Test: Aortic Dissection & Infective Endocarditis - NEET PG MCQ

The image displays a CT scan of the chest revealing an ascending aorta dissection, characterised by a tennis ball appearance.

• Located behind it is the pulmonary artery bifurcation, which appears normal and shows no signs of embolism.
• For acute ascending aortic dissections and intramural hematomas, urgent or emergent surgical intervention is the recommended treatment.
• Type B aortic dissections affect the transverse and/or descending aorta.
• In the case of uncomplicated or stable distal lesions and intramural type B hematomas, medical management is preferred.
• For complicated type B dissections, surgical correction is necessary.

The occurrence of hypertension and chest pain, accompanied by the emergence of a diastolic murmur, indicates the onset of aortic regurgitation.

• Acute aortic regurgitation can arise from the retrograde propagation of aortic dissection.
• Option B: Dysfunction of the papillary muscle would result in a systolic murmur.
• Option C: Regurgitation results in a systolic murmur.
• Option D: This is observed with renal artery stenosis and manifests as heart failure.

The X-ray of a patient with hypertension reveals the presence of mediastinal widening, which is the most frequent plain radiographic observation in cases of aortic dissection.

The diagnosis of aortic dissection can be made using non-invasive methods such as echocardiography, CT, and MRI. Aortography is utilized less frequently due to the reliability of these non-invasive techniques.

• Transthoracic echocardiography is easy to perform and can be done quickly, with an overall sensitivity of 60-85% for detecting aortic dissection.
• Its sensitivity for identifying proximal ascending aortic dissections exceeds 80%, but it is not as effective for detecting dissections in the arch and descending thoracic aorta.
• Transesophageal echocardiography requires more expertise and patient cooperation but is highly accurate, achieving 98% sensitivity and around 90% specificity for ascending and descending thoracic aorta dissections, though it is less effective for the arch.
• This method also provides valuable insights into the presence and severity of aortic regurgitation and pericardial effusion.

Both CT and MRI are extremely accurate in detecting the intimal flap, the extent of the dissection, and involvement of major arteries, with each boasting a sensitivity and specificity of over 90%. They are beneficial for identifying intramural haemorrhage and penetrating ulcers.
MRI additionally allows for the assessment of blood flow, which can help differentiate between antegrade and retrograde dissection. The effectiveness of transesophageal echocardiography, CT, and MRI varies based on the resources and expertise available at specific institutions, as well as the patient’s haemodynamic stability, with CT and MRI being less suitable for patients who are unstable.

For the treatment of late latent syphilis, cardiovascular syphilis is managed with Penicillin G Benzathine administered at a dosage of 2.4 MU i.m. on a weekly basis for a duration of 3 weeks.
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• Bacterial endocarditis and sepsis
• Lymphoproliferative disorders
• Diabetes mellitus
• Hypertension
• Anaemia
• Connective tissue disorders

Burkholderia cepacia exhibits resistance to the majority of antibiotics. Therefore, due to its intrinsic resistance, TMP-SMX, meropenem, and doxycycline are the most effective treatments. Fluoroquinolones and third-generation cephalosporins should only be administered once susceptibility to these agents has been established.

Burkholderia cepacia is responsible for cepacia syndrome, which is characterised by:

• Rapidly progressive distress and sepsis
• Recurrent pneumonia in cystic fibrosis
• Ventilator-associated pneumonia
• Catheter-associated infections
• Wound infections

The fundus examination of a patient with mitral valve infection reveals Roth spots. Choice B is correct.

• The occurrence of recurrent fevers in a patient with pre-existing heart disease increases the risk of developing infective endocarditis.
• Acute bacterial endocarditis is associated with Staphylococcus, while the subacute form is linked to Streptococcus viridans and Enterococci.
• It can also arise from less virulent infections, making choice A accurate.

The causes of Roth spots include:

• Infective endocarditis
• SLE
• Polyarteritis Nodosa
• Severe anaemia
• Leukaemia
• Diabetes mellitus
• Hypertension

The Duke Criteria for diagnosing infective endocarditis include the following:

• Major Criteria
  • Positive blood culture: A typical microorganism associated with infective endocarditis must be identified from two separate blood cultures. This includes:
    • Viridans streptococci
    • Streptococcus gallolyticus
    • HACEK group
    • Staphylococcus aureus
    • Community-acquired enterococci, in the absence of a primary focus
  • Persistently positive blood culture, defined as the recovery of a microorganism consistent with infective endocarditis from:
    • Blood cultures taken more than 12 hours apart
    • All three or a majority of at least four separate blood cultures, with the first and last taken at least one hour apart
  • A single positive blood culture for Coxiella burnetii or a phase I IgG antibody titer greater than 1:800
  • Evidence of endocardial involvement
• Minor Criteria
  • Predisposition: A pre-existing heart condition or injection drug use
  • Fever exceeding 38.0°C (>100.4°F)
  • Vascular phenomena: Major arterial emboli, septic pulmonary infarcts, mycotic aneurysms, intracranial haemorrhages, conjunctival haemorrhages, and Janeway lesions
  • Immunologic phenomena: Glomerulonephritis, Osler's nodes, Roth's spots, and rheumatoid factor
  • Microbiological evidence: A positive blood culture that does not meet the major criteria as mentioned previously, or serological evidence of active infection with an organism consistent with infective endocarditis

Definite endocarditis is characterised by the documentation of:

• Two major criteria, or
• One major criterion and three minor criteria, or
• Five minor criteria

Transesophageal echocardiography is advised for evaluating potential prosthetic valve endocarditis or complicated endocarditis. It is important to exclude single positive cultures for coagulase-negative staphylococci and diphtheroids, which are common contaminants, as well as organisms that infrequently cause endocarditis, such as gram-negative bacilli.

• Prosthetic cardiac valves
• Unrepaired cyanotic congenital heart disease
• Completely repaired defects involving prosthetic material
• Rheumatic fever (including mitral stenosis and aortic regurgitation)
• VSD and congenital aortic stenosis

Peripheral manifestations of injective endocardites

• Osler nodes
• Subungual haemorrhages
• Janeway lesions
• Roth spots
• Petechiae

With dental procedures, it is advisable to be cautious. Rose spots are bacterial emboli on the skin, observed in around 1/3 of typhoid fever cases. These spots are considered classic indicators of untreated disease; however, they may also be present in other conditions, such as Shigellosis and non-typhoidal salmonellosis.

• They typically manifest as a rash between the seventh and twelfth day following the onset of symptoms.
• These spots appear in clusters of five to ten lesions located on the lower chest and upper abdomen.
• They are more prevalent after a paratyphoid infection.

Rose spots usually persist for three to four days. Hematuria may present as a sign of post-infectious glomerulonephritis in infective endocarditis (IE). Additionally, hemiplegia can arise following the formation of a brain abscess in IE.

Organisms Responsible for significant clinical Types of Endocarditis:

Fungal endocarditis is an exceptionally rare condition, representing only 2-4% of all endocarditis occurrences. Aspergillus was identified as the causative agent in 24% of fungal endocarditis cases. The crucial factor in the management of Aspergillus endocarditis is:

• Early detection
• Prompt surgical resection or debridement
• Combination with antifungal therapy

This approach is vital due to the significant risk of embolic complications and cardiac decompensation. The Infectious Diseases Society of America suggests Voriconazole as the preferred treatment option. For candida endocarditis, the recommended regimen includes:

• Liposomal amphotericin B or caspofungin for 6-8 weeks
• With or without flucytosine
• Followed by lifelong management with fluconazole

Due to the potential for recurrent infections, particularly after surgical intervention on infected prosthetic valves, it is advisable to consider lifelong prophylactic treatment with oral triazoles.

Mitral valve vegetations would clearly not travel to the lungs, as this would entail a 'backward flow.'