A1 IHS SAQ (2022/2023)

Question 1

Compare the structure and function of compact bone and spongy bone (8)

Answer 1

Spongy vs Compact Bones
* Spongy Bones are also called cancellous bones
* They light, spongy and soft in nature
* They are made up of trabeculae
* They fill the inner layer of most bones
* Bone marrow cavity absent
* Bone marrow produces red corpuscles and white granular corpuscles
* It forms the epiphyses of long bones
* Trabeculae do not contain arteries

• Compact bones are also called cortical bones
• They are heavy, tough and compact in nature
• They are made up of osteons
• They fill the outer layer of most bones
• Bone marrow cavity present in the centre
• Bone marrow stores fat
• It forms the diaphysis of long bones
• Osteons contain arteries

Question 2

Normocytic anemia causes

Answer 2

Any four:
* Blood loss
* Haemolysis
* Anaemia of chronic disease
* Renal disease
* Mixed nutritional (iron, b12/folate) deficiency
* Bone marrow failure (e.g. drugs, infiltration

Question 3

List 2 red blood cell abnormalities that are causes of splenomegaly.

Answer 3

Hereditary spherocytosis
Sickle cell anaemia

Question 4

Identify two metabolites that accumulate in body fluids and are used to confirm an acute
porphyric attack.

Answer 4

d-ALA, PBG

Question 5

List and briefly describe 3 biochemical parameters by which the laboratory can distinguish
between in vivo and in vitro haemolysis

Answer 5

• Unconjugated bili not raised (no time for haem metabolism)
• Potassium often highly raised (released from red cell cytoplasm)
• Haptoglobin is not decreased

Question 6

Outline 3 ways to avoid causing haemolysis when performing a venesection

Answer 6

Avoid small needles
Transport tubes carefully
Avoid drawing rapidly

Question 7

Acute porphoria gene invovled?

Answer 7

PPOX

Question 8

What should drip contain - porphyric patient

Answer 8

Dextrose

Question 9

3 Severe malaria symptoms?

Answer 9

Non-ambulant
Jaundice
Impaired mental functioning

Question 10

Draw interaction between splenic dendritic cell and CD4+ T cell

Answer 10

Dendritic cell:
MHC II presenting peptide antigen
CD80/86

CD4 cell:
TCR
CD28
CD4

Question 11

List 2 cytokines which would activate the CD4+ T cell to a Th1 phenotype?

Answer 11

IL-12, IFN-y

Question 12

Name 2 plasma cell disorders other than myeloma

Answer 12

Amyloidosis
MGUS

Question 13

State the name of the neoplastic cell in Hodgkin lymphoma.

Answer 13

Reed-sternberg

Question 14

Name in full 3 pathogens that are associated with neutropenic sepsis.

Answer 14

Staph aureus
Escherichia coli
Klebsiella pneumonia

Question 15

Define positive selection (T cell development)

Answer 15

Binding of TCRs of mature T cells to MHC in the thymus

Question 16

Define negative selection (T cell development)

Answer 16

Removal of T cells that bind too strongly to self antigen presented on MHC

Question 17

Why is negative selection of T cells important?

Answer 17

Prevents the formation of self reactive T cells.

Question 18

Identify any four factors that are used to define the metabolic syndrome.

Answer 18

• Increased waist circumference (Abdominal obesity)
• Elevated triglycerides
• Low HDL cholesterol
• Elevated blood pressure
• Raised blood glucose

Question 19

List 2 causes for raised reticulocytes

Answer 19

Bleeding, haemolysis

Question 20

Define hemolytic anemia

Answer 20

Reduced red cell survival, peripheral destruction

Question 21

List 5 symptoms related to hyperviscosity of blood

Answer 21

Peripheral neuropathy
Gout
Headaches
Blurred vision
Hypertension

Question 22

Name the enzyme effected for both anemia and neurological disease caused by VitB12 deficiency

Answer 22

Methionine synthase

Question 23

List 2 malaria chemoprophylactic agents

Answer 23

Malarone
Doxycycline

Question 24

Define hyperparasitemia

Answer 24

> 5% parasitized RBCs

Question 25

Is Beta-thalassemia a quantitative or qualitative hemoglobinopathy? Why?

Answer 25

Quantitative. Produces correct structure, but not enough

Question 26

What is an advantage of being a haemoglobinopathy carrier?

Answer 26

Protection from cerebral malaria

Question 27

How do haemaglobinoapthies protect against severe malaria?

Answer 27

Ineffective haemopoeisis Increased hemolysis

Question 28

What is the inheritence of beta-thalassemia

Answer 28

autosomal recessive

Question 29

List components of CD8 immunological synapse with liver cell

Answer 29

TCR binding to peptide presented on MHC-I CD8+ stabilize Fas on liver cell binding to Fas-ligand on CD8+ cell

Question 30

ADCC activates which cells?

Answer 30

NK cells

Question 31

Describe 3 stages in development of haematopoeitc system

Answer 31

Primitive, pro-definitive, definitive stages. Primitive stage: Blood islands along yolk sac produces large nucleated RBCs, megakaryocytes, macrophages - invade embryo Pro-definitive: Generates eryhro-myeloid progenitors and lympho-myeloid progenitors Definitive: Dorsal aorta cells - produce clusters of HSCs located in lumen of aora through EHT Pro-definitive and definitive wave progenitors travel to liver - RBCs, megakaryocytes, granulocytes, T/B cells, monocytes formed

Question 32

What are B symptoms?

Answer 32

temperature >38 degrees C night sweats >10% weight loss over 6 months

Question 33

Outline any three (3) possible clinical presentations caused by the infiltration of blasts into soft tissues and detectable by X-Ray examination.

Answer 33

Mediastinum mass - SOB Lung parenchyma - SOB Pleural effusion - SOB Bone lesions - bone pain

Question 34

Name the Ph negative neoplasm associated with massive splenomegaly

Answer 34

Primary myelofibrosis

Question 35

Anele Makhamba is found to have splenomegaly associated with her diagnosis of leukaemia. List any five (5) other causes of splenomegaly

Answer 35

Congestion Infection Metastasis of neoplasm RBC abnormalities Autoimmunity Storage disorders Amyloidosis

Question 36

Differential diagnosis of generalized lymphoadenopathy

Answer 36

TB HL Burkitt lymphoma Mono

Question 37

What investigations can be used to invest lymphadenopathy

Answer 37

Sputum Needle biopsy

Question 38

How can lab tests assess renal function

Answer 38

Measure plasma creatinine - estimate GFR with equations

Question 39

Outline progression of acute varicella infection

Answer 39

Skin rash Lesions at multiple stages of development Macule - papule - vesicles - scabs Itchy

Question 40

List complications of acute varicella infection in child

Answer 40

Secondary bacterial infection Pneumonia encephalitis stroke hemorrhagic varicella

Question 41

Outline implications of neonate whose mother had acute varicella infection during pregnancy

Answer 41

If <20 wk: congenital varicella with microphtalmia, limb hypoplasia, skin scarring If >20wk: Risk of zoster early in life Perinatal: Neonatal varicella - severe infection.

Question 42

What class of hormone is cortisol

Answer 42

Steroid hormone, cholesterol precursor

Question 43

Compare storage of steroid and peptide hormones

Answer 43

Steroid hormones - not stored Peptide hormones - membrane bound

Question 44

How would you screen for retinopathy?

Answer 44

Fundoscopy

Question 45

List three (3) microscopic lesions Kyle may develop in his kidneys as a result of poorly controlled diabetes and provide a brief explanation of the pathogenesis of each. (6 marks)

Answer 45

Pappilary necrosis - ischemia Pyelonephritis - glucose in urine cultures bacteria, poor inflammatory response Glomerulosclerosis - proteinuria

Question 46

Dipstix of DKA

Answer 46

+++ glucose +++ ketones

Question 47

Define non-thyroidal syndrome

Answer 47

Sick euthyroid syndrome - thyroid function changes due to severe illness

Question 48

What is the worst outcome of hypoglycemia

Answer 48

Coma - death

Question 49

Why is glucagon raised in diabetics?

Answer 49

No insulin. Insulin usually inhibits glucagon release

Question 50

Why can insulin and glucagon not enter cells?

Answer 50

Large polypeptides - too large and charged to cross plasma membrane Requires membrane protein as receptor - second messenger systems

Question 51

Identify key difference between glycogen stores in liver vs glycogen stores in muscle

Answer 51

Glycogen stores in liver used to maintain constant BLOOD glucose levels in eg. fasted stated In muscle, in low glucose states, glycogen stores used to replenish glucose to generate energy for muscle itself to use