Transcript All of medicine in 12 hours…

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
• Q2.1
Ms Begum, an 18
• List 5 differentials for
year old university
feeling tired all the
student has been
time (5)
feeling progressively
more tired
(exhausted rather
than sleepy) over the
last year.
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)
Q2.7
Draw the oxygen
dissociation
curves of
myoglobin and
haemoglobin (4)
1.0
Lungs
Fractual Concentration
The differing
structures of
myoglobin and
haemoglobin
alter their oxygen
dissociation
curves
Tissues
0
pO2 (torr)
100
Question 2
The final diagnosis is Q2.8
• Where is iron
iron deficiency
absorbed in the body
anaemia
(1)
• What is the major
intracellular iron
storage molecule (1)
Question 2
The GP prescribes Q2.8
• What vitamin pill is
Ferrous Sulphate
prescribed (1)
together with a single
vitamin pill.
• 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
D
G
E
T
V
I
N
O
Infectious / inflammatory
Degenerative
Genetic / Idiopathic
Endocrine
Trauma
Vascular
Iatrogenic / ingested
Neoplastic
Organs
Tired All The Time
I
D
G
E
T
V
I
N
O
Infectious / inflammatory Multiple sclerosis, TB
Degenerative
Genetic / ideopathic
Endocrine
Diabetes, Hypothyroid
Trauma
Vascular
Anaemia
Iatrogenic / ingested
Neoplastic
Lymphoma, leucaemia
Organs / other
Depression, obesity, lifestyle
Anaemia – two classifications
Three basic causes
Three basic cell sizes
• Blood loss
• Reduced erythrocyte
production
• Increased erythrocyte
destruction
• Microcytic
• Normocytic
• Macrocytic
TATT – Initial Tests
Test
For
FBC
Anaemia
Haematologic cancers
TSH
Thyroid function – Free T3 and T4 are usually done later
if needed
Glucose
Diabetes – may be random or fasting
Anaemia – Tests for Cause
Test
For
B12 / Folate B12 / folate deficiency
Haematinics Ferritin / transferrin levels and Total Iron Binding Capacity
(TIBC)
microcytic anaemia
normocytic anaemia
macrocytic anaemia
MCV < 76 femtolitres
MCV = 76-95 fL
MCV > 96 femtolitres
iron deficiency
anaemia of chronic
With megaloblastic
anaemia –commonest disease – commonest haemopoiesis on bone
marrow examination
lead poisoning
Acute haemorrhage
B12 deficiency
Sideroblastic anaemia Haemolytic anaemia
Folate deficiency
Thalassaemia
Bone marrow failure
(aplastic anaemia)
Anaemia of chronic
With normoblastic
disease
Mixed iron and folate
BM
Pyridoxine-responsive Pregnancy
anaemia
chronic renal failure
riboflavin deficiency
Alcohol
Liver cirrhosis
Hypothyroidism /
myxoedema
Protein Basics
Protein Basics
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
Tissues
Fractual Concentration
1.0
Lungs
Myoglobin
Haemoglobin
0
pO2 (torr)
100
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
• Ferritin
•
•
•
•
•
•
•
•
Small
Extracellular
Transporter
Holds 1 or 2 iron
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.