Postpartum Renal Cortical Necrosis Is Associated With Atypical Hemolytic Uremic Syndrome in Developing Countries

Postpartum obstetric complications: a guide for radiologists

The puerperium refers to the 6-8 weeks following delivery, and is a dynamic period in which maternal anatomy and physiology are restored to their prepregnant state. Postpartum complications can be divided into non-obstetric and obstetric. The latter are the topic of this article and can be further classified as infectious, thrombotic, hemorrhagic or cesarean-related. Transvaginal US is often the initial modality in the evaluation of puerperal disorders. CT is probably the most valuable imaging technique when life-threatening conditions are suspected. Pelvic MRI is being increasingly used in cases of inconclusive findings or if further characterization is needed, especially in the setting of postsurgical complications or placental disorders. Diagnostic and interventional radiologists play a pivotal role in the evaluation and management of a variety of puerperal complications. Many of these conditions pose a diagnostic challenge, as imaging findings often overlap with normal postpartum changes, so keeping in mind the patient's clinical information is key.

Plasma Exchange in Postpartum Hemorrhage (PPH)-Associated Thrombotic Microangiopathy (TMA): A Case Report

Thrombotic microangiopathy (TMA) is a rare yet potentially life-threatening condition. The diagnosis is difficult as there are other conditions presenting with features akin to TMA during the peripartum period such as eclampsia, preeclampsia, hemolysis, elevated liver enzymes, low platelets (HELLP) syndrome, and antiphospholipid syndrome. A 28-year-old woman with no significant past medical history developed TMA following a massive hemorrhage after an emergency cesarean section at 41 weeks of gestation. This case was finally diagnosed as postpartum hemorrhage (PPH)-associated TMA. The patient fully recovered after plasma exchange therapy. We posit the value of accumulating case reports, given that the documentation on the efficacy of plasma exchange in PPH-associated TMA is limited.

Pregnancy-Associated Renal Cortical Necrosis and Nonenhanced Functional MRI: A Case Series

Rationale & Objective

Pregnancy-associated renal cortical necrosis is a critical illness with a poor prognosis. We aimed to describe the clinical and magnetic resonance imaging (MRI) characteristics of a case series of patients with acute kidney injury in the setting of pregnancy-associated renal cortical necrosis.

Study Design

Case series.

Setting & Participants

Seventeen patients from a single center diagnosed by nonenhanced functional MRI and/or kidney pathology.

Results

All patients presented with postpartum acute kidney injury stage 3. Of the 17 patients, 15 (88%) had pregnancy-associated atypical hemolytic uremic syndrome, 11 (65%) had postpartum hemorrhage, 7 (41%) had preeclampsia/hemolysis elevated liver enzymes low platelet count syndrome, and 4 (24%) had disseminated intravascular coagulation. On T2-weighted MRI, the diffuse phenotype showed outer cortex swelling in the early phase, with a dark signal rim involving the inner cortex and Bertin column, which became more apparent over time along with cortical thinning, substantially decreasing T2 signal intensity. The focal phenotype showed focally distributed hypointense signals in the cortex. After 8-101 (median: 60) months of follow-up, 4 individuals had estimated glomerular filtration rates ≥60 mL/min/1.73 m², 6 had estimated glomerular filtration rates of 15-60 mL/min/1.73 m², and 7 had kidney failure requiring kidney replacement therapy. The diffuse phenotype was present in all of the individuals who remained kidney replacement therapy dependent.

Limitations

Retrospective study; small sample size.

Conclusions

Different forms of pregnancy-associated thrombotic microangiopathy were the major causative diseases in our pregnancy-associated renal cortical necrosis case series. Nonenhanced functional MRI may provide valuable data for establishing diagnosis and kidney prognosis.

Renal Thrombotic Microangiopathy: A Review

Thrombotic microangiopathy (TMA), a pathological lesion observed in a wide spectrum of diseases, is triggered by endothelial injury and/or dysfunction. Although TMA lesions are often accompanied by clinical features of microangiopathic hemolytic anemia, thrombocytopenia, and ischemic end-organ injury, renal-limited forms of TMA are not infrequently encountered in clinical practice. The presence of renal-limited manifestations can be diagnostically challenging, often delaying the initiation of targeted therapy. Prompt investigation and empirical treatment of TMA is warranted to reduce associated morbidity and mortality. Major advances have been made with respect to the pathophysiology of primary TMA entities, with the subsequent development of novel diagnostic tools and lifesaving therapies for diseases like thrombotic thrombocytopenic purpura and complement-mediated TMA. This article will review the clinical presentation and pathologic hallmarks of TMA involving the kidney, and the disease-specific mechanisms that contribute to the endothelial injury that characterizes TMA lesions. Diagnostic approach and both empirical and disease-specific treatment strategies will be discussed, along with the potential role for emerging targeted disease-specific therapies.

High prevalence of CFHR deletions in Indian women with pregnancy-associated hemolytic uremic syndrome

AIM

Pregnancy-associated hemolytic uremic syndrome (P-aHUS) is an important cause of peripartum acute kidney injury. Studies from Europe have described mutations in complement regulator genes, and data in Indian patients is scarce. Hence this study used multiplex ligation-dependent probe amplification (MLPA) to identify variants in complement genes in P-aHUS patients.

METHODS

We present 17 patients of P-aHUS who were investigated for complement protein levels and genetic analysis with MLPA for complement genes. Plasma exchange therapy was offered to all patients presenting in acute phase.

RESULTS

Mean age 26.74 (3.36) years with 15/17 delivered by caesarean section. Eleven patients received early (within 7 days) plasma exchange, three were dialysis-dependent at 3 months and seven were dialysis-free. Only one of the three patients receiving late (after 7 days) plasma exchange was dialysis-free. MLPA showed that 11 patients had heterozygous deletions of exons 3, 5, 6 of CFHR1 and upstream region of exons 1, 2, 3, 6 and intron 4 of CFHR3 gene while four patients had homozygous deletions at the same loci. Two patients had no MLPA-detectable variations.

CONCLUSION

This study reports a high proportion of deletions of exons of CFHR1 & CFHR3 genes in Indian P-aHUS patients detectable by MLPA by copy number variations. This needs confirmation in large multicentre studies. Plasma exchange can be an effective therapy in the non-availability of Eculizumab.

A Pictorial Review of Postpartum Complications

The postpartum period, also known as the puerperium, begins immediately after delivery of the neonate and placenta and ends 6-8 weeks after delivery. The appearance of physiologic uterine changes during puerperium can overlap with that of postpartum complications, which makes imaging interpretation and diagnosis difficult. Obstetric and nonobstetric postpartum complications are a considerable source of morbidity and mortality in women of reproductive age, and the radiologist plays an important role in the assessment of these entities, which often require a multimodality imaging approach. US and contrast material-enhanced CT are the techniques of choice in the emergency department, and they can show characteristic radiologic findings that enable differentiation between normal and abnormal features to help radiologists and emergency department practitioners to reach a correct diagnosis and provide timely treatment. The spectrum of postpartum complications ranges from relatively self-limiting to life-threatening conditions that can be divided into six categories: infectious conditions (endometritis), thrombotic complications (eg, deep vein thrombosis, ovarian vein thrombophlebitis, HELLP [hemolysis, elevated liver enzymes, and low platelet count] syndrome, or cerebral sinus thrombosis), hemorrhagic conditions (eg, uterine atony, trauma of the lower portion of the genital tract, retained products of conception, uterine artery arteriovenous malformations, or uterine artery pseudoaneurysm), cesarean delivery-related complications (eg, bladder flap hematoma, subfascial hematoma, rectus sheath hematoma, abscess formation, uterine dehiscence, uterine rupture, vesicovaginal fistula, or abdominal wall endometriosis), iatrogenic conditions (eg, uterine perforation), and nonobstetric complications (eg, acute cholecystitis, acute appendicitis, uterine fibroid degeneration, renal cortical necrosis, pyelonephritis, posterior reversible encephalopathy syndrome, or pituitary gland apoplexy). The online slide presentation from the RSNA Annual Meeting is available for this article. ^©RSNA, 2020.

Acute Kidney Injury in Pregnancies Complicated With Preeclampsia or HELLP Syndrome

Acute kidney injury that occurs during pregnancy or in the post-partum period (PR-AKI) is a serious obstetric complication with risk of significant associated maternal and fetal morbidity and mortality. Recent data indicates that the incidence of PR-AKI is increasing, although accurate calculation is limited by the lack of a uniform diagnostic criteria that is validated in pregnancy. Hypertensive and thrombotic microangiopathic disorders of pregnancy have been identified as major contributors to the burden of PR-AKI. As is now accepted regarding preeclampsia, HELLP syndrome and atypical hemolytic uremic syndrome, it is believed that PR-AKI may have long-term renal, cardiovascular and neurocognitive consequences that persist beyond the post-partum period. Further research regarding PR-AKI could be advanced by the development of a pregnancy-specific validated definition and classification system; and the establishment of refined animal models that would allow researchers to further elucidate the mechanisms and sequelae of the disorder.