2. Session 1 - Diagnosis of thalassemia - Dr. Akhil Ranjan Biswas.ppt

Thalassemia is a genetic blood disorder characterized by reduced production of hemoglobin, the molecule in red blood cells that carries oxygen. There are two main types: alpha thalassemia and beta thalassemia, depending on which part of the hemoglobin molecule is affected. Symptoms can range from mild to severe anemia, depending on the type and number of gene mutations inherited. Treatment varies but may include blood transfusions, iron chelation therapy, and in severe cases, bone marrow transplantation

1. Dr. Akhil Ranjon Biswas
Associate Professor, BMT
Dept. of Hematology
Dhaka Medical College & Hospital
[email protected]
Diagnosis of Thalassemia and Related
Hemoglobin Disorders

2. Thalassemia Spectrum

3. Thalassemia Spectrum

4. Thalassemia Spectrum

5. Thalassemia: Phenotypes
Thalassemia
Minor

6. Thalassemia: Phenotypes
Thalassemia
Minor
ThalassemiaI
ntermedia

7. Thalassemia: Phenotypes
Thalassemia
Minor
Thalassemia
Intermedia
Thalassemia
Major

8. Pathophysiology of Phenotypic Heterogenecity: A Glimpase
Stable hemoglobin molecule in adult is a tetramer formed of-
2 alpha globin chain, with,
2 beta (Hb A), gamma (Hb F) or delta (Hb A2) globin chain.
Quantitative imbalance between alpha and non-alpha globin chain
are responsible for clinical expression of thalassemia.

9. Pathophysiology of Phenotypic Heterogenecity of βThalassemia: A
Glimpase

10. Present talk will principally cover β
thalassemia and related disorders

11. According to Disease Potential Thalassemias are
1.Symptomatic Thalassemia: Thalassemia Major & Thalassemia
Intermedia
2.Asymptomatic and silent carrier
From here on, term ‘thalassemia’ will be used for symptomatic
thalassemias.

12. Diagnosis of symptomatic thalassemia (Thalassemia Major &
Thalassemia Intermedia) typically relies on
1.Clinical features (symptoms and signs): Few unique but mostly
non-specific
2.Typical lab findings

13. Clinically Popular Features of Thalassemia
1.Moderate to severe pallor/anemia
2.Mild jaundice
3.Splenomegaly
4.Hepatomegaly
5.Stunted growth
6.Typical facial changes: frontal bossing, prominent maxilla and
zygoma, depressed nasal bridge.
7.Poorly developed or undeveloped secondary sexual character
8.Typical radiological finding

16. Most of those popularly known pictures are associated with mostly
irreversibly complicated thalassemia major, certainly destined to
deadly outcome shortly.
For successful and meaningful management of thalassemia we must
be able to diagnose symptomatic thalasemmia before appearance
of those popular picture
So, clinical features of thalassemias to be redefined

17. Clinical features of thalassemia
Clinical features of thalassemia necessarily mean clinical features of
symptomatic thalassemias, namely thalassemia major and
thalassemia intermedia. Though thalassemia major and
intermedia present generally almost similar features but in
significantly different spectrum.

18. Clinical features of thalassemia
Features of thalassemiamajor
Should present within 2 years of age if addressed properly
Failure to thrive
Repeated infection
Pallor
Splenomegaly(and hepatomegalyif not transfused sufficiently)
May have clinically evidenced jaundice
Regular transfusion required before 2 year of age for normal
growth and development
Bony expansion causing frontal bossing, malarprominence etc
along with growth retardation revealed later in childhood if not
transfused sufficiently.

19. Clinical features of thalassemia
Features of thalassemia intermedia
Very diverse spectrum of expression, in one end it merge with
thalassemia major and on the milder end it merge with thalassemia
minor.
Pallor, splenomegaly etc become clinically evident after 2 year of
age
Heterogeneous clinical expression: some patients require transfusion
since early childhood and some patient may be able to maintain
normal growth and development without any transfusion.
Some patient may present in adulthood with paraplegia due to
extramedullary hemopoiesis in spinal canal, with features related to
iron loading, chronic jaundice, episodic or chronic fatigue etc.
Growth retardation, bone deformity, hepatomegaly only seen in more
severe form of poorly treated or untreated cases.

20. Laboratory investigation
1.CBC:
1.Hb <9 g/dl
2.MCV -low/variable
3.MCH-low
4.MCHC-low or normal
5.RDW-markedly raised
6.WBC & Plt generally
normal
2.PBF : Gross anisopoikilocytosis,
tear drop cells, target cells,
normoblast, basophilic
stippling etc

21. Laboratory Diagnosis
Hemoglobin electrophoresis:
Common thalassemia genotypes are
Compound heterozygous HbE/βthalassemia
Double heterozygous/homozygous βthalassemia (β/βthalassemia)
Less common genotypes are
δβ thalassemia compound heterozygote with Hb E or βthalassemia or homozygous
δβ
Hb Lepore/Hb E, Hb Lepore/β, Hb Lepore/Hb Lepore
Hb H disease
*Hb S/βthalassemia is a sickling disorder rather than thalassemia

22. Laboratory Diagnosis: Hb Electrophoresis
β/βthalassemia:
HbA: 0 to variable
HbF: >15 to 99%
HbA2: Variable but <8%
Most likely βthalassemia major

23. Laboratory Diagnosis: Hb Electrophoresis
β/βthalassemia:
HbA: 0 to variable
HbF: >15 to 99%
HbA2: Variable but <8%
Most likely βthalassemia intermedia

24. Laboratory Diagnosis: Hb Electrophoresis
HbE/βthalassemia:
HbA: 0 to variable
HbF: >15 to variable
HbE: > 40 to variable
HbA2: Variable but <8%

25. Laboratory Diagnosis: Hb Electrophoresis
HbE/βthalassemia:
HbA: 0 to variable
HbF: >15 to variable
HbE: > 40 to variable
HbA2: Variable but <8%

26. β/βthalassemia:
HbA: 0 to variable
HbF: >15 to 99%
HbA2: Variable but <8%
Laboratory Diagnosis: Hb Electrophoresis
δβ/βor δβ/δβthalassemia:
HbA: 0 to variable
HbF: >15 to 99%
HbA2: <3%
δβ/βor δβ/δβthalassemia: Conditions tricky to diagnose

27. Laboratory Diagnosis: Hb Electrophoresis
•26 year old lady
•Height 160 cm
•Well developed 2ndary sexual character
•Occasional transfusion requirement
•Hb 7.5 gm/dl with typical PBF of
thalassemia
Diagnosis?

28. Laboratory Diagnosis: Hb Electrophoresis
This type of electrophoretic
pattern with thalassemia
intermedia like clinical
expression suggest δβ/βor
δβ/δβthalassemia

29. Laboratory Diagnosis: Hb Electrophoresis
Significant aberration from classical electrophoretic pattern is not
uncommon.
So, electrophoresis pattern should always be interpreted in the
context of clinical features, PBF and transfusion history.
Parent screening may be needed in some cases.

30. Laboratory Diagnosis: Additional
Serum bilirubin: total (raised but not >5 mg/dl), direct (normal
unless complicated) & indirect (raised)
Retculocyte count: relative reticulocytopenia
Serum ferritin: usually raised
*Lot more investigations are related to management issues and to be
discussed in relevant sections

31. Carrier Detection
•Detection of asymptomatic/silent carriers are primarily driven by CBC and
almost certainly confirmed by Hb Electrophoresis (capillary preferred)
•There are some other cheaper and easily accessible methods those are
less specific and sensitive
•Relevant types in Bangladesh are
•Hb E trait
•β thalassemia trait
•Homozygous Hb E (Hb E disease)
•δβ thalassemia trait
•Hb Lepore trait
* αthalassemia traits can’t be diagnosed but suspected from blood picture and electrophoresis.

32. •Apparently Healthy
•Age >12 year
•No red cell transfusion in preceding 4 month
CBC
MCV <78 fl or MCH <27 pg
Capillary
Hemoglobin
Electrophor
esis
A2 >3.7%
F <5%
A= Rest
A2+E >12%
F <1%
A= Rest
Hb A= 0%
Hb F= <5%
A2+E= Rest
A2 <3.2
F= 5-20%
A=Rest
A2 <3.3
F <1
A= Rest
(Normal pattern)
Other
patterns
MCV <72fl + Normal MCHC
Hb E traitβ
thalasse
mia trait
Homozygous
Hb E (Hb E
disease)
δβ
thalassemia
trait
Probable α thal
trait when iron
deficiency is
excluded
Expert Consultation

33. Red cell indices in thalassemia minor

34. Mentzerindex ≤12 is most specific but not very sensitive
predictor of thalassemiaminor
MentzerIndex = MCV÷RBC (million/cmm)
MCV cut off value <72 fl is the most sensitive but very unspecific
predictor of thalassemiaminor

35. Red cell indices in thalassemia minor
Mentzer index = 12 Mentzer index = 10

36. Carrier Detection: Hb Electrophoresis (capillary)
βthalassemia trait

37. Carrier Detection: Hb Electrophoresis (capillary)
δβthalassemia trait

38. Carrier Detection: Hb Electrophoresis (capillary)
Homozygous Hb E (Hb E disease)

39. Carrier Detection: Hb Electrophoresis (capillary)
Hb E trait

40. Carrier Detection: Hb Electrophoresis (capillary)
Hb E trait

41. Interpretation of Hb Electrophoresis sometimes may be tricky rather
than straightforward.
Hope to discuss few such tricky tracing in last session.

42. Carrier Detection: Hb Electrophoresis (capillary)
Question?