RBC - patho

Red blood cells (RBCs)

also called erythrocytes, carry oxygen to the tissues and carbon dioxide back to the lungs.

Two Major Categories of RBC Disorders

1. Anemia

2. Hemoglobinopathies

anemia

an inadequate number of healthy RBCs to meet the body's oxygen needs. Common causes include iron, vitamin B12, or folate deficiency, and chronic disease

Hemoglobinopathies

inherited anomalies affecting hemoglobin itself, such as sickle cell anemia (SCA), which change the shape or amount of hemoglobin in the RBC.

RBCs pick up oxygen from the lungs, carry them to the tissues and drop them off, then carry carbon dioxide waste back to the lungs

What is the RBC transport oxygen cycle

anemia

_____ is an inadequate number of healthy RBCs. It is classified by mean corpuscular volume (MCV) — the average size of the RBC.

Microcytic

MCV (mean corpuscular volume) below expected range

• small, pale = hypochromic

  • linked to: iron deficiency anemia (IDA) + Anemia of chronic disease (ACD)

Normocytic

MCV within expected range

• expected size and color

  • linked to: acute blood loss + hemolysis / ACD

macrocytic

MCV above expected range

• large, immature cells

  • linked to: vitamin B12 deficiency + folate deficiency

Iron deficiency (IDA)

RBC size and color - microcytic, hypochromic

leading cause - Inadequate dietary iron, blood loss, pregnancy

key lab clue - Low ferritin, high TIBC

Vitamin B12 deficiency

RBC size and color - Macrocytic

leading cause - Poor intake (vegan diet), pernicious anemia, GI surgery

key lab clue - Low B12; high MMA + homocysteine

Folate Deficiency

RBC size and color - Macrocytic

leading cause - Poor intake, alcohol use, pregnancy, malabsorption

key lab clue - Low folate; high homocysteine only

Hemolytic Anemia

RBC size and color - microcytic to normocytic

leading cause - hereditary conditions (incl. SCD), autoimmune destruction

key lab clue - high reticulocytes, LDH, bilirubin; low haptoglo__bin

IDA and ACD

can look similar (both microcytic), but ferritin tells them apart: low in IDA, high (or normal) in ACD, because in ACD the iron is present but "locked away" by inflammation.

Iron Deficiency Anemia (IDA)

The leading cause of anemia worldwide; results from insufficient iron to support hemoglobin synthesis.

Iron deficiency anemia (IDA) - Etiology & Pathophysiology

● Caused by blood loss (trauma, surgery, GI bleeding, cancer), inadequate dietary iron intake, impaired absorption (celiac disease, Crohn's disease), or increased need (pregnancy, young children).

● Affects an estimated 70% of female clients of reproductive age due to menstrual blood loss.

● Without enough iron, hemoglobin synthesis is impaired, resulting in fewer functional RBCs that cannot carry oxygen efficiently.

● This limits oxygen delivery to the tissues, producing the body's compensatory symptoms.

Iron deficiency anemia (IDA) - manifestations

● Fatigue, weakness, dyspnea, pallor (best assessed in the conjunctiva, oral mucosa, and nail beds), cold hands/feet, and restless legs. Unusual cravings for non-food items (ice, dirt) may occur

Iron deficiency anemia (IDA) - Diagnosis

ow hemoglobin, iron, and ferritin, with a high total ironbinding capacity (TIBC); blood smear shows microcytic, hypochromic RBCs

Iron deficiency anemia (IDA) - management

treat the underlying cause + oral iron supplementation, usually for at least 3 months; pair with vitamin C to boost absorption, avoid tea/coffee/calcium at mealtimes.

Iron deficiency anemia (IDA) - Client education

dietary iron sources — red meat, green leafy vegetables, seafood, legumes, iron-fortified grains.

IDA

"Small and pale" — _____ produces microcytic, hypochromic RBCs. Low ferritin confirms depleted iron stores; TIBC rises as the body tries to grab every bit of iron it can.

Vitamin B12 Deficiency Anemia

A macrocytic anemia caused by inadequate B12 intake or absorption; affects both blood and nerve function.

Causes of Vitamin B12 Deficiency Anemia

strict vegan/vegetarian diets, excess alcohol use, pernicious anemia (autoimmune loss of intrinsic factor), bariatric surgery, and medications such as proton pump inhibitors or metformin.

Vitamin B12 Deficiency Anemia - Etiology & Pathophysiology

● Vitamin B12 is needed for DNA synthesis in developing RBCs. Without it, cells grow but don't divide on time, producing large, immature RBCs (megaloblastic anemia).

● Neutrophils are also affected — their nuclei fail to mature normally, becoming hypersegmented (more than 5 lobes), an early hematologic clue.

● B12 is also required to make myelin, the protective coating on nerves, so deficiency can damage the nervous system

Vitamin B12 Deficiency Anemia manifestations

● Fatigue, pallor, dyspnea, glossitis (smooth, sore tongue); as it progresses — tingling/numbness, gait disturbances, confusion, memory loss, mood changes from nerve demyelination.

Vitamin B12 Deficiency Anemia diagnosis

● Diagnosis: elevated MCV (macrocytic), low hemoglobin/hematocrit; low serum B12; blood smear shows macrocytic RBCs with hypersegmented neutrophils.

● If unclear: elevated methylmalonic acid (MMA) AND homocysteine confirm B12 deficiency (vs. folate deficiency, where only homocysteine is high).

Vitamin B12 Deficiency Anemia management

• oral B12 if dietary cause; parenteral (injectable) B12 if due to malabsorption or lack of intrinsic factor — oral supplements won't be absorbed.

B12 (or folate) deficiency.

Hypersegmented neutrophils + macrocytic RBCs = THINK _______. Only B12 deficiency also causes neurological symptoms (tingling, gait changes) because B12 maintains the nerves' myelin sheath

Folate Deficiency Anemia

Folate (vitamin B9) is required for healthy RBC production; deficiency produces a macrocytic anemia similar to B12 deficiency.

Folate Deficiency Anemia - etiology and pathophysiology

● Usually from inadequate dietary intake. Risk increases with pregnancy (increased need), alcohol use, malabsorption disorders (celiac disease), and certain medications (methotrexate, phenytoin).

● The body's folate stores are limited — deficiency can develop within 8 to 16 weeks on a folate-poor diet.

● Folate is needed to build DNA and produce RBCs; without it, cells can't divide normally, leading to large, dysfunctional RBCs (megaloblastic anemia) — the same mechanism as B12 deficiency.

● Folate is essential for fetal neural tube closure — deficiency in early pregnancy can cause neural tube defects (anencephaly, spina bifida)

Folate Deficiency Anemia - Manifestations

● Fatigue, pallor, glossitis (shared with B12 deficiency), plus decreased appetite, irritability, and diarrhea.

folate Deficiency Anemia - diagnosis

macrocytic anemia on smear, elevated MCV, low hemoglobin/hematocrit; serum folate below 2 ng/mL confirms deficiency.

• Key distinction from B12 deficiency: homocysteine is elevated, but MMA and B12 levels are normal.

folate Deficiency Anemia - management

oral folate supplementation (IV/IM/subQ if needed); must also rule out/treat B12 deficiency, since treating folate alone will not fix B12-related nerve damage. All clients who may become pregnant are counseled on folate intake to prevent birth defects.

B12 and folate deficiency

_____ look the same on a blood smear (macrocytic) — tell them apart with MMA and homocysteine. Both high = B12 deficiency. Only homocysteine high = folate deficiency.

Hemolytic Anemia

Occurs when RBCs are destroyed faster than the body can replace them. Can be inherited or acquired, acute or chronic.

Hemolytic Anemia Etiology & Pathophysiology

● Intracorpuscular causes (always hereditary — a problem within the RBC itself): membranopathies (hereditary spherocytosis/elliptocytosis), enzymopathies (G6PD deficiency), hemoglobinopathies (SCD).

● Extracorpuscular causes (hereditary or acquired — damage from outside the RBC): autoimmune attack, mechanical trauma (prosthetic heart valves), infections (malaria), or reactions to medications/transfusions.

● Classified by location: extravascular hemolysis (RBCs trapped and destroyed by the spleen/liver) vs. intravascular hemolysis (RBCs destroyed/sheared within blood vessels).

Manifestations● Released hemoglobin breaks down into bilirubin faster than the liver can clear it, causing jaundice and dark urine.

Hemolytic Anemia manifestations

Dyspnea, weakness, fatigue, tachycardia; jaundice and dark-colored urine (hematuria) from bilirubin buildup; enlarged liver/spleen in chronic cases.

Hemolytic Anemia diagnosis

elevated reticulocyte count and LDH, elevated unconjugated bilirubin, decreased haptoglobin; direct antiglobulin (Coombs) test if immune-mediated; blood smear may show schistocytes (fragmented RBCs).

Hemolytic Anemia management

treat the cause; severe cases may need blood transfusion, plasmapheresis, or IV fluids/diuretics to flush free hemoglobin and protect the kidneys.

• Later-stage options: splenectomy, corticosteroids, immunosuppressive therapy, depending on the cause

hemolysis

Jaundice + dark urine + high reticulocyte count = THINK _______. A low haptoglobin confirms it — haptoglobin binds and "mops up" free hemoglobin, so it runs out during active hemolysis.

Anemia of Chronic Disease (ACD)

The second most common type of anemia overall, and the most common anemia in clients 65 and older and in hospitalized clients.

Anemia of Chronic Disease (ACD) - Etiology & Pathophysiology

● Also called "anemia of inflammation." Caused by chronic illness: infections, autoimmune conditions, cancer, chronic kidney disease (impairs erythropoietin production), or other long-term inflammatory states.

● Inflammatory cytokines (especially interleukin-6) signal the liver to release hepcidin, which blocks iron release from storage and reduces iron absorption in the gut.

● Result: iron is present in the body but functionally unavailable ("functional iron deficiency") — RBC production (erythropoiesis) is suppressed and RBC lifespan may shorten.

Anemia of Chronic Disease (ACD) - manifestations

Fatigue, weakness, dyspnea, fainting, and dizziness — often subtle due to gradual onset.

Anemia of Chronic Disease (ACD) - diagnosis

normocytic (sometimes microcytic), normochromic RBCs; LOW serum iron and transferrin saturation, LOW reticulocyte count, but ELEVATED ferritin and hepcidin (opposite of IDA, where ferritin is low).

Anemia of Chronic Disease (ACD) - management

treat the underlying condition first. If insufficient: erythropoiesis-stimulating agents (ESAs, e.g., epoetin alfa) to boost RBC production; blood transfusion for severe cases.

Anemia of Chronic Disease (ACD) - nursing focus

balance rest and activity, monitor hemoglobin/ferritin/inflammatory markers, educate on the inflammation-anemia link.

microcytic

ACD vs. IDA — both can be ______ but ferritin tells them apart: LOW ferritin = true iron deficiency (IDA); HIGH/normal ferritin with low iron = ACD (iron is "locked up" by hepcidin, not actually depleted)

Introduction to Hemoglobinopathies

Hemoglobinopathies are inherited blood disorders involving anomalies of hemoglobin, the oxygen-carrying protein in RBCs.

Two Patterns of Hemoglobin Anomaly

● An unexpected TYPE of hemoglobin — as in sickle cell disease (SCD), which causes RBCs to become irregularly shaped.

● A REDUCED AMOUNT of hemoglobin — as occurs in thalassemia.

● Both result in chronic hemolytic anemia from premature destruction of RBCs.

Sickle Cell Disease (SCD): The Umbrella Term

● Hemoglobin SS disease (HbSS) — also called sickle cell anemia (SCA); the most common and most severe form.

● Hemoglobin SC disease (HbSC) and sickle beta-thalassemia — other forms of SCD.

● Sickle cell TRAIT (HbAS) is different — a carrier state with one sickle gene; usually no symptoms, but the gene can be passed on.

sickle cell anemia (SCA/HbSS)

________ most common, most severe form of SCD

healthy blood flow

round, flexible RBCs flow smoothly through the vessel

Sickle cell crisis

rigid, crescent-shaped RBC’s clump and block the vessel

common triggers for sickling

• dehydration

• infection

• acidosis

• temperature extremes

• emotional / physical stress

Blocked vessels → tissue hypoxia → severe (vaso-occlusive crisis) and organ damage

sickled cells are fragile and break down early — lifespan frops 120 days to just 10-20 days

Sickle Cell Anemia:

Nearly all infants born in the U.S. are screened for SCD shortly after birth, allowing early, lifesaving intervention.

Sickle Cell Anemia: Diagnosis

● High-performance liquid chromatography (HPLC) is the cornerstone of diagnosis — identifies and quantifies hemoglobin types; in SCA, shows mostly hemoglobin S with little to no hemoglobin A.

● Genetic (DNA) testing confirms the specific mutation; distinguishes SCA (two HbS genes) from sickle cell trait (one HbS + one HbA gene).

● Hemoglobin level reflects severity of hemolysis — levels below 8 g/dL raise the risk of complications such as stroke and death.

● Elevated LDH, reticulocyte count, and indirect bilirubin support ongoing hemolysis

Sickle Cell Anemia: management

● Hydroxyurea (first-line oral medication) reduces sickling and VOC/ACS risk; other options include L-glutamine and crizanlizumab (IV) to reduce vaso-occlusion.

● Acute crisis care: IV fluids, analgesia (pain control), oxygen therapy, and monitoring for infection with prompt antibiotics.

● Blood transfusions manage severe anemia and help prevent stroke; curative options include blood/bone marrow transplant and emerging gene therapies.

● Prevention: prophylactic penicillin starting by 2 months of age and recommended vaccinations (pneumococcal, Hib, meningococcal) to reduce infection risk.

Hydroxyurea

_______ works by increasing fetal hemoglobin (HbF), which reduces sickling — this is exactly the medication Maria has been taking inconsistently due to nausea.

Sickle Cell Anemia: Early and Ongoing Manifestations

● Dactylitis (painful swelling of the hands/feet from blocked blood flow) is often the first sign in young children.

● Anemia, jaundice, and increased infection risk (especially affecting the spleen) from the rapid destruction of sickled RBCs.

● Fatigue and muscle pain from chronic tissue hypoxia (reduced oxygen delivery).

● Increased risk of blood clots, since hemolysis and free hemoglobin promote a hypercoagulable (clot-prone) state.

Sickle Cell Anemia: The Hallmark: Vaso-Occlusive Crisis (VOC)

● VOC — a sudden, severe, episodic pain crisis — is the hallmark manifestation of SCA, caused by sickled cells blocking blood flow and oxygen delivery.

● Splenic sequestration: sickled cells trap blood in the spleen, causing pain, splenic enlargement, and a sudden drop in hemoglobin.

● Acute chest syndrome (ACS) — sickled cells block pulmonary vessels, causing chest pain and respiratory distress; a MEDICAL EMERGENCY responsible for about 1 in 4 SCA-related deaths.

● Priapism and delayed growth may also occur as children get older.

Sickle Cell Anemia:

Manifestations typically begin around 4 to 6 months of age, once protective fetal hemoglobin (HbF) levels decline.