Lecture 21 - Biochemical Assessment of Iron Status 2

Question 1

what are the possible issues related to iron overload

Answer 1

• acute iron toxicity
• hereditary haemochromatosis
• african iron overload
• other iron overload conditions

Question 2

hereditary haemochromatosis is a what condition

Answer 2

autosomal recessive condition

Question 3

you have poor control of what when you have hereditary haemochromatosis

Answer 3

poor control of iron absorption

Question 4

what happens in hereditary haemochromatosis

Answer 4

iron accumulates in liver, pancreeas and heart muscle which impacts their function

Question 5

what is the effectiveness of treatment like in hereditary haemochromatosis

Answer 5

treatment is very effective if started early

Question 6

what are the biochemical indices that would indicate hereditary haemochromatosis (serum ferritin and transferrin saturation)

Answer 6

serum ferritin :
>300ug/L males
>200ug/L females

transferrin saturation :
>45% men and women

repeated in a fasting sample

Question 7

alongside biochemical indices, what is needed for a diagnosis of hereditary haemochromatosis

Answer 7

biochemical indices must be repeated in a fasting sample

also need conformation that the mutation is present

also need clinical assessment : must be showing some signs

Question 8

what is the definition of clinical assessment

Answer 8

” a medical history and a physical examination are the clinical methods used to detect signs, (observations made by a qualified examiner) and symptoms (manifestations reported by the patient) associated with malnutrition”

Question 9

clinical assessment has to be done alongside …… why ?

Answer 9

alongside other measures of nutritional assessment because otherwise someone could be diagnosed as something that they don’t have

Question 10

what are the individual level uses of iron status indicators

Answer 10

• screening
• clinical assessment

Question 11

when looking at an individuals iron status that is close to but not below the cut offs what usually happens and how is that different to population status

Answer 11

they will usually be treated with iron medication, different to population level were cut offs are strictly used

Question 12

what are the population level uses of iron status indicators

Answer 12

• prevalence estimates of deficiency
• planning appropriate interventions
• evaluating impact of interventions

Question 13

what is the context of individual assessment of Fe status

Answer 13

• availability of assay
• usefulness
• cost

Question 14

what are the indices of individual assessment of Fe status

Answer 14

• haemoglobin
• serum ferritin and C-reactive protein ?
• serum Fe, transferrin saturation = if concerned about possibility of iron overload

Question 15

what type of index data is most useful in population practice

Answer 15

combining indices to look at things such as iron deficiency anaemia etc, instead of things such as low haemoglobin

Question 16

what are the factors affecting validity of cut offs

Answer 16

• method of blood collection
• fasting status / time of day
• assay / equipment used
• infection (inflammation)
• environment and other confounding factors
• genetics

Question 17

what does fasting status / time of day affect validity of cut offs for iron

Answer 17

transferrin saturation changes over the day, usually high in the morning and then decreases throughout the day

Question 18

what happens in terms of iron and inflammation (in the acute phase response to inflammation, infection and malignancy)

Answer 18

• blocks the release of Fe from reticuloendothelial system
• increases translation of ferritin
• leads to shortage of Fe in bone marrow

Question 19

when inflammation is present why does your body try store iron and remove it from circulation

Answer 19

because bacteria need iron in order to grow so your body doesn’t want iron to be where bacteria is

Question 20

what are the important measures of infection when looking at iron too

Answer 20

C-reactive protein

a-1-acid glycoprotein

a-1-antichymotrypsin

Question 21

what are other sources of variation in iron indices

Answer 21

• oral contraceptive agents (decrease transferrin saturation)
• smoking (increases haemoglobin)
• altitude (increases haemoglobin)
• “sports anaemia” (decreases haemoglobin)
• dehydration (increases indices)

Question 22

what is the main cause of anaemia

Answer 22

iron deficiency

Question 23

anaemia can also be caused by

Answer 23

• infection (malaria, HIV)
• decreased erythropoiesis (bone marrow depression, B12 or folate deficiency)
• genetic disorders (thalassemia, sickle cell anaemia)

Question 24

thalassemia presents

Answer 24

abnormal cell shapes

Question 25

if someone has low haemoglobin, normal mean cell volume, low - norm transferrin saturation, high-norm ZPP and high ferritin what do they likely have

Answer 25

chronic disease

Question 26

if someone has low haemoglobin, high mean cell volume, high-norm transferrin saturation, normal ZPP and normal ferritin what do they likely have

Answer 26

macrocytic anaemia

Question 27

if someone has low haemoglobin, low mean cell volume, high transferrin saturation, norm ZPP and norm ferritin what do they likely have

Answer 27

thalassemia

Question 28

the use of haemoglobin results alone is an

Answer 28

overestimate of prevalence of IDA