Postoperative Atypical Hemolytic Uremic Syndrome Treated Successfully with Eculizumab

Atypical hemolytic uremic syndrome after myomectomy: A case report

Atypical hemolytic uremic syndrome (aHUS) is a rare form of thrombotic microangiopathy due to inability to regulate the complement cascade, resulting in thrombocytopenia, intravascular hemolysis, and end-organ damage. Over 70% of cases are associated with mutations in complement or complement regulatory proteins, and some two-thirds have recognized complement-activating conditions triggering an aHUS event. We describe a case of aHUS after abdominal myomectomy in a 42-year-old woman that was managed with plasma exchange and eculizumab (an anti-C5 monoclonal antibody). The diagnosis was confirmed by biopsy of normal-appearing deltoid skin that demonstrated microvascular C5b-9 deposition, diagnostic of systemic complement pathway activation. Although extremely uncommon following gynecologic surgery, aHUS should be considered in the setting of postoperative oliguric acute kidney injury, as prompt diagnosis is necessary to prevent significant morbidity and mortality.

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Thrombotic microangiopathy is a potentially lethal complication of myomectomy.

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Atypical hemolytic uremic syndrome following surgery has been rarely reported.

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Eculizumab is a life-saving treatment for atypical hemolytic uremic syndrome.

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Normal deltoid skin biopsy may support the diagnosis of complement deposition.

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This is a case of atypical hemolytic uremic syndrome after abdominal myomectomy.

A practical approach to evaluating postoperative thrombocytopenia

Identifying the cause(s) of postoperative thrombocytopenia is challenging. The postoperative period includes numerous interventions, including fluid administration and transfusion of blood products, medication use (including heparin), and increased risk of organ dysfunction and infection. Understanding normal thrombopoietin physiology and the associated expected postoperative platelet count changes is the crucial first step in evaluation. Timing of thrombocytopenia is the most important feature when differentiating causes of postoperative thrombocytopenia. Thrombocytopenia within 4 days of surgery is commonly caused by hemodilution and increased perioperative platelet consumption prior to thrombopoietin-induced platelet count recovery and transient platelet count overshoot. A much broader list of possible conditions that can cause late-onset thrombocytopenia (postoperative day 5 [POD5] or later) is generally divided into consumptive and destructive causes. The former includes common (eg, infection-associated disseminated intravascular coagulation) and rare (eg, postoperative thrombotic thrombocytopenic purpura) conditions, whereas the latter includes such entities as drug-induced immune thrombocytopenia or posttransfusion purpura. Heparin-induced thrombocytopenia is a unique entity associated with thrombosis that is typically related to intraoperative/perioperative heparin exposure, although it can develop following knee replacement surgery even in the absence of heparin exposure. Very late onset (POD10 or later) of thrombocytopenia can indicate bacterial or fungal infection. Lastly, thrombocytopenia after mechanical device implantation requires unique considerations. Understanding the timing and severity of postoperative thrombocytopenia provides a practical approach to a common and challenging consultation.

Severe Acute Kidney Injury in Cardiovascular Surgery: Thrombotic Microangiopathy as a Differential Diagnosis to Ischemia Reperfusion Injury. A Retrospective Study

BACKGROUND

Acute kidney injury (AKI) after cardiovascular surgery (CVS) infers high morbidity and mortality and may be caused by thrombotic microangiopathy (TMA). This study aimed to assess incidence, risk factors, kidney function, and mortality of patients with a postoperative TMA as possible cause of severe AKI following cardiovascular surgery.

METHODS

We analyzed retrospectively all patients admitted to the ICU after a cardiovascular procedure between 01/2018 and 03/2019 with severe AKI and need for renal replacement therapy (RRT). TMA was defined as post-surgery-AKI including need for RRT, hemolytic anemia, and thrombocytopenia. TMA patients were compared to patients with AKI requiring RRT without TMA.

RESULTS

Out of 893 patients, 69 (7.7%) needed RRT within one week after surgery due to severe AKI. Among those, 15 (21.7%) fulfilled TMA criteria. Aortic surgery suggested an increased risk for TMA (9/15 (60.0%) vs. 7/54 (31.5%), OR 3.26, CI 1.0013-10.64). Ten TMA patients required plasmapheresis and/or eculizumab, and five recovered spontaneously. Preoperative kidney function was significantly better in TMA patients than in controls (eGFR 92 vs. 60.5 mL/min, p = 0.004). However, postoperative TMA resulted in a more pronounced GFR loss (ΔeGFR -54 vs. -17 mL/min, p = 0.062). There were no deaths in the TMA group.

CONCLUSION

Our findings suggest TMA as an important differential diagnosis of severe AKI following cardiovascular surgery, which may be triggered by aortic surgery. Therefore, early diagnosis and timely treatment of TMA could reduce kidney damage and improve mortality of AKI following cardiovascular surgery, which should be further investigated.

Postsurgical thrombotic microangiopathy: Case series and review of the literature

OBJECTIVES

Describe the clinical presentation, treatment, and outcomes of postsurgical thrombotic microangiopathy (TMA).

METHODS

In this retrospective study, records of individuals diagnosed with TMA developing within 30 days of a surgical procedure at Mayo Clinic from 2000 to 2016 were reviewed. Available literature regarding postsurgical TMA was comparatively reviewed.

RESULTS

Twenty patients were diagnosed with TMA developing within 30 (median 6.5, range (1-28)) days) following a procedure. Preceding procedures included orthopedic (n = 4), vascular (n = 4), abdominal (n = 8), thoracic (n = 2), and other (n = 2). Review of the literature identified 65 patients with postsurgical TMA and cardiovascular procedures were the most common preceding surgery. The majority of patients in the current cohort and literature were treated with therapeutic plasma exchange (TPE). Among the evaluable patients in the current cohort, 100% demonstrated response to TPE; however, 25% required the addition of other therapy including eculizumab to maintain a response 80% of patients in the literature demonstrated a response to TPE.

CONCLUSIONS

Although rare, early recognition and treatment of postsurgical TMA can lead to good outcomes. More research is necessary to determine the underlying pathophysiology and optimal treatment for postsurgical TMA.

Atypical hemolytic uremic syndrome: An unusual postoperative complication

INTRODUCTION AND OBJECTIVES

Thrombotic thrombocytopenic purpura and atypical haemolytic uremic syndrome (aHUS) are acute, rare, life-threatening thrombotic microangiopathies that require swift management. We report a case of acute microangiopathic haemolytic anaemia (MAHA) presenting in perioperative setting.

CLINICAL CASE

After hepatic pericystectomy for hydatid cyst, a 46-year-old female developed MAHA, thrombocytopenia and acute renal failure in the immediate postoperative period. "aHUS" was considered and immediate plasma exchange was initiated. Plasma exchange was performed for 2 weeks with remission of renal dysfunction. Further evaluation of genetic mutations and immunological causes for MAHA were sought. Mutations in complement factor H associated with factor H deficiency were identified, which are associated with increased risk of aHUS.

CONCLUSION

MAHA is a rare postoperative condition, requiring rapid differential diagnosis and treatment. Anaesthetists should bear in mind aHUS as a possible cause of MAHA, especially concerning immediate care for these patients.