Doctors in Japan discovered something unusual: two adults developed serious bleeding problems caused by vitamin K deficiency, but they couldn’t figure out why. Normally, this condition only happens in newborns or people taking blood thinners. After running many tests, the doctors ruled out all the usual causes. This case report suggests there may be a new type of vitamin K deficiency that appears in adults for reasons we don’t yet understand. The findings could help doctors recognize and treat similar patients in the future.

The Quick Take

  • What they studied: Why two adult patients suddenly developed severe bleeding problems related to vitamin K deficiency when doctors couldn’t find a normal explanation
  • Who participated: Two Japanese adults (specific ages and demographics not detailed in abstract) who developed unexpected bleeding disorders
  • Key finding: Both patients had very low levels of blood clotting proteins that depend on vitamin K, and high levels of a marker showing vitamin K deficiency, but standard tests couldn’t explain why
  • What it means for you: If you experience unexplained bleeding or bruising, doctors may need to test for this rare condition. This research helps medical professionals recognize a previously unknown disease pattern, though it remains extremely uncommon

The Research Details

This is a case report, which means doctors documented the medical history and test results of two specific patients with an unusual condition. The researchers carefully tracked what symptoms appeared, what blood tests showed, and what treatments worked. They compared their cases to similar reports in medical literature to see if this might be a new disease pattern. Case reports are like detailed medical detective stories—they help doctors learn about rare conditions by examining real patients in depth.

Case reports are important for identifying new diseases or unusual presentations of known conditions. When doctors see similar patterns in multiple patients, it helps the medical community recognize and diagnose rare disorders faster. This careful documentation can eventually lead to better understanding of causes and treatments.

This study is based on only two patients, so the findings are preliminary and cannot be applied broadly. The strength of this work lies in the thorough evaluation and detailed documentation rather than statistical power. Readers should understand this describes a rare observation, not a proven common condition. The fact that comprehensive testing ruled out known causes adds credibility to the unusual nature of these cases.

What the Results Show

Both patients showed markedly low levels of multiple blood clotting factors (factors II, VII, IX, and X, plus proteins C and S) that normally depend on vitamin K to function properly. Additionally, both had elevated levels of PIVKA-II, a marker that indicates vitamin K deficiency. These findings are similar to what doctors see in newborns with vitamin K deficiency or in patients taking blood-thinning medications like warfarin. However, these adult patients had no history of these typical risk factors. The clinical course of both patients ruled out congenital (present-from-birth) vitamin K-dependent coagulation factor deficiency, suggesting this is an acquired condition that developed during adulthood.

The comprehensive evaluation of both patients included testing for liver disease, malabsorption disorders, antibiotic use, dietary insufficiency, and other known causes of vitamin K deficiency—all came back negative or didn’t explain the findings. This thorough investigation is important because it strengthens the case that something new or unusual is happening in these patients.

The researchers found one similar case reported in medical literature, suggesting this pattern may have been observed before but not formally recognized as a distinct condition. By bringing together these cases, the authors propose calling this ‘idiopathic acquired vitamin K-dependent coagulation factor deficiency’—essentially meaning ‘acquired vitamin K deficiency in adults with unknown cause.’ This naming helps future doctors recognize and report similar cases.

The study involves only two patients, so conclusions cannot be generalized to larger populations. The cause of the vitamin K deficiency remains unknown despite extensive testing, limiting understanding of the disease mechanism. Without more cases, it’s unclear how common this condition is or what the long-term outcomes might be. The study cannot determine if this represents a truly new disease entity or a rare presentation of a known condition.

The Bottom Line

This research is preliminary and does not yet support specific treatment recommendations for the general public. However, it suggests that doctors should consider vitamin K deficiency testing in adults with unexplained bleeding disorders, even when standard causes aren’t apparent. Confidence level: Low to Moderate—this is based on two cases and requires confirmation with additional patients.

This finding is most relevant to hematologists (blood specialists) and internal medicine doctors who may encounter patients with unexplained bleeding. Patients experiencing unexplained bleeding or bruising should discuss comprehensive vitamin K testing with their healthcare provider. The general public should be aware this is an extremely rare condition and should not self-diagnose based on minor bruising.

Since the cause remains unknown, there are no established timelines for treatment or recovery. Management would depend on the underlying cause once identified in future research.

Want to Apply This Research?

  • If diagnosed with this condition, track bleeding episodes (nosebleeds, bruising, gum bleeding) with dates and severity on a 1-10 scale, plus any new symptoms or medication changes
  • Work with your healthcare provider to establish a monitoring schedule and report any new bleeding symptoms immediately rather than waiting for routine appointments
  • Maintain a health log documenting vitamin K levels, clotting factor tests, and bleeding episodes; share this with your medical team regularly to help identify patterns and treatment effectiveness

This research describes an extremely rare condition identified in only two patients. It is not intended to diagnose or treat any medical condition. If you experience unexplained bleeding, bruising, or other concerning symptoms, consult with a qualified healthcare provider for proper evaluation and diagnosis. This case report represents preliminary findings and should not be used for self-diagnosis. Always seek professional medical advice before making any health-related decisions.