CASE STUDY
1/11
74 yo F presents with CBC shown in graphic below. You will note she has macrocytic anemia, which has a wide differential diagnosis (also shown in graphic).
1/11
74 yo F presents with CBC shown in graphic below. You will note she has macrocytic anemia, which has a wide differential diagnosis (also shown in graphic).
2/11
The patient's reticulocyte count was elevated (not shown), possibly accounting for the macrocytosis and pointing to presence of either bleeding or hemolysis.
Hemolysis labs were in fact positive (see graphic below). What is missing in the hemolysis labs?
The patient's reticulocyte count was elevated (not shown), possibly accounting for the macrocytosis and pointing to presence of either bleeding or hemolysis.
Hemolysis labs were in fact positive (see graphic below). What is missing in the hemolysis labs?
3/11
The AST:ALT ratio, which was elevated in this case, and demonstration of positive blood in urine by dipstick in absence of red blood cells under the microscope (i.e., evidence of hemoglobinuria).
The AST:ALT ratio, which was elevated in this case, and demonstration of positive blood in urine by dipstick in absence of red blood cells under the microscope (i.e., evidence of hemoglobinuria).
4/11
The ddx for hemolysis is shown in the graphic below. The first branch point is whether the hemolysis is immune or non-immune. A DAT/Coombs test resolves that question. It was negative in this case.
That leaves non-immune extracorpuscular vs. intracorpuscular causes.
The ddx for hemolysis is shown in the graphic below. The first branch point is whether the hemolysis is immune or non-immune. A DAT/Coombs test resolves that question. It was negative in this case.
That leaves non-immune extracorpuscular vs. intracorpuscular causes.
5/11
With the exception of PNH, all intracorpuscular causes of causes of hemolysis are congenital. The patient's CBC two months prior was normal, ruling out a congenital cause of hemolysis. Thus, the diagnosis is likely to lie in the "extracorpuscular bucket of causes".
With the exception of PNH, all intracorpuscular causes of causes of hemolysis are congenital. The patient's CBC two months prior was normal, ruling out a congenital cause of hemolysis. Thus, the diagnosis is likely to lie in the "extracorpuscular bucket of causes".
6/11
There are several etiologies underlying non-immune extracorpuscular hemolysis, all characterized by the detrimental effect of an environmental factor (mechanical or biochemical) on otherwise normal red blood cells (see graphic below).
There are several etiologies underlying non-immune extracorpuscular hemolysis, all characterized by the detrimental effect of an environmental factor (mechanical or biochemical) on otherwise normal red blood cells (see graphic below).
7/11
Without knowing anything about the case, the one lab test with most discriminately power at this point is a peripheral blood smear (shown in the graphic).
Without knowing anything about the case, the one lab test with most discriminately power at this point is a peripheral blood smear (shown in the graphic).
8/11
The blood smear shows the presence of schistocytes, including a helmet cell in the middle of the field. The ddx can now be narrowed down to TMA (= MAHA + thrombocytopenia + organ damage) vs. isolated MAHA.
The patient's normal PLT count supports a dx of isolated MAHA.
The blood smear shows the presence of schistocytes, including a helmet cell in the middle of the field. The ddx can now be narrowed down to TMA (= MAHA + thrombocytopenia + organ damage) vs. isolated MAHA.
The patient's normal PLT count supports a dx of isolated MAHA.
9/11
Isolated MAHA occurs in valve hemolysis, and much less commonly with marathon running or Congo drum playing.
This patient had received a mechanical mitral valve replacement 2 months earlier. Several weeks later, she developed shortness of breath and dark colored urine.
Isolated MAHA occurs in valve hemolysis, and much less commonly with marathon running or Congo drum playing.
This patient had received a mechanical mitral valve replacement 2 months earlier. Several weeks later, she developed shortness of breath and dark colored urine.
10/11
She required multiple RBC transfusions.
An echo at that time that showed moderate paravalvular leak around the mitral valve.
She underwent closure of 2 perivalvular mitral valve leaks with two 6 mm Amplatz Ductal Occluder II devices.
Her hemolysis and anemia resolved.
She required multiple RBC transfusions.
An echo at that time that showed moderate paravalvular leak around the mitral valve.
She underwent closure of 2 perivalvular mitral valve leaks with two 6 mm Amplatz Ductal Occluder II devices.
Her hemolysis and anemia resolved.
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