Invasive Streptococcus pneumoniae Infection Causing Hemolytic Uremic Syndrome in Children: Two Recent Cases

Abstract

S pneumoniaecontinues to be an uncommon but important cause of HUS. Most cases can be confirmed or at least considered probable without performing a renal biopsy.

Streptococcus pneumoniae-associated hemolytic uremic syndrome

“…Therefore, any invasive pneumococcal infection may result in a range of abnormalities, ranging from isolated hemolytic anemia to full-blown HUS. Serotypes 14, 6B, 9V, 19, 3, 8, 23F [32] and 19A (unpublished observation) are all associated with HUS. Theoretically, different serotypes may produce varying amounts and activities of neuraminidase, thereby influencing the likelihood of a patient's developing HUS.…”

“…Preformed host IgM antibodies then bind the TF antigen and are postulated to initiate the cascade of events leading to HUS. The activated TF antigen is also present on hepatocytes, and this may explain the occurrence of transient hepatic dysfunction in some patients [26,32].…”

“…They also have longer periods of oligo-anuria, more frequent need for acute dialysis (75% vs 59%), longer hospital stays (33 days vs 16 days), more red blood cell and platelet transfusions, and a longer duration of thrombocytopenia [31]. In our review of the 73 patients reported from 1987 to 2007 [14,16,18,19,[22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] 10.1% developed endstage renal failure (ESRF) and 12.3% died in the acute phase. These rates are two-to-three-times higher than those of STEC HUS [43,44,45].…”

“…Possible cases were defined as pneumococcal HUS that could not be differentiated from pneumococcal sepsis or disseminated intravascular coagulation (DIC) with secondary organ failure. Other authors [32] have recommended upgrading all possible cases to probable status, so that the diagnosis is not overlooked.…”

“…Evidence of a thrombotic microangiopathy on renal biopsy can be helpful, but the clinical instability of many patients precludes this procedure. Several investigators have proposed that patients who satisfy the criteria for both HUS and DIC in the setting of pneumococcal infection should be considered as probably having HUS and should be treated accordingly [29,32].…”