Bartonella endocarditis and diffuse crescentic proliferative glomerulonephritis with a full-house pattern of immune complex deposition

Abstract

Background: Bartonella endocarditis is often a diagnostic challenge due to its variable clinical manifestations, especially when it is first presented with involvement of organs other than skin and lymph nodes, such as the kidney.

Case presentation: This was a 13-year-old girl presenting with fever, chest and abdominal pain, acute kidney injury, nephrotic-range proteinuria and low complement levels. Her kidney biopsy showed diffuse crescentic proliferative glomerulonephritis with a full-house pattern of immune complex deposition shown by immunofluorescence, which was initially considered consistent with systemic lupus erythematous-associated glomerulonephritis (lupus nephritis). After extensive workup, Bartonella endocarditis was diagnosed. Antibiotic treatment and valvular replacement surgery were undertaken with subsequent return of kidney function to normal range.

Conclusion: This case demonstrates the importance of considering the full clinical picture when interpreting clinical, laboratory and biopsy findings, because the treatment strategy for infective endocarditis versus lupus nephritis is drastically different.

Keywords: Bartonella henselae; Cat-scratch disease; Diffuse crescentic proliferative glomerulonephritis; Full-house immune complex deposition; Infective endocarditis.

Fig. 1

Echocardiogram. A Transthoracic echocardiogram, before surgery, two-dimensional, Doppler and color Doppler interrogation, parasternal long axis: Bicuspid and thickened aortic valve with vegetation (arrow), moderate to severe aortic valve regurgitation and mild to moderate aortic stenosis, mildly dilated left atrium and left ventricle with mild to moderate hypertrophy. B Transesophageal echocardiogram, after surgery, two-dimensional, Doppler and color Doppler interrogation: There is no left ventricular outflow tract obstruction. On-X mechanical valve shows no vegetation (arrow), with no significant stenosis or regurgitation. Left ventricle is mildly dilated with mild to moderately diminished systolic function

Fig. 2

Kidney biopsy, light microscopy (original magnification 400x). A (hematoxylin and eosin stain): Glomerulus shows severe global endocapillary hypercellularity (curved arrow). There are neutrophils infiltrating in the capillary lumina (straight arrow). B (hematoxylin and eosin stain): A cellular crescent (black curved arrow) surrounds glomerular capillary tufts showing global endocapillary hypercellularity (black straight arrow). There is fibrinoid necrosis (white curved arrow) on the interface of glomerular tuft and crescentic lesion. C (Periodic acid Schiff stain): A fibrocellular crescent (curved arrow) surrounding glomerular capillary tufts with global endocapillary hypercellularity (straight arrow). D (Jones methenamine silver stain): A cellular crescent (black curved arrow) surrounding glomerular capillary tufts with global endocapillary hypercellularity (black straight arrows). There is rupture of glomerular basement membrane and detachment of a glomerular segment floating in the crescentic area (white curved arrow)

Fig. 3

Immunofluorescence microscopy of kidney biopsy (original magnification 400x): Diffuse global granular mesangial and capillary wall deposition of A IgG (2+ intensity, on a scale of 0–3+), B IgA (2–3+), C IgM (3+); D C3 (2–3+), E C1q (3+) and F fibrinogen (3+). Fibrinogen was predominantly detected in the crescentic area (white curved arrows), indicating passage of plasma material to Bowman’s space due to rupture of glomerular basement membrane in the process of fibrinoid necrosis

Fig. 4

Electron microscopy of a glomerulus: A (original magnification 1000x) Multi-foci of subendothelial electron dense deposits (white straight arrows); B (original magnification 8000x) Multi-foci of mesangial electron dense deposits (white straight arrows); C (original magnification 3000x) Severe endocapillary hypercellularity (white straight arrows). D (original magnification 3000x) Severe endocapillary hypercellularity (white straight arrows) and rupture of glomerular basement membrane (black straight arrows) with fibrinoid necrosis and crescentic lesion (white curved arrows) outside of the rupture