Association of acquired thrombotic thrombocytopaenic purpura in a patient with pernicious anaemia

A Rare Presentation of Pernicious Anemia Manifesting as Disseminated Intravascular Coagulation

Pernicious anemia is an autoimmune disorder that is characterized by the presence of autoantibodies to intrinsic factor and parietal cells which results in the inability to absorb vitamin B12. It is the most common manifestation of vitamin B12 deficiency and accounts for 20-50% of cases. Disseminated intravascular coagulation (DIC) is a clinical condition that is a complication of another process which causes the activation of coagulation. A 63-year-old female with a history of hypothyroidism presented with a 1-month history of worsening fatigue, intermittent epigastric pain, nausea, vomiting, and diarrhea. Initial laboratory findings showed severe anemia and macrocytosis with a hemoglobin of 4.3 g/dL and a mean corpuscular volume (MCV) of 138 fL. There was also a significant elevation of the D-dimer, lactate dehydrogenase (LDH), and creatinine. She received three units of packed red blood cells (pRBCs) and fluid resuscitation. A vitamin B12 level was obtained which revealed a severe vitamin B12 deficiency (< 150 pg/mL). Additional workup showed seropositivity for anti-parietal cell antibodies and intrinsic factor blocking antibodies, and an esophagogastroduodenoscopy (EGD) biopsy yielded histologic findings consistent with autoimmune gastritis. She was treated acutely with daily intramuscular B12 injections with improvement in hematologic derangements and symptomatology. Arrested erythropoiesis can lead to apoptosis and the high proliferation of immature erythroblasts results in cells that are more susceptible to impaired deoxyribonucleic acid (DNA) synthesis and results in denatured DNA. Pernicious anemia manifesting as DIC has yet to be described in the literature. Here we describe an interesting case of pernicious anemia manifesting as early DIC resulting from arrest of erythropoiesis evidenced by the international society on thrombosis and hemostasis score of 5, diagnostic for DIC. Early recognition and treatment of this reversible etiology of DIC is essential to the improvement of patient outcomes.

Co-existence of Thrombotic Thrombocytopenic Purpura and Megaloblastic Anaemia: A Case-Based Review

Introduction

Thrombotic thrombocytopenic purpura is a rare and fatal thrombotic microangiopathy characterised by a pentad of microangiopathic haemolytic anaemia, thrombocytopenia, renal abnormalities, neurological abnormalities, and fever. Due to ineffective erythropoiesis, vitamin-B12 deficiency may rarely present as haemolytic anaemia.

Case report

We report a case of a 42-year-old vegetarian female presenting as vitamin B12 deficiency anaemia found to have concomitant TTP, responding to plasmapheresis, corticosteroids, and rituximab therapy.

Discussion

In this case of vitamin B12 deficiency with co-existent TTP, we hypothesise vitamin B12 deficiency as a contributory or precipitating factor for TTP. We reviewed similar cases in the literature to support this hypothesis. Timely detection of TTP and the initiation of treatment is of utmost importance as TTP has a high mortality when left untreated. The possible relationship with Vitamin B12 deficiency needs further exploration.

The roles of homocysteinemia and methylmalonic acidemia in kidney injury in atypical hemolytic uremic syndrome caused by cobalamin C deficiency

BACKGROUND

Cobalamin C (cblC), a vitamin B12 processing protein, plays a crucial role in metabolism for the conversion of homocysteine to methionine and methylmalonyl-CoA to succinyl-CoA. CblC deficiency, an inborn error of cobalamin processing, is a rare cause of atypical hemolytic-uremic syndrome (aHUS) and results in hyperhomocysteinemia and methylmalonic aciduria. Both substances are thought to contribute to thrombotic microangiopathy (TMA) in cblC deficiency patients. However, the roles of homocysteine and methylmalonic acid (MMA) in these patients remain unclear. We want to shed more light on the contributions of homocysteine and MMA levels as contributing factors for thrombotic microangiopathy (TMA)/aHUS by a follow-up of a cblC deficiency patient over 6 years.

CASE DIAGNOSIS

A 27-day-old Hispanic female presented with abnormal C3-carnitine on her newborn screen, poor feeding, decreased activity, and oligouria. She was diagnosed with cblC deficiency after laboratory results revealed elevated serum homocysteine, and serum MMA along with genetic testing showing a homozygous pathogenic frameshift variant in MMACHC. The patient developed aHUS and acute kidney injury (AKI), which resolved after appropriate therapy. Over 6 years, she continued to have normal kidney function with no thrombocytopenia despite persistently elevated homocysteine and MMA levels.

CONCLUSION

We question the roles of homocysteine and MMA as causative of aHUS/TMA in cblC deficiency as they remained elevated during follow-up but did not result in aHUS/TMA or AKI. Hyperhomocysteinemia and/or MMA caused by other metabolic diseases do not result in aHUS/TMA or AKI. This suggests that other nephrotoxic factors may trigger aHUS/TMA in cblC patients.

Pancytopenia and TTP-like picture secondary to pernicious anaemia

A 21-year-old man presented to the emergency department with generalised weakness, weight loss and decreased appetite for few weeks. He had evidence of severe pancytopenia and haemolysis. His peripheral smear with many schistocytes was suspicious for thrombotic thrombocytopenic purpura (TTP). He was supported with blood transfusions and daily plasmapheresis. His platelet counts worsened despite 4 days of therapy. Bone marrow biopsy was significant for hypercellular bone marrow with megaloblastic changes. Further workup revealed normal ADAMTS13 level, low vitamin B12, positive intrinsic factor antibodies and high methylmalonic acid. Diagnosis of pernicious anaemia was established and he was started on daily treatment with intramuscular vitamin B12which subsequently improved his symptoms and haematological parameters. This report highlights the importance of checking vitamin B12level in patients presenting with pancytopenia and TTP-like picture before making a diagnosis of TTP.

A Rare Cause of Thrombotic Thrombocytopenia Purpura- (TTP-) Like Syndrome, Vitamin B12 Deficiency: Interpretation of Significant Pathological Findings

Thrombotic thrombocytopenia purpura (TTP) is a hematological emergency that requires rapid assessment followed by prompt initiation of therapy due to high mortality associated with delayed treatment. TTP has many causes including heritable syndromes, ADAMTS13 deficiency, and drugs-related etiologies. Profound vitamin B12 deficiency can, in rare cases, mimic TTP in presentation, and since plasmapheresis can be of limited benefit, prompt diagnosis is necessary for accurate treatment with B12. Therefore, careful analysis of all clinical signs, symptoms, and labs must be assessed. We report a patient who presented with a diagnosis of TTP, and repeat assessment confirmed a diagnosis of sever vitamin B12 (B12) deficiency with pancytopenia who was appropriately treated with B12.

Cobalamin deficiency presenting with thrombotic microangiopathy (TMA) features: A systematic review

INTRODUCTION

Cobalamin deficiency may result in hematologic characteristics similar to thrombotic microangiopathy (TMA). To facilitate diagnosis, we reviewed reported cases of acquired cobalamin deficiency presenting with TMA features (c.def-TMA).

METHODS

A literature search identified reports of c.def-TMA. Deficiency was defined as B12 levels of <118 pmol/L. Corrected reticulocyte counts and reticulocyte production indexes were calculated. Clinical features were presented as proportion abnormal and results summarized as medians and interquartile ranges (IQR).

RESULTS

Patient level data was extracted from 41 identified cases. Median age (years) was 43 (30-55) with 21/41 (51%) being female. Cobalamin deficiency was noted in 35/40 (87.5%) but fold increases in MMA and HC were 30 and 6, respectively. The etiology was pernicious anemia in 28/41 (68%) cases. Anemia was both universal and severe, with hemoglobin levels of 55 g/L (4.7-6.6). Hypersegmented neutrophils were noted in 23/37 (62%), schistocytes in 29/38 (76%) and median LDH levels 3981 U/L (2004-5467). The RPI was <3.0% in all patients. Thrombocytopenia occurred in 33/41 (80.5%) with a median platelet count of 91 × 10⁹/L (42-112). Plasma infusion or exchange was initiated in 14/41 (34%) with associated complications in 2 cases.

CONCLUSION

Reticulocytopenia (RPI of <3.0%) was a universal finding that aids in differentiating c.def-TMA from other causes of hemolysis. C.def-TMA was associated with severe anemia, generally mild-moderate thrombocytopenia, and significant elevations in LDH.

Pernicious Anemia Associated Cobalamin Deficiency and Thrombotic Microangiopathy: Case Report and Review of the Literature

A 43-year-old Hispanic male without significant previous medical history was brought to emergency department for syncope following a blood draw to investigate a 40 lbs weight loss during the past 6 months associated with decreased appetite and progressive fatigue. The patient also reported a 1-month history of jaundice. On examination, he was hemodynamically stable and afebrile with pallor and diffuse jaundice but without skin rash or palpable purpura. Normal sensations and power in all extremities were evident on neurological exam. Presence of hemolytic anemia, schistocytosis, thrombocytopenia, and elevated lactate dehydrogenase (LDH) was suggestive of thrombotic thrombocytopenic purpura (TTP). However, presence of leukopenia, macrocytes, and an inadequate reticulocyte response to the degree of anemia served as initial clues to an alternative diagnosis. Two and one units of packed red blood cells were transfused on day 1 and day 3, respectively. In addition, one unit of platelets was transfused on day 2. Daily therapeutic plasma exchange (TPE) was initiated and continued until ADAMTS-13 result ruled out TTP. A low cobalamin (vitamin B12) level was evident at initial laboratory work-up and subsequent testing revealed positive intrinsic factor-blocking antibodies supporting a diagnosis of pernicious anemia with severe cobalamin deficiency. Hematological improvement was observed following vitamin B12 supplementation. The patient was discharged and markedly improved on day 9 with outpatient follow-up for cobalamin supplementation.