Haematological Disorders - finished Flashcards
Define thrombosis
Local coagulation or clotting of the blood in a part of the circulatory system
Define atherosclerosis
A disease of the arteries characterized by the deposition of plaques of fatty material on their inner walls
What is sickle cell anaemia
Congenital condition.
Erythrocyte sickling caused by abnormal haemoglobin. Local hypoxia causes erythrocytes to curve and elongate. Effort to maintain viability of RBC’s causes splenomegaly and marrow hyperplasia. Hyperplastic marrow leads to local ischaemia and necrosis.
Who does sickle cell anaemia mostly present in?
African populations
Which bones in sickle cell anaemia usually have radiological signs?
Multiple vertebral bodies Femur Humerus Tibia Small tubular bones of hands, feet and skull.
What is the clinical presentation of sickle cell anaemia?
After 6 months of age patient can develop fatigue, pallor, weakness.
Episodic crises of:
- Abdominal pain
- Jaundice
- Acute bone pain
- Splenomegaly
- Cardiomegaly
- Gallstones and
- Renal failure.
What are the radiological manifestations of sickle cell anaemia?
Marrow Hyperplasia:
- Generalised osteopaenia
- Sparse and coarsened trabecular pattern
- Large vascular channels
- Widened medullary cavity
- Cortical thinning
- Loss of diaphyseal constriction in tubular bones
Skull changes:
- widened diploic space
- granual texture
- ‘hair on end’ trabecular pattern
Spine:
- Prominent osteoporosis with accentuated vertical trabeculae.
- H vertebrae
Small tubular bones:
- soft tissue swelling (as a result of infarction)
General:
- possible solid periosteal response as a result of increased blood viscosity and stasis causing increased pressure on bones (wolf’s law)
How is an ‘H’ vertebrae formed?
After thrombosis of the centra nutrient vessel, central growth is inhibited, producing this characteristic ‘H’ shape.
What is a DD for the middle part of the endplate in the ‘H’ shaped vertebra?
Line of Han - sclerosed vein or channel in vertebra
Define thalassaemia:
Hereditary disorder of haemoglobin synthesis.
Which population group does thalassaemia usually present in?
Mediterranean and asian/indian
What is the clinical presentation of thalassaemia?
Pallor, lethargy, retarded growth, hepatosplenomegaly, inhibited sexual development, maxillary overgrowth.
What are the radiographical appearances of thalassaemia?
Spine:
- involvement of the vertebral body and neural arch
- coarse trabeculae/honeycomb appearance
- thinned cortices
- normal endplates
- osteopaenia
Skull:
- radiating spicules (hair on end)
- widened diploe
- sinuses obliterated
Long bones:
- Erlenmeyer flask deformity (lack of normal metaphyseal-diaphyseal concave constriction)
- Widened medullary cavity
- Cortical thinning
- Honeycomb appearance to medulla
General:
- Osteopaenia
- ‘Honeycomb appearance’ (coarse trabecular patterns)
- Generalised cortical thinning
- Enlarged vascular channels
- ‘Hair on end’ radiating new bone spicules
- Enlarged, ‘bulbous’ posterior ribs
What are some of the non-skeletal anomalies found in thalassaemia?
Cardiomegaly, posterior mediastinal masses, hepatosplenomegaly (as a result of extramedullary haematopoiesis).
Why is bone in thalassaemia hypointense on MRI?
Because of the bone marrow hyperplasia in thalassaemia, yellow marrow gets replaced with red marrow, and as yellow marrow carries fat, the loss of yellow marrow makes images hypointense
What is haemophilia?
A group of blood coagulation disorders characterised by a deficiency of specific clotting factors.
What are the classic clinical features of haemophilia?
Varies with severity.
Severe haemophilia: patients can have spontaneous bleeding or bleeding from minor injuries
Can possibly have haematomas or haemarthrosis, which can cause joint degeneration (due to synovitis and pannus formation)
Haemarthrosis and its subsequent synovitis precipitates fibrosis, bone erosion, osteoporosis, growth disturbance and late cartilage degeneration.
What are the radiological features of haemophilia
Soft tissue swelling Juxtaarticular osteopaenia (due to hyperaemia) - can become generalised with inactivity Subchondral cysts Subchondral sclerosis Poorly defined articular cortex Pseudotumours Enlarged femoral condyles (due to hyperaemia causing accelerated growth and maturation of epiphyseal cartilage) In severe cases, ankylosis of joints.
In severe cases, can see joint disorganisation with complete loss of joint space, articular fragmentation, sclerosis, osteophytes and bony misalignment.
Distal femur:
- grossly enlarged, osteoporotic, and irregular flattened contour to their WB surfaces (megacondyle)
- widening of intercondylar notch possibly because of repeated haemorrhage of the ACL and PCL
Proximal tibia:
- Tibial plateau may flatten
- Epiphysis is large and osteoporotic, with a thin cortex and accentuated vertical trabeculae
