Case Report on Portal Vein Thrombosis Linked With Pregnancy, Iron Deficiency Anemia After C-Section in Patient With PV

As one of the 3 main classic disorders of Philadelphia-negative myeloproliferative neoplasms (Ph-MPNs), polycythemia vera (PV) develops in an estimated 15% of women of childbearing age (15-45 years), with an anticipated rate of roughly 0.3 per 100,000 people.

Due to pregnancy, and most commonly due to iron deficiency, PV may not always present with its actual clinical manifestations. Consequently, PV can be frequently missed and therefore belatedly diagnosed in pregnant women, which may increase risk of thrombotic events and bleeding in this vulnerable population.

A case report published in Clinics and Practice sought to investigate the diagnosis, related complications, and management of PV in a woman of 40 years of age giving birth for the first time who developed portal vein thrombosis 6 weeks after giving birth via C-section.

“In the event of coexistence of a myeloproliferative condition, the risk of thromboembolism is 6 times higher in pregnant women than in non-pregnant women. Furthermore, pregnant women with PV demonstrate an increased likelihood for pregnancy-related complications, such as miscarriage, hypertensive disorders of pregnancy, and intrauterine growth restriction, as well as placental abruption,” noted researchers.

Presenting to the hospital with fever and persistent abdominal pain of acute onset 45 days after undergoing C-section, the woman’s medical history revealed no chronic illnesses, other than iron deficiency anemia (IDA) and occasional episodes of headache. On the day of delivery, her blood count was normal with mild anisocytosis. Her postoperative status was uncomplicated.

“During her pregnancy, she received iron supplementation for a while, without being checked again for correction of anemia due to insufficient compliance of the patient,” wrote the researchers.

“She also mentioned that due to her advanced age for pregnancy (40 years old), she had been given aspirin 100 mg/day from the early weeks of pregnancy till the 38th week, replaced after with LMWH (low molecular weight heparin) for 2 weeks.”

On her readmission to the hospital, a new full blood count (FBC), a computerized tomography (CT), a MRI scan, and a gastroscopy were conducted, which researchers said led to the delayed diagnosis of PV.

Her clinical appearance and nutritional status were found to be normal, auscultation of the lungs appeared to be normal, and the abdomen was soft and sensitive with a palpable spleen. Possible splenomegaly and partial ischemia of the spleen’s upper pole were diagnosed, after the spleen proved to be enlarged, with a small area of reduced echogenicity in the middle and towards its upper pole. The presence of thrombosis in the splenoportal axis’ main branch of the portal vein and the initial part of its left and right branches (extensive thrombosis) was found in the tests.

After being treated immediately with fondaparinux sodium subcutaneously per day, acenocoumarol on gradual administration, and meropenem, the patient was discharged with instructions for continuation of the administered anticoagulant therapy. Her follow-up treatment was eventually altered to LMWH, 7 months after the use of acenocoumarol.

During a follow-up blood screen one year later, abnormal liver laboratory values were found. A second admission to the hospital was then needed approximately 2 months later, with a diagnosis of portal hypertension and esophageal varices being confirmed. LMWH treatment was replaced again by acenocoumarol.

Despite normal hemoglobin and hematocrit levels, due to iron deficiency, elevated lactate dehydrogenase (LDH) and history of portal thrombosis led to suspicion for MPN, for which the V617F mutation in exon 14 of the Janus kinase 2 (JAK2V617F) gene—a genetic mutation present in a majority of patients with PV (97%)—was tested and found positive.

“Serum erythropoietin was tested low (1.8 mIU/mL), and a bone marrow (BM) biopsy was carried out at the same time, revealing panmyelosis (hypercellularity with trilineage growth), megakaryocytic growth with pleomorphic mature megakaryocytes, and minor reticulin fibrosis,” added researchers.

They noted that the patient had not been compliant with standard routine exams for pregnancy, and she had only had 2 blood screening tests on the 8th and 26th weeks.

In reviewing the case study, researchers acknowledged that PV in pregnancy is extremely rare, presenting a challenging diagnosis.

Authors provided major and minor criterion regarding the typical hematological profile of a patient with PV, according to 2016 World Health Organization criteria, in which ​​PV must either meet all 3 major criteria for diagnosis or the first 2 major criteria plus the minor one:

• Major criteria:
  • Red cell mass above average expected value by more than 25%, hemoglobin above 16.5 g/dL in males and above 16 g/dL in women or hematocrit above 49% in men and above 48% in women
  • A BM biopsy demonstrating trilineage growth (panmyelosis) and hypercellularity, with strong erythroid, granulocytic and megakaryocytic proliferation, and pleomorphic adult megakaryocytes (differences in size)
  • The existence of the JAK2V617F or exon 12 mutation
• Minor Criterion:
  • A low level of erythropoietin in the serum
    

They additionally discussed recommendations on the management of PV in pregnancy that are important to follow in order to prevent the most severe complications, such as thrombosis, and less frequently, hemorrhage. Recommendations included the avoidance of using teratogenic medications before getting pregnant, if planned, adhering to joint care with an MPN-experienced hematologist and consultant obstetrician, and for at-risk pregnancies, low-aspirin use is advised.

“Pregnancy is generally not harmful in people with PV and other MPNs, and if it has already been confirmed, abortion is not strongly advised. The most important factors in the management and diagnosis of PV are the prior obstetric history of the patient, which defines whether the pregnancy is of high risk, and the disease status,” they said. “Although it is hard to identify such pathology during pregnancy, a combination of a detailed medical history and a thorough monitoring of the pregnancy is strongly recommended under the joint care of obstetricians and hematologists.”

Reference

Ntounis T, Zioutos KA, Koutras A, et al. Portal vein thrombosis after C-section in a patient with polycythemia vera (PV) due to pregnancy and iron deficiency anemia (IDA). Clin Pract. 2022;12(6):1069-1077. doi:10.3390/clinpract12060109