Vitamin K Deficiency | Dietary Sources, Causes, Symptoms, Diagnosis, Treatment

Summary

This lesson provides a comprehensive overview of vitamin K, covering its importance, sources, and causes of deficiency. Vitamin K, which is vital for blood clotting and bone health, comes from leafy greens and fermented foods. Deficiency can result from inadequate intake, certain medications, or malabsorption disorders, leading to bleeding issues and weakened bones. Neonates are particularly vulnerable to vitamin K deficiency. Diagnosis involves prolonged prothrombin time, and treatment includes vitamin K supplementation, with severe cases requiring blood transfusions. This informative lesson highlights the critical role of vitamin K in health and how to prevent and treat its deficiency.

Takeaways

• 😀 Vitamin K is a fat-soluble vitamin, consisting of vitamin K1 (phylloquinone) and vitamin K2 (menaquinone), which are crucial for various biological processes.
• 😀 Vitamin K is required for the production and modification of coagulation factors (2, 7, 9, and 10) and plays a role in bone development through the carboxylation of osteocalcin.
• 😀 Major dietary sources of vitamin K include leafy greens, vegetables (like spinach, kale, and Brussels sprouts), and fermented foods. Vitamin K2 is predominantly found in fermented foods.
• 😀 The recommended daily intake of vitamin K is 90 micrograms for women and 120 micrograms for men.
• 😀 Vitamin K is absorbed in the gastrointestinal tract with the help of bile and pancreatic enzymes, and is transported through the bloodstream by chylomicrons.
• 😀 Deficiency in vitamin K can occur due to neonatal factors, reduced dietary intake (especially in patients on TPN), malabsorption, certain medications (e.g., warfarin), and genetic conditions like hereditary combined vitamin K dependent clotting factors deficiency (VKCFD).
• 😀 Clinical features of vitamin K deficiency include increased bleeding (e.g., petechiae, purpura, and ecchymosis), and severe forms of bleeding can be fatal, particularly in neonates.
• 😀 Neonates are particularly at risk for vitamin K deficiency bleeding (VKDB), which can occur in early, classic, or late stages, leading to severe hemorrhages like intracranial or gastrointestinal bleeding.
• 😀 Bone health is also affected by vitamin K deficiency, resulting in decreased bone mineralization and osteoporosis, leading to a higher risk of fractures.
• 😀 Vitamin K deficiency is diagnosed through laboratory tests such as prolonged prothrombin time (PT), normal partial thromboplastin time (PTT), and elevated levels of protein induced by vitamin K absence or antagonism (PIVKA2).
• 😀 Treatment of vitamin K deficiency includes prophylactic vitamin K for neonates, and for adults, oral or subcutaneous vitamin K replacement is used. Severe bleeding may require fresh frozen plasma (FFP) transfusions or slow IV vitamin K infusion in neonates.

Q & A

What are the two main types of vitamin K, and how do they differ?

The two main types of vitamin K are vitamin K1 (phylloquinone) and vitamin K2 (menaquinone). Vitamin K1 is primarily found in leafy greens and vegetables, while vitamin K2 is typically found in fermented foods and is produced by certain intestinal flora.

What processes in the body require vitamin K?

Vitamin K is essential for the production and modification of coagulation factors (2, 7, 9, and 10) in the liver, which are involved in blood clotting. It also plays a role in bone development by carboxylating osteocalcin, a protein involved in bone mineralization.

Where do we primarily get vitamin K from in our diet?

The primary dietary sources of vitamin K are leafy greens and vegetables, such as spinach, kale, and brussels sprouts. Vitamin K1 is abundant in these sources, while vitamin K2 is found in fermented foods.

How is vitamin K absorbed in the body?

Vitamin K is absorbed in the jejunum and ileum of the gastrointestinal tract. As a fat-soluble vitamin, it requires bile and pancreatic enzymes to aid in its digestion and absorption, after which it is transported through the bloodstream by chylomicrons.

What is the role of vitamin K in coagulation?

Vitamin K acts as a cofactor for enzymes that modify coagulation factors 2, 7, 9, and 10 by adding gamma-carboxy glutamic acid, which enables these factors to bind to platelets and promote blood clotting.

What are the causes of vitamin K deficiency?

Vitamin K deficiency can be caused by several factors, including neonatal conditions (since vitamin K doesn't cross the placenta well), reduced dietary intake (especially in patients on TPN), malabsorption disorders like Crohn's disease, certain medications (e.g., warfarin), and genetic conditions like hereditary combined vitamin K-dependent clotting factor deficiency.

What are the clinical symptoms of vitamin K deficiency?

The clinical symptoms of vitamin K deficiency primarily involve coagulation issues, leading to an increased risk of bleeding, bruising, and hemorrhages. In neonates, vitamin K deficiency can cause severe bleeding, such as umbilical or gastrointestinal bleeding. Chronic deficiency may also result in bone issues like osteoporosis due to reduced bone mineralization.

How do neonates commonly develop vitamin K deficiency?

Neonates often develop vitamin K deficiency because vitamin K does not cross the placenta effectively. Additionally, certain maternal medications or inadequate breastfeeding without supplementation can increase the risk of deficiency.

How is vitamin K deficiency diagnosed?

Vitamin K deficiency is diagnosed through laboratory tests, including a prolonged prothrombin time (PT), which is typically one of the first signs. Elevated levels of Protein Induced by Vitamin K Absence or Antagonism (PIVKA-2) can also indicate deficiency. However, vitamin K levels themselves can be highly variable and unreliable for diagnosis.

What treatment options are available for vitamin K deficiency?

Treatment for vitamin K deficiency varies by age and severity. In neonates, prophylactic intramuscular vitamin K administration is common. In adults, oral or subcutaneous vitamin K replacement is typically used. For severe bleeding, fresh frozen plasma (FFP) may be administered, and in cases of neonatal vitamin K deficiency bleeding (VKDB), slow intravenous vitamin K infusion may be needed.