Amniotic fluid embolism

McConnell's Sign in a Patient with Amniotic Fluid Embolism and Severe Right Ventricular Dysfunction

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McConnell’s sign may be an early sign of acute RV strain in amniotic fluid embolus.

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TTE could be considered to facilitate timely diagnosis of amniotic fluid embolus.

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The presence of RV dysfunction on TTE may help guide hemodynamic therapies.

Fatal amniotic fluid embolism with typical pathohistological, histochemical and clinical features

Despite the decrease in maternal mortality rate, amniotic fluid embolism (AFE) is still one of the most feared complications of pregnancy due to the high rate of mortality in Japan. The authors present a fatal case of a healthy 39-year-old woman who died during delivery after a normal 40-week second pregnancy. Shortly after the arrival at hospital, an abrupt drop of foetal heart rate was observed, followed by deterioration of consciousness and cardiac arrest of the patient. Prompt cardiopulmonary resuscitation (CPR) was performed but the patient died about an hour and a half after her arrival at hospital. Forensic autopsy confirmed the pathohistological diagnosis of amniotic fluid embolism supported by histochemical analysis results and excluded other possible causes of death. This paper stresses the fundamental importance of autopsy in an unexpected maternal death in conjunction with the significance of data accumulation on maternal death.

Amniotic fluid embolism

The disastrous entry of amniotic fluid into the maternal circulation leads to dramatic sequelae of clinical events, characteristically referred to as Amniotic fluid embolism (AFE). The underlying mechanism for AFE is still poorly understood. Unfortunately, this situation has very grave maternal and fetal consequences. AFE can occur during labor, caesarean section, dilatation and evacuation or in the immediate postpartum period. The pathophysiology is believed to be immune mediated which affects the respiratory, cardiovascular, neurological and hematological systems. Undetected and untreated it culminates into fulminant pulmonary edema, intractable convulsions, disseminated intravascular coagulation (DIC), malignant arrhythmias and cardiac arrest. Definite diagnosis can be confirmed by identification of lanugo, fetal hair and fetal squamous cells (squames) in blood aspirated from the right ventricle. Usually the diagnosis is made clinically and by exclusion of other causes. The cornerstone of management is a multidisciplinary approach with supportive treatment of failing organs systems. Despite improved modalities for diagnosing AFE, and better intensive care support facilities, the mortality is still high.

Forensic Lung Pathology

Sudden and unexpected natural deaths and nonnatural deaths may result from various pulmonary conditions. Additionally, several nonpulmonary conditions of forensic significance may be complicated by the development of respiratory lesions. Certain situations with pulmonary pathology are particularly likely to be critically scrutinized and may form the basis of allegations of medical negligence, other personal injury liability, or wrongful death.1

Aprotinin in the management of coagulopathy associated with amniotic fluid embolus

Amniotic fluid embolus, also known as anaphylactoid syndrome of pregnancy is a rare complication of pregnancy. When it occurs, the maternal mortality rate may be as high as 86%, and in survivors, the morbidity rate may be just as high. Hallmark clinical features include maternal cardiovascular collapse with disseminated intravascular coagulation, and fetal distress. Management centers on strategies to improve oxygenation, support circulation, and correct the coagulopathy. We report the case of a patient who developed amniotic fluid embolus and was effectively managed with aprotinin to control the coagulopathy associated with this devastating complication of pregnancy.

[Amniotic fluid embolism: a review]

Amniotic fluid embolism occurs rarely but is a leading cause of maternal mortality. It is a difficult and somewhat intangible diagnosis that warrants a high index of suspicion by physicians. AFE is an unpredictable, unpreventable, and, for the most part, an untreatable obstetric emergency. Management of this condition includes prompt recognition of the signs and symptoms, aggressive resuscitation efforts, and supportive therapy. Any delays in diagnosis and treatment can result in increased maternal and/or foetal impairment or death. Whereas once the invariable outcome of AFE was death of the mother, today the prognosis is somewhat brighter thanks to increased awareness of the syndrome and advances in intensive care medicine. No laboratory test is specific to attest the diagnosis and autopsy must to be realised in case of maternal death. Although non-specific, the diagnosis of AFE could be supported by the observation of amniotic fluid in the central venous blood as well as in the bronchoalveolar fluid. This easy and quick test will be helpful in decision-making. Prompt and aggressive supportive treatment is required to lessen an otherwise dismal outcome, which may include death and permanent disability. This article provides an account of the protean clinical features, pathogenesis, and principles involved in treatment.

Amniotic fluid embolism

INCIDENCE

Amniotic fluid embolism is a catastrophic syndrome that occurs during pregnancy or in the immediate postpartum period. Multiple case reports have described the clinical findings and have reported variable success with supportive care. There has been discrepancy with respect to the incidence and mortality of amniotic fluid embolism. One likely explanation for this inconsistency is the lack of sensitive and specific diagnostic studies to definitively identify cases of amniotic fluid embolism, leading to both over- and underreporting. Despite the variation in reported incidence and mortality, amniotic fluid embolism remains a life-threatening condition with significant morbidity and mortality for the pregnant woman. It is the fifth most common cause of maternal mortality in the world.

DIAGNOSIS

The diagnosis of amniotic fluid embolism continues to be a clinical diagnosis and a diagnosis of exclusion based on the rapid development of a complex constellation of findings with sudden cardiovascular collapse, acute left ventricular failure with pulmonary edema, disseminated intravascular coagulation, and neurologic impairment. Given the significant morbidity and mortality associated with this condition, a high index of suspicion is warranted. Suspected risk factors have included tumultuous labor, trauma, multiparity, increased gestational age, and increased maternal age. However, many patients who develop amniotic fluid embolism have no obvious risk factors.

MANAGEMENT

Patients with amniotic fluid embolus are best managed using a multidisciplinary approach. There are no pharmacologic or other therapies that prevent or treat the amniotic fluid embolism syndrome, and supportive care typically involves aggressive treatment of multiple types of shock simultaneously. In this article we discuss the clinical presentation of amniotic fluid embolism syndrome as well as current opinions regarding pathophysiology, diagnosis, and management.

The syndrome of amniotic fluid embolism: a potential contribution of bradykinin

OBJECTIVE

Amniotic fluid embolism is a potentially fatal complication of pregnancy; although several hypotheses have been formulated, the pathophysiology of this condition is not well known. An exaggerated release of bradykinin, which is activated by products of the amniotic fluid that enter the maternal circulation, could explain the symptoms that are present in amniotic fluid embolism. The objective of this study was to assess whether bradykinin is involved in amniotic fluid embolism.

STUDY DESIGN

The plasma bradykinin-generating capacity was measured serially in a patient who experienced amniotic fluid embolism.

RESULTS

The plasma bradykinin-generating capacity was found to be very low at the time of the initial clinical manifestations, which were characterized by severe hypotension, cardiorespiratory arrest, and coagulopathy.

CONCLUSION

This study suggests a potential role for bradykinin release in the pathophysiology of amniotic fluid embolism.

Amniotic fluid embolism

Amniotic fluid embolism is a rare syndrome that can have debilitating and lethal consequences. It is a difficult and somewhat intangible diagnosis that warrants a high index of suspicion by physicians. Prompt and aggressive supportive treatment is required to lessen an otherwise dismal outcome, which may include death and permanent disability. This article provides an account of the protean clinical features, pathogenesis, and principles involved in treatment.

Amniotic fluid embolism during caesarean section

Amniotic fluid embolism occurs rarely but is a leading cause of maternal mortality. A high index of clinical suspicion is necessary to make an early diagnosis to reduce morbidity and mortality. We report a non-fatal case of amniotic fluid embolism occurring during a caesarean section, with special emphasis on the mode of development and diagnosis. The initial presentation of this syndrome was a coagulopathy, followed by the usual complications of massive bleeding. Although non-specific, the diagnosis of amniotic fluid embolism was supported by the observation of amniotic fluid in the central venous blood as well as in the broncho-alveolar fluid.

[Amniotic fluid embolism suspected in a case of seizure and mild uterine haemorrhage with activation of coagulation and fibrinolysis]

After a normal pregnancy and labour in a 29-year-old parturient, a single seizure followed by a transient headache was observed during the uterine revision for placental retention. Mild uterine haemorrhage of 150 ml per hour without any uterine atony was associated with activation of clotting and fibrinolysis (decrease of fibrinogen, elevated fibrin soluble complexes and D-dimers). A ten fold value of foetal blood cells in maternal serum suggested the diagnosis of amniotic fluid embolism. Atypical forms of amniotic fluid embolism and their diagnosis are discussed.

[Amniotic fluid embolism: successful evolution course after uterine arteries embolization]

A 28-year-old woman, G3P3, who was otherwise healthy and had taken no medication and had no known allergy, was admitted to our hospital for delivery after a normal pregnancy. An epidural catheter was inserted for analgesia and labour was induced with oxytocin. Two hours later, she suffered a sudden cardiac arrest. She was immediately treated and, since a normal cardiac rhythm and a blood pressure of 90 mmHg has been obtained 30 minutes later, a 3750 g child was delivered by caesarean section. Soon after delivery, a life-threatening uterine haemorrhage appeared, due to DIC. Evolution was favourable, after bilateral uterine arteries embolization had been performed. The diagnosis of amniotic fluid embolism was established by the clinical course, the absence of local cause and the presence of a large number of amniotic cells in the mother's peripheral blood. Tryptase blood concentration was normal in the mother's blood.

Multiple organ dysfunction syndrome (MODS) in the obstetric population

Multiple organ dysfunction syndrome (MODS) has the potential to negatively affect obstetric outcomes of critically ill maternity patients. This pathophysiologic condition may often be indistinguishable from that which occurs during normal pregnancy. The normal adaptations of pregnancy, in their exaggerated form, may cause functional change to become dysfunctional in the maternal patient. Although pregnancy is considered a state of health, MODS is a grave condition with terminal outcomes. Regional perfusion deficits in oxygen and global defects of volume are two potential pathologic sequelae. Many general medical and obstetric causes may be identified. An exaggerated systemic inflammatory response syndrome (SIRS) precedes this patterned process of death. This article will apply current theories, assessment, and treatment practices of MODS to the obstetrical populace.

Disseminated intravascular coagulation: a review of etiology, pathophysiology, diagnosis, and management: guidelines for care

The pathophysiologic mechanisms, clinical, and laboratory manifestations of DIC are complex in part due to interrelationships within the hemostasis system. Only by clearly understanding these extraordinarily complex pathophysiologic interrelationships can the clinician and laboratory scientist appreciate the divergent and wide spectrum of often confusing clinical and laboratory findings in patients with DIC. Many therapeutic decisions to be made are controversial and lack validation. Nevertheless, newer antithrombotic agents, and agents that can block, blunt, or modify cytokine activity and the activity of vasoactive substances appear to be of value. The complexity and variable degree of clinical expression suggests that therapy should be individualized depending on the nature of DIC, age, etiology of DIC, site and severity of hemorrhage or thrombosis and hemodynamics and other appropriate clinical parameters. At present, treatment of the triggering event, low-dose heparin or antithrombin concentrate and wise choice of components when indicated appear to be the most effective modes of therapy.

Amniotic fluid embolus: a review of the research literature

The diagnosis of Amniotic Fluid Embolus (AFE) is often missed clinically leading to the incorrect attribution of a major post-partum haemorrhage, which may accompany AFE, to uterine atony. This paper reviews the research on AFE with particular emphasis on the clinical presentation and diagnosis; both before and after death. It begins by dealing with the difficulty of defining AFE due to confusion about the underlying pathophysiological events. As this paper will demonstrate, the theory that AFE is an embolic event is no longer valid. A description of the clinical manifestations is provided so that these can be explained by the contemporary theory of AFE as an 'anaphylactoid' reaction. Finally, the difficulties of diagnosis, particularly laboratory diagnosis, will be discussed. The research indicates that it is not possible to accurately diagnose AFE, either, pre or post mortem, by any currently available laboratory tests. Because of better diagnosis it is now known that AFE in not uncommon and, if it is diagnosed early, a much higher rate of intact survival can be achieved than was previously thought possible.

Radiological-pathological correlation: alveolar pattern

This review summarizes important pathological lesions of the lung that typically present radiographically with an 'alveolar pattern'. For each entity, the latest findings as to its pathogenesis, aetiology and pathology are reviewed in the introductory remarks. We then present the typical radiological appearances alongside macroscopic and microscopic pathological photographs. It is hoped that the parallel presentation of radiological image with the pathology will enhance the understanding of the diverse range of diseases the aevolar pattern comprises.

Syndromes of disseminated intravascular coagulation in obstetrics, pregnancy, and gynecology. Objective criteria for diagnosis and management

This article presents current understanding of the causes, pathophysiology, clinical, and laboratory diagnosis, and management of fulminant and low-grade DIC, as they apply to obstetric, pregnant, and gynecologic patients. General medical complications leading to DIC, which may often be seen in these patients, are also discussed. Considerable attention has been given to interrelationships within the hemostasis system. Only by clearly understanding these pathophysiologic interrelationships can the obstetrician/gynecologist appreciate the divergent and wide spectrum of often confusing clinical and laboratory findings in patients with DIC. Objective clinical and laboratory criteria for diagnosis of DIC have been outlined to eliminate unnecessary confusion and the need to make empiric decisions regarding the diagnosis. Particularly in the obstetric patient, if a condition is observed that is associated with DIC, or if any suspicion of DIC arises from either clinical or laboratory findings, it is imperative to monitor the patient carefully with clinical and laboratory tools to assess any progression to a catastrophic event. In most instances of DIC in obstetric patients, the disease can be ameliorated easily at early stages. Many therapeutic decisions are straightforward, particularly in obstetric and gynecologic patients. For more serious and complicated cases of DIC in these patients, however, efficacy and choices of therapy will remain unclear until more information is published regarding response rates and survival patterns. Also, therapy must be highly individualized according to the nature of DIC, patient's age, origin of DIC, site and severity of hemorrhage or thrombosis, and hemodynamic and other clinical parameters. Finally, many syndromes that are often categorized as organ-specific disorders and are sometimes identified as independent disease entities, such as AFE syndrome, HELLP syndrome, adult shock lung syndrome, eclampsia, and many others, either share common pathophysiology with DIC or are simply a form of DIC. These entities represent the varied modes of clinical expression of DIC and illustrate the diverse clinical and anatomic manifestations of this syndrome.