Acute fatty liver of pregnancy

　　The etiology of acute fatty liver of pregnancy (AFLP) is unknown. Since AFLP occurs in the late stages of pregnancy and only termination of pregnancy offers a hope for recovery, it is speculated that the etiology may be hormonal changes induced by pregnancy, which disrupt fatty acid metabolism, leading to the accumulation of free fatty acids in liver cells and other organs such as the kidneys, pancreas, and brain, causing multi-organ damage. In recent years, there have been reports of recurrent cases and genetic defects in offspring, so some suggest that it may be an inherited genetic disease. In addition, the damaging effects of multiple factors such as viral infection, intoxication, drugs (such as tetracycline), malnutrition, and hypertensive diseases in pregnancy on mitochondrial fatty acid oxidation may also be related.

　　Acute fatty liver of pregnancy often leads to stillbirth, fetal death, preterm birth, and postpartum hemorrhage. A few patients may also develop pancreatitis and hypoproteinemia. Initially, the symptoms may include nausea, vomiting, headache, and fatigue, often accompanied by preeclampsia. The condition may suddenly worsen 1-2 weeks after the onset, with symptoms such as jaundice, liver failure, oliguria, renal damage, and may also include hypoglycemia and coagulation dysfunction. Progressive damage to liver and renal function, accompanied by persistent severe hypoglycemia and negative uric acid, are significant characteristics.

　　The early onset of acute fatty liver of pregnancy is characterized by persistent nausea, vomiting, fatigue, upper abdominal pain or headache, with jaundice appearing within a few days to one week and progressively deepening, usually without itching. Abdominal pain may be limited to the upper right quadrant, or it may be diffuse, often accompanied by hypertension, proteinuria, edema, and in a few cases, transient polyuria and thirst. If delivery does not occur and the condition continues to progress, complications such as coagulation dysfunction (skin petechiae, ecchymosis, gastrointestinal bleeding, gingival bleeding, etc.), hypoglycemia, altered consciousness, psychiatric symptoms, and hepatic encephalopathy, oliguria, anuria, and renal failure may occur, leading to death within a short period of time.

　　Fatty liver that occurs during pregnancy includes fatty liver caused by pregnancy vomiting and acute fatty liver caused by late pregnancy. The former occurs after pregnant women have severe and prolonged vomiting, and there may be manifestations of malnutrition due to insufficient dietary intake. The liver injury can disappear after supplementing sufficient calories and nutrients. With the relief and control of pregnancy vomiting, liver function damage and fatty liver can be completely restored. Once the disease is diagnosed, an elective cesarean section should be performed as soon as possible to terminate pregnancy. Acute fatty liver can usually recover quickly, thus preserving the lives of both mother and child. Natural childbirth and induction of labor will only worsen the condition, so there are no benefits and only drawbacks. Preventing respiratory tract infections and avoiding the use of tetracycline may help reduce the incidence of acute fatty liver of pregnancy.

　　Acute fatty liver of pregnancy (AFLP) is a rare and fatal disease unique to the late pregnancy period, and the following examination methods are needed for diagnosis:

　　1. Blood routine:Peripheral blood white blood cell count is elevated, up to (15.0～30.0)×109/L, with toxic granules, and erythrocytes and alkaline granule erythrocytes can be seen; platelet count is reduced, and macrothrombocytes can be seen in peripheral blood smears.

　　2. Serum:Total bilirubin is moderately or severely elevated, mainly direct bilirubin, generally not exceeding 200μmol/L; blood transaminase is slightly or moderately elevated, ALT does not exceed 300U/L, and there is an enzyme-bilirubin separation phenomenon; serum alkaline phosphatase is significantly elevated; serum albumin is low, and β-lipoprotein is elevated.

　　3. Blood glucose:It can drop to 1/3 to 1/2 of the normal value, which is a significant feature of AFLP; blood ammonia increases, and when liver encephalopathy occurs, it can reach 10 times the normal value.

　　4. Thrombin:Prothrombin time and partial thromboplastin time are prolonged, and fibrinogen is reduced.

　　5. Blood uric acid:Creatinine and blood urea nitrogen are elevated, especially the degree of increase in uric acid is not proportional to renal function. Sometimes hyperuricemia may exist before the clinical onset of AFLP.

　　6. Urobilin:Urobilinogen positive, urobilinogen negative, and urobilinogen negative are one of the important diagnoses, but positive urobilinogen does not exclude AFLP.

　　7. Imaging examination:B-ultrasound shows diffuse high-density areas in the liver area, with uneven echo intensity, showing a snowflake-like pattern, with typical fatty liver waveforms. CT and MRI examinations can show excessive fat in the liver, and the liver parenchyma shows uniform and consistent density reduction.

　　8. Pathological examination:Pathological examination is very helpful for the diagnosis of AFLP, and liver biopsy can be performed under B-ultrasound localization.

　　For patients with acute fatty liver of pregnancy, the following dietary principles should be remembered:

　　1. High-protein diet: 1.2 to 1.5 grams per kilogram of body weight can be provided daily, high protein can protect liver cells, and can promote the repair and regeneration of liver cells. High-quality protein should account for an appropriate proportion, such as tofu, bean curd sticks, and other soy products, as well as lean meat, fish, shrimp, and skimmed milk, etc.

　　2. Ensure the supply of fresh vegetables, especially green leafy vegetables, to meet the body's need for vitamins. However, vegetables and fruits high in sugar should not be consumed in large quantities.

　　3. Eat more foods rich in methionine, such as millet, foxtail millet flour, sesame,油菜, spinach, cauliflower, beetroot, dried shrimp, dried scallops, and light meat, which can promote the synthesis of phospholipids in the body and assist in the transformation of fat in liver cells.

　　Acute fatty liver of pregnancy is an acute onset disease with rapid changes in condition, so it is necessary to pay attention to seeking medical treatment in a timely manner. The following is an introduction to the conventional treatment methods for this disease:

　　1. General Treatment

　　Patients should rest in bed, consume a diet low in fat and protein, and high in carbohydrates, ensure sufficient calories, and correct hypoglycemia by intravenous dextrose; pay attention to the balance of water and electrolytes, and correct acidosis.

　　2. Exchange of Blood or Plasma Exchange

　　Plasma exchange therapy can clear irritants in the blood, replenish the missing coagulation factors in the body, reduce platelet aggregation, and promote the repair of vascular endothelium. This treatment method is commonly used abroad and has achieved good efficacy.

　　3. Component Blood Transfusion

　　The treatment with a large amount of frozen fresh plasma can achieve effects similar to plasma exchange therapy. Red blood cells, platelets, human serum albumin, fresh blood, and other substances can be administered according to the situation.

　　4. Liver Protection Therapy

　　Vitamin C, branched-chain amino acids (hexamino acids), adenosine triphosphate (ATP), coenzyme A, and other substances can help protect the liver and should be used according to circumstances.

　　5. Adrenal Cortex Hormones

　　It is recommended to use hydrocortisone for short-term use to protect renal tubular epithelium, and 200-300mg should be administered intravenously daily.

　　6. Other

　　Anticoagulants and H2 receptor blockers should be used according to the condition to maintain the pH of gastric juice greater than 5, to prevent stress ulcers. Dialysis therapy or artificial kidney can be used for treatment after diuresis is ineffective due to renal failure. Use antibiotics with minimal impact on liver function, such as ampicillin, to prevent and treat infections.

　　7. Obstetric Management

　　Once acute fatty liver of pregnancy is diagnosed or highly suspected, regardless of the severity or timing of the condition, it should be terminated as soon as possible.

　　8. Treatment of the Condition

　　The timing of treatment for acute fatty liver of pregnancy is closely related to the prognosis of the disease. Conservative treatment has a very high maternal and infant mortality rate, and it should be as early as possible to perform liver puncture for diagnosis. It is dangerous to perform liver puncture when there is a tendency to hemorrhage after organ failure, and it is not advisable to do so. After diagnosis, the delivery should be carried out as soon as possible and the maximum level of support treatment should be provided.