Vitamin K Deficiency
What is vitamin K deficiency?
Vitamin K is an essential lipid-soluble vitamin which is important to bone and heart health, as well as blood clotting and brain function. A deficiency of vitamin K is rare in healthy adults due to its presence in a variety of commonly eaten foodstuffs, including green leafy vegetables, oils and grains.
However, people of any age can develop a vitamin K deficiency, which may be triggered by factors including liver disease, malnutrition and as a consequence of taking certain prescription drugs. The condition is also relatively common in breastfed infants.
A nutritionally balanced diet is normally sufficient to prevent a vitamin K deficiency. If a deficiency does develop, it can usually be treated effectively if detected early.
Vitamin K deficiency symptoms
- Excessive bleeding (from a cut, wound, injection or puncture, for example)
- Easy bruising
- Heavy menstrual bleeding
Symptoms in infants
Infants are at an increased risk of developing a vitamin deficiency until they begin to eat regular foods, which will usually be around 4 to 6 months after birth.
Signs and symptoms which could indicate vitamin K deficiency in infants include:
- Bruising (especially around the head or face)
- Bleeding (particularly from the nose or navel)
- Paleness (may be noticeable in the gums of darker-skinned infants)
- Yellowing of the skin (occurring three or more weeks after birth, distinct from newborn jaundice, which typically clears by the time the baby is two weeks old)
- Stool that is bloody, dark or sticky (tarry)
- Blood in the vomit
- Excessive tiredness
If any of these signs and symptoms occur or there is any suspicion of a vitamin K deficiency, urgent medical attention should be sought.
Vitamin K deficiency bleeding
Infants with a vitamin K deficiency are susceptible to vitamin K deficiency bleeding (VKDB), a symptom which stems from the blood being unable to clot. This bleeding can occur anywhere, including internally. If bleeding is internal, it can be extremely difficult to notice and may lead to serious complications and even death.
Factors that increase an infant’s chances of developing VKDB include:
- Breastfeeding: Children who are exclusively breast-fed are roughly 20 times more likely to experience VKDB. This is due to the low levels of vitamin K in breast milk compared to formula milk, as well as the low levels of bacteria that helps the body to synthesize vitamin K.
- Pharmaceuticals: Certain medication taken by the mother can increase the chances of an infant developing VKDB. These include rifampicin, isoniazid, anticoagulants and anticonvulsant agents.
- Warm environments: Extended exposure to a warm environment can make late-developing VKDB more likely. Late-developing VKDB usually peaks at around 3-8 weeks.
- Liver disease: There is increased risk if an infant has an unsuspected liver disease, especially alpha-1-antitrypsin deficiency.
- Malabsorption: An inability to absorb vitamins due to factors such as cystic fibrosis, celiac disease and diarrhea.
Prevention and treatment in infants
A vitamin K supplement should be given to the infant as soon as VKDB is suspected. In severe cases, fresh frozen plasma may also be administered to the infant. If an infant has lost a large amount of blood, a blood transfusion may also be necessary.
To help prevent VKDB from occurring, a vitamin K supplement is routinely given, with parental permission, to infants after birth in many parts of the world, including the United States and United Kingdom. It is sometimes called “the vitamin K shot”, but may be administered orally. The procedure is considered safe by healthcare professionals.
Vitamin K deficiency causes and risk factors
A vitamin K deficiency can occur in people of any age, but newborn infants are particularly at risk. This is due to a lack of vitamin K reaching the fetus before birth and the lack of vitamin K in breast milk.
Other risk factors for a vitamin K deficiency include:
- Liver disease
- Conditions that affect the body’s ability to absorb vitamin K (such as celiac disease, Crohn’s disease and tropical sprue)
- Biliary tract disease
- Certain drugs (such as cholestyramine, salicylates, rifampin and barbiturates)
It should be emphasized that a vitamin K deficiency in healthy adults is rare due to the vitamin’s presence in a variety of foodstuffs, notably green leafy vegetables, oils and grains.
Vitamin K deficiency diagnosis
Diagnosing a vitamin K deficiency will typically begin with a physical examination by a doctor. If a deficiency is suspected, the next stage of diagnosis will normally be blood testing. A blood test can reveal the level of prothrombin (a clotting agent) in the blood, which will be lower than average in the case of a vitamin K deficiency.
However, as low levels of prothrombin can also be symptomatic of other conditions, the diagnosis will generally be confirmed with a vitamin K injection. If symptoms subside following the injection, the diagnosis can be confirmed.
Vitamin K deficiency prevention
Most healthy adults are able to prevent a deficiency of vitamin K by maintaining a diet containing foodstuffs which are rich in the vitamin, such as:
- Green leafy vegetables (such as kale, chard, watercress and spinach)
- Oils (such as olive, cottonseed and soya bean)
- Grains (such as rye grain, spelt and buckwheat)
In some cases, a vitamin K supplement (menadiol sodium phosphate) may be administered to those at risk of developing a vitamin K deficiency.
Vitamin K deficiency treatment
The appropriate treatment method for a vitamin K deficiency depends on the severity of the condition (particularly the severity of the associated bleeding) and its underlying cause.
If bleeding reaches life-threatening levels, fresh frozen plasma (blood product containing coagulating properties) will be administered. In other cases (or after fresh frozen plasma has been administered), a vitamin K supplement will be administered to the individual, usually intravenously or into the muscle.
Centers for Disease Control and Prevention. “Frequently Asked Questions (FAQ’s): Vitamin K and the Vitamin K Shot Given at Birth.” December 5, 2017. Accessed March 6, 2018. ↩