CASE 1

A 35-year-old woman is undergoing aortic valve replacement for chronic aortic valvulitis from rheumatic fever. She was doing well until about a week prior to admission, when she developed worsening dyspnea. A chest radiograph showed pulmonary edema and mild cardiomegaly with a prominent left heart border. An echocardiogram revealed high grade aortic stenosis.

She has an uncomplicated surgical procedure, in which a porcine bioprosthesis is impanted. She does well for three weeks, but then develops a low-grade fever that persists for several days. Blood cultures are performed, and 2 of 5 cultures grow an organism.

Question 1.1 - Why was a bioprosthesis used?

Question 1.2 - What are complications of prosthetic valves?

Question 1.3 - What are the likely microbiologic agents to cause this infection?

Question 1.4 - How does the setting for this disease contribute to the microbiologic risk (nosocomial infection)?

Question 1.5 - What antibiotic regimen is indicated?

CASE 2

A 22-year-old man has a low-grade fever with malaise for the past two weeks. He becomes more acutely ill toward the end of the week, with peripheral edema. He sees a physician, who auscultates a shrill systolic murmur. A chest xray shows bilateral pleural effusions. There are several nodular densities in both lungs, one of which in the right upper lobe reveals an air-fluid level. Echocardiography is performed. A blood culture is taken.

Question 2.1 - What pre-existing disease do you think this patient had?

Question 2.2 - Where do you think the infection is?

Question 2.3 - Explain the pulmonary lesions.

Question 2.4 - What is the organism?

Question 2.5 - Name other implantable devices that may be complicated by infection.

Question 2.6 - What antibiotic regimen is indicated?

CASE 3

A 28-year-old man has had a mild fever for the past 4 days along with non-productive cough and sore throat. He then develops mild dyspnea and chest pain that is more substernal than pleuritic, but poorly localized. Two days later he is no better, and sees his physician. On physical examination, the lungs are clear to auscultation. There is a friction rub. The heart rate is regular and there are no murmurs.

Laboratory findings include:

• Hemoglobin 13.9 g/dL

• Hematocrit 42.0%

• MCV 92 fL

• Platelet count 330,000/microliter

• WBC count 7100/microliter

• CK-MB slightly elevated

• Troponin I moderately elevated

Further History

An EKG is performed and shows shows ST segment elevations.

Question 3.1 - What cardiac disease is present?

Question 3.2 - What are the possible infectious agents that produce these findings?

Question 3.3 - How can you confirm the diagnosis?

CASE 4

A 55-year-old woman has undergone an orthotopic heart transplant for cardiomyopathy. She recovers well from surgery and during the first post-transplant month has weekly endomyocardial biopsies that show mild acute rejection. This is treated with an increase in immunosuppressive therapy, and the rejection subsides. In week 5, she develops a fever and chest pain.

A chest xray shows mild pulmonary edema. A chest CT shows no pulmonary infiltrates or masses. The heart shows some minimal heterogeneity in attenuation that involves the left ventricular wall and septum. An echo shows no valvular lesions, but there is slightly decreased wall motion and reduced cardiac output. Another endomyocardial biopsy is performed.

Question 4.1 - What type of heart disease do you think is present?

Question 4.2 - What are possible infectious agents?

Question 4.3 - What is the diagnosis?

Question 4.4 - What antibiotic regimen is indicated?

CASE 5

A 9-year-old girl has an indurated area of erythema and swelling just lateral to her left eye, accompanied by posterior cervical lymphadenopathy. She has unilateral painless edema of the palpebrae and periocular tissues.

These findings are followed two days later by malaise, fever, anorexia, and edema of the face and lower extremities.

On physical examination a week later there is hepatosplenomegaly and generalized lymphadenopathy. She then goes into severe congestive heart failure.

Her 32-year-old father also has congestive heart failure, with pedal edema and ascites. If an EKG were performed on him, it would show a right bundle-branch block, or possibly atrioventricular block, premature ventricular contractions, or tachy- and bradyarrhythmias. He suffers a cerebrovascular accident and recovers with minimal loss of function of his right upper extremity. He later develops dysphagia, odynophagia, chest pain, and regurgitation, complicated by aspiration pneumonitis. He develops abdominal pain and constipation.

Question 5.1 - What are the possible infectious causes for these findings?

Question 5.2 - Where do you think this family lives? What are their living conditions like?

Question 5.3 - How is the diagnosis of the child's acute disease made?

Question 5.4 - How is the diagnosis of the father's chronic disease made?

Question 5.5 - Describe the cardiac findings.

Question 5.6 - What antibiotic regimen is indicated?

CASE 6

A 5-year-old girl develop a fever of 101 F with sore throat and difficulty swallowing. Several days later she develops edema of the neck with difficulty breathing. She then becomes listless. She is taken to the family physician who notes persistent fever. Auscultation of the chest reveals minimal basilar crackles. The heart rate is regular, with tachycardia to 110 beats/minute. No murmurs are heard.

It is noted that the child has a foul breath along with massive swelling of the tonsils, and cervical lymphadenopathy, with striking edematous swelling of the submandibular region and anterior neck. Examination of the oropharynx reveals marked edema of the uvula and a dirty grey, leathery-appearing membrane over the posterior pharyngeal region. A similar membrane is seen over the posterior nasal septum. When a portion of this membrane is removed for culture, there is mucosal bleeding.

Laboratory findings include:

• Hemoglobin 13.3 g/dL

• Hematocrit 40.2%

• MCV 94 fL

• Platelet count 270,000/microliter

• WBC count 25,100/microliter

• WBC differential: Segs 73, bands 6, lymphs 16, 5 monos

Additional History

Laboratory findings include:

• AST 85 U/L

• ALT 49 U/L

• Total Bilirubin 0.7 mg/dL

• CK-MB slightly elevated

• Troponin I moderately elevated

Question 6.1 - What is the most likely diagnosis?

Question 6.2 - Explain the cardiac findings.

CASE 7

A 7-year-old boy has been listless and tired for the past several days. He is taken to the family physician who notes vital signs with T 36.6 C, P 100, R 16, BP 90/60 mm Hg. On auscultation of the chest there is a murmur of mitral regurgitation, an S3 gallop, and a friction rub. There is marked tenderness and swelling of the small joints of the hands as well as the ankles and wrists. There is a macular eruption with rounded borders concentrated on the trunk.

Laboratory findings include:

• Hemoglobin 14.1 g/dL

• Hematocrit 42.9%

• MCV 93 fL

• Platelet count 299,000/microliter

• WBC count 5,100/microliter

• WBC differential: Segs 53, bands 3, lymphs 32, 14 monos

• C-reactive protein elevated

• Troponin I slightly elevated

Question 7.1 - What cardiac manifestations are present?

Question 7.2 - What additional laboratory test(s) would you order?

Question 7.3 - What antecedent illness was he likely to have?

Question 7.4 - Explain the pathogenesis for this disease.

CASE 8

A 68-year-old man develops orthopnea and paroxysmal nocturnal dyspnea, worsening over the past 3 years. A chest xray shows linear calcification of the ascending aorta. On physical examination, auscultation of the chest reveals a regular heart rate and rhythm, but there is a murmur of aortic regurgitation. Echocardiography reveals aortic root dilation to 4 cm.

Question 8.1 - What are the cardiovascular manifestions seen here?

Question 8.2 - What laboratory test(s) would you order?

Question 8.3 - What is the diagnosis?

Question 8.4 - Explain the pathophysiology for this condition.

CASE 9

A 30-year-old man develops a high fever and malaise. His roommate takes him to the emergency department of a local hospital. On examination by the physician, he is found to have vital signs with T 39.1 C, P 105, R 16, and BP 80/40 mm Hg. On auscultation of the chest, a loud murmur is heard. A blood culture is drawn. An echocardiogram is performed.

He is given IV antibiotic therapy and appears to be improving over the next 36 hours, but then he has a sudden loss of consciouness and there is right papilledema. Emergent MR imaging with gadolinium enhancement of the brain is performed.

Question 9.1 - What is the most likely diagnosis for his presenting illness?

Question 9.2 - What is the blood culture most likely to grow?

Question 9.3 - What antibiotic regimen is indicated?

Question 9.4 - What did the echo show?

Question 9.5 - Explain the complication involving the brain.