What Is Hypervitaminosis A?

Hypervitaminosis A, also known as vitamin A poisoning, is a toxic lesion of the skin, hair, bone, and central nervous system caused by a large or long-term excessive intake of vitamin A or carotenoids.

Basic Information

Visiting department: Emergency Department
Common causes: Caused by a large intake of vitamin A

Common symptoms: Symptoms of acute and chronic poisoning
Contagious: no

Causes of excessive vitamin A

Too much vitamin A can cause acute poisoning due to a large intake of vitamin A at one time. Adults can use a lot of foods rich in vitamin A. Most children are caused by accidentally taking a lot of vitamin AD preparations; they can also be caused by long-term excessive intake of vitamin A. Preparations, foods rich in carotenoids or vitamin A cause chronic poisoning. Carotene is a natural precursor of vitamin A. A large intake of carotenoid-rich foods may cause caroteneemia. Carotene yellow skin disease occurs when carotene is 3 to 4 times higher than normal levels. Carotene can be stored in Sebaceous glands rich in areas such as nasolabial folds, forehead and thickest parts of skin stratum corneum, such as palms and soles of feet, if carotene xanthophytes appear, you should pay attention to whether there is too much carotenoid intake and whether there is too much vitamin A Symptoms.

Clinical manifestations of excessive vitamin A

1. Acute poisoning occurs within hours after ingestion of the poisoned adult, and manifests as nausea, vomiting, severe headache, dizziness, drowsiness, etc. After 12 to 24 hours, skin redness and swelling may occur, followed by extensive skin desquamation. The thickest part of the sole is obvious. Babies present with vomiting, drowsiness, and bulging of the front palate caused by intracranial hypertension.
2. Chronic poisoning Chronic poisoning lesions are dry skin, rough, desquamation, and itching, and cracked lips; bone changes can cause painful edema in the limbs, elevated liver transaminase, and can be irritable, irritable, lethargic, anorexia, weight loss and Diffuse hair loss and other manifestations. In severe cases, liver splenomegaly, portal hypertension, and ascites may appear.

Vitamin A Examination

1. Detection of Plasma Vitamin A Content Plasma Vitamin A is significantly higher than the normal value of 2.10 mol / L. When vitamin A poisoning occurs, plasma vitamin A is higher than 5.10 mol / L. Serum retinol concentration is not sensitive to the diagnosis of excessive vitamin A. Its normal range is 1 to 3 mol / L, but because of liver reserve and homeostasis regulation, the range change is small even if a large amount of vitamin A is ingested.
2. Blood biochemical detection Plasma alkaline phosphatase increased, blood ester increased, protein decreased, and transaminase increased.
3. X-ray examination showed that multiple long tubular bones showed extensive periosteal bone along the backbone, and the middle of the backbone was the thickest. Adults may have calcification of the ligaments around the spine, but the sacroiliac joints are not invaded, and the ligaments around the joint capsule may also be calcified. Or ossification. Infants may experience delayed ossification of the skull, which is table tennis-like. Early healing of the growth plate can occur in the lower limbs.

Vitamin A diagnosis

According to the patient's history of taking a large amount of vitamin A preparation or taking vitamin A for a long time, clinical manifestations such as dry skin, rough skin, desquamation, and pruritus, elevated levels of plasma vitamin A can be diagnosed.

Differential diagnosis of vitamin A excess

1. Vitamin C Deficiency Vitamin C deficiency skeletal imaging examinations indicate general osteoporosis, while excessive vitamin A can appear extensive periosteum bone.
2. Pruritus Too much vitamin A has a history of excessive intake of vitamin A or carotenoids, and elevated plasma vitamin A levels.
3. Fatty eczema Fatty eczema is more common in the elderly and is more common in the winter. It occurs in the lower leg extension, manifesting as dry skin, small cleft palate, desquamation, with varying degrees of itching, and plasma vitamin A levels do not increase.

Vitamin A hyperthyroidism treatment

Suspend taking vitamin A drugs and stop eating foods high in vitamin A to avoid excessive vitamin A supplementation. After stopping vitamin A intake for a few weeks, symptoms can disappear. After symptoms disappear, you can consume vitamin A drugs and food in appropriate amounts.

Vitamin A prognosis

Too much vitamin A can disappear within a few weeks after stopping vitamin A intake, and the prognosis is good. However, treatment for acute poisoning can lead to death.