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Hyalisation of muscle fibrils of skeletal, intercostal, diaphragmatic and cardiac muscles. Histologically there is '''[[Zenker Degeneration - Pathology|Zenker degeneration]]''' and occasionally also '''[[Myocardial - Pathology#Mineralisation|dystrophic calcification]]'''.
==Introduction==
Hyalisation of muscle fibrils of skeletal, intercostal, diaphragmatic and cardiac muscles. Histologically there is '''[[Zenker Degeneration|Zenker degeneration]]''' and occasionally also '''[[Myocardial Mineralisation|dystrophic calcification]]'''.
Grossly the condition is seen as grey/yellow streaks on the innermost part of the myocardium.
Grossly the condition is seen as grey/yellow streaks on the innermost part of the myocardium.
The condition is associated with '''Vitamin/Selenium deficiency'''. Also known as [[Muscles Degenerative - Pathology#Nutritional myopathy|'''nutritional myopathy''']] or '''[[White Muscle Disease - Pathology|White muscle disease]]'''.
The condition is associated with '''Vitamin/Selenium deficiency'''. Also known as [[:Category:Muscles - Degenerative Pathology|'''nutritional myopathy''']] or '''[[White Muscle Disease|White muscle disease]]'''.
The myocardium of the left ventricle is most affected as it has the largest metabolic demand and so the largest production of anti-oxidants and the greatest need for Vitamin E/Selenium. This manifests clinically as left sided heart failure with clinical signs:
The myocardium of the left ventricle is most affected as it has the largest metabolic demand and so the largest production of anti-oxidants and the greatest need for Vitamin E/Selenium. This manifests clinically as left sided heart failure with clinical signs:
*Pulmonary oedema.
*Pulmonary oedema.
*Acute ataxia and collapse with the skeletal muscles affected.
*Acute ataxia and collapse with the skeletal muscles affected.
Also associated with a diet over-rich in unsaturated fatty acids seen in pigs (Vitamin E/Selenium unavailable as used up by the unsaturated fats).[[Category:Cardiovascular_System_-_Metabolic_Pathology]][[Category:Myocardial_Pathology]]
Also associated with a diet over-rich in unsaturated fatty acids seen in pigs (Vitamin E/Selenium unavailable as used up by the unsaturated fats).
* The term "hyaline degeneration" is applied to several types of degeneration or infiltration.
** "Hyaline" is a descriptive term meaning "glassy".
*** Used in pathology when structureless material appears in section, and stains red with eosin
**** Describes a variety of conditions in which structureless materials are present.
* Is applied to both extra- and intra-cellular degenerations/ infiltrations. ** '''Extracellular'''
*** Protein hyaline casts in the renal tubules.
**** From excessive protein passing through glomerulus.
**** When fresh urine is examined under the microscope, casts may be seen as elongated glassy tubes.
*** Hyaline membranes
**** Proteinaceous effusions into pulmonary alveoli
**** Prevent gaseous exchange. ** '''Intracellular'''
*** Hyaline degeneration of skeletal muscle.
**** In vitamin E/ selenium deficiency.
* There are two forms of hyaline degeneration that deserve their own mention.
** Fibrinoid degeneration.
** Amyloid infiltration.
===Fibrinoid Degeneration===
* Fibrinoid degeneration features a material which is fibrin-like.
* Is essentially a focal death of cells in the walls of small blood vessels (usually arterioles).
** Parts of the vessel wall become replaced by a granular material.
*** Pinkish-red (i.e. eosin-staining).
*** Has some of the appearance and staining properties of fibrin.
*** Consists partly of degenerated muscle and elastic fibres, and partly of an increased amount of protein ground substance around the degenerated fibres.
*** Looks like a red smudge in the vessel wall when viewed histologically.
* The presence of the fibrin-like material may suggest
** A local hypersensitivity reaction
** Hypertension
===Amyloidosis===
* Also known as amyloid infiltration
* Deposition of a proteinaceous hyaline substance in extracellular sites.
** Sites of deposition vary with species.
* The kidney is a common site of deposition.
** Amyloid is deposited under the capillary endothelium and progressively increases in volume.
* There are various categories of amyloid.
** Is essentially an abnormal protein produced in the body
** In most cases, it is produced in response to sustained antigenic stimulation caused by a chronic suppurative process.
*** E.g. a foot abscess, mastitis.
* Amyloid is a relatively inert substance.
** When it accumulates, it is not easily removed.
{{Learning
|flashcards = [[Myocardial Pathology Flashcards]]
}}
[[Category:Degenerations and Infiltrations]]
[[Category:Cardiovascular_System_-_Metabolic_Pathology]][[Category:Myocardial_Pathology]]
[[Category:Cardiology Section]]
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