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Microbiology: A Systems Approach, 2 nd ed. Chapter 20: Infectious Diseases Affecting the Cardiovascular and Lymphatic Symptoms. 20.1 The Cardiovascular and Lymphatic Systems and Their Defenses. Cardiovascular System Blood vessels and heart Moves blood in a closed circuit
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Microbiology: A Systems Approach, 2nd ed. Chapter 20: Infectious Diseases Affecting the Cardiovascular and Lymphatic Symptoms
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
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
Lymphatic System • One-way passage • Returns fluids from the tissues to the cardiovascular system
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
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
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
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
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
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
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
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
Hemorrhagic Fever Diseases • Caused by viruses in one of four families: • Arenaviridae • Filoviridae • Flaviviridae • Bunyaviridae
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
Dengue Fever • Usually mild • Sometimes it can progress to dengue hemorrhagic shock syndrome • Causes severe pain in muscles and joints
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
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
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
Q Fever • Abrupt onset of fever, chills, head and muscle ache, and occasionally a rash • Sometimes complicated by pneumonitis, hepatitis, and endocarditis
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
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
HGA and HME • Similar signs and symptoms • Acute febrile state • Headache, muscle pain, and rigors
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
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