Transcript Pathogenesis of skeletal muscle dysfunction in the elderly

Manifestation of Novel Social Challenges of the
European Union
in the Teaching Material of
Medical Biotechnology Master’s Programmes
at the University of Pécs and at the University
of Debrecen
Identification number: TÁMOP-4.1.2-08/1/A-2009-0011
Manifestation of Novel Social Challenges of the
European Union
in the Teaching Material of
Medical Biotechnology Master’s Programmes
at the University of Pécs and at the University
of Debrecen
Identification number: TÁMOP-4.1.2-08/1/A-2009-0011
Gyula Bakó and Erika Pétervári
Molecular and Clinical Basics of Gerontology – Lecture
6
DISORDERS AND
DISEASES OF
LOCOMOTOR ORGANS
PART 1
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Outline
• Changes of the
musculoskeletal system in the
elderly
• Common diseases of locomotor
organs in the elderly –
causes of falls, chronic
immobilization and disability
• Immobilization and
remobilization in the elderly
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Geriatric Giants
Immobility
(Falls)
Incompetence
(Confusion)
Impaired
homeostasis
Incontinence
Iatrogenic
disorders
Factors adversely affecting
locomotor organs in the
elderly
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Organ damage
• Pain, rigidity of
joints and muscles
• Impaired renal
function
• Associated chronic
diseases
• Multiple medications
,
higher risk for side
effects
• Impaired fluid and
food intake
• Failing memory,
Functional disorders
• Gait disturbances
• Impaired selfreliance
• Impaired ability to
carry out household
duties
• Limited leisure
activities
Social difficulties
• Financial problems
• Inappropriate
housing
Changes of the
musculoskeletal system in
the elderly
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I Changes and dysfunction of
the skeletal muscles in the
elderly
II Aging-associated changes in
the joints
III Aging-associated changes in
the bones
I: Changes of the skeletal
muscles: sarcopenia in the
elderly
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Body weight decreases between 30-75
years of age, mainly due to a
progressive decrease in the number and
size of muscle fibers and that of
muscle mass.
Causes:
• reduced physical activity
• changes in CNS and peripheral nervous system
within which a decreased number of active
motor units are found
• decrease in protein synthesis in skeletal
muscle fibers
Pathogenesis of skeletal
muscle dysfunction in the
elderly
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I Neurological causes
(pronounced in peripheral
neuropathies)
• Reduced number and size of motor
neurons in the spinal cord
• Decrease in the axonal conductivity
• Decrease in the neuromuscular
transmission
- number of neuromuscular end
plates
- number of acetylcholine
Pathogenesis of skeletal
muscle dysfunction in the
elderly
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IIPrimary muscle damage
• Injury induced by contractures
• Altered signal transduction in the
muscle (impaired effects of trophic
factors, hormone resistance)
• Reduced number of type II muscle
Age-related changes in body composition: muscle
fibers
Age
(years)
25
75
Muscle loss Adipose
mass
tissue
30%
15%
20%
40%
Bone
10%
8%
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Loss of type II muscle
fibers
• About 50% of the muscle mass is lost
by the time we develop sarcopenia due
to old age. It affects mostly type II
(fast twitch) muscle fibers in
contrast to type I (slow twitch)
muscle fibers.
• Type II muscle fibers are responsible
for fast, intensive contractions,
while type I fibers are responsible
for slow, long lasting movements.
• Due to the loss of muscle fibers with
age, 20% of the maximal isometric
Pathogenesis of skeletal
muscle dysfunction in the
elderly (cont.)
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III Combined neuromuscular
mechanisms
• Disorders of the electric discharge of
muscle fibers
• The stimulus- contraction process is
disrupted
IV Common abnormal biochemical processes
affecting the muscle
• oxidative stress
• mutation in the mitochondrial DNA
• vasculopathies developing with age
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II: Aging-associated changes
in the joints
Cartilage coating the bone endings contains
chondrocytes, which produce collagen fibers,
hyaluronic acid and proteoglycans building a
high water-containing, elastic substance.
The proteoglycans attached to hyaluronic acid
and aggregated within the collagen network
are saturated with water and thus provide the
cartilage with the capacity to resist
compression and to re-expand after
compression.
In the elderly, the amount and water content
of the cartilage mass decrease, its
resistance against mechanical impacts is less
Aging of the joints
 arthrosis
•  water binding of
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hyaluronic acid
• changed composition (not the amount) of
proteoglycans

Reduced water content (in arthrosis it
increases) and amount of cartilage mass
lead to less resilient cartilage.
Without the protective effects of the
proteoglycans, the collagen fibers of
the cartilage become susceptible to
degradation.
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Aging in soft tissues
• Impairment of
collagene
synthesis, that
of posttranslational
modification of
collagene
• Alterations in
the quantity and
quality of
intercellular
matrix (menisci,
intervertebral
Mechanical
resistance of
soft tissues
are decreased
III: Aging-associated
changes
in the bones
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Bone mass decreases from the age of 55 by
around 1%/year in men and by 3-4%/year in
women (peak bone mass is reached at 25-35
years of age, its value is higher in men).
During the course of aging metabolic activity
of osteoblasts is decreasing.
Causes of deterioration of bone mass:
inactivity, vitamin D deficiency; hormones:
estrogen, progesterone, calcitonin,
parathormone (secondary hyperparathyroidism),
cortisol; alcohol; smoking.
Consequences:
Common diseases of
locomotor organs in the
elderly
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• Osteoarthrosis, the most common
disease of locomotor organs of people
over 50
• Rheumatoid arthritis
• Gout
• CPPD arthritis (pseudo-gout)
• Osteoporosis
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Osteoarthrosis (OA)
degenerative joint disease
Definition:
Each element of the joint becomes
gradually and progressively injured
causing swelling, pain, stiffness and
functional loss.
A degenerative process leads to
incongruence of the articular cartilage
surfaces, inflammation of the joint
capsule (synovitis), muscle atrophy and
a crackling noise (called “crepitus”)
when the affected joint is moved.
Osteoarthrosis (OA)
focal degeneration of the
joints
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New bone outgrowths:
• beneath the lesion (subchondral)
• at the edge, called “spurs” or
osteophytes narrowing of the joint
space
Thickened
bone
“Spurs” or
osteophytes
Calcificati
on of lax
tendons
(ligaments)
Cartila
ge
particl
es
Loss of
cartila
ge
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Osteoarthrosis (OA)
degenerative joint disease
Prevalence:
It affects 30% of the adult population.
90% of people over 60 have radiological
signs of arthrosis.
Incidence:
88 (hip joints), 20 (knee), and 300
(hand)/100,000/year
Significance:
It is the most common cause of
disablement and NSAIDs’ (non-steroidal
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OA a multifactorial
degenerative joint disease
Causes:
Basic causes:
• bipedalism (erect posture and work),
increased burden on the joints at the knees
• extended life span
Risk factors for faster progression:
• Mechanical causes: obesity, congenital
disorders, macro- and microtrauma, overuse,
previous inflammation of the joints and bone
necrosis.
• Metabolic causes: defects in collagen
synthesis, diabetes, hyperthyroidism,
hypothyroidism, hyperparathyroidism,
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Clinical signs of OA
•
•
•
•
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•
•
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Usually above 40 years of age
Moderate pain in one or more joints
Pain at initiation of movement
In the beginning, the pain ameliorates at
rest, later it is aggravated by rest
Morning stiffness < 30 minutes
Impaired function: instability, diminished
movements , decrease in muscle strength
Crepitation, crackling noise
Swelling, deformity
Abnormal alteration of the axis
Lack of systemic symptoms
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Therapeutic measures
Pharmacological
treatment
• Pain
killers/analgetics
• NSAID
• Intra-articular
steroids
Psycho-social
treatment
• Patient education
• Improvement of lifestyle and diet
Weight reduction
Consultations
patients
with
Orthoses
(amputee knee shell,
knee brace, orthotic
heel support, arch
support )
Other treatments
• Physiotherapy
• Surgical intervention