Native ("without structural heart disease") aortic valve endocarditis is
very rare in children [1]. We report a child who developed ‘native’
aortic valve endocarditis secondary to Staphylococcus aureus
bacteremia.
A 7-year-old boy presented with cellulitis over the
medial aspect of the left upper thigh and pyomyositis of the left vastus
lateralis accompanied by severe restriction of the left hip joint. These
complaints had developed over the last 12 days. MRI detected
osteomyelitis of the proximal metaphysis of the left femur with mild
left hip joint effusion. His Hb was 10.2 g/dL and WBC count was 29,000
cells/cu.mm, with 84% polymorphs and 16% lymphocytes. Pus aspirated from
the thigh abscess grew methicillin-sensitive Staphylococcus aureus.
Therapy with standard intravenous doses of
ceftriaxone, gentamicin and vancomycin was started. Three days later,
the children developed breathlessness, cough and left-sided precordial
inspiratory chest pain. Transthoracic echocardiography showed a large
(3.1 x 3.3 cm), mobile, friable, vegetation of the right coronary cusp
of a tricuspid aortic valve, an aortic para-valvular abscess (4 x 2.2
cm) communicating with the aorta, moderate pericardial effusion and
trivial aortic regurgitation, tricuspid regurgitation and mitral
regurgitation. The child was started on digoxin, furosemide and
enalapril for heart failure.
On day four of admission, the child required tube
thoracotomy for right sided pneumothorax. Over the next three weeks,
there was symptomatic improvement in the child’s general appearance and
appetite with resolution of local left thigh inflammation and heart
failure. However mild fever persisted. On the 28th day of hospital stay,
the child suddenly complained of palpitations. Widened pulse pressure
(BP 110/40/0 mmHg) was detected and intensity of the aortic
regurgitation murmur had increased. Echocardiography repeated on day 29
of admission showed an aneurysm of the right sinus of Valsava and
destruction of right aortic cusp by the vegetation causing severe aortic
regurgitation. However, in view of the high operative risk, the cardiac
surgeon deferred intervention till the completion of antibiotics [2].
Acute intractable congestive heart failure developed on day 52 of
admission necessitating endotracheal intubation and cardiopulmonary
resuscitation. Rupture of the sinus of Valsava aneurysm was suspected
for the sudden cardiac deterioration. He eventually succumbed 55 days
after admission. Parents declined consent for autopsy.
In conclusion, the development of ‘native’ aortic
valve endocarditis in the present case was due to the overwhelming
bacteremia evident by multiple sites of infection involving soft tissue,
bone and chest. Other host risk factors like primary or secondary
immunodeficiency and bicuspid aortic valve had been ruled out. Till
date, Staphylococcus aureus native valve infective endocarditis
remains a poorly understood condition [1]. Aortic valve endocarditis due
to Staphylococcus aureus is at the greatest risk for periannular
extension of infection [3]. Periannular extension causes annular
abscesses, aneurysms or fistulous communications [3]. Clinical signs of
periannular extension are non-specific, viz. persistence of
fever, recurrent emboli, worsening heart failure and new pathological
murmurs [3,4]. Therefore recognition of periannular extension of
infection often gets delayed with disastrous consequences as in the
present case.
Acknowledgments: Dr SN Oak, Director (Medical
Education and Major Hospital, Municipal Corporation of Greater Mumbai)
and Dean of Seth GS Medical College and KEM Hospital for granting
permission to publish this manuscript.
References
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2. Anguera I, Miro JM, Cabell CH, Abrutyn E, Fowler
VG Jr, Hoen B, et al. Clinical characteristics and outcome of
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