Acute renal failure and pregnancy

Acute renal failure and pregnancyEpidemiology:

The frequency of acute renal failure (ARI) in pregnancy is very different in developed and developing countries. Prevalence and prognosis data can not be interpreted without taking into account the geographic context in which they were obtained.

The IRA has become, in France, an exceptional complication of pregnancy. Its incidence has declined significantly in developed countries since the legalization of abortion. Thus, before the legalization of abortion in France, the prevalence of ARI was estimated at 1/3 000 births, most of the gestational kidney failure being attributable to the septic complications of clandestine abortions in the first trimester of pregnancy. Since its legalization (1975), this prevalence is estimated at 1/20 000. In recent years, gestational ARIs occur mainly in the 3 rd trimester in a context most often of severe preeclampsia. These changes explain that gestational ARIs represent only a tiny percentage of ARI in adults (less than 1.5% in the years 1990-2000, versus 20-50% in the years 1950-1970).

The lower incidence of gestational IRA is even stronger when a strong policy to facilitate pregnancy monitoring has been put in place. The implementation of a strict and mandatory monitoring of pregnancy makes it possible to target parturients who are at high risk of fetal or maternal complications and to optimize their care.

The incidence of gestational ARI and its main etiologies therefore remain closely linked to the health policies and facilities of each state.

Acute renal failure of the first trimester of pregnancy:

FUNCTIONAL ACUTE RENAL FAILURE ASSOCIATED WITH GRAVID VOMITINGS:

Uncontrollable vomiting in the first trimester complicates approximately 0.3% of pregnancies before the 12th week of amenorrhea (AS). They can sometimes by their duration, their intensity and the associated digestive intolerance, be accompanied by an important extracellular dehydration. This plasma hypovolemia is responsible for renal hypoperfusion (a decrease in renal blood flow), which is responsible for a decrease in the glomerular filtration rate that defines functional renal insufficiency (also known as prerenal insufficiency).

Positive diagnosis:

The diagnosis is generally mentioned at the beginning of the first trimester in a young patient ( < 20 years old) primiparous, presenting for several days incoercible vomiting.

Biological examinations (blood and urine ionograms) quickly confirm the diagnosis.

The blood and urinary ionograms show:

– hemoconcentration: elevated protein and hematocrit;

– a metabolic alkalosis (loss of HCl + contraction alkalosis): generally major increase in plasma bicarbonate [HCO 3 – ] > 30 mmol / l);

– hypokalemia often major [K + ] < 3mmo ll -1 );

– a normal or low natremia (if ingestion of water remains possible);

A low natriuresis [Na + ] u < 20 mmol l -1 ;

A urinary excreted fraction of Na + FE · Na + < 1%;

– concentrated urine: [urea] u [urea] p > 10, [creatinine] u / [creatinine] u > 40, without proteinuria, without hematuria on the urine test strip. Fasting ketonuria is possible without glycosuria or hyperglycemia.

Slight hepatic cytolysis ( < 5-10 N) and increased bilirubin can be observed (20% of cases).

Therapeutic strategy:

In the case of renal failure, symptomatic treatment includes parenteral rehydration in a hospital setting.

The volume expansion by crystalloids (physiological saline NaCl 0.9%) makes it possible to correct the sodium depletion as well as the metabolic alkalosis. The potassium deficit must systematically be compensated. The exceptional and transient use of dialysis may be necessary in case of acute tubular necrosis secondary to intense and / or prolonged dehydration.

The symptomatic treatment of vomiting will use antiemetics (metoclopramide or doxylamine) or, in uncontrollable forms, chlorpromazine or promethazine.

Prognosis:

In case of early treatment, renal function recovers ad integrum.

ACUTE RENAL FAILURE IN A SEPTIC CONTEXT: SEPTICAL ABORTION

Clandestine abortions under aseptic conditions can be complicated by uterine infection, uterine perforation and septic shock.

Positive diagnosis:

The diagnosis should be considered in principle in a woman of childbearing age in a context of gynecological sepsis.Pregnancy is not always declared, especially since the delivery was “clandestine”. The clinical examination makes it possible to direct the diagnosis in front of vulvar wounds, metrorrhagia, leucorrhea and vaginal pains. An abdominal contracture makes one fear a uterine perforation or a pelviperitonitis.

The clinical examination and the complementary examinations look for signs of multi-organ failure: pulmonary edema lesions (polypnea, hypoxia, hypocapnia), cytolytic hepatitis, disseminated intravascular coagulation (prothrombin [TP] level, low fibrinogen, partial thromboplastin time [ TCK] extended, fibrin degradation product [PDF] (+), D-dimer [DD] (+), thrombocytopenia), renal failure.

Therapeutic strategy and nephrological prognosis:

The treatment will be symptomatic and specific:

– specific: systematic early antibiotic therapy (ampicillin

– clavulanic acid + aminoside + metronidazole) associated with exploratory laparotomy in case of peritonitis or suspicion of uterine perforation;

– symptomatic: haemodynamic substitution and other visceral failures.

Prognosis :

Life-threatening may be compromised in case of multi-organ failure (maternal death rate of 15%).

If the acute course is over, the risk of chronic renal failure due to cortical necrosis remains significant (8%). The diagnosis is suspected in case of absence of diuresis and persistent renal insufficiency after 3 weeks of effective symptomatic management. Magnetic resonance angio-imaging (MRI) can establish the diagnosis by showing the absence of total or partial cortical vascularization. In the absence of angio-MRI or CT angiography, conventional arteriography confirms the diagnosis by showing a bilateral dead tree appearance. Recovery is possible in cases of partial necrosis, often at the cost of hypertension and subsequent renal failure. Most patients unfortunately remain on chronic dialysis.

Acute renal failure of the third trimester of pregnancy:

ACUTE RENAL FAILURE IN A PRECLAMPSY CONTEXT:

Kidney failure is a rare complication of preeclampsia.

Preeclampsia is characterized by activation of the endothelial cells responsible for activation of platelet aggregation (small arteriole thrombosis, thrombocytopenia), haemolysis, capillary leak syndrome in the capillaries and arterioles. (interstitial edema, even pulmonary edema lesion) and vasoconstriction aggravating tissue ischemia (HTA and placental hypoperfusion). Capillary leak syndrome and vasoconstriction result in plasma hypovolemia responsible for functional worsening of organic nephropathy. Renal organ failure is characterized by glomerular endotheliosis (glomerular flocculus endothelial cell turgor) inconsistently associated with sub-endothelial immunoglobulin M (IgM) and complement C3 fractions. These two elementary lesions cause a decrease in the glomerular capillary lumen.Functionally, these lesions are associated with variable-rate proteinuria, more rarely renal failure.

Positive diagnosis:

The prevalence of ARF in severe preeclampsia is estimated to be 0.8-7.4%, or between 8-31% for HELLP syndrome (hemolysis, elevated liver enzyme, low platelet). HELLP syndrome, in its complete form, complicates 25% of severe preeclampsia.

The diagnosis is discussed after 21 weeks in a parturient with recently discovered hypertension (HTA) associated with de novo proteinuria. In this context, renal insufficiency of variable severity is associated with a proteinuria generally high flow (nephrotic syndrome), a water often marked sodium hypostasis (edema, ascites, pleural effusion) usually without hematuria.

Kidney failure is often part of a multi-organism attack:

Hepatic impairment (50% of cases) may occur, the expression of which may be upper gastric pain associated with hepatic cytolysis, rarely jaundice. More unusually, liver damage may be complicated by hematoma or liver rupture.

Haematological involvement is characterized by “mechanical” haemolysis (increased lactodehydrogenase (LDH) and conjugated bilirubin, decreased haptoglobin, presence of schizocytes) and thrombocytopenia. In cases of renal failure, biological stigmata of disseminated intravascular coagulation (DIC) are often observed (84%).

The combination of hemolysis, hepatic cytolysis and thrombocytopenia defines the HELLP syndrome (33-50%).

Neurological involvement (47%) is very diverse: unusual headaches, behavioral disturbances, convulsions (defining eclampsia), focal deficits, cortical blindness.

A retroplacental hematoma (32-40%) is often associated in this case with a CIVD.

Treatment:

The therapeutic strategy is guided by the severity of the maternal picture (single or multiple visceral failure), the presence or absence of a retroplacental hematoma, the existence or not of fetal distress and the term of pregnancy.

Rapid termination of pregnancy:

The rapid termination of pregnancy is immediately necessary:

– for fetal reasons: in case of acute fetal distress when the term is greater than 24-26 weeks;

– for maternal reasons: in case of eclampsia, hematoma or liver rupture, respiratory distress, retroplacental hematoma.

The modalities of termination of pregnancy will be discussed below.

Programmed interruption of pregnancy:

If the term is greater than 34 weeks, it is inappropriate to continue the pregnancy given maternofoetal risks incurred.The work is triggered vaginally unless contraindicated. During work, maternal complications and fetal viability are regularly assessed. Thorough maternal surveillance is maintained for at least 48 hours postpartum due to possible worsening of visceral involvement with preeclampsia during this period.

Temporize under strict maternal-fetal control:

This attitude is conceivable only when the health facility taking care of the pregnant woman has means of continuous clinical and biological surveillance of the mother, and that she has the possibility of performing a fetal monitoring at least twice a day and has within her a neonatal resuscitation unit (in France, a level III maternity facility which also has adult resuscitation). Without these conditions, it seems dangerous and illicit to propose a wait-and-see attitude given the risk of vital maternal or fetal complications that may occur at any time.

The aim of this wait-and-see attitude discussed between 26-32 AS is to obtain a fetal maturation, especially of the lungs. In practice, the goal is to delay delivery until the end of 32 weeks to limit the short and long-term complications of diseases related to prematurity: hyaline membrane disease, cerebral hemorrhages, etc.

The available therapeutic means and objectives to be achieved in the patient with preeclampsia and renal failure are as follows.

– Optimize plasma volemia.

These patients all have plasma hypovolemia and, to a varying degree, capillary leak syndrome. Careful volume expansion (crystalloid or human albumin) is undertaken under strict control of pulmonary tolerance (respiratory rate, pulse oximetry, and regular pulmonary auscultation). Some authors propose to carry out this expansion under control of the measurements obtained by right catheterization: the filling being modulated according to the pulmonary capillary pressure (objectives Pcap 10-15 cmH 2 O). The main risk is pulmonary edema and / or massive pleural effusion resulting in hypoxia potentially deleterious to the fetus. In case of hypoxia, stopping volume expansion, oxygen therapy, and non-invasive ventilation usually helps to overcome the problem.

– Control of blood pressure.

Blood pressure (BP) should be lowered if diastolic blood pressure (DBP) exceeds 110 mmHg (target: DBP 100-110 mmHg), but should be gradual and moderate. Any abrupt and / or excessive decrease in AP would lead to an aggravation of placental ischemia, the most dramatic expression of which would be in utero death. Labetalol is the oldest product used and its long-term safety has been established in the fetus.

However, this product is increasingly replaced by nicardipine, which is also attributed a tocolytic action.

– Corticotherapy.

Given the risk of premature delivery, a short course of corticosteroids is administered for 24 to 48 hours to accelerate fetal lung maturation, reduce neonatal mortality, and the risk of neonatal respiratory distress and intraventricular hemorrhage of the new -born. Betamethasone is usually given in two 12 mg injections intramuscularly at 12 hour intervals. Based on case series or retrospective castemoin studies, several teams note a benefit of corticosteroids in terms of control of maternal symptomatology: stabilization or correction of thrombocytopenia and hepatic cytolysis.However, no studies have shown a benefit to the fetus or to the prolongation of the gestation period.

– Magnesium sulfate.

In Anglo-Saxon countries and on the basis of recent prospective studies confirming the appropriateness of these practices, intravenous magnesium sulphate (loading dose 2-4 g, maintenance 1-3 mg h -1 ) allows reduce the risk of seizures and possibly delay the delivery date. Its use in combination with calcium channel blockers is not recommended due to an increased risk of complications related to magnesium sulfate (hypoventilation alveolar). Her interest in the parturient with renal insufficiency is not demonstrated. In addition, the use of magnesium sulphate should be avoided in cases of severe renal impairment, given an increased risk of overdose (alveolar hypoventilation).

– Correction of hemostasis disorders.

Platelet transfusions are only considered in case of bleeding or caesarean section if the platelet count is less than 30 000 ml -1.42 In cases of CIVD associated with haemorrhage of delivery (retroplacental hematoma), it may be necessary to transfuse, in addition to globular pellets, fibrinogen and antithrombin III pellets.

– Triggering the delivery.

Under strict fetal and maternal control, in cases of acute fetal distress (SFA), uncontrollable hydrosodeal inflation (pulmonary edema, pleural effusion), respiratory distress, oligoanuric IRA, increased thrombocytopenia ( < 50,000 / Ml ), hepatic cytolysis or hepatic hematoma, or aggravation of the neurological state, it is necessary, without state of mind, to trigger the delivery, whatever the term.

This therapeutic strategy, which is cumbersome in terms of surveillance, makes it possible to delay the delivery date by an average of 7 to 10 days, the benefit of which is to reduce the risk of neonatal respiratory distress and intraventricular haemorrhage of the newborn. Delivery occurs in more than 50% of cases by caesarean section for fetal reasons (term < 32, SFA) or more rarely for maternal reasons (hepatic hematoma, convulsions, respiratory distress). This strategy allows to obtain a term at birth of 30-32 SA.

Indications of dialysis:

The use of dialysis is considered in cases of persistent renal failure oligoanuric or life threatening hydroelectrolytic disorders after fetal extraction. Less than 10% of patients require treatment in extrarenal treatment.

Indications of renal biopsy:

If renal failure fits into a clear nosological setting of severe preeclampsia, renal biopsy can not be justified to confirm the diagnosis. On the other hand, in case of diagnostic doubt with other nosological entities, the interest of such an examination must be discussed in consultation with the nephrologist.

If kidney failure persists beyond 3 weeks, cortical necrosis is feared. The diagnosis can be confirmed by an angio-MRI or, failing that, by arteriography.

Prognosis:

Maternal Prognosis:

– Vital prognosis.

The deaths are fortunately exceptional (0-13%). Pejorative factors are association IRA, CIVD, retroplacental hematoma (HRP), intrahepatic hematoma broken regardless of term.

Usually, in a few days, postpartum, visceral failures fade. However, vital complications secondary to preeclampsia remain the second leading cause of direct obstetric mortality in France. Recidivism during subsequent pregnancies is not the rule.

– Renal prognosis.

In most cases, renal function is recovered ad integrum (97-100%), although extrarenal clearance was initially necessary (0-31% of patients required dialysis).

More rarely ( < 1%), especially with retroplacental hematoma and / or DIC, chronic renal failure may persist. It is sometimes severe enough to warrant continued dialysis. In most of these cases, morphological investigations (arteriography, angio-MRI, angioscan) or histological investigations then show cortical necrosis. In cases of severe nephrotic syndrome, segmental and focal hyalinosis has been described in addition to glomerular preeclampsia lesions. In these cases, the nephrological prognosis is generally favorable: the proteinuria disappears in a few weeks or months without recurrence in subsequent pregnancies.

Fetal prognosis:

15 to 38% of ARI-associated preeclampsia are complicated by perinatal death. especially in cases of CIVD and associated retroplacental hematoma, versus 5% in cases of simple severe preeclampsia with or without HELLP syndrome. The fetal prognosis is primarily related to the term at the time of delivery; it is all the more pejorative because the term is early and the IUGR important. A child born to a mother with kidney failure has a birth and creatinine level comparable to that of her mother. These metabolic disorders in a child with normal renal function may lead, in the first days of life, osmotic polyuria.

“Reasonable” care must achieve zero maternal mortality and perinatal mortality not exceeding 15-20%.

Differential diagnoses:

In practice, the diagnosis of ARI associated with severe preeclampsia is hardly a problem and, in the event of an ARI above 21 AS, the course is rapidly favorable postpartum in 2-7 days. .

However, in the case of an earlier onset ( < 21 weeks of age), when haemolytic anemia and thrombocytopenia persist, or clinical worsening beyond 1 week postpartum, a microangiopathy independent of preeclampsia ( uremic and hemolytic syndrome). In these forms, a thorough etiological investigation must be conducted in search of an infectious pathology (invasive diarrhea, Escherichia coli, Shigella, Campylobacter, Salmonella), a dysimmunitary pathology (including primary antiphospholipid syndrome), a medical cause, etc.

Therapeutic management including plasma exchange and transfusion of fresh frozen plasma can be discussed in addition to symptomatic treatment (strict control of PA, extrarenal treatment, etc.).

GRAVID ACUTE STÉATOSE:

If hepatic failure dominates the picture, the diagnosis is that of acute hepatic steatosis gravidarum (SHAG).

Positive diagnosis:

With an ARF appearing in the third trimester, the diagnosis of acute PID is evoked in the presence of abdominal pain, vomiting, jaundice, moderate hypertension and polyuropolydypsin syndrome.

Biological examinations show an increase in free bilirubin, an often moderate cytolysis ( < 10 N), hepatic insufficiency (lower prothrombin rate, hypoglycemia, etc.), a decrease in fibrinogen and biological stigmata of CIVD. The presence of a “brilliant” liver in ultrasound is, in this context, suggestive of the diagnosis of SHAG.

The importance of hepatic insufficiency, the discretion of cytolysis and the presence of a glossy liver on ultrasound enable the diagnosis of acute PID to be made and the diagnosis of HELLP syndrome to be ruled out.

Therapeutic strategy:

The termination of pregnancy can interrupt the pathological process.

However, in case of a term of less than 32 weeks, in the absence of SFA, in the absence of signs of severity (absence of hepatic insufficiency, encephalopathy, severe ARI, DIC) and within the framework of strict maternofoetal surveillance (maternity level III in France) a wait-and-see attitude can be proposed. This delay is used to administer corticosteroids to accelerate fetal lung maturity. This attitude will have to be questioned quickly in case of maternal aggravation (encephalopathy, Tp < 50%) or SFA.

Maternal Prognosis:

Currently, under conditions of diagnosis and early management, maternal mortality is less than 10%.

Nephrological prognosis:

The use of renal cleansing is rarely necessary. When extrarenal clearance is required, following fetal extraction, continuous hemofiltration or continuous venous hemodiafiltration is preferred over sequential hemodialysis. In case of hepatic encephalopathy, it avoids the sudden changes in intracranial pressure causing some deaths.

Renal function usually recovers ad integrum away from the acute episode.

ACUTE OBSTRUCTIVE RENAL FAILURE:

The obstruction of the urinary tract by the uterine gravidarum remains an exceptional cause of renal failure. This elimination diagnosis is confirmed a posteriori by the rapid normalization of renal function after uterine evacuation.

Positive diagnosis:

The diagnosis is generally evoked in front of an ARI appearing at the approach of the term in a parturient having a hitherto uncomplicated pregnancy. Hydramnios and twin pregnancy could be considered as aggravating factors through mechanical compression of the ureters. On ultrasound, pelvises and ureters appear dilated upstream of the sacred promontory, without this image being considered pathognomonic.

Therapeutic strategy and nephrological prognosis:

Childbirth allows a normalization of renal function in a few days usually without sequelae, allowing retrospective confirmation of the diagnosis.

Acute renal failure: other etiologies

ACUTE GLOMERULONEPHRTH / SYSTEM DISEASES:

The occurrence of rapidly progressive renal failure associated with variable flow proteinuria and hematuria should be discussed with glomerulonephritis. This diagnosis is exceptionally discussed in the third quarter, given the much higher incidence of preeclampsia-related kidney disease. However, an atypical clinicobiological presentation in the 3 rd trimester, the presence of extranephrological signs, or their early onset ( < 21 AS) must give rise to a multidisciplinary analysis (obstetrician, nephrologist, internist) in order to quickly orient the diagnostic procedure. A kidney biopsy must sometimes be performed to affirm with certainty the diagnosis of nephropathy and to define the best therapeutic management. Its realization is discussed during pregnancy only before 32 SA.

SYSTEMIC DISEASES:

Pregnancy may be accompanied by a lupus flare-up in women with a disease that could not be controlled before the onset of pregnancy. Renal attacks occur more readily in the 3 rd trimester or postpartum.

More rarely, the diagnosis of lupus can be made during pregnancy in acute renal failure of glomerular profile: rapidly progressive renal failure, variable flow proteinuria, hematuria associated with normal or low BP. The association of extranephrological signs directs the diagnosis: polyarthritis, Raynaud’s syndrome, vespertilio, etc.

The search for antinuclear antibodies and deoxyribonucleic acid antacid (DNA) antibodies, the fall of the complement help to guide the biological diagnosis. Renal biopsy is discussed before 32 weeks in order to better define the therapeutic strategy (possible immunosuppressive treatment).

An ARI during pregnancy may also be indicative of other systemic diseases: microscopic polyangiitis, Wegener granulomatosis, polyarteritis nodosa, rheumatoid purpura, etc.).

ACUTE RENAL FAILURE ASSOCIATED WITH THERAPEUTIC USE IN PREGNANCY: INDOMETACIN:

Exceptionally indomethacin used formerly during the threats of preterm delivery could be complicated by IRA as in non-pregnant adults.

ACUTE RENAL FAILURE / PYELONEPHRY:

Pyelonephritis exceptionally complicate IRA during pregnancy, except in case of late diagnosis. Outside the context of septic shock, an adverse change in renal function in 24-72 hours, despite the correction of hydroelectrolytic disorders and appropriate antibiotic therapy may lead to propose the rise of probe in double J. Indeed, an obstructive uropathy does not may not always be formally eliminated, given the physiological dilatation of pyelocalical cavities and ureters during pregnancy.

RENAL FAILURE / ADDICTION:

As with any adult addict, cocaine used during pregnancy can lead to an ARI.

How to give birth / anesthesia:

INDICATIONS OF LOW-BED DELIVERY:

In the case of a term greater than 32 weeks, in the absence of SFA, retroplacental hematoma or “major” maternal visceral failure, vaginal delivery is preferred.

INDICATIONS OF THE CAESAREAN:

Caesarean section is indicated for SFA, retroplacental hematoma and, for many teams, in case of a term of less than 32 weeks.

Renal failure, eclampsia, thrombocytopenia and hepatic cytolysis are not, in themselves, situations requiring caesarean section.

MODALITIES OF ANESTHESIA: LOCAL OR REGIONAL ANESTHESIA?

Epidural anesthesia (APD) is the anesthesia of choice in case of preeclampsia including cesarean section. It offers many maternal advantages: a stable analgesia makes it possible to avoid the hemodynamic jolts linked to the nociceptive and fetal stimulations, by improving the uteroplacental blood flow. The main contraindication to APD remains hemostasis disorders. Despite the low incidence of peri-medullary hematoma, Ivy bleeding time is required when the platelet count is less than 120,000 / mm 3 , as thrombocytopenia is often associated with platelet dysfunction. APD can be performed when bleeding time, prothrombin time, activated partial thromboplastin time and fibrinogen are normal on a check-up taken less than 2 hours before the puncture.

General anesthesia has many drawbacks especially at the time of anesthetic induction: hypertensive outbreaks responsible for left ventricular failure with pulmonary edema and / or cerebral hemorrhage. The anesthetic induction must be preceded by the ingestion of an antacid and a volume expansion (500 ml of crystalloid). The use of morphinomimetics is strongly recommended (alfentanyl 8 to 10 μg kg -1 ). The treatment of hypertensive relapses uses fast-acting and short-acting antihypertensives (nicardipine and labetalol).

Conclusion:

The IRA must remain an exceptional complication of pregnancy.

The legalization of abortion helps to avoid ARI related to septic complications of illegal abortions. Early management of intractable vomiting in the first trimester should avoid their metabolic complications. In the 3 rd quarter, early detection of women with severe pre-eclampsia must allow rapid and appropriate management of signs of fetal and maternal suffering.

Finally, women with gestational renal failure should be treated in centers where obstetrical, pediatric, nephrological and resuscitation skills are available.

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Editor-in-chief of the Medical Actu website; general practitioner graduated from the Faculty of Medicine of Algiers in 2005 currently practicing as a liberal.

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