W2 Case Studies - Iron Deficiency & St. John's Wort Rxns

Question 1

Which populations are MOST at-risk for iron deficiency?

Answer 1

MOST at risk = Pre-menopausal women, pregnant women, women with heavy menses

Other populations at risk = strict vegetarians/vegans, infants, toddlers, adolescents, those w/ celiac disease

(Hark. p. 85)

Question 2

What are the two most common etiologies for iron deficiency?

Answer 2

Low iron intake and decreased iron absorption

Hark, p. 85

Question 3

What sources of blood loss (besides menses) can lead to iron deficiency?

Answer 3

frequent blood donation, GI bleeding, neoplasms, IBD, parasitic infections, hemorrhoids, chronic hematuria

(Hark, p. 85)

Question 4

What is the main reason that fatigue is a common presentation of iron deficiency?

Answer 4

Iron is necessary for hemoglobin synthesis in RBCs > hemoglobin is needed for oxygen transport + delivery from the lungs to the tissues > oxygen is necessary for ATP production (less iron = less hemoglobin = less oxygen transport = less ATP production)

(Hark, p. 85)

Question 5

What are clinical signs of iron deficiency? (that could be observed on an NFPE)

Answer 5

Pallor, mouth changes (glossitis, angular stomatitis), poor capiliary bed refilling, pale mucosa and soft, brittle or spooned nails (spooned nails usually w/ prolonged deficiency)

(Hark p. 75 & 85)

Question 6

What are clinical symptoms of iron deficiency?

Answer 6

Fatigue, weakness, dyspnea, tachycardia, cold intolerance, pica, pagophagia, decreased work/exercise tolerance, cognitive impairment, greater susceptibility to infections

(Hark p. 75 & 85)

Question 7

What are clinical symptoms of iron deficiency in infants/children?

Answer 7

Adverse birth outcomes, low IQ, learning and/or behavioral issues

(Hark, p.75)

Question 8

What three means of assessment are used to diagnose iron deficiency?

Answer 8

Laboratory testing + physical signs + symptoms

Hark p. 85

Question 9

Name the following lab value within an iron panel:

Total amount of iron that can be bound by proteins in the blood. Since transferrin is the main iron-binding protein, __________ is a good indirect measurement of the amount of transferrin available to bind to iron.

Answer 9

Total iron binding capacity = TIBC

(Hark, p. 85) ; https://www.testing.com/tests/transferrin-and-iron-binding-capacity-tibc-uibc/

Question 10

Why is TIBC typically high in iron deficiency?

Answer 10

TIBC increases in iron deficiency to compensate for low iron availability

(Hark, p. 85) ; https://www.testing.com/tests/transferrin-and-iron-binding-capacity-tibc-uibc/

Question 11

Because serum ferritin is an ___ ___ ___, chronic infection, inflammation or diseases causing tissue and organ damage can raise it’s concentration independent of iron status (masking depleted tissue stores)

Answer 11

acute phase reactant

Hark, p. 86

Question 12

Name the following lab value within an iron panel:

Measures the extent to which iron binding sites are vacant on transferrin. Under normal conditions, transferrin is typically one-third saturated with iron.

Answer 12

Transferrin saturation (%)

(Hark, p. 86) ; https://www.testing.com/tests/transferrin-and-iron-binding-capacity-tibc-uibc/

Question 13

The following factors describe which lab value within an iron panel?

• Varies diurnally (higher in AM, lower in PM)
• Increases after meals
• Decreases with infection and inflammation

Answer 13

Serum iron

Hark, p. 88

Question 14

In iron deficiency anemia, RBCs are often _______ (small due to insufficient hemoglobin production) and ______ (pale)

Answer 14

microcytic = small
hypochromic = pale 

(Hark. p. 88)

Question 15

Are reticulocyte counts usually HIGH or LOW in iron deficiency anemia? Why?

Answer 15

Reticulocyte count = # of new RBCs

Reticulocyte counts are LOW, indicating decreased bone marrow production of RBCs

(Hark, p. 88)

Question 16

List the four RBC indices within a CBC often used to help dx/monitor anemia

Answer 16

MCV = mean corpuscular volume
MCH = mean corpuscular hemoglobin
MCHC = mean corpuscular hemoglobin concentration
RDW = red blood cell distribution width

https://medlineplus.gov/lab-tests/red-blood-cell-rbc-indices/

Question 17

True or false: As physiologic iron levels decrease, the efficiency of GI absorption of iron increases

Answer 17

True

Hark p. 87

Question 18

What mineral inhibits iron absorption?

Answer 18

Calcium

Hark p. 86-87

Question 19

What is the one population group that should be routinely screened for iron deficiency, regardless of symptoms?

Answer 19

Pregnant women - even if asymptomatic

Hark, p. 87

Question 20

Iron is best absorbed in which form - ferrous or ferric?

Answer 20

Ferrous (ferrous salts of iron are generally used for oral supplementation - i.e. ferrous sulfate, succinate, lactate, fumarate, glycine sulfate, glutamate, gluconate)

(Hark, p. 87)

Question 21

What is the standard dose of elemental iron for deficiency?

Answer 21

60 mg of elemental iron 2x/day

Hark, p. 87

Question 22

How should iron dosage be modified if constipation & GI distress occur with supplementation?

Answer 22

When these symptoms occur, the dose should be reduced by one half, but continued. Stool softeners may also be prescribed

(Hark, p. 87)

Question 23

Are enteric-coated or delated-release iron preparations recommended?

Answer 23

No - these preparations cause iron to be released distally in the small intestine or in the colon, where the iron is not well absorbed

(Hark, p. 87)

Question 24

____ _____ is the most widely available parenteral form of iron and contains ___mg/mL of elemental iron. This is typically only administered in clients with severe malabsorption, ongoing blood loss, those experiencing chronic hemodialysis, or those unable to take oral iron.

Answer 24

Iron dextran - 50 mg/dL

Hark, p. 87

Question 25

How many months of oral supplementation is recommended for the treatment of iron deficiency?

Answer 25

3 months. Some recommend 6-12 months, but as iron status improves, a lower proportion of the supplement dose is absorbed and the benefits are reduced. Patients should be monitored carefully since side effects are common.

(Hark, p. 88)

Question 26

If anemia does not correct with iron supplementation, what are the 4 main causes that must be considered?

Answer 26

1. Impaired absorption - i.e. celiac disease, malabsorptive disease, concomitant use of binders
2. Poor adherence to supplementation (i.e. due to side effects)
3. Excess iron loss / increased needs
4. Thalassemia

(Hark, p. 88)

Question 27

The hormone ________ plays a central role in controlling iron absorption. The levels of this hormone are influenced by inflammatory markets such as IL-6, IL-22, and type 1 interferon.

Answer 27

Hepcidin

Hark, p. 88

Question 28

What is the most sensitive indicator of iron deficiency?

a. plasma iron
b. TIBC
c. plasma ferritin
d. circulating transferrin

Answer 28

c. plasma ferritin

Question 29

The sole iron exporter in iron-transporting cells is:

a. ferritin
b. hemoglobin
c. ferroportin
d. transferrin

Answer 29

c. ferroportin - Ferroportin transports iron from the inside of a cell to the outside of a cell where it eventually will be transported in the bloodstream.

Question 30

The herbal remedy St John’s Wort may interact with which of the following medications?

a. Statin drugs
b. Digoxin
c. Coumadin
d. All of the above

Answer 30

d. All of the above - The herbal remedy St John’s Wort, used to treat mild to moderate depression, may have adverse reactions with statin drugs, digoxin, and coumadin. It may decrease the effectiveness of all of these medications by interfering with the biochemical pathways by which they are metabolized.