iBSc: Question 2 By Alan McLeod

Getting the best marks Read the whole question – a latter section may give you a clue about an earlier one. To see how many points you need look at the marks allocated – for example a 3 point question is generally looking for 3 salient points If giving a list answer put the best answers first – examiners will not usually mark answers too far down a list Always write something – it may get you part of a mark and is anonymised so no one will think you are stupid! If you genuinely have no clue then re-write the question to see if this sparks some ideas. If not then move on and come back at the end. And remember – always write something. Good luck!

Question 2 Ms Begum, an 18 year old university student has been feeling progressively more tired (exhausted rather than sleepy) over the last year. Q2.1 List 5 differentials for feeling tired all the time (5)

Question 2 You are asked to do arrange some first line tests Q2.2 What blood tests would you order (3)

Question 2 After blood tests Ms Begum is diagnosed as having anaemia Q2.3 List the three types of anaemia based on red cell volume together with the size range of each. (6) Q2.4 List two causes of each type of anaemia from the list above. (6)

Question 2 Ms Begum’s haemoglobin level is 7.8 g/L Q2.5 Haemoglobin is a Quaternary protein structure – what does this mean (2) Q2.6 What type of structure is myoglobin (1)

pO 2 (torr) Fractual Concentration TissuesLungs The differing structures of myoglobin and haemoglobin alter their oxygen dissociation curves Q2.7 Draw the oxygen dissociation curves of myoglobin and haemoglobin (4)

Question 2 The final diagnosis is iron deficiency anaemia Q2.8 Where is iron absorbed in the body (1) What is the major intracellular iron storage molecule (1)

Question 2 The GP prescribes Ferrous Sulphate together with a single vitamin pill. Q2.8 What vitamin pill is prescribed (1) Why is this vitamin given to this patient? (1)

The Answers View these on ‘note view’ rather than on full screen – additional notes are provided for some slides

Generating Differentials: I’D GET VINO… I Infectious / inflammatory D Degenerative G Genetic / Idiopathic E Endocrine T Trauma V Vascular I Iatrogenic / ingested N Neoplastic O Organs

Tired All The Time I Infectious / inflammatory Multiple sclerosis, TB D Degenerative G Genetic / ideopathic E Endocrine Diabetes, Hypothyroid T Trauma V Vascular Anaemia I Iatrogenic / ingested N Neoplastic Lymphoma, leucaemia O Organs / other Depression, obesity, lifestyle

Anaemia – two classifications Three basic causes Blood loss Reduced erythrocyte production Increased erythrocyte destruction Three basic cell sizes Microcytic Normocytic Macrocytic

TATT – Initial Tests TestFor FBCAnaemia Haematologic cancers TSHThyroid function – Free T3 and T4 are usually done later if needed GlucoseDiabetes – may be random or fasting Anaemia – Tests for Cause TestFor B12 / FolateB12 / folate deficiency HaematinicsFerritin / transferrin levels and Total Iron Binding Capacity (TIBC)

microcytic anaemianormocytic anaemiamacrocytic anaemia MCV < 76 femtolitresMCV = fLMCV > 96 femtolitres iron deficiency anaemia –commonest lead poisoning Sideroblastic anaemia Thalassaemia Anaemia of chronic disease Pyridoxine-responsive anaemia anaemia of chronic disease – commonest Acute haemorrhage Haemolytic anaemia Bone marrow failure (aplastic anaemia) Mixed iron and folate Pregnancy chronic renal failure riboflavin deficiency With megaloblastic haemopoiesis on bone marrow examination B 12 deficiency Folate deficiency With normoblastic BM Alcohol Liver cirrhosis Hypothyroidism / myxoedema

Protein Basics

Primary Structure Amino acid sequence Secondary Structure Folded primary structure –Alpha helix –Beta pleated sheet Tertiary Structure Complex of secondary structures –e.g. myoglobin Quaternary structure Associated tertiary structures –e.g. Haemoglobin

Myoglobin Haemoglobin pO 2 (torr) Fractual Concentration TissuesLungs

Iron Uptake & Storage Iron is a vital element for life Humans have no active way of excreting iron 1-3 g stored 80% in haemoglobin 1 g lost / day from skin / mucosal shedding 1 g lost / day extra in menstruation Absorbed Duodenum + upper jejunum Exact mech unknown About 10% of intake Lead toxicity reduces absorption Vit C increases absorption

Important Molecules Transferrin Small Extracellular Transporter Holds 1 or 2 iron Ferritin Large Intracellular Storage molecule Up to 45,000 iron

The End The slides here should allow you to mark your own work – remember 1 mark per answer up to the maximum for the question. Multiply by 3 to get percentage points. I assume a 60% pass mark. Sorry but I am unable to give further advice on answers due to time constraints.