Discussion and Conclusions
Syphilis is a sexually transmitted infection caused by
spirochaeteTreponema pallidum. It presents with a wide range of symptoms
and sign depending on the stage of the disease. Kidney involvement is
rare but a well described manifestation of syphilis with the prevalence
ranging from 0.3% to 10% of patients diagnosed with secondary syphilis
[5]. It can cause glomerulopathies, tubular pathology and vasculitic
lesions in the kidney. The most common glomerular lesion is membranous
nephropathy presenting as acute onset nephrotic syndrome [6]. Other
syphilis associated glomerular diseases are MCD, FSGS, MPGN, and RPGN.
Rapidly progressive glomerulonephritis (RPGN) is an atypical and very
rare presentation of syphilis. Patients present with hematuria,
proteinuria, and rapidly increasing serum creatinine over a short period
of time. This may or may not be accompanied by other features suggestive
of secondary syphilis [2, 4]. The pathogenesis consists of immune
complex-mediated glomerular injury as evidenced by the presence of
treponemal antigens and antibody to Treponemal pallidum on
pathologic examination of renal tissue [7]. Syphilis related
glomerulonephritis is diagnosed based on positive serology, histologic
evidence of GN with rapid and sustained resolution after treatment with
penicillin or the presence of anti-treponemal antibodies or treponemal
antigens in the glomerular deposits [8].
Treatment of syphilis-related RPGN includes parenteral penicillin for
underlying syphilitic infection [9-10]. There are prior reports
describing complete and rapid resolution of renal lesion and
normalization of kidney function with penicillin alone [2, 11]. The
role of immunosuppressive therapy is unknown, given the paucity of
evidence whether it’s beneficial for induction in the acute treatment
phase.
Our patient presented with typical clinical feature compatible with RPGN
pattern, active urine sediment with rapidly deteriorating renal
function. Positive confirmatory treponemal test along with rapid and
sustained improvement in renal function after a course of penicillin
supports the diagnosis of syphilis related RPGN.
There were several limitations in management of this case, namely lack
of renal biopsy to confirm RPGN and lack of serologic tests to rule out
other causes of RPGN.
RPGN is a very rare and atypical presentation of syphilis. However, with
a global re-emergence of syphilis it’s essential to recognize this
atypical renal manifestation of syphilis. This case highlights the
significance of considering syphilis as a reversible cause in any
patient presenting with a clinical picture suggestive of RPGN.