Hematologic System

Hemostasis

Stopping of blood flow (clot formation), Physical barrier to infection and prevents blood loss

Hemostasis process

1. Inflammatory mediators are released from platelets & other cells

2. A clot is formed

3. Protective scab is formed

4. Clot followed by a scab is called a thrombus

5. Regeneration of cells occurs under thrombus

6. Once regeneration is done, enzymes degrade the thrombus

Sickle Cell Disease Pathophysiology

• Single gene mutation with autosomal recessive inheritance

  • Homozygous: disease phenotype

  • Heterozygous: carrier

• Point mutation leads to altered structure of beta chain of HgB in RBCs

  • Sickled shape, known as HbS

Sickle Cell Disease Clinical Manifestations

• Jaundice

• Anemia

• Pain

• Organ damage

• Infection

• Related to proportion of HbS in the circulation

Sickle Cell Disease Diagnostic Criteria

• Genetic screening

• Hemoglobin electrophoresis: blood test that uses an electric current to separate and identify different hemoglobin types

• CBC: low RBCs indicate anemia, measures HgB, high WBCs indicate infection

• Urinalysis: monitors kidney damage and complications (such as sickle cell nephropathy)

• Tests of liver and kidney function: used to monitor organ damage and complications (sickled cells block blood vessels, cutting off O2 to major organs)

Leukemia Pathophysiology

• Malignant neoplasms of blood and blood-forming organs

• Acute

  • Lymphocytic (ALL)

  • Myeloid (AML)

• Chronic

  • Lymphocytic (CLL)

  • Myelogenous (CML)

Acute Lymphocytic Leukemia (ALL)

• Begins in lymphoblasts

• Most common in children

• Affects lymphoid cells which make infection-fighting B and T cells

Acute Myeloid Leukemia (AML)

• Begins in myeloid stem cells

• More common in adults

• Affects myeloid cells which make RBCs, platelets, and certain WBCs

Chronic Lymphocytic Leukemia (CLL)

• Affects lymphoid cells that form WBCs

• Originates in the lymphoid lineage

• Involves abnormal and dysfunctional B-lymphocytes that accumulate slowly in the bone marrow, blood, and lymph nodes

• Often shows no initial symptoms

• Slow progression

• Targeted therapies like BTK or BCL2 inhibitors, monoclonal antibodies, or chemotherapy

Chronic Myelogenous Leukemia

• Originates in the myeloid lineage

• Involves precursor cells that normally mature into RBCs, platelets, granulocytes, or monocytes

• Grows slowly but can become aggressive

• Treated with tyrosine kinase inhibitors (TKIs)

Leukemia Manifestations

• Anemia

• Headache

• Bruising

• Visual disturbances

• Bleeding (epistaxis)

• Nausea/Vomiting

• Lymph node and organ enlargement

• Fatigue

• Weight loss

• Bone pain

• Fever

Leukemia Diagnostic Criteria

• Patient history and physical exam

• CBC

• Bone marrow biopsy: detects abnormal WBCs and identifies the type of leukemia, helps determine treatment

• Cytologic examination of blood cells: presence of immature, poorly differentiated cells indicate leukemia

Lymphoma Pathophysiology

• Derived from WBCs and lymph tissues

• Form solid organ tumors in the lymph tissues and later in bone marrow

• Classified as

  • Hodgkins lymphoma

  • Non-Hodgkins lymphoma

Lymphoma Clinical Manifestations: Hodgkin

• Painless, progrssive enlargement of cervical (neck) lymph nodes

• Low-grade fever

• Night sweats

• Pruritus (itching)

• Weight loss

• Fatigue

Lymphoma Clinical Manifestations: Non-Hodgkin

• Painless enlargement of lymph nodes

• Systemic manifestations such as B symptoms:

  • Unexplained fever

  • Drenching night sweats

  • Weight loss

  • Fatigue

  • Pruritus

Lymphoma Diagnostic Criteria: Hodgkin

• Presence of Reed-Sternberg cells

Lymphoma Diagnostic Criteria: Non-Hodgkin

• History and physical exam

• Lymph node biopsy

• Chest and abdominal CT scans: used to stage NHL, measure tumor size, and check for organ involvement

DIC Pathophysiology

• Uncontrolled activation of clotting factors resulting in widespread thrombi formation

• Depletion of coagulation factors and platelets leads to massive hemorrhage

• Initiated by endothelial injury

DIC Clinical Manifestations

• Excessive hemorrhage

  • Bruising

  • Petechiae (tiny red/purple/brown spots caused by minor bleeding from broken capillaries)

  • Epstaxis (bleeding)

• Excessive clotting

  • Headache

  • Weakness

  • Seizure, coma

• Renal

  • Poor urine output

  • Renal failure

• Respiratory

  • Cough

  • SOB

  • Respiratory distress

  • Chest pain

DIC Diagnostic Criteria

• History and physical exam

• Prothrombin time (how many seconds it takes to form a clot; High in DIC)

• Activated partial thromboplastin time (normal is 30-40 sec.; High in DIC)

• Platelet count (low in DIC)

• Fibrinogen level (under 1.0 g/L or 100 mg/dL in DIC)

• D-dimer test (elevated in DIC)

Iron Deficiency Anemia Pathophysiology

• Insufficient iron stores to meet needs for RBC development

• Major causes:

  • Inadequate iron intake

  • Chronic hemorrhage

  • Iron malabsorption

  • High iron demands

Iron Deficiency Anemia Clinical Manifestations

• Often asymptomatic

• Pallor of the skin and mucous membranes

• Fatigue, weakness, lightheadedness, syncope, and headache

• Breathlessness, palpitations, tachycardia

• Brittle nails and hair, mouth sores

• Pica (craving non-food items with no nutritional value)

Iron Deficiency Anemia Diagnostic Criteria

• History and Physical exam

• Lab studies

  • Hemoglobin, hematocrit

  • Mean corpuscular volume

  • Mean corpuscular hemoglobin concentration

  • RBC indices

  • Serum ferritin

Pernicious Anemia

A decrease in RBCs occurs when the intestines cannot absorb vitamin B12 because the stomach lacks intrinsic factor

• Primarily autoimmune

• Can stem from non-autoimmune causes that damage the stomach lining (ex. stomach surgery, prolonged gastritis, inherited intrinsic factor deficiency)

Pernicious Anemia Clinical Manifestations