Chapter 21_AFernando_audio

Overview of Microbial Diseases

• Focus on microbial diseases affecting the cardiovascular system and systemic diseases.

• Understand the causative agents, symptoms, and signs of diseases.

• Learn how to identify organisms and their clinical manifestations.

• Review and details are essential; consider using flashcards for memorization of microbes and clinical manifestations.

Cardiovascular System Basics

• The cardiovascular system consists of:

  • Heart: Pumps blood.

  • Blood: Made of serum and blood cells.

    • Red Blood Cells (Erythrocytes)

    • White Blood Cells (Leukocytes)

    • Platelets: Essential for clotting.

  • Blood Vessels: Arteries and veins.

• Understanding the anatomy and structure helps identify where microbes may infect and cause disease.

  • Blood flow direction: Heart → Arteries → Capillaries → Veins

  • Oxygenated blood vs. deoxygenated blood.

Key Terms Related to Blood Infections

• Septicemia: Presence and growth of bacteria in blood; harmful to the host.

• Bacteremia: Presence of bacteria in blood.

• Toxemia: Release of bacterial toxins into the blood; can cause fever and shock.

• Lymphangitis: Inflammation due to infection in the lymphatic system.

Clinical Manifestations

• Symptoms commonly associated with infections:

  • Fever, chills, nausea, vomiting, diarrhea, malaise (fatigue), and low blood pressure (hypotension).

  • Disseminated Intravascular Coagulation (DIC): Clotting throughout the body.

  • Petechiae: Small hemorrhagic lesions.

• Effects of toxins can vary based on the type (exotoxins vs. endotoxins). Exotoxins are released from living organisms; endotoxins are part of the bacterial wall, particularly from gram-negative bacteria.

Pathogens and Their Virulence Factors

• Pathogens: Microorganisms causing disease.

• Virulence Factors: Characteristics that enable microbes to cause disease, often influenced by their environment (opportunistic vs. nosocomial infections).

  • Endotoxins produced by gram-negative bacteria can lead to severe septicemia.

Diagnosis and Treatment

• Clinical diagnosis often based on symptoms. Laboratory tests can confirm microbial infection.

• Prompt administration of antimicrobial drugs is critical.

• Differentiation between broad-spectrum and narrow-spectrum treatments based on the infection type.

Endocarditis

• Definition: Infection of the heart valves or inner heart lining.

• Causative agent: Often viridans streptococci.

• Symptoms include fever, fatigue, and heart murmurs.

• Risk factors include patients with abnormal hearts and prior heart conditions.

• Diagnosis usually involves culturing blood samples.

Lyme Disease

• Caused by Borrelia burgdorferi, transmitted through tick bites.

• Symptoms: Rash at the bite site, neurological symptoms, and severe joint pain.

• Disease progression involves two hosts: deer and humans.

• Prevention methods include the use of repellents and protective clothing.

Infectious Mononucleosis

• Caused by the Epstein-Barr Virus (EBV).

• Initial symptoms: Severe sore throat and swollen lymph nodes.

• Transmission through saliva (often referred to as kissing disease).

• Neutropenia occurs as the virus affects lymphocyte counts.

Cytomegalovirus Disease

• Asymptomatic in most cases; can severely affect neonates or immunocompromised individuals.

• Transmitted through contact with infected body fluids or vertically during pregnancy.

• Complications can include birth defects and hearing issues in infants.

Ebola Virus

• Causes African viral hemorrhagic fever.

• Symptoms include fever, fatigue, and severe internal hemorrhaging.

• Transmitted through contact with bodily fluids.

• Treatment involves fluid and electrolyte replacement; vaccinations are under development.

Protozoan and Helminthic Diseases

• Plasmodium (causes malaria): Life cycle requires both human hosts and female anopheles mosquitoes.

  • Symptoms include fever and chills with red blood cell destruction.

• Understanding these life cycles is crucial for effective diagnosis, treatment, and prevention of malaria.

Conclusion

• Comprehensive understanding of microbial diseases affecting the cardiovascular system is vital for diagnosis and treatment.

• Reviewing and remembering key terms, symptoms, and causative agents is essential for exam success.