Ch. 19 - Disorders of Iron and Heme Metabolism Flashcards
(141 cards)
1
Q
The anemias associated with iron and heme typically
are categorized as anemias of ________ _______ resulting
from the lack of raw materials for hemoglobin assembly.
A
impaired production
2
Q
Inadequate production of ____________ leads to diminished
production of heme and thus hemoglobin, but with a relative
excess of iron.
A
protoporphyrin
3
Q
The result of inadequate production of protoporphyrin
A
sideroblastic anemia
4
Q
functional molecules
A
heme-based cytochrome,
muscle myoglobin,
hemoglobin
5
Q
Iron may be unavailable for incorporation into
heme because of _____________ or __________
A
inadequate stores of body iron
impaired
mobilization.
6
Q
The anemia associated with inadequate stores is
termed:
A
iron deficiency anemia
7
Q
the anemia resulting
from impaired iron mobilization is known as
A
anemia of chronic
inflammation
8
Q
an example of a chronic inflammation condition
A
rheumatoid arthritis
9
Q
the iron
supply is adequate and mobilization is unimpaired but an
intrinsic RBC defect prevents production of protoporphyrin or
incorporation of iron into it, the resulting anemia is called:
A
sideroblastic anemia
10
Q
refers to the presence of nonheme iron in
the developing RBCs
A
sideroblastic
11
Q
develops when the INTAKE OF IRON IS INADEQUATE to meet a standard level of demand, when the NEED FOR IRON EXPANDS, when there is IMPAIRED ABSORPTION, when
there is CHRONIC LOSS OF HEMOGLOBIN from the body
A
iron deficiency anemia
12
Q
Approximately how much of iron is lost from the body each day?
A
1 mg of iron
13
Q
Iron is lost from the body mainly in the _____________________ and __________.
A
mitochondria of desquamated skin and sloughed intestinal epithelium
14
Q
Causes of iron deficiency when the level of iron intake
is inadequate to meet the needs of an expanding erythron
A
-infancy
(especially in prematurity), childhood, and adolescence
-pregnancy and nursing
15
Q
Causes of impaired absorption
A
- celiac disease
- diseases that decrease stomach acidity
- gastrectomy or bariatric surgeries
- medications such as antacids
16
Q
hemolysis that results in the loss of small amounts of
heme iron from the body over a prolonged period of time
A
chronic hemorrhage
17
Q
Excessive
heme iron can be lost through?
A
-chronic gastrointestinal bleeding from ulcers
-gastritis due to alcohol or aspirin ingestion,
-tumors
parasitosis
-diverticulitis
-ulcerative colitis
-hemorrhoids
18
Q
In women, what conditions such as can also lead to heme iron loss?
A
-prolonged menorrhagia (heavy menstrual
bleeding)
-fibroid tumors
-uterine
malignancies
19
Q
Individuals with chronic
intravascular hemolytic processes, such as ________________, can develop iron deficiency due to the
loss of iron in hemoglobin passed into the urine.
A
paroxysmal nocturnal
hemoglobinuria
20
Q
iron is distributed among three compartments, what are these?
(1) the storage compartment, principally as ferritin in
the bone marrow macrophages and liver cells; (2) the transport
compartment of serum transferrin; and (3) the functional
compartment of hemoglobin, myoglobin, and cytochromes.
A
(1) the storage compartment, principally as ferritin in
the bone marrow macrophages and liver cells
(2) the transport
compartment of serum transferrin
(3) the functional
compartment of hemoglobin, myoglobin, and cytochromes.
21
Q
True or false. Hemoglobin and intracellular ferritin constitute nearly 85% of
the total distribution of iron.
A
False. *95%
22
Q
The body strives to maintain iron balance by accelerating
absorption of iron from the intestine through a decrease
in the production of ________ in the liver.
A
hepcidin
23
Q
What stage of iron deficiency is defined by the exhaustion of the
storage pool of iron?
A
Stage 2
24
Q
What stage of iron deficiency is characterized by a progressive loss
of storage iron?
A
Stage 1
25
(Stage 2) The serum iron and serum ferritin levels
decrease, whereas ______________, an indirect
measure of transferrin, increases
total iron-binding capacity (TIBC)
26
(Stage 2) ___________________, the porphyrin
| into which iron is inserted to form heme, begins to accumulate.
Free erythrocyte protoporphyrin (FEP
27
(Stage 2) ____________ stain of the
| bone marrow in stage 2 shows essentially no stored iron
Prussian blue
28
True or false. Iron deficiency in stage 2 is subclinical, and
testing is not likely to be undertaken.
True
29
What stage of iron deficiency is frank anemia?
Stage 3
30
(Stage 3) True or false. The hemoglobin
concentration and hematocrit are high relative to the reference
ranges.
False. *low :))
31
(Stage 3) True or false. FEP and transferrin receptor levels continue to decrease.
False *increase
32
Nonspecific symptoms of anemia
fatigue and weakness
33
A severe sign due to due to iron deficiency in the rapidly proliferating
cells of the alimentary tract
sore
| tongue (glossitis)
34
A severe sign characterized by inflamed cracks at
| the corners of the mouth
angular cheilosis
35
may be seen if the deficiency
| is long-standing
Koilonychia
| spooning of the fingernails
36
cravings for
| nonfood items
pica
37
Craving for ICE
pagophagia
38
_______________________
| can lead to a loss of nearly 900 mg of iron,
pregnancy and nursing
39
Growth requires
a. _____ for the cytochromes of all new cells, b. ________for new
muscle cells, and c. __________ in the additional RBCs needed
to supply oxygen for a larger body.
a. iron
b. myoglobin
c. hemoglobin
40
True or false. Cow’s milk
| is a good source of iron
False
41
iron supplementation is also
| recommended for breastfed infants after how many months of age?
6 months
42
___________ and __________ can lead to gastritis and
| chronic bleeding.
-Regular aspirin
ingestion
-alcohol consumption
43
Iron deficiency is associated with infection by hookworms. Give two examples.
Necator americanus and Ancylostoma duodenale
44
Iron deficiency is also associated with infection
with other parasites, such as: __________, ___________, and __________ in which the heme iron
is lost from the body due to intestinal or urinary bleeding.
Trichuris trichiura, Schistosoma
| mansoni, and Schistosoma haematobium
45
___________ develops when RBCs are hemolyzed
by foot-pounding trauma and iron is lost as hemoglobin
in the urine
“Marching anemia”
46
The tests for iron deficiency can
| be grouped into three general categories:
- screening
- diagnostic,
- specialized.
47
When iron deficient erythropoiesis is under way, the CBC
| results begin to show evidence of ________, ________ and, _________
anisocytosis, microcytosis,
| and hypochromia
48
The classic picture of iron
deficiency anemia in stage 3 includes a decreased _________
level.
hemoglobin
49
An RDW greater than ___ is expected and may precede
| the decrease in hemoglobin.
15%
50
As the hemoglobin level continues to fall, microcytosis and hypochromia become more prominent, with
progressively declining values for ____, _____, and _____
MCV, MCH, and MCHC
51
A low
________________ confirms a diminished rate of effective
erythropoiesis, because this is a nonregenerative anemia
absolute reticulocyte count
52
_____________ may be present,
particularly if the iron deficiency results from chronic bleeding,
but this is not a diagnostic parameter.
Thrombocytosis
53
True or false. White blood cells
| (WBCs) are typically normal in number and appearance.
True
54
Iron
deficiency should be suspected when the CBC findings show a
hypochromic, microcytic anemia with an (a. elevated b. decreased) RDW but no
consistent shape changes to the RBCs.
a. elevated
55
____________ remain the backbone for diagnosis of iron deficiency
Iron studies
56
______________ is
| a measure of the amount of iron bound to transferrin in the serum.
Serum iron
57
______ is an indirect measure of
transferrin and the available binding sites for iron in the
plasma.
TIBC
58
True or false. Ferritin is not truly an extracellular protein.
True *because it provides an intracellular storage repository for metabolically active iron
59
_____________ is an
| easily accessible surrogate for stainable bone marrow iron
Serum ferritin
60
Serum ferritin
| and serum iron values are (a. increased b.decreased) in iron deficiency anemia
b. decreased
61
Transferrin levels (a. increase b. decrease) when the hepatocytes detect low
iron levels, and research shows that this is a transcriptional and
posttranslational response to low iron levels.12
a. increase
62
It is important that specimens for iron studies are drawn
| while ______ and when levels are highest.
fasting
| early in the morning
63
Iron absorbed from a meal can falsely
| (a.elevate b. decrease) levels
a. elevate
64
The reticulocyte
| hemoglobin value is analogous to the ___, but for reticulocytes.
MCH
65
The ___ is the average weight of hemoglobin per cell
| across the entire RBC population
MCH
66
The ________________ is able to assess iron deficient erythropoiesis within days
as the first iron deficient cells leave the bone marrow.
reticulocyte hemoglobin value
67
```
Even in stage 2 of iron
deficiency, before anemia is apparent, the reticulocyte hemoglobin
will be (a. low b. high)
```
a. low
68
Test results for
| the accumulated porphyrin precursors to heme are (a. elevated b. decreased)
a. elevated
69
In
the absence of iron, FEP may be preferentially chelated with
zinc to form __________________
zinc protoporphyrin (ZPP)
70
The FEP and zinc
| chelate can be assayed ____________
fluorometrically
71
A __________________ provides a less invasive and less expensive
diagnostic assessment.
therapeutic trial of iron
72
With routine stains, the iron deficient
bone marrow appears a. ___________ early in the progression of
the disease, with a decreased b. ________________ ratio as a
result of increased erythropoiesis.
a. hyperplastic
| b. myeloid-to-erythroid
73
As the disease progresses,
__________ subsides, and the profound deficiency of iron leads
to slowed RBC production.
hyperplasia
74
_________________ (i.e.,
| rubricytes) show the most dramatic morphologic changes
Polychromatic normoblasts
75
Without the pink provided by hemoglobin, the cytoplasm
| remains ____ after the nucleus has begun to condense.
bluish
76
The
cell membranes appear irregular and are usually described as
_______
shaggy
77
The first therapy for iron deficiency is to treat any underlying
contributing cause, such as?
hookworms, tumors, or ulcers.
78
As
in the treatment of simple nutritional deficiencies or increased
need, dietary supplementation is necessary to replenish the
body’s iron stores. Oral supplements of _______________________________are the standard
prescription.3
```
ferrous sulfate (3
tablets/day containing 60 mg of elemental iron)
```
79
The supplements should be taken on an
| (a. empty b. full) stomach to maximize absorption
a. empty
80
What can be used in rare cases in which intestinal absorption
of iron is impaired, as with gastric achlorhydria?
parenteral
| administration of iron dextrans
81
(Response to Treatment) The reticulocyte hemoglobin will correct within how many days?
2 days
82
(Response to Treatment) The reticulocyte counts (relative and absolute) begin to
increase within how many days?
5 to 10 days
83
The anticipated rise in hemoglobin
appears in a. ______ (how many weeks), and levels should return to
normal for the individual by about b. ______ (how many months) after the initiation
of adequate treatment
a. 2 to 3 weeks
| b. 2 months
84
The peripheral blood film and
indices still reflect the microcytic RBC population for several
months, but the _________ population eventually predominates.
normocytic
85
Iron therapy must continue for another ____________ (how many months)
to replenish the storage pool and prevent a relapse.
3 to 4 months
86
This anemia represents the most common
| anemia among hospitalized patients
Anemia of Chronic Inflammation
87
Who was the first to suggest that although the underlying
diseases seem quite disparate, the associated anemia may be
from a single cause, proposing the concept of anemia of
chronic disease
Cartwright
88
True or false. Chronic
blood loss is not among the conditions leading to the anemia
of chronic disease.
True
89
The central feature
| of anemia of chronic inflammation
sideropenia
90
The cause of anemia of chrosnic inflammation is now understood to be
largely what?
impaired ferrokinetics
91
hormone produced by
hepatocytes to regulate body iron levels, particularly absorption
of iron in the intestine and release of iron from macrophages
Hepcidin
92
exports iron from enterocytes into the plasma, reducing
| the amount of iron absorbed into the blood from the intestine
Transmembrane protein: Ferroportin
93
When body iron
levels a. _______, hepcidin production by hepatocytes decreases,
and b. ________ export more iron into the plasma
a. decrease
| b. enterocytes
94
When iron levels
are high, hepcidin increases, enterocytes export (a. more b. less) iron into
the plasma, and macrophages and hepatocytes retain iron.
b. less
95
an iron-binding protein in
| the granules of neutrophils
Lactoferrin
96
Acute phase reactants
hepcidin, lactoferrin, ferritin
97
The peripheral blood picture in anemia of chronic inflammation
is that of a mild anemia with hemoglobin concentration
usually ______ g/dL and without reticulocytosis.
9 to 11
98
Because hepatocyte production
of transferrin is regulated by iron levels, the low TIBC
(an indirect measure of transferrin) reflects the (a.abundant b. diminished) iron
stores in the body.
a. abundant
99
Iron deficiency
anemia and anemia of chronic inflammation can be distinguished
in such situations by measuring _______________.
serum (soluble) transferrin
| receptors
100
Therapeutic administration of ____________ can correct
| anemia of chronic inflammation
erythropoietin
101
Trulaloo or false. The best course of treatment in anemia of chronic inflammation is effective control or
alleviation of the underlying condition.
True
102
True or false. As in iron deficiency, the anemia of chronic inflamm may be microcytic and hypochromic.
True
103
True or false. In contrast to iron deficiency, however, iron is abundant
in the bone marrow in the anemia of chronic inflamm.
True
104
a cofactor
in the first step of porphyrin synthesis which glycine is condensed with succinyl coenzyme A to form
aminolevulinic acid
Pyridoxine
105
Certain drugs that can induce sideroblastic
| anemia
chloramphenicol or isoniazid
106
A toxin that interferes with porphyrin synthesis
Lead
107
The most critical steps when lead interferes with porphyrin synthesis
1. The conversion of aminolevulinic acid to porphobilinogen;
the result is the accumulation of aminolevulinic acid.
2. The incorporation of iron into protoporphyrin IX by ferrochelatase
(also called heme synthetase); the result is accumulation
of iron and protoporphyrin.
108
```
Accumulated aminolevulinic acid is measurable
in the (a. stool b. blood c. urine)
```
c. urine
109
protoporphyrin is measurable in an
| extract of RBCs as___ or ___.
FEP or ZPP
110
Anemia, when present in lead poisoning, is most often
normocytic and normochromic; however, with chronic exposure
to lead, a ________, _________clinical picture may be
seen.
microcytic, hypochromic
111
Hereditary Disorders Included in Sideroblastic Anemias
X-linked
| Autosomal
112
The presence of a
hemolytic component is supported by studies showing impairment
of the _______________by lead, which makes
the cells sensitive to oxidant stress as in glucose-6-phosphate
dehydrogenase deficiency
pentose-phosphate shunt
113
chronic
| poisoning results in ______ of the marrow
hypoplasia
114
a classic finding associated with lead toxicity
Basophilic
| stippling
115
Lead
inhibits _______________, an enzyme involved in the
breakdown of ribosomal ribonucleic acid (RNA) in reticulocytes
pyrimidine 5′-nucleotidase
116
In the case of lead,
___________________________are often used to
chelate the lead present in the body so that it can be excreted
in the urine
salts of ethylenediaminetetraacetic acid
117
The term ________ is most often
| used to refer to the hereditary conditions
porphyria
118
The fluorescence of
the accumulated compounds can be used diagnostically as
described earlier for FEP. In a sample of bone marrow, the
erythroblasts will be _______ under a fluorescent microscope.
bright red
119
It occurs when there is a need for repeated transfusions, as in
the treatment of anemias such as thalassemia.
Accumulation of excess iron
120
It is when the iron present
in the transfused RBCs exceeds the usual 1 mg/day of iron
typically added to the body’s stores by a healthy diet.
transfusion-related hemosiderosis
121
may develop as a result of mutations
| affecting the proteins of iron metabolism
Hemochromatosis
122
```
a gene on the short arm of chromosome
6 that encodes an HLA class I–like molecule that is
closely linked to HLA-A
```
HFE
123
The most common of the two
mutations substitutes tyrosine for ________ at position 282
(Cys282Tyr)
cysteine
124
the other mutation substitutes _________ for histidine
| at position 63 (His63Asp).
aspartate
125
The normal ____ protein binds
| β2-microglobulin intracellularly.
HFE
126
Interaction of HFE with _____________ reduces transferrin binding to the receptor, inhibiting
cellular iron absorption
transferrin
| receptor 1
127
The _______________
either does not bind β2-microglobulin and thus does not reach
the cell surface, or does not bind the transferrin receptor 1 if
it does reach the cell surface
mutated HFE molecule
128
The (a. active b. passive) transport of iron into the
plasma seems to be crucial in the pathophysiology of hereditary
hemochromatosis.
a. active
129
the gene that codes
| for hemojuvelin
HJV (HFE2)
130
In hepatocytes, what substances regulate hepcidin expression
-iron-bound transferrin
-HFE
-transferrin
receptor 2
-hemojuvelin
131
The first
| cellular reaction to excess iron is?
form hemosiderin
132
essentially a degenerate and non–metabolically active form of
ferritin
hemosiderin
133
the traditional characterization
| of hemochromatosis
“bronzed diabetes”
134
occurs more frequently in patients with hemochromatosis.
Hepatocellular carcinoma
135
The phenotypic expression of the tissue damage
in hereditary hemochromatosis is more
common in (a.men b. women)
a. men
136
In classic hereditary hemochromatosis,
individuals usually harbor ______ g of iron by the time their
disease becomes clinically evident at the age of 40 to 60 years
20 to 30 g
137
Withdrawal of blood
by phlebotomy provides a simple, inexpensive, and effective
means of removing iron from the body. The regimen calls
for weekly phlebotomy early in treatment to remove about
___ mL of blood per treatment
500
138
iron-chelating drug that is a classic treatment for people who cannot be treated by phlebotomy
Desferrioxamine
139
When stained using Prussian blue, the iron appears in
deposits around the nucleus of the developing cells. These cells
are called?
ringed sideroblasts
140
In the pathogenesis of the anemia of chronic inflammation,
| hepcidin levels:
Increase during inflammation and reduce iron
| absorption from enterocytes
141
Sideroblastic anemias are anemias that result from:
Failure to incorporate iron into protoporphyrin IX
