Myelodysplastic syndromes and aplastic anaemia Flashcards
Define myelodysplastic syndrome
Myelodysplastic syndrome is an acquired disorder whereby a you get clones of dysfunctional myeloid cells.
You get cytopenia, dysfunctional rbc, myelocytes and thrombocytes, and an increased risk of developing AML.
Who does myelodysplasia affect?
The elderly
List some MDS bone marrow morphological features by cell type
Neutrophils:
- bilobed: pseudo Pelger-Heut anomaly
- thinning and longing out of nuclear lobe connections: myelokathexis
- hypogranulation: dysgranulopoeisis
Red blood cells:
- Dyserythropoeisis of red blood cells
- Auer rods (this suggests AML)
- Cytoplasm blebs
- Ringed sideroblasts
Thrombocytes:
-micro thrombocytes
What do you called bilobed neutrophils?
Pseudo-Pelger-Heut anomaly
Differential for bilobed neutrophils
What is myelokathexis?
Where the lobes of neutrophils are connected by thin strands
What features does dyserythropoiesis entail in MDS?
Erythrocyte precursors conjoined by cytoplastmic bridges
What do ringed sideroblasts mean?
Siderotic granules around the nucleus as a ring
What do myeloblasts with auer rods suggest?
AML (very bad)
What is the classification system used for MDS?
WHO classification - based on number of dysplastic lineages
What scoring system is used to predict survival and the likelihood of developing acute myeloid leukemia? What is this system based on?
IPSS-R:
BM blast percentage
Karyotype
Degree of cytopenia (neutrophils + platelets)
Hb count
How many genetic abnormalities would confer poor prognosis for MDS?
More than 3 abnormalities
What is the evolution of MDS? How long does it take for symptoms to show?
Weeks/months
Blood counts deteriorate, worsening consequences of marrow failure
AML evolution
As a rule of thumb, what is the cause of death in these patients?
1/3 will die from infection
1/3 will die from bleeding
1/3 from acute leukemia
Curative treatment of MDS. What’s the main problem with these?
- SCT - allogeneic stem cell transplant
- Intensive chemotherapy
They are sometimes too intense for the elderly.
Supportive treatment of MDS
Transfusions
Antibiotics
Growth factors - erythropoeitin, G-CSF, TPO/thromopoetic receptor agonist (to enhance platelet production)
List some biological supportive drugs for MDS, and how they work
Azacytidine and decitabine - both are hypomethylating
If the white count is high (which is unusual), what drug is used?
Hydroxyurea, also called hydroxycarbamide
Name another type of chemo that can be used in low doses for MDS
Low dose chemo - cytarabine
Name a type of biological modifier which is used for a specific variant of MDS
Lenalidomide - used for the 5q del variant
List some primary causes of BM failure
Congenital - Fanconi’s anaemia
Diamond-Blackfan anaemia
Kostmann’s syndrome
Acquired idiopathic aplastic anaemia - most common cause
What is Fanconi’s anaemia?
Inherited aplastic anaemia, pancytopenia due to a DNA repair defect. Autosomal recessive.
What is Diamond-Blackfan syndrome?
RBC deficiency, presents neonatally within 1 year
What is Kostmann’s syndrome?
Severe neutropenia
Secondary causes of BM failure?
Haematological - cancer
Non - haematological - fibrosis, sold mets
Infection - HIV, parvovirus, hepatitis
Chemicals (benzene), drugs, radiation
Autoimmune
Drugs and marrow failure
Predictable - dose dependent, common
Phenylbut??? NSaid??
List two antibiotics that cause cause BM failure
Chloramphenicol - but you can still get it as eye drops
Sulphonamide
List diuretics that cause cause BM failure
Thiazides
Antithyroid drugs which can cause BM failure
Carbimazole
Aplastic anaemia definition epidemiology
BM appears EMPTY
Bimodal distribution; teenagers and 60s - Asian?
Classification of aplastic anaemia
Idiopathic - vast majority
Inherited causes - dyskeratosis congenita
Fanconi anaemia
Shwachman-Diamond syndrome
Second - radiation/drugs/viruses e.g. hepatitis,HIV,SLE
Miscellaneous - paroxysmal nocturnal haemoglobuinuria
Thymoma
What is idiopathic aplastic anaemia?
Failure of BM to produce red blood cells pobably
Triad of bone marrow failure findings
Anaemia - tiredness, breathlessness
Leucopenia - infection
Platelets - bleeding
How do you diagnose aplastic anaemia?
Bloods - cytopenia
BM biopsy - hypocellular
How does aplastic anaemia look?
Looks empty in the bone marrow; fatty replacement
Differentials for pancytopenia and hypocellular marrow
ITP
Anorexia nervosa
Mycopbacteiral infeciton
AML
Hypocellular acute lymphoblasctic leukemia
hairy cell leukemia
Severe aplastic anaemia criteria
Camitta criteria -
Low reticulocytes <20x10^9L
Low neutrophils <0.5x10^9L
Low platelets <20x10^9L
Bone marrow <25% cellularity
Management of bone marrow failure
- Seek and remove any causes of BM failure
- Supportive blood/platelet transfusions, antibiotics, iron chelation therapy
- Immunosuppressive therapy - e.g. antithymocyte globulin, steroids, CyA
- Drugs to promote marrow recovery - oxymetholone, TPO receptor agonists
- Stem cell transplantation
- Other treatments in refractory cases
How common is
Supportive therapy for aplastic anaemia
Blood products
Antimicrobials
Iron chelation therapy - ferritin
What are the consequences of immunosuppressive therapy for AA?
Relapse of AA (35 percent)
Clonal haematological disorders - myelodsyplasia, leukemia
Risk of solid tumours
What is the most common cause of BM failure, and the most common inherited cause of it?
Most common cause - idiopathic
Most common inherited cause - Fanconi’s anaemia
What is fanconi anaemia?
IT IS THE MOST COMMON FORM OF INHERITED APLASTIC ANAEMIA, causing pancytopenia due to a DNA repair fault
Genetics of Fanconi anaemia?
Autosomal recessive or X-linked
Symptoms of Fanconi
Short stature
Cafeau lait or hypopigmented spots
Small head/eyes
Thumb abnormalities
Hydrocephaly
Consequences of fanconi anaemia
Aplastic anaemia - by the age of 10
Leukemia and myeldysplasia
Liver dsiease
Cancer (epithelial)
Dyskeratosis congenita
Marrow failure
Cancer predisposition
Somatic abnormalities
Triad for DC
Skin pigmentation
Leukoplakia
Nail dystrophy
consequences of DC
Management of BM failure
Supportive ???
Genetics of DC
Telomere shortening
act to prevent chromosomal fusion or rearrangements drugin chromosal replication
Protect the genes at the end of the chromosome from degradation
DC
X-linked - DKC1
????????????? also automosomal? see slide
Telomeric shortening is a feature of
Both dyskeratosis congenita AND aplastic anaemia
If a patient is above 50, what do you try?