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Dobos-Kovács, Mihály Osteopathies • Several different substances are needed for the normal development of the bones – In case some materials are not available in proper amount, typical l

Pathology of the locomotor

system

Skeletal system

bones

– abnormalities of the osteogenesis

Transformation of the vertebrae

and bones

• Twisted leg syndrome

• Spread leg syndrome

Transformation of the vertebrae

– devolution of the vertebra

– and tilting at the same time Anatomy

• functional anatomy

– The spinal column is parallel with the ground in a newly hatched chick on the first day

– the physiological lordosis develops on the first week

– and so does the position, pose typical for the species

Photo: Dr Dobos-Kovács, Mihály

Spondylolisthesis

weeks of age

– The pectoral muscles grow considerably

– later it is even more explicit

– pulls the 6 thoracic vertebra and moves it from its normal position….

– The spinal column suffers refraction at the level of the 6th vertebra…

Photo: Dr Dobos-Kovács, Mihály

Spondylolisthesis

During walking

• from the direction of the hind legs

• power acts forward and downward

– On the previously tilted vertebra

• the back of the vertebra moves

– up and forward

• the front of the vertebra moves

– down and backwards

• the 6 thoracic vertebra moves downwards

– slips (devolution)

• and tilts from its original pose

Photo: Dr Dobos-Kovács, Mihály

Photo: Dr Dobos-Kovács, Mihály

Spondylolisthesis

• Typical lesion in large meat type chicken hybrids with

huge pectoral musculature

– affects smaller or larger part of the flock

– husbandry problems (keeping and nutrition factors) are also

involved

• The 6th vertebra which moved from its original

position…

– compresses the ventral part of the spinal cord

– Waller-degeneration occurs in the motoric nerve tracts

– weakness and paralysis develops in the hind legs

• consequences:

• the affected animals first limp, later are not able to

move

– no drinking (uricosis)

– exsiccosis

Transformations of the spinal

column

• Lordosis

– the spinal column bends up

• Kyphosis

– the spinal column bends down

• Scoliosis

– the spinal column bends in S shape

Transformations of the spinal

column

• In case of spondylolisthesis

– and during spondylosis too

• pain occurs

– due to the compression of the spinal cord

• and due to the compression of the nerve tracts too

• The bird tries to reach the less painful pose

(position of the spinal column)

– in most cases immediately gets paralyzed

• The abnormal pose of the spinal column

– ossifies soon and gets fastened

Photo: Dr Dobos-Kovács, Mihály

Photo: Dr Dobos-Kovács, Mihály

Transformation of the bones

• Tibiarotation

–the tibiotarsal bone gets twisted around its longitudinal axis

–usually turns laterally

• 45-90-180°

–the distal part of the join turns with

–and so does the lower part of the leg

–The joint turns too

The tendon follows the joint, it remains in the pit!!!

• Twisted leg syndrome

• Spread leg syndrome

Photo: Dr Dobos-Kovács, Mihály

• The cause is not known

– genetic predisposition?

– malnutrition?

– husbandry problems?

• Increasingly often seen in young poult

– according to field experiences

– malsecretion maldigestion and malabsorption

increases the possibility of the lesion

– in young age

• Rickets is the predisposing factor in guinea

fowl chicks for the tibiarotation

Twisted leg syndrome

• The disease starts with the lateral or medial rotation

of the distal part of the tibiotarsal joint

– the leg follows the turning part of the joint with the tarsal bone

– the distal part of the leg turns out or in together with the tibiotarsal joint

– It looks like the joint was twisted

• Diagnosed in broiler chicken and turkey

Twisted leg syndrome

• The pathogenesis is not cleared yet

• The appearance of the syndrome increases with the appearance of new genetic lines in broiler chicken and turkey industry

• It highlights the predisposition of the modern hybrids towards this condition

Spread leg syndrome

back

– the legs turn from the coxofemoral joint

– it can occur uni- or bilateral

– high humidity during hatching?

– according to observations it develops in

newly hatched birds on slippery floor

in 2-3 weeks old birds

Photo: Dr Dobos-Kovács, Mihály

Photo: Dr Dobos-Kovács, Mihály

Osteopathies

• Several different substances are needed for the normal development of the bones

– In case some materials are not available in proper amount, typical lesions develop in the bones

• Forms:

– Osteopathy due to lack of vitamin D3 (rickets)

– Osteopathy due to lack of calcium

• Rickets due to Ca deficiency

– Osteopathy due to lack of phosphorus

• rickets due to P deficiency

– Osteopathy due to lack of proteins

– Osteopathy due to lack of vitamins

– Osteopathy due to lack of minerals

– Osteopathy due to lack of viral infection

– Other osteopathies

Osteopathy due to lack of

vitamin D3 (rickets)

• this is the original disease

–lack of sunshine – not enough vitamin D was produced in the skin

–vitamin D supply was not enough for the animal

• the original meaning of the disease:

–rickets is the incomplete development and ossification of the

growing bones

• incomplete development and ossification of the growing bones

due to lack of vitamin D

–there is enough Ca and P in the feed

–no vitamin D3, no transport proteins are produced which are

eccential for the Ca absorption from the gut

• In broader meaning:

–Besides the rachitis caused by lack of vitamin D

–We call rickets the osteopathies due to lack of Ca- and/or P!!!

• In case of rachitis lesions develop in all growing bones

• Most important to check

–The long bones, the ribs and the sternum

Rickets

• In the long bones of birds

– enchondral ossification is examined in the proximal epiphysis

• The parts of the proximal epiphysis:

– Epiphyseal cartilage

– Proliferation zone

• production of cartilage

• necrotizes and calcification occurs

– Growth zone

• With the active bone marrow

• resorption of the calcified cartilage

• new bone replaces the cartilage

Photo: Dr Dobos-Kovács, Mihály

Rickets due to lack of vitamin D or Ca

• In the deep layers of the epiphyseal cartilage new

chondrocytes and cartilage is formed

–later the chondrocytes necrotize and the cartilage calcifies

–active bone marrow intrudes into that layer

–and it resorps the necrotized and calcified cartilage

• Production of new bone tissue

–At the beginning osteoid is formed

–This calcifies

–1:9 - Ca-carbonate and Ca-phosphate

–+ small amount of Mg-phosphate and calcium-fluoride

• In case of rickets due to lack of vitamin D3 in the long

bones

–epiphyseal cartilage is produced

–The other processes are slower or do not floolw the cartilage

prodution

• So the epiphyseal cartilage becomes thicker

–The cartilage extends due to the bodyweight

–The end becomes butt, and painful, the bone bends

Photos: Dr Dobos-Kovács Mihály

Photos: Dr Dobos-Kovács, Mihály

The bone can be broken without sound

• There is constant ossification and the depots

are used up

• The compacta of the bone becomes thinner

and the bone is spongy

– juvenile osteoporosis

Photo: Dr Dobos-Kovács, Mihály

Osteopathies

– Lack of amino acids

• Lysine

– hypoplastic type of bones are produced

– Lack of vitamin C

– Lack of nicotinic acid

• vitamin B5, niacin

• rickets-like lesions

– Lack of vitamin A

Osteopathy due to lack of vitamins

Osteopathy due to lack of vitamin C

• the malfunction of the mesenchymal cells

• because of their fatty infiltration

–cartilage and osteoid production

–deceased production of the basic substance

• no problem with the calcification

Osteopathy due to lack of vitamin niacin

(rickets-like lesion)

• the lesions are similar like in case of osteopathy due

to lack of P

• in geese

Osteopathy due to lack of vitamin A

• the enchondral ossification is decreased

–In some case the skull and the vertebrae are also affected

Osteopathy due to lack of minerals

• Osteopathy due to lack of manganese (Mn)

– perosis

• the Achilles-tendon slips from the sulcus to the side

• the distal end of the leg turns lateral

– appears in young chicks and poult

– rarely in pheasant and other birds

• Osteopathy due to lack of zinc (Zn)

– Zn is essential to the development of the skeleton

• when Zn is missing, the lesions appear in the distal epiphysis of the tibia

Perosis

• Osteopathy due to lack of Manganese (Mn)

– this lesion is mainly seen in case inadequate

amount of manganese is available

– but lack of other substances can also induced

similar lesions

• pyridoxine (vitamin B6)

• biotin (vitamin B7 or H)

• nicotinic acid (vitamin B5 or niacin)

• folic acid /folacin/- (vitamin Bc or M)

• choline (vitamin B komplex)

– alone or in combination

• the manganese influences the enchondral

ossification

– the extracellular substance (the matrix) of the

cartilage is produced in decreased amount

Perosis

tendinis at the distal end of the tibiotarsal bone grows slower

– the lateral part becomes shorter

– the Achilles-tendon can easily slip to the lateral side

– the distal end of the leg turns out

– the distal end of the tibiotarsal bone is more smooth then normally

– the sulcus and the bone condyles are flat

Photo: Dr Dobos-Kovács, Mihály

• The lateral epyphyseal cartilage grows and ossifies faster then the medial

– The distal epyphisis of the tibia bends inward

– the Achilles-tendon slip to the middle from the sulcus tendinis

Photo: Dr Dobos-Kovács, Mihály

Osteopthies caused by viruses

• Short beak and dwarfism syndrome of mule duck

–SBDS

• Mulard = pekin duck ♀ x Muscovy duck ♂ hybrid,

„mule duck”

• Pathogenesis

–the mulard ducklings develop slowly and heterogenously

• from young age already

–Lack of development shows on the bones of the beak and

tarsus

• the beak becomes shorter then normally, the head is

deformed

• looks like the beak and head of goose

–the tongue grows normally, so it hangs out from the beak

–and dries out on the air

–the animals look smaller, underdeveloped

• because of the shortness of the tarsus Photo: Dr Palya, Vilmos

Photo: Dr Palya, Vilmos

– the waterfowl are very sensitive

• especially duck

– In NaCl (table salt, especially natrium) deficency rickets-like lesions develop

• similar to osteopathies due to lack of Ca and vitamin D

• the proliferation zone of the epiphyseal cartilage becomes thicker

• the osteoid tissue is not properly calcified, and the matrix is less

Disturbances of mineralization

• Osteoporosis

• Osteomalatia

• Osteodystrophia fibrosa

Osteoporosis

• develops in case the balance between the bone remodelling (resorption and formation) splits and the resorption exceeds formation

– faulty mineralization of the bones

– which cause the bones to become porous within, with a lot of embedded hollow-like spaces

– the cortex of the bone becomes thinner

– osteoporosis often develops in the epiphysis of the bone

– more brittle bones, and get fractured easily

• appears in all ages

• in young age it is called juvenile osteoporosis

– in broilers the malsecretion, maldigestion, malabsorption syndrome can lead to osteoporosis

– in poult the PEMS or other independent viral enteritides

– the nutrirent supply is not adequate in these cases

• proteins, vitamins, minerals

Osteoporosis

• In pullets or adult the quality and the

quantity iof the feed influences the

appearance of osteoporosis

– the most often seen causes are lack of protein,

vitamins A, B2 and C, lack of Cu, Mn, Zn

– In this case the osteoporosis effect

multitudinous birds and bones! – systemic,

generalized lesion

• Solitary osteoporosis

– partial (affects few bones only) osteoporosis

– In case of disuse (paralysis, mechanical trauma)

– atrophia ex inactivitate

– osteoporosis occurs on areas where the

remodelling is very intense

• f.e epiphysis

Osteoporosis

In cage layers

• osteoporosis occurs usually at the end of the egg laying season

– It is called „caged layer fatigue”

– involving bone brittleness, paralysis, and death

– the bone loss results in increased bone fragility and susceptibility to fracture

• affected bones are the pelvis, vertebrae, sternum, ribs, humerus and femur

• the fractures cause compression of the nerves, resulting in innervation problems and decreased loadability

– „caged layer paralysis”

Osteomalacia

• the softening of the bones caused by defective bone

mineralization secondary to inadequate amounts of available

phosphorus and calcium

– it develops in adult birds – in bones finished growing

• in case inadequate amounts of Ca and P are available

• The body resorps the wanted minerals from the already

formed bone to cover the needs

– f.e Ca required for egg laying

• generalized bone condition in which there is inadequate

mineralization of the bone

• the compact and the spongy (trabecular) bones loose their

strength

• the bones of the adult bird are

– easily cut, sawed

– the spongy bone is more visible

– the bone bend

– With histopathology:

• broad, not calcified, elastic, soft osteoid can be observed

• In case the statics of the bones is disturbed

• the trabecules move from the normal position

• The organism tries to get back the balance

• It can occur in both growing or finished bones

–in different forms of rickets

–in case of osteomalacia, osteoporosis

• Appears in different bones

–the bones might enlarge

• The regular lamellar structure of the bone disappears, the lamellae of the bone are thin and - in certain areas - dissolved due to the vigorous osteolysis

• Pathogenesis

–Increased activity of the osteoclasts (resorption)

–The compact and the trabecular bone become porous

• thin, irregularly positioned spicules

–Angiofibroblast replaces the bone tissue

–proliferating osteoblasts are present in great number, and osteoid tissue produced by them can be seen without calcification

Regressive changes in the bones

• Atrophy (atrophia ossium)

• Usuration of the bone

–lacunar resorption following constant pressure (soft tumor)

• Osteochondrosis

• Epiphysiolysis

• Dyschondroplasia

• Remnant of the embryonic cartilage

• Discoloration, pigmentation of the bones

–Melanosis

–Discoloration caused by accumulation of tetracycline

• Necrosis of the bone

–femoral head necrosis

Atrophy

• occurs in long bones following disuse of the leg

– the compact becomes thinner

– the trabecules become thinner and decrease in number too

– atrophy of the exposed muscles usually also seen

• It can be observed if chronic inflammation develops

in the hind legs (joints or tendon sheets)

– orthoreoviral arthritis/tenosynovitis

– lesions of the bones

– tibiarotation, lack of Zn or Mn

• It is painful

• the animal does not stand on this side

– atrophia ex inactivitate

Osteochondrosis

• Regressive change in the bones

–Disturbance of the normal development of the bone

–different forms of the disease

–appears in fast growing broiler chickens

• Described in several bones

–In the cervical and thoracic vertebraa

–In the femur and in the antitrochanter

• The lesions are microscopic and occur between the

epiphyseal cartilage and the proliferation zone

–serous infiltration, degeneration and blockage of the blood

vessels (thrombosis) can be seen in the proliferation zone

• According the data in some broiler flock 50% of the

chickens is affected to some extent

–most of them show clinical signs too

• osteochondrosis often occur togetehr with some

other skeletal lesions

Epiphysiolysis

• Mainly in the proximal epiphysis of the femur

– loose structure with decreased strength

– in fast growing broiler chickens

• The two parts (epiphysis and diaphysis) of the bone separate from each other

– at the proximal epiphysis

– due to a minor trauma (slightly in excess of normal physical stimulus)

•normal movements (like jumping), handling

– between the two parts degenerative changes and necrosis can

be observed

• if the separation occurs in life, bleeding can be seen

– It can appear in carcasses following preparation for the dissection

Epiphysiolysis

Photos:

Dr Dobos-Kovács, Mihály

Dyschondroplasia

• In the growing long bones

–most often seen in the proximal epiphysis of the tibiotarsal bone

–in the proximal and distal epiphysis of the femur

–in the tarsometatarsal bone and in the proximal epiphysis of the humerus

• Affected: meat-type chicken, duck, turkey

• Characteristics in the long bones:

–in the growth zone of the epiphysis remnant cartilage is observed without blood vessels

–the abnormal cartilage occurs circumscribed or in the whole length of the bone

• The cartilage produced in the epiphysis

–does not contain blood vessels

–no calcification is seen

–It does not develop to osteoid and later bone tissue

• The bone are soft, weak, bend under the body weight