Infections and inflammations of the heart Notes

NOTES NOTES INFECTIONS & INFLAMMATION OF THE HEART GENERALLY, WHAT ARE THEY? PATHOLOGY & CAUSES ▪ Heart infections, inflammation (may affect epicardium, myocardium, endocardium) ▪ May include: infective endocarditis, Libman-Sacks endocarditis, myocarditis, rheumatic fever ▪ May cause/be caused by/coexist with other infections COMPLICATIONS ▪ Heart failure, arrhythmias, fibrosis ▪ Infective, Libman–Sacks endocarditis can cause ▫ Damage to heart valves: dysrhythmias, valve dysfunction ▫ Invasion of myocardium: heart failure, heart block, sepsis ▫ Vegetation can embolize to extremities: infarction/ischemia causing stroke, pulmonary edema, glomerulonephritis SIGNS & SYMPTOMS ▪ See individual disorders DIAGNOSIS ▪ See individual disorders TREATMENT ▪ See individual disorders OSMOSIS.ORG 85

INFECTIVE ENDOCARDITIS osms.it/endocarditis PATHOLOGY & CAUSES ▪ Infection of endocardium, usually with bacteria, may include heart valve ▪ Valves have small blood vessels → damage to valve, vessels → microbes in blood escape into valvular tissue/microbes enter small vessels → infection ▪ Valve endothelial lining damaged ▪ Microbes enter body via: dental/surgical procedures, injection with infected needle/ infected substance, wound/abscess ▪ Vegetation: fibrin, leukocytes, microbes attach to thrombosis → abnormal growth → potential embolism ▪ Often affects left side heart valves ▫ Predisposing conditions: mitral valve prolapse, bicuspid aortic valves TYPES ▪ Classified by microbial cause ▫ Acute bacterial endocarditis: infection of normal valves, rapid progression ▫ Subacute bacterial endocarditis: indolent infection of abnormal valves (e.g. S. viridans) ▫ Endocarditis in IV drug users: Methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas, Candida ▫ Prosthetic valve endocarditis: Staphylococcus epidermidis within 60 days of replacement; after 60 days, resembles native valve endocarditis CAUSES Viridans streptococci (most common) ▪ Low virulence ▪ Found in mouth ▪ Attacks previously damaged valves ▪ Small vegetations: don’t destroy valve Staphylococcus aureus ▪ High virulence 86 OSMOSIS.ORG ▪ ▪ ▪ ▪ Found on skin Infects damaged, healthy valves Large vegetations: can destroy valve Most commonly contracted from IV drug use Staphylococcus epidermidis ▪ Infects prosthetic material (e.g. prosthetic heart valves) ▪ Enters body during valve surgery/infected IV catheter: sticks around valve/catheter ▪ Nosocomial infection (infection in hospital) ▪ Gut flora ▫ Enterococcus faecalis ▫ Streptococcus bovis ▪ Severe colorectal disease (e.g. colorectal cancer/ulcerative colitis): bacteria migrate into bloodstream Coxiella burnetii ▪ Exposure to infected animals (e.g. cows, sheep, goats) ▪ Q fever → months/years later, endocarditis ▪ Affects those at high risk: immunocompromised, pregnant individuals, pre-existing heart valve defect ▪ Diagnosis difficult Candida albicans ▪ Fungal endocarditis ▪ Connected with IV drug use Culture-negative endocarditis ▪ Cannot be linked to bacteria using blood cultures ▪ Aortic vascular infection, persistent low fever, rash ▪ Often caused by Coxiella burnetii HACEK organisms ▪ Haemophilus, Aggregatibacter, Cardiobacterium, Eikenella, Kingella ▪ Gram-negative bacteria ▪ Normal flora of mouth, throat

Chapter 12 Infections & Inflammation of the Heart Nonbacterial thrombotic endocarditis ▪ Damage in valve exposes collagen, tissue factor → platelets, fibrin adhere → form tiny thrombosis → mitral valve regurgitation ▫ Bacteremia → bacterial attach to thrombi → bacterial endocarditis RISK FACTORS ▪ Valvular problems ▫ Mitral valve prolapse ▫ Bicuspid aortic valves ▫ Prosthetic valves ▫ Valves affected: mitral > aortic, tricuspid ▪ Congenital cardiac defects ▪ Damage to valves due to rheumatic heart disease ▪ IV drug use (esp. tricuspid valve) ▪ Chronic hemodialysis ▪ Poor dentition SIGNS & SYMPTOMS ▪ Anorexia, weight loss, fatigue ▪ See mnemonic below DIAGNOSIS DIAGNOSTIC IMAGING Chest X-ray ▪ Enlarged heart, possible pulmonary congestion Echocardiogram ▪ Inflamed heart muscle walls, dilation LAB RESULTS ▪ Elevated troponin, creatine kinase levels (due to heart muscle damage) Cardiac muscle biopsy ▪ Definitive diagnosis ▪ Risky procedure, performed only if test results would change treatment plan OTHER DIAGNOSTICS ECG ▪ Sinus tachycardia (increased heart rate) ▪ T-wave inversions ▪ “Saddle-shaped” ST segment elevations TREATMENT MNEMONIC: FROM JANE Signs & Symptoms Fever Roth spots: antigen-antibody complex deposits in eyes Osler nodes: painful antigenantibody complex deposits in pads of digits Murmur: turbulent blood flow past damaged heart valve Janeway lesions: erythematous lesions due to emboli; small, painless, flat Anemia Nail-bed hemorrhage (splinter hemorrhages): deposition of emboli Emboli: vegetations detach from valve, deposit elsewhere (nail beds, kidneys, spleen, central nervous system) ▪ Viral: improves slowly over time ▪ Arrhythmias resolve as inflammation improves MEDICATIONS ▪ Antibiotics ▪ Signs of heart failure: managed with medication, fluid balance SURGERY ▪ Heart transplant in severe cases (e.g. Chagas, giant cell myocarditis) OSMOSIS.ORG 87

Figure 12.2 Bacterial vegetations on the mitral valve in endocarditis. Figure 12.1 Janeway lesions are hemorrhagic macules or nodules that may appear on the palms of the hands or soles of the feet in cases of infective endocarditis. Figure 12.3 Roth spots seen in the retina. 88 OSMOSIS.ORG

Chapter 12 Infections & Inflammation of the Heart LIBMAN–SACKS ENDOCARDITIS osms.it/endocarditis PATHOLOGY & CAUSES ▪ Autoimmune endocarditis associated with systemic lupus erythematosus (SLE), advanced malignancy, rheumatoid arthritis ▪ AKA nonbacterial thrombotic endocarditis/ verrucous endocarditis CAUSES ▪ Antigen-antibody complexes settle in endocardium ▫ Arises on valves /chordae tendineae, most often mitral valve ▫ Arises even on atrial/ventricular endocardium ▫ Sterile vegetations: aortic valves COMPLICATIONS ▪ ▪ ▪ ▪ Damage to heart valves Invasion of myocardium Vegetations may embolize In rare cases, may cause secondary infective endocarditis SIGNS & SYMPTOMS DIAGNOSIS ▪ Must exclude infective endocarditis (may coexist) DIAGNOSTIC IMAGING Transesophageal echocardiogram (TEE) ▪ Small, warty, vegetations on both atrial and ventricular sides of valves ▪ Regurgitation, valve insufficiency LAB RESULTS ▪ CRP, WBC levels, and antiphospholipid/ anticardiolipin antibody level may aid in differentiation TREATMENT ▪ Treat underlying SLE MEDICATIONS Anticoagulants ▪ E.g. heparin, direct thrombin, Xa inhibitors ▪ Address embolic risk ▪ Regurgitant murmurs ▫ Bilateral vegetations on valve leaflets ▪ Clinical manifestations indicate systemic emboli ▫ Kidney: flank pain, hematuria ▫ Skin: rash, digital ischemia ▫ Cardiac/central nervous system (CNS): chest pain, stroke OSMOSIS.ORG 89

MYOCARDITIS osms.it/myocarditis PATHOLOGY & CAUSES ▪ Inflammation of/damage to myocardium ▪ Swelling impairs myocardial contraction → less blood pumped out of heart with each heartbeat CAUSES Coxsackieviruses A & B infections ▪ Viral infections → lymphocytic myocarditis: B, T cells, water invade interstitial space ▪ Common in North America Trypanosoma cruzii ▪ Single-cell protozoan → Chagas disease ▪ Amastigotes within heart muscle cells (intracellular stage of trypanosomes) → necrosis of heart muscle cells ▪ Common in South America Trichinella ▪ Intestinal roundworm may move into heart → myocarditis Borrelia burgdorferi ▪ Lyme disease bacterium Toxoplasma gondii ▪ Single cell parasite harbored by cats Systemic lupus erythematosus (SLE) ▪ Non-infectious myocarditis ▪ Immune system attacks myocardium Drug-associated/hypersensitivity ▪ Adverse drug reaction inflames heart ▪ Eosinophils enters blood vessels in myocarditis Giant cell ▪ Inflammation of heart from unknown cause ▪ Macrophages fuse to form single giant cell 90 OSMOSIS.ORG RISK FACTORS ▪ Viruses that cause flu-like illnesses, HIV/ AIDS, Lyme disease, strep, staph infections, parasites COMPLICATIONS ▪ Heart failure, fibrosis, arrhythmias SIGNS & SYMPTOMS ▪ Clinical manifestations of heart failure (e.g. fatigue, shortness of breath, hepatomegaly, edema) ▪ Acute heart failure → cardiogenic shock ▪ Arrhythmias (e.g. ventricular fibrillation, ventricular tachycardia) → sudden cardiac death ▪ Fever ▪ Positional chest pain, related to pericarditis: better/worse depending on body’s position DIAGNOSIS DIAGNOSTIC IMAGING Chest X-ray ▪ Enlarged heart, possible pulmonary congestion Echocardiogram ▪ Inflamed heart muscle walls, dilation LAB RESULTS ▪ Elevated troponin, creatine kinase levels (due to heart muscle damage) Cardiac muscle biopsy ▪ Definitive diagnosis ▪ Risky procedure, performed only if test results would change treatment plan

Chapter 12 Infections & Inflammation of the Heart OTHER DIAGNOSTICS ECG ▪ Sinus tachycardia (increased heart rate) ▪ T-wave inversions ▪ “Saddle-shaped” ST segment elevations MNEMONIC: BCD ST3G Common Causes of Myocarditis Borrelia burgdorferi Coxsackieviruses A and B Drug-associated TREATMENT ▪ Viral: improves slowly over time ▪ Arrhythmias resolve as inflammation improves MEDICATIONS ▪ Antibiotics ▪ Signs of heart failure: managed with medication, fluid balance SURGERY ▪ Heart transplant in severe cases (e.g. Chagas, giant cell myocarditis) Systemic lupus erythematosus Trypanosoma cruzi Trichinella Toxoplasma gondii Giant cell Figure 12.4 Histological appearance of myocardium in viral myocarditis. OSMOSIS.ORG 91

RHEUMATIC FEVER osms.it/rheumatic-heart-disease PATHOLOGY & CAUSES ▪ Autoimmune inflammatory disease caused by complication of streptococcal infection ▪ Develops after streptococcal pharyngitis (strep throat) from Group A beta hemolytic streptococcus CAUSES Molecular mimicry ▪ Antibodies against streptococcal M-protein cross-reacts with proteins on myocardium, heart valves, joints, skin, brain → cytokinemediated inflammatory response ▪ Inflammation results in widespread pathology Pancarditis ▪ Inflammation of endometrium, myometrium, pericardium (three layers of heart tissue) ▪ Myometrium: Aschoff bodies (microscopically viewed nodules caused by inflammation) → leads to fibroid necrosis ▫ Characteristic feature of pancarditis ▫ Anitschkow cells (enlarged macrophages inside Aschoff bodies), caterpillar-like nuclei ▪ Pericardium: pericarditis causes pain, friction rub due to visceral pericardium rubbing against parietal pericardium Chronic rheumatic heart disease ▪ Repeated exposure to group A betahemolytic streptococcus → immune attacks on tissues (esp. heart tissue) ▪ Valves (typically mitral valve, sometimes aortic) develop scar tissue → leaflets thicken, fuse → commissural fusion ▫ Stenosis AKA “fish-mouth”/“buttonhole” stenosis ▫ Regurgitation (blood flows backward) ▪ Chordae tendineae attached to valves thicken 92 OSMOSIS.ORG TYPES ▪ When only a subset of symptoms present, classified as the following Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal Infections (PANDAS) ▪ Neuropsychiatric symptoms Poststreptococcal reactive arthritis ▪ Joint symptoms RISK FACTORS ▪ Small number of individuals with strep throat develop rheumatic fever, more likely in children/those in areas of poverty, crowding ▪ Rheumatic fever primarily affects children 5–7 years old, 20 days after infection ▪ One third of cases asymptomatic SIGNS & SYMPTOMS Acute rheumatic fever ▪ Following symptoms develop 2–4 weeks after streptococcal pharyngitis ▪ Fever ▪ Migratory polyarthritis of joints: temporary inflammation, swelling, joint pain ▪ Erythema marginatum: non-itchy, reddish rash, rings on arms/trunk ▪ Subcutaneous nodules: firm collagen lumps under skin ▫ Reaction to hypersensitivity ▫ Painless ▫ Back of wrist, outside elbow, front of knee ▪ Pancarditis (inflammation of three layers of heart) ▪ Dyspnea, sharp chest pain ▪ Friction rub heard on auscultation due to pericarditis ▪ Impaired ability of heart to contract

Chapter 12 Infections & Inflammation of the Heart (myocarditis) → heart failure, death ▪ Sydenham’s chorea: rapid, jerky movements of face, arms from damage to basal ganglia ▫ Autoimmune reaction on basal ganglia of brain ▫ Appears late (three months after infection) Chronic rheumatic heart disease ▪ Symptoms dependent on type of damage to heart: aortic stenosis, aortic regurgitation, mitral stenosis, mitral regurgitation, pulmonic regurgitation PANDAS ▪ Pediatric, abrupt onset, episodic course of symptoms ▪ Neurologic abnormalities: motoric hyperactivity (fidgeting), choreiform movements in stressed postures (sudden, jerky movements), frank chorea (rapid, irregular, jerks, movements continuous while awake but improve with sleep) ▪ Obsessive-compulsive disorder/tic disorder ▪ Minor criteria ▫ Signs/symptoms: fever (>38.5°C/101.3°F), arthralgia ▫ Laboratory evidence: increased acute phase reactants (↑ erythrocyte sedimentation rate, ↑ C-reactive protein, ↑ leukocytosis) ▫ Electrocardiograph: prolonged PR interval ▪ Evidence of recent infection ▫ Positive throat culture ▫ Positive rapid antigen detection test ▫ Elevated antistreptolysin O titre (ASO) ▪ Exception: Sydenham’s chorea/pancarditis independently may indicate rheumatic fever ▪ Electrocardiogram changes Chronic rheumatic heart disease ▪ Previous repeated cases of rheumatic fever ▪ Diagnosis depends on damage done to heart: aortic stenosis, aortic regurgitation, mitral stenosis, mitral regurgitation, pulmonic regurgitation Poststreptococcal reactive arthritis ▪ Arthritis occurring after a streptococcal infection DIAGNOSIS OTHER DIAGNOSTICS Jones criteria for acute rheumatic fever ▪ Evidence of previous group A streptococcus infection plus two major criteria/one major plus two minor criteria MNEMONIC: JONES Figure 12.5 Anitschkow cells (enlarged macrophageswith linear nucleoli) in an Aschoff body (a granuloma) in a case of rheumatic myocarditis. Major criteria Joints: polyarthritis myOcarditis: O = vaguely heart-shaped Nodules: subcutaneous Erythema marginatum Sydenham’s chorea OSMOSIS.ORG 93

TREATMENT MEDICATIONS Rheumatic fever ▪ Goals of treatment: control, eradicate streptococcus, prevent complications, relieve joint pain, relieve fever ▫ Antibiotics: penicillin G ▫ Anti-inflammatory agents: aspirin, non-steroidal anti-inflammatory drugs (NSAIDs), steroids ▫ Antipyretics: NSAIDs ▫ Rest Rheumatic heart disease ▪ Prevent repeated attacks/acute rheumatic fever, streptococcal infections ▪ History of acute rheumatic fever: prophylactic treatment for extended period (benzathine penicillin G/oral penicillin V, 10 years to life) OTHER INTERVENTIONS Rheumatic fever ▪ Maintain dental health ▪ Strict long-term, prophylaxis: history of bacterial endocarditis, heart transplant, artificial heart valve, other congenital defect Figure 12.6 Massive cardiomegaly secondary to aortic and mitral valve disease in a severe case of rheumatic fever. Figure 12.7 Gross pathology of acute rheumatic endocarditis; there is a line of acute inflammation (valvulitis) along the closure line of the mitral valve. 94 OSMOSIS.ORG