HELLP syndrome
HELLP syndrome | |
---|---|
hemolytic uremic syndrome[2] | |
Treatment | Delivery of the baby as soon as possible, management of blood pressure[1][2] |
Prognosis | <1% risk of death (mother); 7.3% to 11.9% risk of death (child)[3] |
Frequency | ~0.7% of pregnancies[2] |
HELLP syndrome is a
The cause is unknown.[1] The condition occurs in association with pre-eclampsia or eclampsia.[1] Other risk factors include previously having the syndrome and a mother older than 25 years.[1] The underlying mechanism may involve abnormal placental development.[4] Diagnosis is generally based on blood tests finding signs of red blood cell breakdown (lactate dehydrogenase greater than 600 U/L), an aspartate transaminase greater than 70 U/L, and platelets less than 100×109/l.[2] If not all the criteria are present, the condition is incomplete.[2]
Treatment generally involves delivery of the baby as soon as possible.[1] This is particularly true if the pregnancy is beyond 34 weeks of gestation.[2] Medications may be used to decrease blood pressure and blood transfusions may be required.[1]
HELLP syndrome occurs in about 0.7% of pregnancies and affects about 15% of women with eclampsia or severe pre-eclampsia.
Signs and symptoms
The first signs of HELLP usually start appearing midway through the
HELLP syndrome patients experience general discomfort followed by severe
Risk factors
Elevated
The risk of HELLP syndrome is not conclusively associated with a specific genetic variation, but likely a combination of genetic variations, such as
Pathophysiology
The pathophysiology is still unclear and an exact cause is yet to be found. However, it shares a common mechanism, which is
Inflammation and coagulation
As a result of endothelial cell injury, a cascade of pathological reactions manifests and become increasingly severe and even fatal as signs and symptoms progress. Following endothelial injury, vasospasms and platelet activation occur alongside the decreased release of the
Low platelet count
vWF degradation in HELLP syndrome is inhibited due to decreased levels of degrading proteins, leading to an increased exposure of
Blood breakdown
As a result of the high number of angiopathies, the
Liver
During the coagulation cascade, fibrin is deposited in the liver and leads to hepatic sinusoidal obstruction and
Diagnosis
Early and accurate diagnosis, which relies on laboratory tests and imaging exams, is essential for treatment and management and significantly reduces the morbidity rate. However, diagnosis of the syndrome is challenging, especially due to the variability in the signs and symptoms and the lack of consensus amongst healthcare professionals. Similarities to other conditions, as well as normal pregnancy features, commonly lead to misdiagnosed cases or more often, delayed diagnosis.[6][25]
There is a general consensus regarding the main three diagnostic criteria of HELLP syndrome, which include
- A helmet cells, which indicate erythrocyte damage. [citation needed]
- Thrombocytopenia, which is the earliest antithrombin III.[citation needed]
- Elevated serum levels of certain proteins, in particular, LDH, alanine transaminase (ALT) and aspartate transaminase (AST), are indicative of hepatic dysfunction. Extremely high serum levels of these proteins, specifically LDH levels > 1,400 IU/L, AST levels > 150 IU/L and ALT levels > 100 IU/L, significantly elevate the risk of maternal mortality.[31][2][8][9][23][32][34][35][36][37][excessive citations]
A number of other, but less conclusive, clinical diagnostic criteria are also used in diagnosis alongside the main clinical diagnostic criteria for HELLP syndrome.
- De novo manifestation of hypertension with diastolicpressure above 160mmHg and 110 mmHg, respectively.
- leucocytosis and elevated uric acidconcentrations > 7.8 mg.
- Decreased serum haptoglobin and haemoglobin levels.
- Increased serum bilirubin levels and visual disturbances.[38][39]
Imaging tests, such as
Classification
A classification system, which was developed in Mississippi, measures the severity of the syndrome using the lowest observed platelet count in the patients alongside the appearance of the other two main clinical criteria. Class I is the most severe, with a relatively high risk of morbidity and mortality, compared to the other two classes.[41]
- Class I HELLP syndrome is characterised by a platelet count below 50,000/µL.
- Class II HELLP syndrome is characterised by a platelet count of 50,000-100,000/µL.
- Class III HELLP syndrome is characterised by a platelet count of 100,000-150,000/µL.
Another classification system, introduced in Memphis, categorises HELLP syndrome based on its expression.
- Partial expression of the condition is characterised by the manifestation of one or two of the main diagnostic criteria.
- The complete expression of the condition is characterised by the manifestation of all three main diagnostic criteria.[42]
Treatment
The only current recommended and most effective treatment is delivery of the baby, as the signs and symptoms diminish and gradually disappear following the delivery of the
Prognosis
With treatment, maternal mortality is about 1 percent, although complications such as placental abruption, acute kidney injury, subcapsular liver hematoma, permanent liver damage, and retinal detachment occur in about 25% of women. Perinatal mortality (stillbirths plus death in infancy) is between 73 and 119 per 1000 babies of woman with HELLP, while up to 40% are small for gestational age.[47] In general, however, factors such as gestational age are more important than the severity of HELLP in determining the outcome in the baby.[48]
Epidemiology
HELLP syndrome affects 10-20% of pre-eclampsia patients and is a complication in 0.5-0.9% of all pregnancies.[6][49] Caucasian women over 25 years of age comprise most of the diagnosed HELLP syndrome cases.[50] In 70% of cases before childbirth, the condition manifests in the third trimester, but 10% and 20% of the cases exhibit symptoms before and after the third trimester, respectively. Postpartum occurrences are also observed in 30% of all HELLP syndrome cases.[51]
History
HELLP syndrome was identified as a distinct clinical entity (as opposed to severe pre-eclampsia) by Dr. Louis Weinstein in 1982.[31] In a 2005 article, Weinstein wrote that the unexplained postpartum death of a woman who had haemolysis, abnormal liver function, thrombocytopenia, and hypoglycemia motivated him to review the medical literature and to compile information on similar women.[10] He noted that cases with features of HELLP had been reported as early as 1954.[10][52]
See also
References
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