Acute Infective Endocarditis

What is the likely diagnosis?

Acute Infective Endocarditis

By: Ashleigh Alario, Amanda Bullock, Caitlyn Cannone, and Elisabeth Jeffcote

The goal in treating infective endocarditis: to eradicate the infectious agent from the thrombus

In addition to medication...

If the causative microorganism is...

then the treatment is...

• Surgical intervention is considered in select patients only
• These patients include those: with fungal infections, infections with aggressive anti-biotic resistant bacteria who respond poorly to antibiotic treatment, and those who have persistent blood cultures after a week of antibiotic treatment

Infective endocarditis

treatment

• Successful treatment requires antibiotic therapy
• Choice of antibiotic requires identification of the causative organism
• If a provider suspects a patient to be diagnosed with infective endocarditis, they will first start them on a broad-spectrum antibiotic and then alter the course of treatment when culture and sensitivity labs return with specifics on the organism

Case Study

Management of infective endocarditis

• Maintain cardiovascular stability
• Maintain adequate oxygenation
• While treatment is in progress, blood cultures should be obtained every 24 to 48 hours
• This will provide proof of when the infection has cleared from the blood stream
• Cardiac diet is recommended

A 28 year-old man comes to the urgent care clinic complaining of 6 days of fevers with shaking chills. He tells you, "I don't feel well and I think I may have the flu." Today he developed new painful lesions on the pads of his fingers, prompting him to come to the ER. Over the past 2 days, he has developed a productive cough with greenish sputum, which is occasionally blood-streaked. He reports no dyspnea, but sometimes experiences chest pain on deep inspiration. He does not have headache, abdominal pain, urinary symptoms, vomiting, or diarrhea. He has no significant medical history, he smokes cigarettes and marijuana regularly, drinks several beers daily, but denies intravenous drug use.

On physical examination, he is alert and talkative. He has no oral lesions, and fundoscopic examination reveals no abnormalities. His jugular veins show prominent V waves, and his heart rhythm is tachycardic but regular with harsh systolic murmur at the left sternal border that increases with inspiration. Chest examination reveals rales bilaterally. Skin examination is remarkable for painful nodules on the pads of several fingers and toes that range in color from red to purple (Osler nodes). He has multiple splinter hemorrhages in the nail beds and painless hemorrhagic macules on the palms of his hands (Janeway lesions). On both forearms, he has linear streaks of induration, hyperpigmentation, with some small nodules overlying the superficial veins, but no erythema, warmth or tenderness.

Etiology

There are multiple types of endocarditis involving different pathogens.

Native Valve Endocarditis

Intravenous Drug Abuse (IVDA) Infective Endocarditis

Underlying causes:

• Rheumatic valve disease (30%)
• Congenital heart disease (15%)
• Mitral valve prolapse (20%)
• Degenerative heart diseases

Causative infectious agents:

• Streptococcus species (70%)
• S. viridans, S. bovus, enterococci
• Staphycoccus species (25%)
• Associated with a more aggressive acute course

• Most commonly caused by S. aureus (50% of cases)
• Increasing percentage of MRSA in recent years

• Often difficult to diagnose
• Requires high index of suspicion in IV drug users
• Pulmonary symptoms (pleuritic chest pain, CXR abnormalities) may be present with tricuspid infection
• Murmur may be absent in patients with tricuspid disease

(Brusch, 2016)

Prosthetic Valve Endocarditis

• Early PVE (presents shortly after surgery)
• Usually caused by S. aureus and S. epidermis
• Often nosocomial acquired, antibiotic-resistant organisms and (such as MRSA)
• Late PVE (presents in a subacute fashion)
• Usually caused by streptococci (most commonly coagulase-negative)

Prosthetic aortic valve infections have a high association with abscess/fistula formation with valvular dehiscence

• Can lead to shock, heart failure, heart block, pericardial tamponade, and peripheral emboli

(Brusch, 2016)

Fungal Endocarditis

Nosocomial Infective Endocarditis (NIE)

Relatively uncommon

• Found in IV drug users and ICU patients receiving broad spectrum ABX
• Often produces negative blood cultures
• Diagnosis usually made after microscopic examination of large emboli

Associated with new therapeutic modalities

• Central or peripheral intravenous catheters
• Rhythm control devices (pacemakers, defibrillators)
• Hemodialysis shunts and catheters
• Chemotherapy and hyperalimentation lines

Causative agents are related to the underlying bacteremia

• Most commonly gram-positive cocci

High mortality rate

• Patients with NIE often have significant comorbidities and are of more advanced age

(Brusch, 2016)

Learning Objectives

Acute Infective Endocarditis

• Recognize clinical manifestations of IE
• Identify types and causes of IE
• Describe the pathogenesis of IE
• Identify diagnostic tests for IE
• Understand how to clinically manage IE

Labs:

Na+: 135 meq/L Glucose (random): 145 mg/dL

K+: 3.7 meq/L Hct: 40%

Cl-: 100 meq/L WBC: 19,500/ mm3

HCO3-: 22 meq/L PMNs: 80%

BUN: 17 mg/dL ESR: 30 mm/hr

Creatinine: 1.1 mg/dL UA:pale, yellow with trace

proteinuria and hematuria

Vital Signs:

BP: 128/76 Left arm HR: 109 RR: 23, unlabored

Temp: 102.5 F Ht: 5' 7" Wt: 150 lbs.

CXR:

Multiple peripheral, ill-defined nodules some with cavitation.

Further Diagnosis for This Patient

Predictors of Fatal Outcomes

Septic pulmonary embolus:

• Blood-streaked sputum
• Pain with deep inspiration

http://www.emsworld.com/article/12102491/prehospital-care-of-pulmonary-embolism

Suspected Tricuspid valve vegetation:

• Elevated jugular venous pressure indicates right-sided valvular disease
• Pulmonary embolus occurs from right-sided vegetation

(Hammer & McPhee, 2014; Spelman & Sexton, 2016)

Prior to the development of antibiotics, the mortality rate associated with Staphylococcus aureus was between 75% and 83%. Today, the mortality rate associated with Staphylococcus aureus is 20%.

(van Hal et. al., 2016)

Early diagnosis and initiation of antibiotic therapy is the best way to prevent fatal outcomes.

Factors associated with poor or fatal outcomes

• Diabetes: Patients with diabetes experience poorer outcomes than those without diabetes. This is likely due to the body's delayed healing in the presence of high blood sugar levels.

• Kidney involvement: Patients experience poor outcomes and higher mortality rates when the kidneys become involved in the presence of endocarditis. This is reflected in high creatinine levels (> 2 mg/dL) and low serum albumin related to protein wasting in the urine.

• Regurgitation: Patients with severe aortic or mitral valve regurgitation had higher mortality rates than those that did not.

• Multiple valve involvement: Patients with multiple infected valves have a higher mortality rate.

• Previous history of endocarditis

(Erbay et. al., 2010)

Let's look closer at this patient's case:

• WBC 19, 500/mm3, fever of 102.5, and elevated bands at 80%: These values tell us the patient has an infection. “Your body produces more WBCs for several reasons...when you have an infection or allergic reaction...when you are under stress or have inflammation” (Medline, 2015).

• ESR 30 mm/hr: Elevated ESR is consistent with inflammation. “Erythrocyte Sedimentation Rate (ESR) and C-reactive protein (CRP) tests are often done to detect or monitor patients with suspected inflammatory disorders” (Singh, 2014).

Microbiology

Manifestations in This Patient

Chest X- Ray:

Hemodynamic changes caused by valvular damage:

• Elevated jugular venous pressure = prominent V wave, tachycardia
• Regurgitation of blood through valve = harsh systolic murmur that increases with inspiration

multiple peripheral, ill-defined nodules some with cavitation.

Altered blood flow through cardiopulmonary system:

• Pulmonary edema = rales on auscultation, productive cough

Peripheral vascular damage secondary to bacteremia:

• Vascular occlusions by microthrombi cause localized immune-mediated vasculitis = Osler nodes on pads of fingers and toes
• Microabscesses caused by neutrophil infiltration of capillaries = Janeway lesions on palms of hands
• Nail bed splinter hemorrhages, forearm linear streaks of induration, hyperpigmentation, and superficial vein nodules

IE Causative Agents

• Proteinuria and Hematuria: The glomeruli are not filtering properly, and protein and blood spill into the urine. “Patients with infective endocarditis (IE) can develop several forms of renal disease: a bacterial infection-related immune complex-mediated glomerulonephritis” (Radhakrishnan, 2016). We also see low serum albumin as a consequence of protein in the urine.

Janeway lesions

*cavitation

(Hammer & McPhee, 2014; Sexton & Fowler, 2016)

Photo from: http://www.xraymachines.info/article/714535939/cavitating-lung-cancer-from-the-new-chest-x-ray-vol-2-/

Osler nodes

* Multiple pulmonary nodules

Photo from: https://openi.nlm.nih.gov/detailedresult.php?img=PMC2186338_1477-7819-5-123-1&req=4

The bacteria travel from the infective heart valve to the lungs. The nodules grow with bacteria, and have the potential to rupture. When this happens, cavitation is seen on the chest x- ray. "A cavity has been defined in the radiology literature as (pathologically) “a gas-filled space within a zone of pulmonary consolidation or within a mass or nodule, produced by the expulsion of a necrotic part of the lesion via the bronchial tree'” (Gadkowski & Stout, 2008).

Pathogenesis

• Endocardial injury (congenital or acquired from cardiac disease) causes platelets and fibrin to adhere to heart valve
• Bacteria introduced into the bloodstream (i.e. from IV drug use, dental procedures, infected skin lesions) then colonizes on valves, causing infected vegetation
• Bacterial growth occurs inside endothelial cells and the fibrin matrix
• Bacteria and platelet aggregates continue to expand and become entrapped within the vegetation
• Host immune response is unable to effectively attack the infection

(Sexton, 2016)

Possible causative organisms of infective endocarditis:

A group of fastidious gram-negative coccobacillary organisms:

• Haemophilus species
• Aggregatibacter species
• Cardiobacterium hominis
• Eikenella corrodens
• Kingella species

Account for 2% of IE cases, but 5-10% of cases when injection drug use is not a factor.

These organisms grow slowly in blood culture media and require longer incubation times to identify.

(Sexton, 2016)

How is Infective Endocarditis Diagnosed?

• IE is diagnosed based on the combination of medical history, symptoms, and test results.

Quiz Questions

Medical History

Diagnostic signs and symptoms

The following risk factors in a patient's history/ co-morbid conditions are red flags that can point to a diagnosis of infective endocarditis:

1. What organism is not commonly implicated in infective endocarditis?

•Flu-like symptoms, such as fever, chills, fatigue (tiredness), aching muscles and joints, night sweats, and headaches.

•Shortness of breath or a cough that won't go away.

•A new heart murmur or a change in an existing heart murmur.

•Skin changes such as:

◦Overall paleness.

◦Small, painful, red or purplish bumps under the skin on the fingers or toes.

◦Small, dark, painless flat spots on the palms of the hands or the soles of the feet.

◦Tiny spots under the fingernails, on the whites of the eyes, on the roof of the mouth and inside of the cheeks, or on the chest. These spots are from broken blood vessels.

•Nausea (feeling sick to your stomach), vomiting, a decrease in appetite, a sense of fullness with discomfort on the upper left side of the abdomen, or weight loss with or without a change in appetite.

•Blood in the urine.

•Swelling in the feet, legs, or abdomen.

• History of IV drug use
• Poor oral hygiene
• Recent dental procedure
• Past diagnosis of endocarditis
• Presence of artificial heart valves
• Presence of heart defects
• Immunosuppressed state

3. Which of the following is considered a risk factor for IE?

a. Female sex

b. 30-40 years of age

c. Recent ear infection

d. Poor dentition

2. Which of the following lab values is NOT consistent with a diagnosis of IE? Why?

a. Proteinuria

b. Decreased ESR

c. Elevated C- reactive Protein

d. Increase number of bands

(National Institute of Health, 2010)

Photo from: http://www.heart.org/HEARTORG/Conditions/CongenitalHeartDefects/TheImpactofCongenitalHeartDefects/Infective-Endocarditis_UCM_307108_Article.jsp#.WCtL8TszVaQ

Diagnostic Tests

• Blood cultures: Blood cultures are used to see if bacteria is growing in the blood. A good indicator that infective endocarditis is present.

• Echocardiogram: An echo allows the doctor to visualize the structures of the heart. "Your doctor uses the pictures to look for vegetations, areas of infected tissue (such as an abscess), and signs of heart damage" (National Heart, Lung, and Blood Institute, 2010).

• Other blood tests: Other blood tests including CBC with differential and ESR may be used. This can demonstrate elevated white count in the presence of infection, and elevated ESR in the presence of inflammation.

• X- ray, MRI, CT: Imaging may be done of other organs that may be affected by the spread of infection. Most notably are the lungs, kidney, and brain.

References

Quiz Questions

5. What are three goals of the management of IE?

4. Which clinical manifestations in this patient resemble hemodynamic changes caused by valvular disease?

a. pulmonary edema

b. heart murmur

c. prominent V wave

d. B & C

American Heart Association. (2016, October). Infective Endocarditis. Retrieved Novermber 20, 2016, from

http://www.heart.org/HEARTORG/Conditions/CongenitalHeartDefects/TheImpactofCongenitalHeartDefects/Infective-Endocarditis_UCM_307108_Article.jsp#.WCtL8TszVaQ

Cavitating Lung Cancer. Retrieved November 20, 2016, from X- ray machines, http://www.xraymachines.info/article/

714535939/cavitating-lung-cancer-from-the-new-chest-x-ray-vol-2-/

Erbay, A., Erbay, A., Canga, A., Keskin, G., Sen, N., Atak, R., … Duru, E. (2010). Risk factors for in-hospital mortality in

infective endocarditis: Five years’ experience at a tertiary care hospital in turkey. The Journal of heart valve disease, 19(2), 216–24. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/20369506

Gadkowski, B. L., & Stout, J. E. (2008). Cavitary pulmonary disease. Clinical Microbiology Reviews, 21(2).

doi:10.1128/CMR.00060-07

Hammer, G.D., & McPhee, S.J. (2014). Pathophysiology of disease: An introduction to clinical medicine, (7th ed.).

New York: McGraw-Hill

Luh, S. P., Lai, Y. S., Tsai, C. H., & Tsao, T. C. (2007). The chest x-ray revealed multiple pulmonary nodular les.

Retrieved November 20, 2016, from PubMed Central, https://openi.nlm.nih.gov/detailedresult.php?img=PMC2186338_1477-7819-5-123-1&req=4

National Heart, Blood, and Lung Institute. (2010, October 1). How is Endocarditis diagnosed?

Retrieved November 20, 2016, from https://www.nhlbi.nih.gov/health/health-topics/topics/endo/diagnosis

National Heart, Blood, and Lung Institute. (2010, October 1). What are the signs and symptoms of Endocarditis?

Retrieved November 20, 2016, from https://www.nhlbi.nih.gov/health/health-topics/topics/endo/signs

Sexton, D. J. (2016). Pathogenesis of vegetation formation in infective endocarditis. In Calderwood, S. B. (Ed.),

UpToDate. Retrieved from http://www.uptodate.com/home/index.html

Sexton, D.J & Fowler, V.G. (2016). Clinical manifestations and evaluation of adults with suspected native valve

endocarditis. In C.M. Otto & E.L. Baron (Eds.), UpToDate. Retrieved from http://www.uptodate.com/home/index.html

Spelman, D., & Sexton, D. J. (2016). Complications and outcome of infective endocarditis. In Calderwood, S. B.,

Aldea, G. S., & Kasner, S. E. (Ed.), UpToDate. Retrieved from http://www.uptodate.com/home/index.html

Pierce, D., Calkins, B., Thornton, B. (2012). Infective Endocarditis: Diagnosis and Treatment. American

Treatment. American Family Physician. Retrieved from http://www.aafp.org/afp/2012/0515/p981.html

van Hal, S., Jensen, S., Vaska, V., Espedido, B., Paterson, D., & Gosbell, I. (2016).

Predictors of Mortality in Staphylococcus aureus Bacteremia. Retrieved November 20, 2016, from American Society for Microbiology, http://cmr.asm.org/content/25/2/362.full

Answers with

Rationale

1. Candida species

2. B- decreased ESR. ESR is elevated in more than 90% of cases. This is a measure of inflammation, which is characteristic of endocarditis. Similarly, C- reactive protein will be elevated. Bands are elevated because a "left shift" is observed in bacterial infection. Protein also leaks into the urine due to glomerular damage.

3. D - Poor dentition allows dental bacteria to enter the bloodstream

4. B &C- presence of a heart murmur and prominent V wave both indicate hemodynamic changes. Pulmonary edema is an example of altered blood flow through cardiopulmonary system

5. Maintain cardiovascular stability, maintain

adequate oxygenation, eradicate the infectious agent from the thrombus