-IBIS-1.5.0-
tx
cardiovascular system
anemia: nutritional deficiency/blood loss
diagnoses
definition and etiology
definition:
Reduction in red cell mass from decreased RBCs and/or hemoglobin.
etiology:
A discussion follows of the anemias that are caused by blood loss and by deficient iron, B12, folic acid, copper and vitamin C.
blood loss (acute post-hemorrhagic anemia): although sudden loss of a third of the blood volume can be fatal, as much as two-thirds of the blood may be slowly lost over 24 hours without death occurring. Symptoms follow a sudden decrease in the blood volume due to compensatory hemodilution, as well as a diminished oxygen-carrying capacity of the blood.
iron deficiency (chronic post-hemorrhagic anemia): this is the most common type of anemia. Hemorrhage must be ruled out in any adult presenting with iron deficiency anemia. Pregnancy causes anemia in women, as does prolonged heavy menses. In men, slow gastrointestinal bleeding is the primary cause for anemia.
The stages of iron deficiency anemia are:
1: iron depletion from body stores
2: decreased plasma iron levels, with increased transferrin
3: anemia with RBCs and indices which appear normal
4: microcytosis, then hypochromia
5: signs and symptoms of anemia
vitamin B12 deficiency (pernicious anemia): absorption of vitamin B12 occurs in the terminal ileum and requires the presence of gastric HCl and intrinsic factor. B12 is stored in the liver in sufficient quantities to sustain an individual for 3-5 years on a B12-deficient diet. The anemia typically develops insidiously as the liver stores are diminished. Vegans have greater risk for B12 deficiency since most significant sources of B12 are in animal products.
folic acid deficiency: most folic acid anemia is due to poor dietary intake. Liver stores are good for only 2-4 months of a deficient intake. Absorption of folic acid is decreased by alcohol, intestinal malabsorption diseases, oral contraceptives, and anticonvulsants.
copper deficiency: this is most often seen in infants and children. In adults it may be associated with sprue, nephrotic syndrome or kwashiorkor.
vitamin C deficiency: this is often associated with anemia. It is normally hypochromic but may be normocytic, microcytic, or macrocytic. When it is macrocytic, further investigation may reveal concurrent folic acid deficiency.
signs and symptoms
blood loss:
signs and symptoms:
faintness, dizziness, thirst, cold sweat, tachycardia, tachypnea and shortness of breath with exertion, orthostatic hypotension, shock, and death if the blood loss is severe and untreated
lab findings:
early: RBC count, hemoglobin, hematocrit are deceptively high (due to the compensating vasoconstriction)
after some hours: decreased RBCs and hemoglobin in proportion to the severity of the anemia
anemia is normocytic
iron deficiency anemia:
signs and symptoms:
as reported above in blood loss, pica (craving dirt or paint) or pagophagia (craving ice), Plummer-Vinson syndrome with dysphagia; in late stages: glossitis, cheilosis, koilonychia
lab findings: (dependent on degree of iron deficiency)
increased serum transferrin
decreased serum ferritin and serum iron
increased TIBC
decreased hemoglobin (6-12 mg/dl)
decreased RBC (3.5-5.0 million/cu. mm)
decreased MCV, MCHC, and MCH
RBCs are hypochromic and microcytic
vitamin B12 deficiency:
signs and symptoms:
splenomegaly and hepatomegaly; anorexia; occasional constipation and diarrhea; vague abdominal pain; glossitis ( burning of the tongue); neurological involvement (even if there is no clear anemia), especially peripheral nerves although spinal cord conditions are also seen
lab findings:
macrocytic anemia with an MCV > 100
basophilic stippling of RBCs, anisocytosis, poikilocytosis
hypersegmentation of granular leukocytes
(+) Schilling test with pernicious anemia only, not with dietary deficiency
serum vitamin B12 assay - low levels of serum vitamin B12
folic acid anemia:
signs and symptoms: include those typical to B12 anemia; the neurologic symptoms present with B12 deficiency do not occur
lab findings:
(+) folate depletion: otherwise, the peripheral blood and bone marrow findings are identical to B12 anemia
serum folic acid levels decreased (< 5 ng/ml)
decreased erythrocyte folate levels
copper deficiency anemia:
lab findings:
megaloblastic anemia with significant vascularization in the cytoplasm of developing RBCs
vitamin C deficiency anemia:
signs and symptoms:
clinical signs of scurvy (bleeding gums, easy bruising, frequent illnesses, nosebleeds, slow healing); anemia
lab findings:
decreased plasma levels of ascorbic acid (can be down to 0 in overt scurvy)
decreased/absent ascorbic acid in buffy coat
(+) Rumpel-Leede test
decreased serum alkaline phosphatase
(+) microscopic hematuria
(+) associated lab findings (e.g., FA deficiency)
course and prognosis
conventional treatments:
1. blood loss: stop the bleed, plasma or blood transfusion, chemical agents capable of transporting oxygen, rest, fluids, iron replacement
2. iron deficiency: a slow bleed must be ruled out. Treatment in uncomplicated iron deficiency is iron replacement therapy for at least 6 months.
3. vitamin B12 deficiency: B12 1000 ug IM 2-4/wk. until the indices are normalized then monthly
4. folic acid deficiency: folic acid 1 mg/day orally
5. copper deficiency: copper sulfate replacement therapy completely reverses the anemia
6. vitamin C deficiency: vitamin C 500 mg/day orally. If there is macrocytemia, then replace folic acid also, as above.
differential diagnosis
Since anemia is a symptom rather than a specific disease entity, it is important to probe the cause. Initial direction may be obtained from thorough history and pertinent physical examination, along with the morphologic evidence gathered from blood work. Determine whether the anemia is from blood loss, decreased production or increased destruction. The differential is systematic, and widely described in standard reference texts, whose flowcharts are an excellent guide to workup prior to consultation with a hematologist.
footnotes