Low dose, oral epsilon aminocaproic acid for renal papillary necrosis and massive hemorrhage in hemoglobin SC disease

The nephropathy of sickle cell trait and sickle cell disease

Sickle cell syndromes, including sickle cell disease (SCD) and sickle cell trait, are associated with multiple kidney abnormalities. Young patients with SCD have elevated effective renal plasma flow and glomerular filtration rates, which decrease to normal ranges in young adulthood and subnormal levels with advancing age. The pathophysiology of SCD-related nephropathy is multifactorial - oxidative stress, hyperfiltration and glomerular hypertension are all contributing factors. Albuminuria, which is an early clinical manifestation of glomerular damage, is common in individuals with SCD. Kidney function declines more rapidly in individuals with SCD than in those with sickle cell trait or in healthy individuals. Multiple genetic modifiers, including APOL1, HMOX1, HBA1 and HBA2 variants are also implicated in the development and progression of SCD-related nephropathy. Chronic kidney disease and rapid decline in estimated glomerular filtration rate are associated with increased mortality in adults with SCD. Renin-angiotensin-aldosterone system inhibitors are the standard of care treatment for albuminuria in SCD, despite a lack of controlled studies demonstrating their long-term efficacy. Multiple studies of novel therapeutic agents are ongoing, and patients with SCD and kidney failure should be evaluated for kidney transplantation. Given the high prevalence and severe consequences of kidney disease, additional studies are needed to elucidate the pathophysiology, natural history and treatment of SCD-related nephropathy.

Sickle cell nephropathy. Clinical manifestations and new mechanisms involved in kidney injury

Kidney problems are among the most common complications in sickle cell disease (SCD). They occur early in childhood and are one of the main factors related to mortality in these patients. The main underlying pathogenic mechanisms are vaso-occlusion and haemolysis. The renal medulla has ideal conditions for the sickling of red cells due to its low partial pressure of oxygen, high osmolarity and acidic pH. Initially, sickle-cell formation in the vasa recta of the renal medulla causes hyposthenuria. This is universal and appears in early childhood. Microscopic and macroscopic haematuria also occur, in part related to renal papillary necrosis when the infarcts are extensive. Release of prostaglandins in the renal medulla due to ischaemia leads to an increase in the glomerular filtration rate (GFR). Adaptively, sodium reabsorption in the proximal tubule increases, accompanied by increased creatinine secretion. Therefore, the GFR estimated from creatinine may be overestimated. Focal segmental glomerulosclerosis is the most common glomerular disease. Albuminuria is very common and reduction has been found in 72.8% of subjects treated with ACE inhibitors or ARB. Recent evidence suggests that free haemoglobin has harmful effects on podocytes, and may be a mechanism involved in impaired kidney function in these patients. These effects need to be better studied in SCD, as they could provide a therapeutic alternative in sickle cell nephropathy.

Sickle cell nephropathy. Clinical manifestations and new mechanisms involved in kidney injury

Kidney problems are among the most common complications in sickle cell disease (SCD). They occur early in childhood and are one of the main factors related to mortality in these patients. The main underlying pathogenic mechanisms are vaso-occlusion and haemolysis. The renal medulla has ideal conditions for the sickling of red cells due to its low partial pressure of oxygen, high osmolarity and acidic pH. Initially, sickle-cell formation in the vasa recta of the renal medulla causes hyposthenuria. This is universal and appears in early childhood. Microscopic and macroscopic haematuria also occur, in part related to renal papillary necrosis when the infarcts are extensive. Release of prostaglandins in the renal medulla due to ischaemia leads to an increase in the glomerular filtration rate (GFR). Adaptively, sodium reabsorption in the proximal tubule increases, accompanied by increased creatinine secretion. Therefore, the GFR estimated from creatinine may be overestimated. Focal segmental glomerulosclerosis is the most common glomerular disease. Albuminuria is very common and reduction has been found in 72.8% of subjects treated with ACE inhibitors or ARB. Recent evidence suggests that free haemoglobin has harmful effects on podocytes, and may be a mechanism involved in impaired kidney function in these patients. These effects need to be better studied in SCD, as they could provide a therapeutic alternative in sickle cell nephropathy.

Preliminary experience with epsilon aminocaproic acid for treatment of intractable upper tract hematuria in children with hematological disorders

PURPOSE

Gross, intractable hematuria is rare in children. Although the role of epsilon aminocaproic acid in the management of refractory hematuria is well established in the adult population, few data exist about its use in children for this indication. We present our initial experience with epsilon aminocaproic acid for the treatment of intractable hematuria after more conservative measures failed, and propose an algorithm for administration of epsilon aminocaproic acid in children.

MATERIALS AND METHODS

We reviewed the charts of all patients treated with epsilon aminocaproic acid for intractable gross hematuria at our institution during a period of 36 months. All patients underwent hematological evaluation and any underlying bleeding dyscrasias were addressed. All patients also underwent renal and bladder ultrasound, retrograde pyelogram and ureteroscopy. Demographic information, medical and surgical histories, and epsilon aminocaproic acid dosing and outcomes were recorded.

RESULTS

Three boys and 1 girl 11 to 17 years old were treated with epsilon aminocaproic acid. Three patients had sickle trait (1 with nutcracker phenomenon) and 1 had hemophilia A. Three patients required packed red blood cell transfusions to maintain hematocrit. Three renal angiograms were performed, all of which were nondiagnostic. Duration of hematuria ranged from 1 to 52 weeks before administration of epsilon aminocaproic acid. Endoscopic evaluation demonstrated hematuria localized to 1 ureteral orifice in all 4 patients. All patients received 100 mg/kg epsilon aminocaproic acid orally every 6 hours, which uniformly led to cessation of hematuria.

CONCLUSIONS

Epsilon aminocaproic acid is useful for the management of gross refractory hematuria when more conservative measures fail. Because of its potential side effects, it should be used cautiously.