Chapter 21 Cardiovascular system diseases

Structure of the Cardiovascular System

• The cardiovascular system includes various components with critical functions:
  • Heart: Central pump of the system.
  • Main Vessels: Includes the aorta (main artery), superior vena cava, and inferior vena cava (main veins).
  • Pulmonary Vessels: Connect the heart to the lungs for oxygen exchange.
  • Valves: Ensure unidirectional blood flow and prevent backflow.

Bacterial Cardiovascular and Systemic Diseases

1. Septicemia, Bacteremia, and Toxemia

• Definitions:
  • Bacteremia: Presence of bacteria in blood, often harmless.
  • Septicemia: Reproducing microbes in blood causing illness, may become fatal.
  • Toxemia: Presence of bacterial toxins in blood, causing more severe symptoms.
  • Lymphangitis: Infection/inflammation of lymphatic vessels, often an early sign of septicemia.

2. Signs and Symptoms

• Common symptoms include fever, chills, nausea, vomiting, diarrhea, and malaise.
• Septic shock can develop rapidly, leading to multi-organ failure.
• Petechiae: Small hemorrhagic lesions that may occur.
• Osteomyelitis: Infection can spread to bones causing severe infections.
• Variability: Toxemia symptoms depend on the type of toxin (exotoxins vs. endotoxins).

3. Pathogens and Virulence Factors

• Caused by various bacteria, often opportunistic or nosocomial pathogens.
• Gram-negative bacteria like Escherichia, Klebsiella common in septicemia.
• Virulence factors include:
  • Presence of capsule to resist phagocytosis.
  • Endotoxin production leading to severe immune reactions.

4. Pathogenesis and Epidemiology

• Main routes include direct inoculation from injuries, therapies, and surgeries.
• Immunocompromised individuals at higher risk.
• Endotoxins activate immune responses, which can damage host tissue leading to severe conditions.

5. Diagnosis and Treatment

• Diagnosis often requires blood culture, although many cases are culture-negative.
• Treatment focuses on quick identification and antimicrobials. New therapies include antibodies targeting LPS.
• Prevention stresses the need for early treatment in at-risk populations.

Specific Cardiovascular Diseases

1. Endocarditis

• Symptoms: Fever, fatigue, malaise, tachycardia.
• Causes: Often due to Streptococcus species, particularly in patients with abnormal heart conditions.
• Diagnosis/Treatment: Intravenous antibiotics; prophylactic therapy for high-risk patients.

2. Gas Gangrene

• Cause: Clostridium perfringens introduced in dead tissue.
• Symptoms: Severe pain, swelling, foul-smelling drainage, and systemic symptoms.
• Treatment: Surgical debridement, antibiotics like clindamycin and penicillin, and in severe cases, amputation.

3. Brucellosis

• Etiology: Caused by Brucella species leading to fluctuating fevers.
• Transmission: Through contaminated dairy and direct contact with infected animals.
• Treatment: Doxycycline, often combined with streptomycin.

Viral Cardiovascular and Systemic Diseases

1. Infectious Mononucleosis

• Causative Agent: Epstein-Barr Virus (EBV).
• Symptoms: Severe sore throat, fatigue, and swollen lymph nodes.
• Transmission: Through saliva.
• Prevention: Difficult due to widespread nature of EBV; treatment focuses on managing symptoms.

2. Dengue Fever

• Symptoms: Initial fever, severe headaches, muscle pains followed by rash; may lead to internal bleeding in severe cases.
• Causative Agents: Dengue viruses transmitted by Aedes mosquitoes.
• Treatment: No specific antiviral therapy; prevention focuses on mosquito control.

3. Ebola Virus Disease

• Symptoms: Severe fever, headache, muscle pain, vomiting, diarrhea, potential multi-organ failure.
• Transmission: Direct contact with infectious bodily fluids.
• Fatality Rates: High, between 50-90% depending on the outbreak.
• Treatment: Supportive care and experimental therapies like monoclonal antibodies.

Protozoal and Helminthic Cardiovascular Diseases

1. Malaria

• Causative Agent: Plasmodium species (e.g., P. falciparum).
• Symptoms: Recurrent fevers, chills, and severe systemic effects.
• Transmission: Through bites of infected Anopheles mosquitoes.
• Treatment: Antimalarials (e.g., Quinine, Doxycycline).

2. Toxoplasmosis

• Causative Agent: Toxoplasma gondii.
• Symptoms: Generally asymptomatic but severe in immunocompromised individuals.
• Transmission: Via ingestion of oocysts from cat feces or undercooked meat.
• Treatment: Pyrimethamine and sulfadiazine in severe cases.

3. Chagas Disease

• Causative Agent: Trypanosoma cruzi.
• Symptoms: Swelling, fever, can lead to chronic cardiac issues after years.
• Transmission: Through bites from Triatoma bugs.
• Diagnosis: Microscopic identification or Xenodiagnosis; treatment mostly effective if early.

General Conclusion

• Systemic infections involving the cardiovascular system present severe health risks and require prompt diagnosis and intervention. Understanding signs, symptoms, etiology, and treatment options is crucial for effective management and prevention of morbidity and mortality associated with these diseases.