Clinico-Pathological Study of Hemolytic Uremic Syndrome In Ain Shams University Hospitals
Mariam Bahaa El Din Abd El Hamid;
Abstract
SUMMARY
H
US is defined by the triad of mechanical, non-immune hemolytic anemia with fragmented erythrocytes (schizocytes), thrombocytopenia and acute renal failure. It is the most common cause of acute renal failure in childhood. HUS is broadly classified as typical or atypical. The underlying histological lesion is TMA, characterized by thickening of arterioles and capillary walls, with prominent endothelial damage (swelling and detachment), subendothelial accumulation of proteins and cell debris, and fibrin and platelet-rich thrombi obstructing vessel lumina. TMA predominantly affects the renal microvasculature, although the brain, heart, lungs and gastrointestinal tract may be involved.
To our knowledge, ours is the first study in Egypt to evaluate the clinico-pathological findings in HUS, this study comprised 39 cases of HUS during the period from January 2003 to December 2013. In our study, children and adult age groups were included. Children group were 54% and adult group was 46%. Female gender was 56% while male was 44%.
The etiology was known in 17 cases out of 39; six cases (15%) were D+ HUS and eleven cases (28%) were secondary HUS. In the remaining 22 cases (57%), etiology could not be determined. From the eleven cases of secondary HUS, eight cases were associated with malignant hypertension, two occurred postpartum and one was associated with systemic lupus erythematosus and antiphospholipid antibody syndrome. Three (8%) of our 39 cases presented with central nervous symptoms and two cases (5%) were recurrent, they were all children.
We found that known cases of secondary HUS were adults while known cases of D+ HUS were either children or adults with significant P-value = 0.006.
The pathological findings were classified morphologically into early, late and overlap phases and also into glomerular, arterial and combined TMA patterns. Twenty nine cases (74.5%) out of 39 showed early phase of renal injury while 6 cases (15.5%) featured late phase and 4 cases (10%) showed overlap features. As regards patterns 22 cases (56.6%) out of 39 showed combined TMA whereas 15 cases (38.1%) showed glomerular TMA and only two cases (5.3%) were arterial TMA.
Cases of early phase (n = 29) showed either glomerular or combined pattern with no pure arterial pattern while cases of late phase (n = 6) elicited any of the three morphological patterns.
Pure glomerular TMA was more prevalent in children (80%) than adults (20%) while the two cases of pure arterial TMA were present in adults only with statistically significant P- value = 0.018.
Early phase was little more pronounced in children (55.2%) than adults (44.8%) while late phase was more pronounced in adults (66.6%).
When we did a correlation between the available etiology and pathological patterns and phases of renal injury, we found that most cases of secondary HUS (81.8%) presented with combined TMA with significant P-value = 0.015 and also most cases of secondary HUS (63.6%) presented by early phase of renal injury with non significant P-value.
Conclusions:
Renal biopsy is not a routine investigation in HUS, it is only indicated when the diagnosis is in doubt or recurrent or severe disease. The significance of renal biopsy is to confirm the diagnosis and gives an impression on the prognosis of the patient as arterial involvement carries a worse prognosis. Also the etiology of HUS can not be determined from the morphologic changes of HUS as the basic morphologic changes are similar in most cases.
HUS is primarily a disease of children but it can also occur in adults especially the atypical. The D+ HUS occurs commonly in children while secondary HUS in adults. The pure glomerular TMA occurs more commonly in children while pure arterial involvement occurs in adults, therefore prognosis is expected to be better in children. Electron microscopy is important to confirm the diagnosis and exclude the presence of electron dense deposits when HUS gives the picture of membranoproliferative. The immunofluoresence findings are non specific in HUS.
H
US is defined by the triad of mechanical, non-immune hemolytic anemia with fragmented erythrocytes (schizocytes), thrombocytopenia and acute renal failure. It is the most common cause of acute renal failure in childhood. HUS is broadly classified as typical or atypical. The underlying histological lesion is TMA, characterized by thickening of arterioles and capillary walls, with prominent endothelial damage (swelling and detachment), subendothelial accumulation of proteins and cell debris, and fibrin and platelet-rich thrombi obstructing vessel lumina. TMA predominantly affects the renal microvasculature, although the brain, heart, lungs and gastrointestinal tract may be involved.
To our knowledge, ours is the first study in Egypt to evaluate the clinico-pathological findings in HUS, this study comprised 39 cases of HUS during the period from January 2003 to December 2013. In our study, children and adult age groups were included. Children group were 54% and adult group was 46%. Female gender was 56% while male was 44%.
The etiology was known in 17 cases out of 39; six cases (15%) were D+ HUS and eleven cases (28%) were secondary HUS. In the remaining 22 cases (57%), etiology could not be determined. From the eleven cases of secondary HUS, eight cases were associated with malignant hypertension, two occurred postpartum and one was associated with systemic lupus erythematosus and antiphospholipid antibody syndrome. Three (8%) of our 39 cases presented with central nervous symptoms and two cases (5%) were recurrent, they were all children.
We found that known cases of secondary HUS were adults while known cases of D+ HUS were either children or adults with significant P-value = 0.006.
The pathological findings were classified morphologically into early, late and overlap phases and also into glomerular, arterial and combined TMA patterns. Twenty nine cases (74.5%) out of 39 showed early phase of renal injury while 6 cases (15.5%) featured late phase and 4 cases (10%) showed overlap features. As regards patterns 22 cases (56.6%) out of 39 showed combined TMA whereas 15 cases (38.1%) showed glomerular TMA and only two cases (5.3%) were arterial TMA.
Cases of early phase (n = 29) showed either glomerular or combined pattern with no pure arterial pattern while cases of late phase (n = 6) elicited any of the three morphological patterns.
Pure glomerular TMA was more prevalent in children (80%) than adults (20%) while the two cases of pure arterial TMA were present in adults only with statistically significant P- value = 0.018.
Early phase was little more pronounced in children (55.2%) than adults (44.8%) while late phase was more pronounced in adults (66.6%).
When we did a correlation between the available etiology and pathological patterns and phases of renal injury, we found that most cases of secondary HUS (81.8%) presented with combined TMA with significant P-value = 0.015 and also most cases of secondary HUS (63.6%) presented by early phase of renal injury with non significant P-value.
Conclusions:
Renal biopsy is not a routine investigation in HUS, it is only indicated when the diagnosis is in doubt or recurrent or severe disease. The significance of renal biopsy is to confirm the diagnosis and gives an impression on the prognosis of the patient as arterial involvement carries a worse prognosis. Also the etiology of HUS can not be determined from the morphologic changes of HUS as the basic morphologic changes are similar in most cases.
HUS is primarily a disease of children but it can also occur in adults especially the atypical. The D+ HUS occurs commonly in children while secondary HUS in adults. The pure glomerular TMA occurs more commonly in children while pure arterial involvement occurs in adults, therefore prognosis is expected to be better in children. Electron microscopy is important to confirm the diagnosis and exclude the presence of electron dense deposits when HUS gives the picture of membranoproliferative. The immunofluoresence findings are non specific in HUS.
Other data
| Title | Clinico-Pathological Study of Hemolytic Uremic Syndrome In Ain Shams University Hospitals | Other Titles | الدراسة الاكلينيكية الباثولوجية لمتلازمة انحلال الدم اليوريمي فى مستشفيات جامعة عين شمس رسالة | Authors | Mariam Bahaa El Din Abd El Hamid | Issue Date | 2014 |
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