Thalassemia Flashcards

1
Q

Chromosome affected in thalassemia major

A

Chr. 11

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2
Q

Hb Electrophoresis results in a newborn (Day 0) vs adults (or 6 mnths old baby)

A

DAY 0 Adult (or 6mnths)

HbF: 95% HbF: 2%
HbA: 2% HbA: 95%
HbA2: 3% HbA2: 3%

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3
Q

First Hb to develop in a fetus

A

Gower 1, followed by Gower 2, followed by Portland

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4
Q

Sited of hematopoiesis @2wks, 14wks & 38wks.

A

2wks.: Yolk sac (Gower 1)
14 wks.: Liver, spleen (HbF)
38 wks.: Bone marrow (HbA starts appearing)

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5
Q

Most common site of hematopoiesis in newborn (Day 0)

A

Skull>Vertebra>Sternum>Ribs>Clavicle>Long bones>Flat bones (basically, all bones)

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6
Q

Most common site of hematopoiesis after 18yrs of age

A

Flat bones

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7
Q

Hallmark feature of all hemolytic anemias? Exception?

A

Hallmark feature: Splenomegaly

Exception: Sickle cell anemia

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8
Q

Kind of defect present in Thalassemia Major

A

(Alpha2, Aplha2) i.e., Alpha4 tetramers

Normal: Alpha2, Beta2

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9
Q

Reason for ineffective erythropoiesis

A

Most of the defective RBC produced die within the BM itself, while the remaining die in the spleen. So the BM is doing the necessary work to produce RBCs but its of no use as the ones produced are defective.

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10
Q

Reticulocyte levels in hemolytic anemias? Exception?

A

Reticulocytosis seen in hemolytic anemias

Exception: Thalassemia Major (reticulocytopenia)

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11
Q

Clinical features of px with thalassemia major

A
  • Young kid
  • Severe anemia (Pallor) w/ CHF (excessive sweating on
    breastfeeding, lethargy, pulm. edema, dyspnea)
  • Splenomegaly
  • Frontal/Maxillary prominence (d/t BM expansion) — Chipmunk facies
  • Extramedullary hematopoiesis: Splenohepatomegaly (spleen more enlarged than liver cuz spleen doing double duty, of hematopoiesis, as well as destruction of defective RBCs)

Chipmunk Facies - Prominent cheek bones, prominent frontal & maxillary bones, upturned nostrils (upward facing nostrils)

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12
Q

% of Beta chain production in different types of beta thalassemia

A

Thalassemia Major: (Beta0, Beta0) - 0% production
Thalassemia Intermedia: (Beta0, Beta+) - 50% production
Thalassemia Minor: (Beta+, Beta+) - 90% production
(asymptomatic, incidental dx - dec. Hb)

Severity: Major>Intermedia>Minor

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13
Q

Screening test for thalassemia

A

NESTROFT (Naked Eye Single Tube RBC Osmotic Fragility Test)

  • Osmotic fragility: DEC. IN THALASSEMIA
    INC. IN HEREDITARY SPHEROCYTOSIS
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14
Q

IOC for thalassemia

A

HPLC (High Performance Liquid Chromatography) > Hemoglobin electrophoresis

  • Hb Electrophoresis: If HbA2 > 3%, indicates thalassemia
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15
Q

Prenatal dx. for thalassemia

A
  • Chorionic villi sampling @ 10-12 wks. AOG
  • Amniocentesis or Chordocentesis if mother presents @
    2nd trimester
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16
Q

Peripheral smear finding in thalassemia. Also seen in?

A

Target cells [microcytic hypochromic RBCs, w/ central pink dot (alpha tetramer)]

Also seen in Chronic Liver Idease

17
Q

Reticulocyte count in thalassemia major vs other thalassemias

A

Reticulocyte count DECREASED in thalassemia MAJOR,

INCREASED in other thalassemias

18
Q

Earliest radiologic findings in thalassemia and other findings too

A

Earliest finding: Squaring of metacarpals on XRay Hand

Other finding: Crewcut appearance on XRay Head (d/t widening diploic space and presence if trabeculations cuz of marrow expansion)

19
Q

Management of thalassemia px and its complications

A

Rx.: Packed RBC, transfused every 2 months (cuz life
span of packed rbc is 60-80days) i.e., 6-12 units
PRBC/yr
Complications: 1) Iron toxicity —— Bronze diabetes (Rx. Oral Deferiprone)

  • Oal deferiprone started @ 4-5 yrs of age to prevent iron toxicity.
    2) Iron overload may lead to yersina enterocolitica infection
    3) Increased transfusion dependency by 50%: Elective Splenectomy
20
Q

Chromosome affected in alpha thalassemia

A

Chr. 16

21
Q

Types of alpha thalassemia based on the number of genes affected.

A

If 1 alpha gene malfunct. —— 75% prod. —— Silent carrier
If 2 alpha genes malfunct. —— 50% prod. —— Alpha
Thalassemia dse.
If 3 alpha genes malfunct. —— 25% prod. —— Hb H dse. (Behaves like
thalassemia major)
If all 4 genes malfunct. —— 0% prod. —— Hb BARTS (4 gamma chains)

  • Hb BARTS: i) Gamma chains and not beta chains cuz at birth, adult Hb
    is very less, while HbF (w/ gamma chains) is more.
    ii) Have high oxygen affinity d/t gamma chains. So, oxygen
    availability in tissues decrease, leading to severe anemia,
    CHF and non-immunogenic Hydrops fetalis
  • Non-Immunogenic Hydrops Fetalis —— Hb BARTS
    Congenital Nephrotic Synd.
    Complete Heart Block:
    neonatal lupus (leads to CHF; affects babies born to mothers w/ SLE)
    Immunogenic Hydrops Fetalis —— Rh Incompatibility
22
Q

Screening test, IOC and TOC for alpha thalassemia

A

Screening Test - NESTROFT (Naked Eye Single Tube RBC Osmotic Fragility Test)

IOC - HPLC. (High Performance Liquid Chromatography)

TOC: Allogenic Bone Marrow Transplantation

Rx. Packed RBC transfusion

23
Q

Usual diameter of a normal RBC and a normal capillary

A

RBC: 7mm
Capillary: 2mm

24
Q

RBC flexibility d/t?

A

1) Spectrin
2) Ankyrin
3) Pallidin
4) Protein 4.3

25
Q

Defect in Hereditary spherocytosis

A

Defect in Ankyrin, making the RBC rigid. Due to this, RBCs get stuck in the splenic capillaries and thus undergo accelerated and extravascular hemolysis.

26
Q

Clinical manif. of hereditary spherocytosis

A

Px. usually symptomatic in the 1st. 2 yrs of life

  • Pathologic jaundice
  • Anemia
  • Splenomegaly
  • Gall stones: Pigment stones: Ca Bilirubinate (Radio opaque)
  • Non-healing ulcer @ medial malleolus
  • Aplastic crisis: Human Parvo virus B19 (causes Erythema infectiosum -
    Slapped cheek appearance)
27
Q

Non-healing ulcer in children @medial malleolus d/t?

Non-healing ulcer in adults @medial malleolus d/t?

A

In children: Hereditary spherocytosis and sickle cell disease
In adults: Varicose veins

28
Q

Peripheral smear finding in px. w/ hereditary spheroctosis

A

RBCs that lack central pallor

29
Q

Hb and reticulocyte levels in hereditary spherocytosis

A
  • Dec Hb

- Dec. reticulocytes

30
Q

Screening of hered. spherocytosis

A

NESTROFT (Naked Eye Single Tube RBC Osmotic Fragility Test)

31
Q

Management of hered. sphero.

A

Elective splectomy

32
Q

Post Splenectomy px are susceptible to?

A

Elective splenectomy may make the px susceptible to inf. by capsulated organisms (pneumococcus, meningiococcus, H. influenza, etc)

33
Q

Prophylaxis for px scheduled for elective splenectomy

A
  • Pneumococcal vaccine
  • Meningiococcal vaccine
  • H. Influenza vaccine
  • Influenza A vaccine (H3N1 vaccine)
  • Given 4 weeks prior to surgery
34
Q

Post splenectomy blood smear findings? A.S.I?

A

Howel jolly bodies and Cabot rings

A.S.I: 1) Megaloblastic anemia

      2) Myelodysplasia
      3) Lead poisoning