You will be presented with the full text of a biomedical research paper. Please write an abstract for this paper. Your response should include the abstract and no additional text.

Paper text:
schistocytes are fragmented red blood cells due to the flow of blood through damaged capillaries and indicate endothelial injury .
they are typical of microangiopathic hemolytic anemia seen in life threatening conditions like disseminated intravascular coagulation or thrombotic thrombocytopenic purpura / hemolytic uremic syndrome .we report a rare sub - acute presentation of pernicious anemia with hemolysis , thrombocytopenia and numerous schistocytes that was initially diagnosed as a more serious thrombotic thrombocytopenic purpura .
a 31-year - old caucasian woman presented with fatigue and paresthesia of both feet for 1 week .
prothrombin time , partial thromboplastin time , serum fibrinogen , and serum fibrin degradation product levels were normal .
thrombotic thrombocytopenic purpura ( ttp ) was suspected due to the constellation of sub - acute onset of fatigue and paresthesia along with thrombocytopenia , schistocytes and an elevated ldh .
plasmapheresis was initiated for possible ttp . however , platelet count worsened despite plasmapheresis for 4 days . on re - evaluation ,
pernicious anemia was confirmed by the presence of anti - intrinsic factor antibodies , elevated serum gastrin level and atrophic gastritis .
clinicians must be aware of unusual clinical presentation of vitamin b12 deficiency with schistocytes as the management is simple and effective .
schistocytes are fragmented red blood cells due to the flow of blood through damaged capillaries and indicate endothelial injury .
they are typical of microangiopathic hemolytic anemia seen in life threatening conditions like disseminated intravascular coagulation ( dic ) or thrombotic thrombocytopenic purpura ( ttp)/hemolytic uremic syndrome ( hus ) .
we report a rare sub - acute presentation of pernicious anemia with hemolysis , thrombocytopenia and numerous schistocytes that was initially diagnosed as a more serious ttp .
a 31-year - old caucasian woman presented with fatigue and paresthesia of both feet for 1 week .
patient had chronic diarrhea and weight loss of 5 lbs . over the past few months .
initial laboratory tests showed that hemoglobin was 5.7 g / dl , hematocrit 15.7% , platelet count was 81,000/mm and white blood cell count 4,200/mm .
total bilirubin was elevated at 2.2 mg / dl , and direct bilirubin was 0.5 mg / dl with normal liver enzymes .
prothrombin time , partial thromboplastin time , serum fibrinogen , and serum fibrin degradation product levels were within normal limits .
peripheral smear revealed numerous schistocytes , anisocytosis and macro - ovalocytes ( figure 1 ) .
laboratory data on the day of admission and 4 months prior to presentation are described in table 1 .
laboratory values on admission compared to 4 months before admission thrombotic thrombocytopenic purpura ( ttp ) was suspected due to the presence of sub - acute onset of fatigue and paresthesia along with thrombocytopenia , schistocytes and an elevated ldh .
plasmapheresis was initiated for possible ttp . however , platelet count worsened to 42,000/mm despite plasmapheresis for 4 days . on re - evaluation ,
vitamin b12 was 125 pg / ml ( normal 130 - 777 pg / ml ) , serum folate was 19 ng / ml ( normal 2.8 - 15.6 ng / ml ) , and methylmalonic acid was 6258 mmol / ml ( normal 73 - 376 mmol / ml ) .
pernicious anemia was confirmed by the presence of anti - intrinsic factor antibodies , elevated serum gastrin level 1578 pg / ml ( normal 0 - 115 pg / ml ) .
our patient was symptom free with hemoglobin 12.4 g / dl and platelet count 248,000/mm .
vitamin b12 is needed for the synthesis of deoxy ribo nucleic acid ( dna ) and division of blood cells .
deficiency of vitamin b12 leads to an arrest in the maturation of nucleated precursors and results in hemolysis in the bone marrow .
this manifests clinically as hemolytic anemia with indirect hyperbilirubinemia and an elevated serum ldh levels .
an increase in the rbc membrane rigidity and a decrease in erythrocyte deformability were reported in b12 deficiency .
the biological effects of endothelial dysfunction are vasoconstriction , increased platelet aggregation , activation of coagulation system and monocyte adhesion to the endothelium .
schistocytes can also be seen in patients with preeclampsia , malignant hypertension , renal failure , mechanical heart valves , vitamin b12 deficiency and occasionally in normal individuals .
ttp is differentiated from dic by presence of normal coagulation parameters ( prothrombin time , partial thromboplastin time , and serum fibrinogen ) .
since the total body stores of vitamin b12 are 2 to 5 mg , it usually takes years to develop vitamin b12 deficiency once its absorption ceases .
rapid hematologic deterioration following exposure to nitrous oxide has been described in vitamin b12 deficient individuals .
clinicians must be aware of unusual clinical presentation of vitamin b12 deficiency with schistocytes as the management is simple and effective .
context : schistocytes are fragmented red blood cells due to the flow of blood through damaged capillaries and indicate endothelial injury . 
 they are typical of microangiopathic hemolytic anemia seen in life threatening conditions like disseminated intravascular coagulation or thrombotic thrombocytopenic purpura / hemolytic uremic syndrome .we report a rare sub - acute presentation of pernicious anemia with hemolysis , thrombocytopenia and numerous schistocytes that was initially diagnosed as a more serious thrombotic thrombocytopenic purpura.case report : a 31-year - old caucasian woman presented with fatigue and paresthesia of both feet for 1 week . 
 past medical history included hypertension and gastro - esophageal reflux disease . 
 examination revealed scleral icterus and pallor . 
 examination of the abdomen did not show hepatosplenomegaly . 
 initial laboratory tests showed severe anemia , and low platelets . 
 indirect bilirubin and serum lactate de hydrogenase were elevated . 
 prothrombin time , partial thromboplastin time , serum fibrinogen , and serum fibrin degradation product levels were normal . 
 peripheral smear revealed numerous schistocytes , anisocytosis and macro - ovalocytes . 
 thrombotic thrombocytopenic purpura ( ttp ) was suspected due to the constellation of sub - acute onset of fatigue and paresthesia along with thrombocytopenia , schistocytes and an elevated ldh . 
 plasmapheresis was initiated for possible ttp . however , platelet count worsened despite plasmapheresis for 4 days . on re - evaluation 
 , vitamin b12 was found to be low . 
 treatment with intra - muscular vitamin b12 led to symptomatic and hematologic improvement . 
 pernicious anemia was confirmed by the presence of anti - intrinsic factor antibodies , elevated serum gastrin level and atrophic gastritis.conclusion:clinicians must be aware of unusual clinical presentation of vitamin b12 deficiency with schistocytes as the management is simple and effective .