Module 14: Diseases of tha cardiovacular and lymphatic system

Sepsis and Septic shock (causes)

Sepsis: Presence of toxin or pathogen in the blood causes systemic sever inflammatory response

Septicemia: The proliferations of pathogens in the blood

Sepsis and Septic shock

Signs and symptoms:

• Temp > 38 C, chills, nausea, diarrhea, malaise, change in mental status

• Septic shock:

  • Sudden drop in blood pressure to low levels due to dilation of blood vessels which decreases oxygen/blood flow to body. This can lead to organ failure or death

  • Triggered by molecules of LPS and lipoteichoic acid

  • Decrease in temperature, decrease in urine output, rapid breathing, aberrant blood clotting, increase in heart rate, and anxiety

• Lymphangitis:

  • Inflamed lymphatic vessels which are seen as red streaks under the skin from site of infection

  • usually accompanies sepsis and septicemia

Endocarditis

• Inflammation of the endocardium

• Subacute bacterial endocarditis develops slowly, normally due to an infection by Streptococcus viridians or other alpha-hemolytic streptococci. Acute bacterial endocarditis progresses rapidly, normally due to an infection by Staphylococcus aureus

• Bacteria grow on the heart valve which can be spread to blood vessels

• WBC that normally travel in your bloodstream can’t reach the heart valves due to lack of direct blood supply

Signs and Symptoms:

• Prolonged fever, heart murmur, poor appetite, feeling weak, and joint pains.

Treatment:

• IV of antibiotics; heart valve replacement may be needed

Pericarditis

• Inflammation of the pericardium, may also occur, causing a sharp stabbing pain behind the breastbone

• arises from infected layers of pericardium rubbing against each other

• Symptoms usually mild

Brucella melitensis (Virulence factors)

• Non-motile G- coccobacilli and lacks capsule

• Endotoxin, grow & replicate in phagocytes, evades Ab

• Intracellular parasite in animal hosts

• Dangerous to handle because it can become airborne

• Worlds most common bacterial zoonosis

Brucellosis (Undulating fever)

Causative agent: Brucella melitensis

Transmission:

• Via unpasteurized and contaminated dairy products or direct contact with animal secretions (zoonotic)

Incubation:

• 1-3 weeks

Signs and symptoms:

• Fluctuating fever that spikes every 24 hours, chills, sweats, weight loss

Yersinia pestis (Virulence factor)

• G- bacilli with a bipolar staining pattern, also known as "safety pin" appearance.

• Plasmid; survive and proliferate in phagocytic cells; capsule; biofilm formation

The plague (Black Death)

Causative agent: Yersinia pestis

Vector:

• Rat flea (parenteral transmission)

Signs and symptoms:

• Bubonic plague is most common form but not communicable. Swollen, smooth, reddened, and painfully inflamed lymph nodes (bubos) arise

• If bacteria escapes from bubo and enters bloodstream it can cause septicemia plague

• Disseminated intravascular coagulation can cause subcutaneous hemorrhaging (Black Death) which can lead to pneumonic plague if bacteria makes it to the lungs. This can make the disease very communicable. This can lead to hypoxia and hemoptysis and death (90% morality rate)

Treatment

• Recovery provides immunity

• vaccine available
  

Borrelia burgdorferi (virulence factor)

• Unusual metabolism, antigenic variation, endotoxin

• Larger than normal spirochete

• Loose coils

• Can be passed through placenta of a pregnant woman (congenital transmission)

Lyme Disease

Causative agent: Borrelia burgdorferi

Vector:

• tick (parenteral transmission)

Symptoms:

• 1st phase: bulls-eye rash at bite site (erythema migrans)

• 2nd phase: irregular heartbeat, Bell’s palsy, oppressive fatigue, memory loss

• 3rd phase: arthritis due to immune responses

Treatment:

• No vaccine available for humans; natural immunity to reinfection variable

Relapsing Fever

Causative agent: All species of Borrelia except B. burgdorferi

Vector:

• Soft ticks that feed on rodents in the summer

Symptoms:

• Fever (>40.5 C) that subsides after 3-5 days but relapses occur (shorter and less severe each time)

• Jaundice

• Rose colored skin spots

Diagnosis:

• observe bacteria in blood

Epstein-Barr virus (Virulence)

• Replicated within resting memory B cells so that virus can become latent

Infectious Mononucleosis ( Mono)

Causative agent: Epstein-Barr virus

Transmission:

• Saliva

Signs and symptoms:

• Resemble strep throat at first

• Persistent infection in the mouth and throat causing severe sore throat, swollen lymph nodes, extreme fatigue, and loss of appetite

• Young adulthood infection are symptomatic due to intense immune response

Diagnosis:

• Detection of heterophile antibodies produced from infected B cells (lymphocytes with unusual lobed nuclei that proliferate in blood)

• Remain chronically infected because it is part of herpes family

Cytomegalovirus (human herpes virus 5)

• Large herpesvirus that remains latent in WBC

• Not affected by immune cells due to slow replication and movement between cells allows the virus to evade antibody detection

Transmission:

• Large amounts of bodily fluids

Disease:

• cytomegalic inclusion disease (CID) is a concern especially if the mother is infected during pregnancy.

• This virus is a teratogen and can lead to mental retardation, hearing loss, and other complications

• Greater effect on immunocompromised hosts

Symptoms

• similar to mono but are eating fine and not tired

Diagnosis:

• Formation of “owl’s eyes” via microscopy

• Infection in adults is asymptomatic or resemble mono

Dengue virus (AKA “breakbone fever”)

Vector:

• Ades mosquito

Symptoms:

• intense headache, slight bleeding in the nose/gums, and severe pain in muscle, joints, and bones

• Dengue hemorrhagic fever (DHF) has emerged - high mortality rates

Ebola hemorrhagic fever (EHF) (Ebolavirus)

• 3 days after infection hemorrhaging due to malfunction of blood clotting system

Natural host:

• fruit bat

Signs and symptoms:

• fever

• headache

• myalgia

• cough

• abdominal pain

• vomiting and diarrhea

• Delirium

• Stupor

• Coma

• organ failure

Transmission:

• contact with blood/body fluid (sometimes via needles)

• 90% fatal in humans

Emerging Viral hemorrhagic fevers

• Enveloped RNA virus with animal reservoirs

Signs and symptoms:

• Headache and muscle pain followed by high fever, dizziness, exhaustion, vomiting blood. profuse bleeding internally & externally; death via organ failure or shock

Treatment:

• Supportive care - electrolyte and fluid replacement; anticoagulants; blood replacement (no antiviral options)