Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

RHS- Path > RBC disorders 3 > Flashcards

RBC disorders 3 Flashcards

1
Q

What is autoimmune hemolytic anemia

A

hemolytic anemia with a defect extrinsic to RBCs caused by antibodies that recognize red cells and lead to their premature destruction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Pathogenesis of AIHA

A

Antibodies can either opsonize the RBC themselves or initiate a complement activation→can form opsonins or membrane attack complex→hemolysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How to diagnose AIHA

A

Coombs antiglobulin test

- reagent used is anti human globulin— an antibody against human antibodies/ complement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Explain direct Coombs test

A

Autoantibodies against RBCs on patient RBCs + Coombs reagent = agglutination/clumping —> positive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Explain indirect Coombs test

A

Patient serum with autoantibodies+ commercially available test RBCs + Coombs reagent = agglutination/clumping—> positive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Warm antibodies are _____ antibodies that bind to RBCs at ______C. It opsonize RBCs → splenic macrophages → _________ hemolysis. This causes warm hemolysis disease

A

Warm antibodies are IgG antibodies that bind to RBCs at 37C. IgG opsonize RBCs → splenic macrophages → extravascular hemolysis. This causes warm hemolysis disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What happens with IgM antibodies that bind at cold temperatures

A

IgM binds to RBCs in exposed fingers, toes, ears etc.→fixes complement→C3b forms
Blood recirculates to warmer areas→IgM falls off before MAC is formed
C3b opsonizes RBCs→ splenic macrophages→ extravascular hemolysis

Pentameric IgM causes agglutination: Cold agglutinin disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What happens with IgG antibodies that bind at cold temperatures

A

IgG binds to RBCs in exposed fingers, toes, ears etc.→fixes complement →doesn’t fall off when blood recirculates to warmer areas→MAC (membrane attack complex) formed → intravascular hemolysis

Cold hemolysin disease/ paroxysmal cold hemoglobinuria (PCH)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Warm hemolysin

A

Target antigen – most commonly Rh
IgG coated RBCs bind to Fc receptor on phagocytes→ remove a bit of membrane→ spherocytes formed→lysed in spleen

  • Chronic anemia, splenomegaly
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

AIHA associated with SLE, drugs like alpha methyl dopa and B- cell neoplasms like chronic lymphocytic leukemia

A

Warm hemolysin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

AIHA associated with Mycoplasma, EBV (Epstein Barr virus), CMV (cytomegalovirus), HIV and B-cell neoplasms

A

Cold agglutinin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Cold agglutinin

A

Clumped/ agglutinated RBCs seen in peripheral smear with some spherocytes

Raynaud phenomenon when exposed to cold

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Which AIHA associated with viral infections in children

A

Cold hemolysin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Cold hemolysin

A

Usually normocytic RBCs with evidence of intravascular hemolysis

Acute, self limiting. Can be fatal is severe

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Megaloblastic anemia

A

Impairment of dna synthesis due to vitamin b 12 and folic acid deficiency. Needed for synthesis of thymidine

  • leads to ineffective hematopoiesis
  • abnormally large erythroid precursors and red cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Causes of vitamin b12 deficiency

A

Decreased intake
• Inadequate diet
• Strict vegans Impaired absorption

Impaired absorption 
• Pernicious anemia (autoimmune attack on gastric mucosa)
• Gastrectomy 
• Malabsorption
• Fish tapeworm infestation
17
Q

Cause of folic acid deficiency

A
  • Decreased intake of green vegetables (eg.alcoholics)
  • Impaired absorption
  • Increased requirement like in pregnancy
  • Folic acid antagonist drugs like methotrexate
18
Q

Vitamin b12 absorption

A
  1. After ingestion of B12-containing diet, gastric pepsin releases the B12 from the food allowing it to bind with a salivary protein (Haptocorrin)
  2. By the action of pancreatic proteases in the duodenum, B12 is released from the B12-Haptocorrin complex
  3. The free B12 then attaches to intrinsic factor (IF) produced from the gastric parietal cells
  4. The B12-IF complexes pass to the distal ileum and get absorbed via a receptor of IF into the enterocytes.
  5. The absorbed B12 is then transported in the blood by Transcobalamin to the liver
19
Q

Outcomes of B12 deficiency

A
  • increased homocysteine and tetrahydrofolate
  • folate trap—> decrease folate —>cannot do thymidylate synthesis—> megaloblastic anemia

Neurological symptoms due to increased methyl malonyl CoA

20
Q

Findings in megaloblastic anemia

A
  • ineffective hematopoiesis —> pancytopenia
  • low reticulocyte count
  • As a result to make more cells→precursors increase→bone marrow becomes hypercellular
  • In all cells→ delayed nuclear maturation + normal cytoplasmic maturation and Hb accumulation→nuclear cytoplasmic asynchrony
  • An-iso-poikilo-cytosis (variation in shape and size of RBCs)
  • erythroid family—> megaloblasts making mature RBCs called macrocytes
  • Granulocyte family—> Giant metamyelocytes making mature neutrophils that are larger and show nuclear hypersegmentation
21
Q

What makes a neutrophil hypersegmented?

A

There are >5 nuclear lobes instead of normal 3-4 lobes

22
Q

What else is seen in megaloblastic anemia

A

• Intramedullary hemolysis → mild jaundice
• Beefy tongue
• Neurological symptoms in vitamin B12 deficiency
- paraparesis, sensory ataxia, lower limb paresthesia
• Start with serum vitamin B12 and Folate levels
• Schilling test- not done anymore → inability to absorb an oral dose of B12

23
Q

What should be done before starting treatment for folate deficiency?

A

Very important to exclude B12 deficiency before starting treatment for folate deficiency. It might transiently correct the anemia, however, while depleting the little remaining B12 and lead to worsening of the neurological symptoms

24
Q

Pernicious anemia

A

Autoantibodies against parietal cells which make intrinsic factor which is required for b12 absorption

chronic atrophic gastritis → prominent infiltrate of lymphocytes and plasma cells

Clinical features: particularly autoimmune thyroiditis and adrenalitis

25
Q

How to diagnose pernicious anemia

A
  • Moderate to severe megaloblastic anemia
  • Leukopenia with hyper segmented granulocytes
  • Low serum vitamin B12
  • Elevated serum levels of homocysteine and methylmalonic acid
  • Serum antibodies to intrinsic factor are highly specific for pernicious anemia
26
Q

Most sensitive investigation for iron deficiency anemia

A

Serum ferritin

27
Q

Lab investigations in iron deficiency anemia

A 
Almost absent iron
Reduced serum ferritin 
Reduced transferrin saturation 
Increased TIBC
reduced serum iron
Increase RBC protoporphyrin
Anisocytosis - RDW increased 
Micro cystic hpochromic RBCs 
Reduced reticulocyte count
28
Q

Clinical features of iron deficiency anemia

A
  • Due to anemia- fatiguability, tiredness, pallor, malaise
  • Due to the underlying disorder- GI or gynecologic disease, malnutrition, malabsorption
  • Due to depletion of iron containing enzymes- koilonychia, alopecia, atrophic changes in tongue and gastric mucosa
  • Due to depletion of iron from CNS- pica (craving for stuff like clay, flour etc.) and periodical movements of limbs during sleep (“restless leg syndrome”)
  • Plummer Vinson syndrome- esophageal webs + iron deficiency + atrophic glossitis
29
Q

How to treat Iron Deficiency Anemia (IDA)

A
  • Oral iron therapy- increases reticulocytes in about 5-7 days followed by a steady normalization of RBC indices
  • Intravenous iron- patients who are unable to tolerate oral iron; acute needs; persistent gastrointestinal or menstrual blood

RHS- Path (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions