4 Discribe The Pathology Flashcards
Describe the four distinct pathological stages of Legg-Calve-Perthes disease.
- Avascular stage
– ossification centre becomes necrotic - Revascularisation stage
– resorption of the necrotic bone; replaced by new immature bone cells; remodelling of bone contour - Remodelling/repair
– formation and replacement of immature bone cells by normal bone cells; remodelling of femoral head - Deformity
– femoral head flatter and enlarged
– acetabulum is larger and shallow
– femoral neck in shorter and more acutely angled
– greater trochanter is enlarged
State the clinical manifestations seen in Congenital Dislocation of the Hip (CDH)
Clicking hip Barlow’s manoeuvre Ortolani’s sign limb shortening (Allis sign = knees not at the same level) tightness of adductors Increase in telescoping of the limb Asymmetrical buttock folds Trendelenburg gait (significant limp)
Plain film radiograph of the hip indicates a flattened and sloping acetabular roof and a misshaped and flattened femoral head.
Name the pathology you consider is most like causing the child’s symptoms.
Describe the pathology affecting the hip (other than the femoral head and acetabulum).
congenital dislocation of the hip
Femoral neck
Neck is anteverted & in valgus position (1.0 mark)
Fibrocartilagenous labrum
After dislocation /subluxation, the labrum often enlarged and folds into the cavity impeding complete reduction (2.0 marks)
Ligamentum Teres
Lengthened and redundant (1.0 mark)
Transverse acetabular ligament
Pulled superiorly (1.0 mark)
Capsule
Gradually elongates at the femoral neck (1.0 mark)
Outline the radiographic features of osteoarthritis
X-ray studies closely parallel underlying pathological sequence Asymmetrical distribution Non uniform loss of joint space Osteophytes Subchondral sclerosis Subchondral cysts Intra-articular loose bodies Articular deformity Joint subluxation
Outline the pathology of osteoarthritis
Mechanical injury to articulating cartilage ® chondrocyte response release of proteolytic enzymes further damaging to fibres of cartilage
formation of cracks in cartilage influx of synovial fluid into cartilage cracks (1.5 marks for explaining the changes in the articular cartilage, not necessarily using these specific terms)
Micro fractures in underlying subchondral bone ® new blood vessel grow in the subchondral bone of the epiphysis attempt to heal cracks in the cartilage. Osteoclast and osteoblast activity resorption of bone in micro fractures (osteoclasts) and thickening of subchondral bone (osteoblasts) Formation of osteophytes at the periphery of the joint Subchondral bone becomes exposed (eburnated– “ivory-like”-bone) leaking of synovial fluid via cracks into subchondral space form subchondral bone cysts. With destruction of cartilage ® closing of joint space. (7 marks for explaining the changes taking place in the subchondral bone including sclerosis, cysts, osteophytes and reduced joint space. These changes are important as they are visible on plain film radiograph)
Hyperplasia of synovium with inflammation (synovitis) and thickening of joint capsule due to inflammation and oedema (1.5 marks for explaining the changes in the synovium and joint capsule, but not necessarily using these specific terms)
A 13 year old girl presented to her general medical practitioner with acute right knee pain. She is feverish and has chills. The knee is red, hot and swollen. There is no history of acute trauma.
The girl has a history of a bacterial throat infection.
Plain film radiographs of the knee are inconclusive but indicate a slight “permeative” appearance in the distal metaphysis of the femur.
Name the condition you suspect,
Describe the pathology of the condition you suspect.
Osteomyelitis
Begins generally in metaphysis because capillaries terminate here slow blood flow bacteria able to escape the capillaries establish a foci for proliferation of the bacteria in the marrow → localised suppurative response leads to disruption of blood supply to the bone ischaemia bone becomes necrotic separates from viable surrounding bone sequestrum. Pus formation purulent exudate extends into endosteal vascular channels that supply the cortex → pus gets under the periosteum → pus builds up between cortex and periosteum damaging periosteal blood vessels →reactive periosteal bone formation in a response to the destruction results in a sheath of new bone called an involucrum → eventually pus penetrates the periosteum via a draining sinus called a cloaca → finds its way to surrounding soft tissue abscess formation.
Because Osteomyelitis is an infectious process, inflammation will be contributing to her signs and symptoms.
Describe the blood flow changes, the movement of fluid and cells from the blood to the interstitium, and the mechanisms which cause these changes to occur during acute inflammation
Directly after injury, due to vasoconstriction, transient ischemia takes place. Ischemia may last from a few seconds to a couple of minutes.
This is followed by a progressive, persistent vasodilatation these vascular changes are followed by blood flow changes there is a rapid blood flow due to the vasodilatation. With the dilation of the small blood vessels, a pulsating of the whole capillary bed results (hyperemia) a lot of heat is generated during these processes due to ↑ blood flow Slowing of blood flow then takes place until stasis occurs due to a loss of plasma into the neighbouring tissue as a result of ↑ permeability of vesselsThe WBC (white blood cells or leukocytes) move to the vessel endothelium → margination takes place (pavementing) → leukocytes adhere to the endothelium. The endothelium openings enlarge and allow the leukocytes to pass through by means of pseudopodia and amoeboid movement (leukocyte migration though the endothelium and basement membrane = diapedesis). The leukocytes then migrate through the interstitium to the inflamed area under influence of the released chemical substances (mediators) by means of chemotaxis. The movement of leukocytes and protein rich fluids from intravascular to extravascular space (interstitium) causes swelling and the stretching of the tissue and released chemicals cause pain. Phagocytosis by the leukocytes takes place with the destruction of the toxic agent. Grossly injured cells (tissues) will lose their function and die.
Plain film radiographs reveal the radial head and neck have altered anatomy
Describe the type and pattern of fracture at these locations
Radial head - Fracture line is usually vertical involving the articular surface with cortical displacement at the fracture site. There is deformity, angulation and/or depression maybe be present producing a “double cortical” sign. Fat pad displacement is a sign of intra articular fracture involvement and can be seen both anteriorly and posteriorly
(4 marks)
Radial Neck: - impaction most common. Between the neck and head maybe seen as an angulation, a transverse fracture line, or comminution with displacement
(2 marks)
Plain film radiographs reveal bony disruption to the proximal fifth metatarsal
Describe the radiographic appearance of this type of trauma
Jones’ fracture involves a fracture at the base of the fifth metatarsal which typically extends into the 4-5 intermetatarsal facet; - Jones fracture is located within 1.5 cm distal to tuberosity of 5th metatarsal
After examination there is pain on pressure to the medial heel as well
Explain this musculoskeletal injury
Classic symptoms of plantar fasciitis include severe pain which is worse in the morning/after rest and improves after moving around; pain is aggravated by weight bearing all day, and becomes progressively more severe;
pain is described as dull aching or sharp; be specific about the point of maximal tenderness in relation to the medial calcaneal tuberosity; tenderness is typically produced with dorsiflexion of toes (MTP’s) tensioning the plantar fascia accentuating tenderness on palpation of the fascial band;
Plain film radiographs reveals a sever eversion injury to the ankle involving the tibia and fibular
Describe the type and pattern of fracture at these locations
Transverse fracture of medial malleolus or disruption of deltoid ligament;
External rotation then results in rupture of the anterior tibio-fibular ligament or its bony insertion;
Short oblique or spiral fracture of the fibula above the level of the joint; & the inter-osseous membrane is ruptured up to the level of fibula fracture
Posterior tibio-fibular ligament rupture or avulsion at the posterior malleolus; (4 marks)
Or
the sturdy medial (deltoid) ligament of the ankle, often tearing off the medial malleolus due to its strong attachment.
The talus then moves laterally, shearing off the lateral malleolus or, more commonly, breaking the fibula superior to the tibio-fibular syndesmosis. If the tibia is carried anteriorly, the posterior margin of the distal end of the tibia is also sheared off by the talus. A fractured fibula in addition to detaching the medial malleolus will tear the tibio-fibular syndesmosis.
The combined fracture of the medial malleolus, lateral malleolus, and the posterior margin of the distal end of the tibia is known as a “trimalleolar fracture.” Note that in a “trimalleolar fracture” the posterior distal end of the tibia is erroneously labelled as a malleolus
Plain film radiographs reveal no bony disruption to tibia, fibula or the tarsals
Name the ligament involved and describe the type and pattern of soft tissue injury
Anterior Talo-fibular sprain:- with an inversion force of the foot, there is injury to anterolateral capsule, ATFL, & anterior tibiofibular ligament; - about 40% of patients will have this injury type with ankle sprain
After examination there is pain on pressure to the proximal fifth metatarsal and on reviewing the radiographs something seems to have pulled away from the bone
Describe the radiographic appearance of this type of trauma
Avulsion fracture of 5th metatarsal styloid;
Plain film radiographs reveal the radial head and neck have altered anatomy
Describe the type and pattern of a fracture at these locations
Radial head - Fracture line is usually vertical involving the articular surface with cortical displacement at the fracture site. There is deformity, angulation and/or depression maybe be present producing a “double cortical” sign. Fat pad displacement is a sign of intra articular fracture involvement and can be seen both anteriorly and posteriorly
(4 marks)
Radial Neck: - impaction most common. Between the neck and head maybe seen as an angulation, a transverse fracture line, or comminution with displacement
(2 marks)
Describe the causes of carpal tunnel syndrome
Compression of the median nerve could be caused by:
Reduction of the tunnel capacity, i.e. bony or ligament changes
Increase in the volume of the tunnel contents i.e. inflammation of the tendons, synovial swelling, tumours, and oedema in the wrists.
Or could include the following……
Carpal tunnel syndrome can be a feature of many systemic diseases e.g. rheumatoid arthritis, and diabetes mellitus.
It could result from wrist injury, could occur during pregnancy, use of birth control drugs, in labourers with repetitive use of the wrists.
