Microbiology: A Systems Approach, 2 nd ed.

1. Microbiology: A Systems Approach, 2nd ed. Chapter 20: Infectious Diseases Affecting the Cardiovascular and Lymphatic Symptoms

2. 20.1 The Cardiovascular and Lymphatic Systems and Their Defenses • Cardiovascular System • Blood vessels and heart • Moves blood in a closed circuit • Also known as the circulatory system • Provides tissues with oxygen and nutrients and carries away carbon dioxide and waste products

3. The Heart • Divided into two halves, each half divided into an upper and lower chamber • Upper chambers: atria; lower chambers: ventricles • Covered by the pericardium • Three layers to the wall of the heart (from outer to inner) • Epicardium • Myocardium • Endocardium

4. Figure 20.1

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6. Lymphatic System • One-way passage • Returns fluids from the tissues to the cardiovascular system

7. Figure 14.10

8. Defenses of the Cardiovascular and Lymphatic Systems • Cardiovascular system is highly protected, however, if microbes do invade they gain access to every part of the body • Bloodstream infections are systemic infections; often with the suffix –emia • Viremia • Fungemia • Bacteremia • Septicemia (can lead to septic shock) • Defenses in the bloodstream- leukocytes

9. 20.2 Normal Biota of the Cardiovascular and Lymphatic Systems • None • Some microorganisms may be present transiently (filtering out of tissues) but they do not colonize the systems in the healthy state

11. 20.3 Cardiovascular and Lymphatic System Diseases Caused by Microorganisms • Endocarditis • Inflammation of the endocardium • Usually refers to an infection of the valves of the heart • Acute and subacute, with similar symptoms (in subacute the symptoms develop more slowly and are less pronounced) • Fever, anemia, abnormal heartbeat • Sometimes symptoms similar to heart attack • Abdominal or side pain may be reported • Petechiae over the upper half of the body and under the fingernails may be present • In subacute cases, may have enlarged spleen

12. Figure 20.3

14. Septicemias • Occurs when organisms are actively multiplying in the blood • Many different bacteria and a few fungi can cause this condition • Fever- prominent symptom • Patient appears very ill, may have an altered mental state, shaking chills, and gastrointestinal symptoms • Often exhibits increased breathing rate and respiratory alkalosis • Low blood pressure

16. Plague • Three possible manifestations • Pneumonic plague: respiratory disease • Bubonic plague • Bacterium injected through a flea bite • Enters the lymph and is filtered by a lymph node • Infection causes inflammation and necrosis of the node • Results in a swollen lesion called a bubo, usually in the groin or axilla • Incubation period: 2 to 8 days, ending with the onset of fever, chills, headache, nausea, weakness, and tenderness of the bubo • Septicemic plague: when the case progresses to massive bacterial growth in the blood

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21. Tularemia • Sometimes called rabbit fever, because it has been associated with outbreaks of disease in wild rabbits • Pathogen of concern on the lists of bioterrorism agents • Tick bites: most frequent arthropod vector • Incubation period of a few days to 3 weeks • Symptoms: headache, backache, fever, chills, malaise, and weakness • Further symptoms tied to the portal of entry: ulcerative skin lesions, swollen lymph glands, conjunctival inflammation, sore throat, intestinal disruption, pulmonary involvement

23. Lyme Disease • Nonfatal • Evolves into a slowly progressive syndrome that mimics neuromuscular and rheumatoid conditions • Early symptom: rash a the site of a tick bite • Other early symptoms: fever, headache, stiff neck, and dizziness • Second stage: cardiac and neurological symptoms develop

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29. Infectious Mononucleosis • Majority caused by Epstein-Barr virus (EBV) • Most of the remainder caused by cytomegalovirus (CMV) • Sore throat, high fever, and cervical lymphadenopathy • Long incubation period- 30 to 50 days • Also may exhibit a gray-white exudates in the throat, skin rash, and enlarged spleen and liver • Sudden leukocytosis • Fatigue

30. Figure 20.11

32. Hemorrhagic Fever Diseases • Caused by viruses in one of four families: • Arenaviridae • Filoviridae • Flaviviridae • Bunyaviridae

33. Yellow Fever • Capillary fragility • Disrupts the blood-clotting system • Begins with fever, headache, and muscle pain • Sometimes progresses to oral hemorrhage, nosebleed, vomiting, jaundice, and liver and kidney damage

34. Dengue Fever • Usually mild • Sometimes it can progress to dengue hemorrhagic shock syndrome • Causes severe pain in muscles and joints

35. Ebola and Marburg • Related viruses, cause similar symptoms • Extreme manifestations of of hemorrhagic events with extensive capillary fragility and disruption of clotting • Patients bleed from their orifices, mucous membranes, and experience massive internal and external hemorrhage • Often manifest a rash on the trunk in early stages

36. Lassa Fever • Most cases asymptomatic • In 20% of the cases a severe hemorrhagic syndrome develops • Chest pain, hemorrhaging, sore throat, back pain, vomiting, diarrhea, and sometimes encephalitis • Patients who recover often suffer from deafness

38. Nonhemorrhagic Fever Diseases • Brucellosis • On the CDC list of possible bioterror agents • Bacteria is carried into the bloodstream by phagocytic cells, creating focal lesions in the liver, spleen, bone marrow, and kidney • Fluctuating pattern of fever accompanied by chills, profuse sweating, headache, muscle pain and weakness, and weight loss

39. Figure 20.12

40. Q Fever • Abrupt onset of fever, chills, head and muscle ache, and occasionally a rash • Sometimes complicated by pneumonitis, hepatitis, and endocarditis

41. Figure 20.13

42. Cat-Scratch Disease • Symptoms start after 1 to 2 weeks • Cluster of small papules at the site of inoculation • In a few weeks, lymph nodes swell and can become pus-filled • Only about 1/3 of patients experience high fever

43. Figure 20.14

44. Trench Fever • Highly variable symptoms • 5- to 6-day fever • Leg pains, especially in the tibial region • Headache, chills, and muscle aches • Macular rash can occur • Endocarditis can develop

45. HGA and HME • Similar signs and symptoms • Acute febrile state • Headache, muscle pain, and rigors

46. Rocky Mountain Spotted Fever (RMSF) • 2 to 4 days incubation • First symptoms: sustained fever, chills, headache, and muscular pain • Distinctive spotted rash within 2 to 4 days after the prodrome • In most severe untreated cases, enlarged lesions merge and become necrotic • Other manifestations: cardiovascular disruption; conditions of restlessness, delirium, convulsions, tremor, and coma

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50. Malaria • The world’s dominant protozoan disease • 10- to 16-day incubation period • First symptoms: malaise, fatigue, vague aches, and nausea with or without diarrhea • Next symptoms: bouts of chills, fever, and sweating • Symptoms occur at 48- or 72-hour intervals • The interval, length, and regularity of symptoms reflect the type of malaria