pt 8 Flashcards

(50 cards)

1
Q

What is the main pathological consequence of anaemia?

A

Tissue hypoxia

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2
Q

Name two non-specific symptoms of anaemia.

A

Fatigue, headaches, faintness

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3
Q

What sign on physical exam is specific for anaemia?

A

Pallor (e.g., conjunctiva)

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4
Q

What three routine lab tests diagnose anaemia?

A

↓ RBC count, ↓ Hb, ↓ PCV

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5
Q

What does anisocytosis on a blood film indicate?

A

Variation in RBC size

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6
Q

What is poikilocytosis?

A

Variation in RBC shape

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7
Q

What is anisochromasia?

A

Variation in RBC hemoglobinization

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8
Q

What are two broad causes of anaemia?

A

↓ production (e.g., bone marrow failure, haematinic deficiency) or ↑ loss/destruction (haemorrhage, haemolysis)

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9
Q

What RBC indices derive from PCV and RBC count?

A

MCV (cell size) and MCH (Hb per cell)

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10
Q

How do you calculate the mean cell volume (MCV)?

A

PCV (l/L) ÷ RBC count (×10¹²/L)

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11
Q

What does the mean cell hemoglobin concentration (MCHC) represent?

A

Hb concentration per unit volume of RBCs

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12
Q

In iron-deficiency anaemia, describe RBC appearance.

A

Microcytic, hypochromic

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13
Q

Where is dietary iron absorbed and what is required?

A

Duodenum/stomach; gastric HCl for Fe³⁺→Fe²⁺ reduction

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14
Q

How is iron stored and transported?

A

Stored as ferritin/haemosiderin; transported by transferrin

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15
Q

List four causes of iron-deficiency anaemia.

A

increased demand (pregnancy), chronic blood loss, poor diet, malabsorption

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16
Q

How is iron-deficiency anaemia treated and monitored?

A

Find/treat cause, oral iron replacement; monitor reticulocyte count & Hb

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17
Q

Describe megaloblastic anaemia morphology.

A

Macrocytic oval RBCs, hypersegmented neutrophils, Howell–Jolly bodies

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18
Q

What two deficiencies cause megaloblastic anaemia?

A

Vitamin B₁₂ and folate deficiency

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19
Q

What absorption defect characterizes pernicious anaemia?

A

Lack of intrinsic factor → B₁₂ malabsorption in terminal ileum

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20
Q

Name three causes of folate deficiency.

A

Poor diet/overcooking, malabsorption (coeliac, sprue), ↑ utilisation (pregnancy, haemolysis)

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21
Q

What defines anaemia of chronic disease (ACD)?

A

Anaemia associated with ↓ RBC proliferation and impaired iron utilization in chronic infections, immune disorders, or neoplasms

22
Q

Name three chronic conditions commonly causing ACD.

A

Chronic microbial infections (e.g., osteomyelitis), chronic immune disorders (e.g., rheumatoid arthritis), and malignancies (e.g., Hodgkin lymphoma)

23
Q

What cytokine-driven mechanisms underlie ACD?

A

↓ EPO production, ↑ hepcidin synthesis → ↓ iron release from stores → ↓ RBC production

24
Q

What are the typical laboratory features of ACD?

A

↓ Serum iron & TIBC, ↑ marrow storage iron; RBCs normocytic/normochromic or microcytic/hypochromic

25
How can ACD be distinguished from pure iron-deficiency anaemia?
Soluble transferrin receptor is normal in ACD but elevated in iron deficiency
26
What are the clinical features and treatment of ACD?
Mild anaemia (Hb ≥8 g/dL) with symptoms of underlying disease; correct underlying cause ± EPO therapy
27
How is aplastic anaemia defined?
Pancytopenia (↓ RBCs, neutrophils, platelets) with hypocellular, fatty bone marrow
28
List major acquired causes of aplastic anaemia.
Idiopathic, immune-mediated, alkylating agents/benzene, chloramphenicol, irradiation, hepatitis, CMV infection
29
What are the clinical and laboratory features of aplastic anaemia?
Anaemia, infections, bleeding; pancytopenia with low/absent reticulocytes; bone marrow biopsy shows hypocellularity & fat spaces
30
How is aplastic anaemia managed?
Withdraw offending agent, supportive care (infection control, transfusions), immunosuppression, or bone-marrow transplant
31
What two broad categories of haemoglobin abnormalities exist?
Abnormal globin chain structure (point mutations) and imbalanced globin chain production (thalassaemias)
32
What single mutation causes sickle cell disease?
β-globin gene point mutation (GAG→GTG), Glu→Val at position 6 → HbS (α₂β₂ˢ)
33
Describe sickle cell pathogenesis.
HbS polymerizes at low O₂ → rigid “sickled” RBCs → shortened survival & vaso-occlusion → infarction & haemolysis
34
What are key clinical features of sickle cell disease?
Vaso-occlusive crises (acute bone pain), chronic haemolysis (anaemia 6–8 g/dL), precipitated by infection, dehydration, hypoxia
35
How is sickle cell disease investigated and managed?
Hb 6–8 g/dL, retics 10–20%, blood film shows sickled cells; manage with avoidance of triggers, supportive care, folate, transfusions, hydroxycarbamide
36
What underlies thalassaemia?
Quantitative defects in α or β globin synthesis → imbalanced chain production → precipitation, ineffective erythropoiesis, haemolysis
37
Contrast β-thalassaemia major vs. minor.
Major: severe anaemia in infancy, splenomegaly, marrow expansion; Minor: mild or asymptomatic microcytic anaemia
38
Outline α-thalassaemia spectrum.
Ranges from Hb Bart’s hydrops fetalis (four α deletions) to clinically mild (one deletion), depending on α-chain loss
39
How are thalassaemias diagnosed?
Microcytic hypochromic anaemia, ↑ reticulocytes & nucleated RBCs; confirm by Hb electrophoresis (↑ HbF, ↓ HbA)
40
What is G6PD deficiency?
X-linked RBC enzyme defect → ↓ NADPH & GSH → vulnerability to oxidative damage and haemolysis (100 M affected)
41
Which G6PD variants differ in severity?
Type B/A⁺ (normal), African A⁻ (mild, older-cell deficiency), Mediterranean (severe in all RBC ages)
42
Describe G6PD deficiency pathogenesis.
G6PD deficiency → ↓ glutathione reductase cycle → inability to detoxify ROS → membrane damage → acute haemolysis
43
What triggers haemolysis in G6PD deficiency?
Oxidant stress from fava beans, sulphonamides, quinine, infection, or other oxidative drugs/foods
44
How is G6PD deficiency diagnosed?
Blood count normal between attacks; during attack, blood film shows “bite” & blister cells, ↑ bilirubin; confirm by G6PD assay
45
What is the management for G6PD deficiency?
Avoid known oxidative triggers; transfuse if needed; treat underlying infection
46
What are the five varieties of leukocytes?
Neutrophils, eosinophils, basophils, lymphocytes, monocytes
47
Which leukocytes are phagocytic, and which mediate adaptive immunity?
Granulocytes (neutrophils, eosinophils, basophils) and monocytes are phagocytic; lymphocytes carry out cell-mediated and antibody-mediated responses
48
What is the normal total white cell count?
4.0–11 × 10⁹ /L
49
What percentage and absolute range do neutrophils normally occupy?
45–75% of WBCs, 2.8–7.5 × 10⁹ /L
50
What are normal ranges for lymphocytes, monocytes, eosinophils, basophils, and platelets?
* Lymphocytes: 20–40% (1.5–3.5 × 10⁹/L) * Monocytes: 2–8% (0.2–0.8 × 10⁹/L) * Eosinophils: 1–4% (0.04–0.4 × 10⁹/L) * Basophils: 0.4–1% (0.01–0.1 × 10⁹/L) * Platelets: 150–400 × 10⁹/L