Systemic Effects of Inflammation

Slide 1 · Systemic Effects of Inflammation

Cytokine-driven physiology, hematologic responses, acute-phase proteins and severe systemic inflammation

Dr Abu Suraih Sakhri

MBBS, MD (Pathology)

www.abusuraihsakhri.com

Slide 2 · Learning outcomes

Explain how local inflammatory stimuli induce systemic effects through cytokines.

Trace fever and leukocytosis to their principal cellular mediators.

Interpret acute-phase proteins and related blood-count changes.

Connect excessive cytokine release with major manifestations of septic shock.

Slide 3 · A local inflammatory focus can affect the whole body

Local tissue or microbial stimulus

Inflammatory cytokine production

Signals reach distant organs

Systemic physiologic changes

The initiating lesion need not be widespread.

Circulating mediator effects produce clinically detectable manifestations.

Slide 4 · Cytokines coordinate the systemic response

TNF

Principal mediator of systemic inflammation; Contributes to fever and severe sepsis.

IL-1

Principal mediator of fever and several acute-phase pathways.

IL-6

Major hepatic acute-phase response driver, especially CRP and fibrinogen.

Interferons and other cytokines also contribute; The response is not mediated by one molecule.

Slide 5 · Inflammatory stimuli initiate a shared response

Bacterial products or injury-related stimuli

Activated immune cells

TNF, IL-1, IL-6 and others

Distant tissue response

Bacterial products are examples, not the only inflammatory triggers.

The same cytokines may act on more than one target tissue.

Slide 6 · Systemic responses involve several organ systems

Target / compartment

Major response

Clinical or laboratory clue

Hypothalamus

Temperature regulation

Fever, chills

Bone marrow / blood

Leukocyte mobilization

Leukocytosis or altered differential

Liver

Acute-phase synthesis

CRP, fibrinogen, SAA

Metabolic / vascular systems

Exaggerated cytokine response

Shock, DIC, hyperglycemia

Slide 7 · Fever is a regulated increase in temperature

Fever is prominent in systemic inflammation, particularly infection.

A typical temperature elevation of approximately 1–4°C.

The change reflects cytokine-associated resetting of thermoregulation, rather than simple failure to lose heat.

Slide 8 · Pyrogens are fever-inducing substances

Exogenous pyrogens

Derived from microbes or other external stimuli.

Lipopolysaccharide (LPS) is the textbook example.

Stimulate immune-cell release of endogenous mediators.

Endogenous pyrogens

Produced by host immune responses.

Principally IL-1 and TNF in the described pathway.

Transmit the stimulus toward hypothalamic prostaglandin synthesis.

Slide 9 · Bacterial LPS acts upstream of host mediators

Bacterial LPS

Immune-cell activation

IL-1 and TNF release

Fever-associated signals

LPS acts as an exogenous pyrogen.

The fever pathway depends on the host cytokine response.

Slide 10 · IL-1 and TNF are endogenous pyrogens

Origin

Inflammatory immune response to microbial or other stimuli.

Action

Induce prostaglandin-producing machinery in responding cells.

Consequence

Alter thermoregulatory signaling within the hypothalamic region.

Other inflammatory mediators contribute, but IL-1 and TNF are emphasized in this pathway.

Slide 11 · The hypothalamic vascular interface mediates fever

Circulating IL-1 and TNF

Vascular / perivascular hypothalamic cells

Cyclooxygenase activity

Prostaglandin production

The response can be initiated by signals arriving from peripheral inflammation.

Hypothalamic vascular-associated cells respond to the cytokines.

Slide 12 · Cyclooxygenases link cytokines to prostaglandins

TNF and IL-1

Upregulation of cyclooxygenases

Prostaglandin synthesis

Altered neural signaling

Cyclooxygenases catalyze prostaglandin synthesis.

Their induction provides a mechanistic bridge between cytokines and fever.

Slide 13 · PGE₂ is a key prostaglandin in fever

Production

Induced after IL-1/TNF-dependent prostaglandin synthesis.

Target

Hypothalamic networks governing temperature regulation.

Outcome

A higher thermoregulatory set point.

PGE₂ acts within a coordinated hypothalamic response, not as a direct source of heat.

Slide 14 · The hypothalamus resets the temperature set point

Prostaglandin E₂ signal

Hypothalamic neurotransmitter response

Higher temperature set point

Heat conservation and production

Temperature rises through regulated physiologic responses.

This explains why chills may accompany the onset of fever.

Slide 15 · Vasoconstriction reduces heat loss

Raised thermal set point

Peripheral vasoconstriction

Less cutaneous heat dissipation

Core temperature rises

Reducing skin blood flow helps conserve body heat.

This is one of the mechanisms supporting a higher temperature.

Slide 16 · Brown fat and skeletal muscle contribute heat

Brown adipose tissue

Heat generation is influenced by hypothalamic signals.

Contributes to thermogenic responses.

Skeletal muscle

Muscle activity contributes to heat production.

Shivering is a recognizable systemic manifestation.

Slide 17 · NSAIDs reduce fever through prostaglandin inhibition

NSAID administration

Cyclooxygenase inhibition

Reduced prostaglandin synthesis

Lower fever-driving signal

Aspirin among NSAIDs affecting this pathway.

The primary explanation is suppression of prostaglandin production.

Slide 18 · The possible protective value of fever is uncertain

Experimental evidence in amphibians supports a benefit of elevated temperature during microbial infection.

A potential analogous benefit in mammals as a possibility.

Avoid presenting fever as universally beneficial or universally harmful on this evidence alone.

Slide 19 · Fever: The complete cytokine-to-temperature pathway

Exogenous pyrogen

IL-1 / TNF

Hypothalamic PGE₂

Increased set point

Reduced heat loss and increased thermogenesis implement the new set point.

NSAIDs interrupt the prostaglandin step.

Slide 20 · Leukocytosis is a common systemic response

An elevated circulating leukocyte count is common in inflammatory reactions.

Bacterial infections frequently produce this response.

The increase reflects both immediate marrow release and, during prolonged stimuli, expanded cellular production.

Slide 21 · Early leukocytosis mobilizes marrow granulocytes

Inflammatory cytokines

Accelerated marrow granulocyte release

Mature and immature cells enter blood

Circulating leukocyte count rises

TNF and IL-1 are among the cytokines linked to this early release.

Rapid mobilization precedes later expansion of marrow precursors.

Slide 22 · A left shift indicates immature neutrophils

Observation

Immature neutrophils appear in increased numbers in circulating blood.

Mechanism

Accelerated marrow release accompanies inflammatory demand.

Interpretation

A left shift supports a reactive marrow response but is not an etiologic diagnosis.

Slide 23 · Prolonged inflammation changes marrow output

Sustained infection

More colony-stimulating factors

Precursor proliferation in marrow

Increased leukocyte production

Longer-lasting demand recruits hematopoietic production.

This process differs temporally from rapid release of stored cells.

Slide 24 · Colony-stimulating factors amplify myelopoiesis

Activated macrophages

Important source of colony-stimulating factors during persistent infection.

Marrow stromal cells

Additional source of the growth signals.

Marrow precursors

Expand to increase leukocyte production and replace cells lost at inflammatory sites.

Slide 25 · Marrow recruitment offsets leukocyte consumption

Inflammatory tissue reaction

Leukocyte recruitment and loss

Marrow production increases

Continued cellular supply

The circulating differential is linked to ongoing tissue demand.

Systemic leukocytosis is one consequence of this compensatory program.

Slide 26 · Bacterial infections often produce neutrophilia

An increased absolute neutrophil count is typical of many bacterial infections.

The pattern is consistent with accelerated granulocyte mobilization.

An accompanying left shift indicates entry of immature neutrophils.

Slide 27 · Selected viral infections cause lymphocytosis

Some viral infections are associated with an increased absolute lymphocyte count.

Robbins examples include infectious mononucleosis, mumps and rubella.

This pattern contrasts with the neutrophilia often associated with bacterial infection.

Slide 28 · Eosinophilia suggests particular inflammatory stimuli

Allergic inflammation

Some allergic conditions increase circulating eosinophils.

Interpret with the clinical phenotype.

Helminth infestation

Certain parasitic infestations cause an eosinophilic response.

The leukocyte pattern is not a stand-alone diagnosis.

Slide 29 · Some infections produce leukopenia instead

Leukopenia denotes reduced circulating white blood cells.

Typhoid fever and some viral, rickettsial and protozoal infections as examples.

Sequestration of activated leukocytes in vascular spaces and tissues can contribute.

Slide 30 · A leukemoid reaction can resemble leukemia numerically

Leukemoid reaction

Marked reactive elevation of circulating leukocytes.

May occur with severe inflammatory stimuli.

Leukemia

Neoplastic cause of a high leukocyte count.

Must be distinguished from reactive leukocytosis.

A striking count alone does not determine whether the process is reactive or neoplastic.

Slide 31 · Differential patterns require etiologic context

Blood pattern

Inflammatory setting cited in Robbins

Interpretive caution

Neutrophilia

Many bacterial infections

Not specific for one organism

Lymphocytosis

Selected viral infections

Not universal to viruses

Eosinophilia

Some allergies and helminths

Requires clinical correlation

Leukopenia

Some infections incl. typhoid

Can result from sequestration

Slide 32 · The acute-phase response is a hepatic program

Inflammatory stimulus

Cytokine signals

Hepatocyte protein synthesis

Altered plasma proteins

Acute-phase proteins are produced mainly by the liver.

Their circulating levels can increase markedly during inflammation.

Slide 33 · Acute-phase responses are not limited to acute disease

Acute inflammation

Acute-phase proteins rise after inflammatory cytokine signaling.

Useful evidence of an ongoing host response.

Chronic inflammation

The same proteins may remain increased persistently.

Prolonged synthesis can cause additional consequences.

Slide 34 · Cytokines selectively influence hepatic products

Predominant signal in the source

Hepatic product

Relevant systemic manifestation

IL-6

C-reactive protein

Acute-phase marker

IL-6

Fibrinogen

Rouleaux and raised ESR

IL-1 or TNF

Serum amyloid A

Opsonin function; chronic amyloid risk

Slide 35 · CRP is a cytokine-induced acute-phase protein

C-reactive protein is one of the best-known acute-phase proteins.

IL-6 is especially important for its hepatocyte synthesis.

CRP may bind microbial structures and participate in host defense.

Slide 36 · Fibrinogen is an inflammatory plasma protein

Inflammatory cytokines, especially IL-6, stimulate hepatic fibrinogen synthesis.

Fibrinogen affects red-cell aggregation in plasma.

This physicochemical effect underlies the erythrocyte sedimentation rate.

Slide 37 · Serum amyloid A responds to inflammatory signals

Serum amyloid A is another prominent acute-phase protein.

IL-1 and TNF among the signals stimulating its synthesis.

Persistent SAA production in chronic inflammation has pathologic consequences.

Slide 38 · CRP and SAA can support microbial recognition

Inflammation-associated protein synthesis

CRP / SAA in plasma

Binding to microbial walls

Opsonin and complement effects

These proteins may act as opsonins.

Binding to microbial components can be accompanied by complement activation.

Slide 39 · Acute-phase proteins may aid debris clearance

Cell injury or apoptosis

Phospholipids / nuclear fragments exposed

Selected acute-phase proteins bind

Potential clearance of fragments

Robbins frames this function as a possible contribution.

Binding is not restricted to intact pathogens.

Slide 40 · Fibrinogen promotes erythrocyte rouleaux

Hepatic fibrinogen increases

Fibrinogen interacts with red cells

Rouleaux (stack-like aggregates)

Faster sedimentation

Rouleaux refers to red cells forming linear stacks.

Aggregated red cells sediment differently from isolated erythrocytes.

Slide 41 · ESR reflects fibrinogen-associated red-cell stacking

Inflammation

Higher fibrinogen

Red-cell rouleaux

Erythrocyte sedimentation rate rises

ESR is an indirect consequence of inflammatory changes in plasma proteins.

It is a general indicator of inflammation, not a test of the cause.

Slide 42 · An elevated ESR is nonspecific

Multiple inflammatory stimuli can produce an elevated ESR.

The pathway depends on altered red-cell sedimentation behavior.

An ESR result must be interpreted with clinical history and other findings.

Slide 43 · Persistent SAA production can lead to amyloidosis

Chronic inflammatory stimulus

Sustained SAA production

Amyloid-related precursor burden

Secondary (AA) amyloidosis

This is a consequence of persistent, not merely transient, acute-phase activity.

Secondary amyloidosis further in its amyloid chapter.

Slide 44 · CRP and coronary risk: Interpret the source cautiously

Reported association

Elevated CRP was proposed as a marker of myocardial infarction risk in coronary disease.

Pathophysiologic rationale

Inflammation in coronary plaques may facilitate thrombosis.

Important limit

The textbook passage presents a proposed marker and mechanism; It does not establish a diagnostic cut-off or causal proof.

Slide 45 · Hepcidin regulates systemic iron availability

Liver-derived hepcidin

Intestinal iron uptake / macrophage release regulated

Iron supply to erythropoiesis

Hemoglobin production affected

Macrophages recycle iron from senescent erythrocytes.

Hepcidin participates in controlling how that iron becomes available.

Slide 46 · Inflammation-related hepcidin contributes to anemia

Chronic inflammation

Hepcidin elevation

Iron retained away from erythroid precursors

Anemia develops

The mechanism is altered iron availability rather than simply blood loss.

This to anemia accompanying chronic inflammatory states.

Slide 47 · Anemia can coexist with active inflammation

Trigger

Persistent inflammatory cytokine response.

Mediator

Increased hepatic hepcidin.

Effect

Iron sequestration limits access for developing erythroid cells.

The systemic inflammatory response affects blood counts beyond white cells.

Slide 48 · Thrombopoietin supports platelet production

Systemic inflammatory response

Hepatic thrombopoietin upregulation

Megakaryocyte stimulation

Increased platelet production

Thrombopoietin is a major megakaryocyte growth factor.

Megakaryocytes are platelet precursors in the bone marrow.

Slide 49 · Inflammation may produce thrombocytosis

An elevated platelet count can accompany systemic inflammation.

Upregulated thrombopoietin provides a mechanistic link.

The platelet response is a distinct finding from cytokine-driven leukocytosis.

Slide 50 · Inflammation reshapes multiple blood compartments

Lineage / finding

Mediator or mechanism

Expected consequence

White cells

TNF, IL-1; colony-stimulating factors

Leukocytosis / altered differential

Erythrocytes

Hepcidin-mediated iron sequestration

Inflammation-related anemia

Platelets

Thrombopoietin upregulation

Thrombocytosis

Slide 51 · Systemic symptoms extend beyond fever and blood counts

Pulse and blood pressure may increase during the systemic response.

Sweating may decrease as blood flow is redirected away from the skin.

Chills, rigors, altered appetite, sleepiness and malaise are also described.

Slide 52 · Chills and rigors are thermoregulatory manifestations

Chills

Sensation of cold during the response.

May prompt behaviors aimed at seeking warmth.

Rigors

Shivering associated with systemic inflammation.

Contributes to heat generation.

Slide 53 · Redistribution of blood flow conserves heat

Systemic inflammatory signaling

Less flow to cutaneous vascular beds

More flow through deeper beds

Reduced surface heat loss

Decreased sweating with this blood-flow pattern.

The net effect supports elevated core temperature.

Slide 54 · Cytokines also affect brain-associated behavior

Anorexia

Reduced appetite during systemic inflammation.

Somnolence

Increased sleepiness during illness.

Malaise

General feeling of illness and diminished well-being.

These manifestations probably to cytokine action on brain cells.

Slide 55 · Cardiovascular and behavioral effects coexist

Systemic feature

Physiologic domain

Cytokine-linked context

Increased pulse / blood pressure

Circulatory

General inflammatory response

Chills / rigors

Thermoregulation

Conservation and production of heat

Anorexia / somnolence / malaise

Neurobehavioral

Probable brain-cell cytokine effects

Slide 56 · Severe infection can overwhelm adaptive responses

Severe bacterial infection

Large microbial / product burden in blood

Very high cytokine release

Widespread systemic dysfunction

TNF and IL-1 in the excessive cytokine response.

Severe systemic inflammation differs in scale and consequence from ordinary fever.

Slide 57 · Excessive TNF and IL-1 contribute to septic shock

Initiating burden

Bacteria and bacterial products enter or persist in blood.

Mediator excess

Very large amounts of TNF, IL-1 and additional cytokines.

Systemic effects

Coagulation derangement, circulatory collapse and metabolic disturbance.

Slide 58 · Disseminated intravascular coagulation is a severe effect

Disseminated intravascular coagulation (DIC) among manifestations of severe systemic cytokine release.

DIC reflects pathological activation of coagulation throughout the circulation.

In this context, it marks a dangerous loss of localized inflammatory control.

Slide 59 · Hypotensive shock signals circulatory failure

Severe systemic inflammatory responses may produce hypotensive shock.

This contrasts with the increased pulse and blood pressure that may occur during less severe systemic reactions.

Shock is a major manifestation description of septic shock.

Slide 60 · Severe inflammation disrupts glucose metabolism

Excessive cytokine production

Metabolic disturbance

Insulin resistance

Hyperglycemia

Insulin resistance and hyperglycemia are explicitly cited systemic abnormalities.

They accompany other organ-system effects rather than defining the entire syndrome.

Slide 61 · Three major shock features

Major manifestation

System-level consequence

Associated mechanism

Hypotensive shock

Marked circulatory dysfunction

Excess systemic inflammatory mediators

Disseminated intravascular coagulation

Disordered coagulation

Severe cytokine-driven systemic reaction

Insulin resistance / hyperglycemia

Metabolic dysregulation

Inflammatory cytokine excess

These are textbook-described manifestations, not a standalone contemporary diagnostic rule.

Slide 62 · Magnitude determines whether the response becomes harmful

Ordinary systemic response

Fever and constitutional symptoms.

Leukocyte mobilization and hepatic protein synthesis.

Often reflects a coordinated host response.

Excessive response in severe sepsis

Very high circulating inflammatory mediators.

Hypotensive shock, DIC and metabolic derangement.

Can become a cause of tissue-threatening dysfunction.

Slide 63 · Clinical application: Fever with left shift

Illustrative scenario: A patient develops fever during an acute bacterial infection and has increased neutrophils with immature forms.

Which two cytokine-linked pathways explain these findings?

IL-1/TNF → hypothalamic prostaglandins → elevated thermal set point.

Inflammatory cytokines → rapid granulocyte release from marrow → left shift.

Slide 64 · Clinical application: Chronic inflammation and anemia

Illustrative scenario: An inflammatory condition persists; Anemia appears and the ESR is elevated.

What mechanisms can connect both findings to inflammation?

Hepcidin elevation reduces iron availability to erythroid precursors.

Fibrinogen promotes rouleaux formation, accelerating erythrocyte sedimentation.

Slide 65 · Clinical application: Thrombocytosis and raised CRP

Illustrative scenario: A patient with persistent inflammatory disease has increased CRP and a reactive rise in platelet count.

Which hepatic products account for the laboratory pattern?

IL-6 stimulates hepatocyte synthesis of CRP.

Inflammation-associated thrombopoietin upregulation can increase platelet production.

Slide 66 · Clinical application: Deterioration during sepsis

Illustrative scenario: Severe bacterial infection is accompanied by hypotension, coagulation abnormalities and hyperglycemia.

Identify the unifying source-described process.

Extensive cytokine release, especially TNF and IL-1, links infection to widespread systemic disturbance.

The major effects involve vascular, coagulation and metabolic systems.

Slide 67 · Interpret systemic markers within their limitations

Finding

What it supports

What it does not establish

Fever

Systemic thermoregulatory response

Unique cause of inflammation

Neutrophilia / left shift

Reactive marrow mobilization

Specific infectious pathogen

CRP / ESR elevation

Inflammatory acute-phase activity

Specific etiology or lesion

SAA persistence

Potential amyloid precursor burden

Certain amyloid disease in every case

Slide 68 · Integrating the principal systemic pathways

Cytokine-associated target

Molecular / cellular intermediary

Clinical effect

Hypothalamus

COX → PGE₂

Fever

Bone marrow

Granulocyte release; CSFs

Leukocytosis

Liver

CRP, fibrinogen, SAA

Acute-phase response

Iron handling / platelets

Hepcidin; thrombopoietin

Anemia; thrombocytosis

Circulatory / coagulation / metabolism

Large-scale cytokine release

Shock, DIC, hyperglycemia

Slide 69 · Reference and scope

Primary teaching source

Robbins, Cotran & Kumar: Pathologic Basis of Disease, 11th edition (2026).

Chapter 3: Inflammation and Repair — “Systemic Effects of Inflammation.”

Main section begins on printed page 91; continuation on page 92.

Conceptual schematics are original editable PowerPoint drawings. No reproduced textbook figures, photographs or external datasets are used.