Pathophysiology: Mechanisms of Defense, Infection, and Hematological Disorders

Comprehensive vocabulary flashcards based on lecture notes covering innate physical and chemical barriers, inflammatory processes, acquired immunity, hypersensitivities, immunodeficiencies, infectious disease portals of entry, and hematological disorders.

Sjogren's syndrome

An autoimmune disease that dries up all lubricating fluids in the body, compromising mucosal barrier defenses.

Desquamation

The natural shedding of skin cells, which aids in removing bacteria present on the skin surface.

Serous exudate

A clear, gold-colored fluid composed of plasma that seeps into tissue during inflammation when there is little microbial involvement.

Purulent exudate

A thick, whitish or yellowish fluid (pus) formed during an infection, composed of plasma, dead tissue cells, white blood cells, and bacteria.

Degranulation

The process in which tissue mast cells break apart and spill granules of local inflammatory mediators (histamine, leukotrienes, and prostaglandins) into the tissue.

Chemotactic substances

Biochemical mediators that summon other substances or immune cells to a specific area or stimulate them to increase in amount.

Acute phase reactants (APR)

Systemic inflammatory mediators—such as C-reactive protein (CRP), complement, and circulating prostaglandins—that circulate in the bloodstream to amplify the inflammatory response.

Granulation tissue

Healthy, pink, vascularized healing tissue that forms at an injury or irritation site during the resolution of inflammation.

Granuloma

A mass of tissue that has been chronically inflamed and has converted essentially into scar tissue.

Erythrocyte sedimentation rate (ESR)

A lab test measuring how fast red blood cells settle to the bottom of a test tube; elevated rates (such as $100\text{ mm/hr}$) indicate active inflammation due to plasma proteins like fibrin causing RBC clumping.

SIRS (Systemic Inflammatory Response Syndrome)

A state of excessive systemic inflammation going into overdrive without normal braking, defined by two or more criteria such as altered mental status, fever ($> 100.4\text{ }^{\circ}\text{F}$), tachycardia, tachypnea, or abnormal WBC count.

Sepsis

A systemic condition that occurs when a patient has a known or suspected infection combined with the criteria for Systemic Inflammatory Response Syndrome (SIRS).

Septic shock

A severe complication of sepsis where extreme levels of inflammatory mediators induce widespread vasodilation and loss of vessel tone, resulting in severe hypotension (typically systolic BP $< 80\text{ or } 90\text{ mmHg}$) and organ ischemia.

Protected ice

Ice applied to an inflamed area with a towel or barrier between the ice and skin to safely induce local vasoconstriction, reducing tissue swelling and numbing pain.

Phospholipase

An enzyme high up in the arachidonic pathway that catalyzes the breakdown of cell membrane phospholipids into arachidonic acid, and is inhibited by steroid medications.

Prostaglandins (PGs)

Biochemical mediators produced via the arachidonic pathway that function as either proinflammatory mediators or protective agents maintaining platelet function, gastric mucosa, renal function, vasomotor tone, and immunocyte function.

Arachidonic acid pathway

A cell membrane metabolic pathway catalyzed by phospholipase that converts phospholipids into arachidonic acid, leading to the synthesis of leukotrienes and prostaglandins.

NSAIDs (Non-Steroidal Anti-Inflammatory Drugs)

Anti-inflammatory medications (e.g., aspirin, ibuprofen, naproxen) that inhibit prostaglandins lower in the arachidonic pathway, providing mild-to-moderate relief with fewer side effects than steroids.

Cell-mediated immunity

A subtype of acquired immunity directed by T-lymphocytes, including CD4 helper cells, CD8 cytotoxic direct killers, and memory T-cells.

Humoral immunity

A subtype of acquired immunity driven by B-lymphocytes, which differentiate into plasma cells to manufacture disease-specific antibodies.

Natural active acquired immunity

Acquired immunity established when an individual's own plasma cells produce antibodies in response to contracting an actual infection.

Artificial active acquired immunity

Acquired immunity established when an individual's own body produces antibodies in response to receiving a vaccine containing weakened or inactive pathogens.

Natural passive acquired immunity

Temporary acquired immunity obtained when a fetus or infant receives pre-formed maternal antibodies across the placenta or through breast milk, degrading after about $3\text{ months}$.

Artificial passive acquired immunity

Temporary acquired immunity conferred by an injection of pre-formed antibodies (such as TIG) during an acute exposure, lasting approximately $2\text{ weeks}$ before disintegrating.

Acquired immunity classification

The categorizations of adaptive 3rd line defense based on antibody origin (active vs. passive) and method of acquisition (natural vs. artificial).

Opsonization

The process by which antibodies coat a bacterial cell, optimizing its recognition and digestibility by phagocytes.

Anaphylaxis

A severe, systemic Type I IgE-mediated allergic reaction characterized by widespread mast cell degranulation, hives, angioedema, bronchoconstriction, wheezing, dyspnea, and hypotensive shock.

Rheumatic heart disease

An autoimmune hyperinflammatory condition following a streptococcal infection in which post-attack autoantibodies cross-react with and damage self-antigens on heart valves.

Systemic Lupus Erythematosus (SLE)

A systemic autoimmune disorder in which autoantibodies pair with circulating DNA fragments to form immune complexes that deposit in small blood vessels throughout the body, causing vasculitis, butterfly malar rash, serositis, proteinuria, and positive ANA tests.

Rheumatoid Arthritis (RA)

A systemic autoimmune disease in which autoantibodies form immune complexes with collagen, causing inflammatory vasculitis and destruction of joint synovial membranes, leading to morning joint stiffness and positive RF tests.

Human Leukocyte Antigens (HLAs)

Protein self-antigens present on the cell membranes of almost all body cells (except RBCs) that declare tissue identity and determine histocompatibility.

Erythroblastosis fetalis

A severe hemolytic disease of a fetus occurring when maternal anti-Rh antibodies cross the placenta and destroy the red blood cells of an Rh-positive baby in a second or subsequent pregnancy of an Rh-negative mother.

Opportunistic infections

Diseases caused by organisms or normal flora that are usually harmless to immunocompetent individuals, but become pathogenic when host immune defenses are severely compromised.

SCIDS (Severe Combined Immunodeficiency Syndrome)

A congenital genetic condition characterized by a complete absence of both cell-mediated (T-cell) and humoral (B-cell) immune function.

DiGeorge's syndrome

A congenital genetic defect on chromosome $22$ causing failure of thymus development, leading to incomplete T-cell maturation and severe cell-mediated immunodeficiency.

AIDS (Acquired Immunodeficiency Syndrome)

An acquired cell-mediated immunodeficiency caused by HIV, diagnosed when an HIV-positive individual's CD4 count drops below $200\text{ /}\mu\text{L}$ and/or an opportunistic infection develops.

ELISA (Enzyme-Linked Immunosorbent Assay)

An initial screening blood test used to detect antibodies to HIV, positive in $96\%$ of infected individuals within $2\text{ to } 12\text{ weeks}$ of exposure.

Fomite

An inanimate object or vector (such as a stethoscope, IV catheter, or furniture) that can harbour and transmit infectious microorganisms.

Beta-lactamase

An enzyme produced by mutated bacterial strains (such as MRSA and resistant Streptococcus pneumoniae) that destroys penicillin-based antibiotics by dismantling their molecular beta-lactam ring.

Cellulitis

An infection of the dermis and subcutaneous tissue, typically caused by Staphylococcus aureus entering through a skin breach, producing swollen, erythematous, and painful tissue.

Botulism

A disease caused by Clostridium botulinum toxin that blocks acetylcholine receptors at neuromuscular synapses, causing descending, symmetric paralysis.

Tetanus

A disease caused by Clostridium tetani exotoxin (tetanospasmin) that blocks inhibitory neurotransmitters, causing uninhibited nerve impulses leading to lockjaw (trismus) and tetany.

Rabies

A viral infection transmitted via infected host saliva (commonly bats) that travels along the PNS to the CNS, causing brain inflammation, agitation, dysphagia, and hydrophobia; fatal if post-exposure prophylaxis is not given within $14\text{ days}$.

Malaria

A vector-borne protozoal infection transmitted by mosquitoes that reproduces in hepatocytes and infects RBCs, causing mass hemolysis, high fever, chills, anemia, and splenomegaly.

Rubeola

Also known as two-week measles; a viral infection marked by a dense red maculopapular rash spreading downward from the head, accompanied by fever, cough, runny nose, conjunctivitis, and potential encephalitis.

Herpes Zoster

Also known as shingles; a painful skin lesion outbreak along a specific dermatome caused by the reactivation of dormant varicella virus in the nervous system.

Giardiasis

An intestinal protozoal infection contracted from contaminated water that adheres to the intestinal wall and blocks fat absorption, resulting in greasy, frothy, foul-smelling, non-bloody diarrhea.

Pseudomembranous colitis

An antibiotic-associated inflammatory bowel state caused by an overgrowth of Clostridium difficile (C-diff) after normal gut flora is destroyed by long-term antibiotic treatment.

Leukemia

A cancer of the hematopoietic system featuring uncontrolled proliferation of leukocytes, causing bone marrow overcrowding and decreased production of normal blood cells, resulting in leukocytosis, anemia, thrombocytopenia, and infection susceptibility.

Multiple Myeloma

A malignancy of B-lymphocyte plasma cells leading to abnormal immunoglobulin overproduction that infiltrates bones, stimulates osteoclasts to chew bone tissue, and causes pathological fractures and hypercalcemia.

Microcytic anemia

An anemia defined by an RBC count $< 4\text{ million/}\mu\text{L}$ and an MCV $< 80\text{ fL}$, caused by chronic steady loss of RBCs (e.g., heavy menses or occult GI bleeding) leading to iron deficiency and output of smaller, immature RBCs.

Normocytic anemia

An anemia defined by an RBC count $< 4\text{ million/}\mu\text{L}$ with a normal MCV ($80\text{ to } 95\text{ fL}$), resulting either from rapid acute hemorrhage or chronic diseases (e.g., AIDS, lupus, renal failure) slowing RBC production.

Macrocytic anemia

An anemia defined by an RBC count $< 4\text{ million/}\mu\text{L}$ and an MCV $> 95\text{ fL}$, commonly exemplified by pernicious anemia where intrinsic factor loss impairs vitamin B12 absorption, leading to faulty DNA coding of large, dysfunctional RBCs, glossitis, and paresthesias.

Polycythemia

A quantitative erythrocyte disorder marked by an elevated RBC count ($> 6\text{ million/}\mu\text{L}$) and hematocrit ($> 52\%$), causing sludge-like blood viscosity that predisposes to tissue ischemia, thrombosis, and organ failure.

Pancytopenia

A pathologically low count of all blood cell lines (RBCs, WBCs, and thrombocytes) caused by mass sequestration and destruction of blood cells within an enlarged spleen in hypersplenism.