phalanges (tips) of the fingers an ...
.
The prevalence of Mönckeberg's arteriosclerosis in the general population has been estimated as <1% on the basis of an ankle brachial pressure index >1.5;
however the validity of this criterion is questionable.
References
External links
{{Vascular diseases
Vascular diseases