Diseases & Infections of the Cardiovascular & Lymphatic System

Circulatory system

pumps blood in a closed system

Function of the heart

pumps blood

Function of blood vessels

carry blood to & from all regions of the body

What does the circulatory system provide tissues? What does it carry away?

• Provides the tissue with oxygen & nutrients

• carries away CO₂ & waste products

The lymphatic system is a major source of…

• immune cells & fluids

How does the lymphatic system flow?

• one-way passage

• returns fluids from tissues to the cardiovascular system

What does the lymphatic system consist mainly of? What organ does it contain?

• consists mainly of lymph vessels (rough parallel blood vessels)

• spleen

Function of the lymphatic system

• collects fluid that has left the blood vessels & entered tissues

• filters it of impurities & infectious agents

• returns it to the blood

How protected is the cardiovascular system?

highly protected from microbial infection

Why is it bad if microbes invade the cardiovascular system?

microbes gain access to every part of the body & can affect every system causing systemic infections

Systemic infections

when a microbe affects every system of the body

What are 3 defenses of the bloodstream?

• tons of WBCs per mL of blood

• Lymphocytes - specific immunity

• Phagocytes - critical to specific/nonspecific immune response

what does the suffix -emia mean?

medical conditions involving blood

• viruses - viremia

• fungi - fungemia

• bacteria - bacteremia

What is epticemia?

bacteria flourishing & growing in the bloodstream

What can epticemia cause? What does this lead to?

can lead to decreased blood pressure, which leads to septic shock

Describe the normal biota of the cardiovascular & lymphatic systems

There is none

• info is changing

Defense of the lymphatic system

numerous immune defenses

Sepsis

an inflammatory response caused by the spread of bacteria or their toxin from focus of infection

Septicemia

sepsis that involves proliferation of pathogens in the blood

Gram-negative sepsis

Gram-negative sepsis caused by endotoxin release can lead to septic shock, characterized by decreased blood pressure

When does septicemia occur?

occurs when organisms are actively multiplying in the blood

Signs & symptoms of septicemia

• fever

• altered mental state

• shaking

• chills

• GI symptoms

• increased breathing rate

• respiratory alkalosis

• low blood pressure resulting in loss of fluid from the vasculature

What is a bacterial infection of the heart?

subacute bacterial endocarditis

what causes subacute bacterial endocarditis?

alpha-hemolytic streptococci, staphylococci, or enterococci

Subacute bacterial endocarditis usually arises from…

a focused infection (tooth infection)

What procedure has decreased incidence of subacute bacterial endocarditis?

prophylaxis before dental procedures

What are predisposing factors of subacute bacterial endocarditis?

preexisting heart abnormalities

Signs of subacute bacterial endocarditis (3)

• fever

• anemia

• heart murmur

What sign can subacute bacterial endocarditis lead to?

can lead to valve destruction

Rheumatic fever

autoimmune complication of Streptococcal infection

How is rheumatic fever expressed?

expressed as arthritis or inflammation of the heart

What is one instance rheumatic fever can result from?

can result from Streptococcal sore throat

• untreated strep throat

What is important in avoiding rheumatic fever?

Prevention & prompt treatment are key

What are the characteristics of the symptoms of Lyme’s disease

slow-acting, progressive symptom

Signs/symptoms of Lyme’s disease

• most cases develop bull’s eye rash

• fever, headache, stiff neck, dizziness

• progresses to cardiac & neurological symptoms

What does Lyme disease develop into?

develops into crippling polyarthritis after several weeks to montjs

What microbe causes Lyme disease?

Borrelia burgdorferi

Where does Borrelia burgdorferi live? What does this mean for humans?

bacteria lives in a tic, humans are accidental hosts

What shape is Borrelia burgdorferi?

large spirochete with 3-10 irregularly spaced coils

How does Borrelia burgdorferi evade the immune system?

by changing surface antigens

It’s possible that ______ ______ contributes to the pathology of Lyme disease

immune response

What kind of microbe causes the plague?

bacteria

What are the 3 manifestations of the Plague?

• Pneumonia plague

• Bubonic plague

• Septicemic plague

What is bubonic plague? Mortality?

• infection causes inflammation & necrosis of the lymph node or bubo

• mortality rate (even w treatment): 15%

What is pneumonia plague? Mortality?

• respiratory disease

• near 100% mortality rate

What does septicemic plague result in? Mortality rate?

• results in disseminated intravascular coagulation, subcutaneous hemorrhage, & purpura that degenerates into necrosis & gangrene

• Mortality: 30-50% w treatment, 100% w/o

What microbe causes tularemia? What is the infectious dose?

• Francisella tularensis

  • gram-negative, facultative intracellular parasite

• Infective dose: 10-50 organisms

What is it listed as on the Category A bioterrorism agent list?

pathogen of concern

What are the chief reservoirs of tularemia? What are some other reservoirs?

• Major reservoirs: rabbits & rodents

• other: skunks, beavers, opossums, foxes other wild animals

Tularemia incubation period

few days to 3 weeks

Immediate symptoms of tularemia (6)

• headache

• backache

• fever

• chills

• malaise

• weakness

Later symptoms of tularemia (6)

• skin lesions

• swollen lymph glands

• eye inflammation

• sore throat

• intestinal disruption

• pulmonary involvement

Prevention of tularemia

live attenuated vaccine for high-risk individuals

How is brucellosis transmitted?

contact w infected animals or contaminated animal products

Which bacterial species causes brucellosis?

Brucella species

How does Brucella enter the body? Where does it reproduce?

• enters through the mucosa or skin

• reproduces in macrophages

How does brucellosis spread inside the body?

via lymphocytes to liver, spleen, or bone marrow

Signs of brucellosis

malaise, fever that spikes each evening

What else can brucellosis lead to?

endocarditis, hepatomegaly, splenomegaly

What is the treatment for brucellosis?

antibiotic therapy

What bacteria causes anthrax?

Bacillus anthracis

How long can anthrax endospores survive in soil?

60 years

How can grazing animals acquire antrhax?

by ingesting the endospores

How can humans contract anthrax?

By handling hides from infected animals

How can endospores that cause anthrax enter the body?

Through cuts in the skin, respiratory tract or mouth

What is the suspected infectious dose for anthrax?

2-9 endospores

Which form of anthrax can lead to septic shock?

pulmonary form

What are the three forms of anthrax

pulmonary, cutaneous, & GI forms

How do the cutaneous/, GI, and inhalation/lungs forms of anthrax occur? How does someone get it from injection?

• cutaneous - spores enter through scrape

• GI - consuming raw or undercooked infected meat

• Inhalation - breathing in airborne spores

• injection - injecting contaminated illicit drugs

What are the survival rates of the cutaneous, GI, inhalation, and injection types of anthrax

• cutaneous - 98% survival with prompt care

• GI - 60% survival with care

• Inhalation/lung - 55% survival with aggressive & early treatment

• injection - 50% survival with rapid treatment

Gangrene

soft tissue death from ischemia

• blood doesn’t travel freely & infection can develop

• tissue dies

What can increase risk of gangrene?

any condition that affects blood flow

What bacteria causes gangrene?

Clostridium perfringens

Gangrene: virulent factors

• toxins that break down skin, destroy tissue, & constrict blood vessels

• enzymes that break down cell walls

What causes infectious mononucleosis

Epstein-Barr Virus (EBV)

Where does the virus multiply in the disease infectious mononucleosis? Where is it present?

virus multiplies in the parotdid gland & is present in saliva

How is infectious mononucleosis transmitted/spread?

ingestion of saliva from infected individuals

Infectious mononucleosis: virulent factors

• ability to establish long-term latency in host B-lymphocytes by integrating its DNA into the host cell’s nucleus

• causes proliferation of atypical lymphocytes

What virus causes dengue fever? What transmits this virus?

• flavivirus

• transmitted by Aedes mosquitos

dengue fever signs/symptoms: “breakbone fever”

severe pain in muscles & joints

Dengue hemorrhagic fever has high rates of _____ & _____

morbidity & mortality

How did Vietnam eliminate dengue?

by adding crustaceans to water, tanks & wells. They ate the mosquitos & larvae

What microbe causes chikungunya?

Alphavirus transmitted by Aedes albopictus

Symptoms of chikungunya

• similar to dengue

• severe joint pain that can last years

• neurological symptoms can last years

What microbe causes ebola & marburg?

Filovirus (family Filoviridae)

Which two diseases are the symptoms of ebola & marburg similar to? What are some symptoms?

• symptoms are similar to Yellow Fever & dengue

• virus causes capillary fragility

• patients bleed from orifices & mucus membranes

• massive internal/external hemorrhage

What are the mortality rates for Marburg & Ebola

• Marburg: 25%

• Ebola: 97%

Is there any vaccines for ebola?

new vaccine for Ebola Zaire

How is malaria transmitted?

by the female Anopheles mosquito

How many deaths does malaria cause annually?

1 million deaths annually

What causes the release of fever-inducing chemicals into the bloodstream in malaria?

Invasion of merozoites

In malaria, Plasmodium metabolizes