Immune System

functions of the immune system

• Protects against infectious organisms: Bacteria, Viruses, Fungi, Parasites

• Identifies and destroys abnormal cells

• Supports tissue healing and recovery

• Maintains physiological homeostasis

host

A person (or animal) that harbors an infectious organism

vector

an insect or organism that transmits the disease-causing

organism between two individual hosts

Communicable diseases

can be passed from any animal to any other

contagious diseases

Infectious diseases that can pass from person to person

bone marrow

• Produces all blood cells from hematopoietic stem cells

• Site of B-lymphocyte maturation

• Source of leukocytes involved in immune defense

thymus

• Most active during infancy through adolescence

• Site of T-lymphocyte maturation

• Develops immunocompetent T cells capable of recognizing antigens

spleen

• Filters blood and removes aged or abnormal blood cells

• Contains macrophages that remove pathogens and cellular debris

• Serves as an important site for immune surveillance

lymphatic

• Lymphatic vessels transport lymph fluid and immune cells

• Lymph nodes filter pathogens and foreign substances

• Sites where immune responses are initiated

Leukocytes (White Blood Cells)

Produced in the bone marrow and specialized for immune defense

Granulocytes

• neutrophils: first response to bacterial infection/inflammation

• eosinophils: defend against parasite —> allergic rxns

• basophils: release histamine and other inflammatory mediators

lymphocytes

• B Cells: Produce antibodies against specific antigens

• T Cells: Coordinate immune responses and destroy infected cells

monocytes

circulate in the blood to remove pathogens through phagocytosis

macrophages

reside within tissues to remove pathogens through phagocytosis

antigen

• Any substance recognized as foreign by the immune system

• Triggers an immune response

ex. bacteria, viruses, fungi, parasites, and allergens

antibodies (immunoglobins)

• Proteins produced by B lymphocytes

• Bind specifically to antigens

• Help neutralize or eliminate pathogens

Five Classes of Immunoglobulins

IgG, IgA, IgM, IgE, IgD

(GAMED)

complement proteins

• plasma proteins fxn as chemical cascade

• amplify immune response

• promote inflammation

• enhance pathogen destruction

fxn of lymphatic system

• Returns excess fluid to circulation

• Filters pathogens

• Transports immune cells

• Monitors for foreign antigens

common lymph regions

• Cervical

• Axillary

• Inguinal

enlarged lymph nodes

often indicate infection

innate immunity

NONSPECIFIC

• present at birth

• immediate response

• targets many threats similarly

• no immunological memory

• 1st line of defense

adaptive immunity

SPECIFIC

• develops after birth

• slower initial response

• targets SPECIFIC

• immunological memory

• long-term protection

lines of defense against infection

1: physical

2: nonspecific response

3: adaptive immunity

common systemic signs of infection

⚬ Fever

⚬ Fatigue

⚬ Lymphadenitis (swollen lymph nodes)

⚬ Localized pain

⚬ Redness

⚬ Heat

⚬ Swelling

⚬ Unusual muscle or joint pain

fever

• most common sign of infection

• >100.4

• low grade= <102

• high grade= >102

symptoms accompanying fever

• Malaise

• Fatigue

• Myalgia

• Arthralgia

• Loss of appetite

• Sweating (diaphoresis)

red flag s/s

• Altered mental status

• Severe headache

• Neck rigidity

• Chest pain

• Dyspnea

• Syncope

normal body temp

37 C

98.6 F

fatigue

may indicate:

• Ongoing infection

• Chronic illness

• Overtraining syndrome

• Immune dysfunction

tender lymph nodes

• Acute infection

• Inflammatory processes

Nontender lymph node

• Chronic disease

• Autoimmune disorders

• Malignancy

Bilateral Cervical Lymphadenopathy

• Infectious mononucleosis

• Viral infections

Classic Inflammatory Signs

• Redness (rubor)

• Heat (calor)

• Swelling (tumor)

• Pain (dolor)

Inflammatory signs could indicate

• Skin infection

• Cellulitis

• Abscess formation

• Localized inflammatory conditions

Pain associated with infection

• Appears without injury

• Persists at rest

• Is widespread rather than localized

• Progressively worsens

mono red flags

Left upper quadrant pain, referred shoulder pain, dizziness, signs of internal bleeding

Osteomyelitis s/s

Fever, pain, swelling, fatigue, weight loss

Septic Arthritis

⚬ Rapid swelling

⚬ Severe pain

⚬ Limited ROM

⚬ Fever (may or may not occur if the infection is

contained in only one joint)

Common Characteristics of Autoimmune diseases

⚬ Chronic inflammation

⚬ Periods of flare-up and remission

⚬ Multiple body systems may be involved

what is rheumatoid arthritis (RA)

Chronic inflammatory disease affecting synovial joints

• immune system mistakenly perceives the

  synovial lining of a joint as foreign tissue and attacks

  it

common s/s of RA

Morning stiffness >1 hour,

Symmetrical joint involvement (usually more than 3

joints), Pain and swelling, Progressive joint deformity

AT considerations

• lifetime medications

• reconstructive surgeries

• monitor flare ups

• Avoid excessive joint stress

• Modify activity as needed

• Recognize risk for joint deformity and ruptured tendons

Systemic Juvenile Idiopathic Arthritis “Still’s disease”

Occurs in adolescents with a clinical presentation similar

to standard RA in addition to fevers and rash

⚬ Prognosis is usually better

• Participation in athletics should be under the guidance of the treating physician and depends on the severity of the disease

Systemic Lupus Erythematosus (SLE)

Multisystem autoimmune disease affecting multiple organs.

• • The most common onset is between 15 and 44 years, and is more common in women than in men

• • 2-3x as many Black women develop lupus compared to women of other races

• “the great imitator”

SLE s/s

Fatigue, Joint pain, Fever, Photosensitivity, Skin rashes, Oral or nasal ulcers

Non-erosive arthritis involving multiple joints

• Malar ("Butterfly") Rash Across cheeks and nose

systemic organ involvement w SLE

⚬ Serositis (pleuritis or pericarditis)

⚬ Neurologic disorders (seizures, psychosis)

⚬ Renal disease (proteinuria, kidney involvement)

⚬ Hematologic abnormalities (anemia, leukopenia, thrombocytopenia)

management of SLE

⚬ Control inflammation

⚬ Manage symptoms

⚬ Reduce organ damage

⚬ Maintain function

chronic fatigue and overtraining syndrome s/s

• persistant fatigue

• poor performance

• sleep disturbance

• mood changes

• increase illness frequency

• increased HR/ BP body temp

• changes in body weight or bowel habits

immune system effects of overtraining syndrome

• elevated cortisol

• supressed immune function

• increased infection risk

management of overtraining syndrome

• recovery

• reduced training load

• improved sleep

• nutrition

human immunodficiency virus (HIV)

⚬ T lymphocytes primarily affect B cells, phagocytes, and other immune

system cells, impairing both innate and adaptive immune responses

⚬ Increases the risk of multiple opportunistic infections

early symptoms of HIV

⚬ Fever

⚬ Rash

⚬ Lymphadenopathy

⚬ Flu-like illness

⚬ Initial signs may be mistaken for influenza or other viral infection for the

first 1-3 weeks, then subside

Hepatitis B Virus

more common, present in more body tissues and fluids, and more durable outside the body, and is more easily communicated than HIV.

HBV transmission

• blood exposure

• sexual contact

• shared needles

• certain body fluids

HBV s/s

• fatigue

• nausea

• abdominal pain

• jaundice

• dark urine

lyme disease

• most common vector borne disease in the US

• vector: black legged tick

• transmission requires 36-48 hrs of attachment

lyme disease early s/s

• fever

• fatigue

• headache

• muscle aches

• joint pain

lyme disease s/s stages

• Stage 1: Early Localized

⚬ Bullseye rash (erythema migrans)

⚬ Flu-like symptoms

• Stage 2: Early Disseminated

⚬ Facial paralysis (Bell's palsy)

⚬ Cardiac symptoms

⚬ Multiple rashes

• Stage 3: Late Disseminated

⚬ Arthritis

⚬ Neurological symptoms

⚬ Chronic joint pain

tick removal

⚬ Use tweezers

⚬ Pull straight upward

⚬ Avoid crushing tick body

West Nile Virus

• Considered a seasonal epidemic in North America, with most cases reported during the summer and early fall

• transmitted through mosquitos

• most of the time are asymptomatic

WNV s/s

Fever, Headache, Fatigue, Body aches, Rash

WNV severe effects

Encephalitis, Meningitis, Neurological deficits

Anaphylaxis

Exaggerated immune response to an antigen

urticaria (hives)

⚬ Raised wheals

⚬ Itching

⚬ Redness

causes of hives

⚬ Allergens

⚬ Physical stimuli

⚬ Stress

⚬ Infection

treatment of hives

⚬ Antihistamines

⚬ Trigger avoidance

Cholinergic Urticaria

triggered by increse in body temp

⚬ Small itchy hives

⚬ Burning sensation

⚬ Occasionally respiratory symptom

Anaphylaxis s/s

⚬ Difficulty breathing

⚬ Wheezing

⚬ Throat swelling

⚬ Facial swelling

⚬ Hypotension

⚬ Dizziness

AT role in case of anaphylaxis

⚬ Activate EMS

⚬ Administer epinephrine if indicated

⚬ Monitor airway and breathing

Exercise-Induced Anaphylaxis s/s

⚬ Flushing

⚬ Hives

⚬ Wheezing

⚬ Hypotension

⚬ Shock

insect sting local rxns

• pain

• swelling

• redness

insect sting systemic rxns

• generalized hives

• respiratory compromise

• anaphylaxis

chickenpox (varicella) s/s

Fever, Fatigue, Vesicular rash

• Incubates for 2 weeks and then causes general systemic symptoms

• Most contagious immediately following vesicle formation

• Once vesicles burst, drain, and crust, no longer contagious

**Avoid aspirin due to the risk of Reye syndrome

mumps

Cased by the paramyxovirus virus

• Incubates for 2-4 weeks, then causes general systemic signs before

salivary and parotid glands swell

• Contagious from about 1 week before glandular swelling through

resolution

mumps

key: parotid gland swelling

⚬ Fever

⚬ Facial swelling

⚬ Difficulty swallowing

measles

Caused by the rubeola virus

• Incubates for 2 weeks, then initiates flu-like symptoms, followed by 1 week of numerous red skin eruptions

• Contagious from the time of infection until the rash subsides

measles s/s

⚬ Fever (high grade)

⚬ Cough

⚬ Runny nose

⚬ Conjunctivitis