# Situation: A 34-year-old woman has had chronic diarrhea with pale, bulky, foul-smelling stools that float, a 6-kg weight loss over 6 months, and iron-deficiency anemia. Celiac disease is suspected. She reports easy bruising and bleeding gums. Results are shown with normal ranges in parentheses. International normalized ratio (INR): 1.9 (0.8–1.2) Platelet count: 260,000/mm³ (150,000–400,000) Serum calcium: 8.2 mg/dL (8.6–10.2) Which cause of her bruising do these findings MOST support?

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> subject: Nursing Practice IV — Care of Clients with Problems in Nutrition and Gastrointestinal, Metabolism and Endocrine, Perception and Coordination

## 문제

Situation: A 34-year-old woman has had chronic diarrhea with pale, bulky, foul-smelling stools that float, a 6-kg weight loss over 6 months, and iron-deficiency anemia. Celiac disease is suspected.

She reports easy bruising and bleeding gums. Results are shown with normal ranges in parentheses.
International normalized ratio (INR): 1.9 (0.8–1.2)
Platelet count: 260,000/mm³ (150,000–400,000)
Serum calcium: 8.2 mg/dL (8.6–10.2)
Which cause of her bruising do these findings MOST support?

## 보기

1. Low serum calcium slowing the clotting cascade
2. Poor absorption of a fat-soluble clotting vitamin **✔ 정답**
3. Platelet loss linked to her iron-deficiency anemia
4. Vitamin C deficiency weakening the capillary walls

**정답: 2**

## 해설

Vitamin K is fat-soluble, so fat malabsorption reduces its absorption, lowers vitamin K–dependent clotting factors, and prolongs the INR. The normal platelet count and the high INR together point to vitamin K deficiency; the low calcium reflects vitamin D and calcium malabsorption.

## 심화 해설

Why the bruising occurs

Celiac disease damages the small-bowel mucosa, which impairs the absorption of dietary fat. Because vitamin K is a fat-soluble vitamin, fat malabsorption reduces its uptake. Vitamin K is required for the hepatic γ-carboxylation of clotting factors II, VII, IX, and X [1]. Without adequate vitamin K, these factors remain undercarboxylated and functionally inactive, which prolongs the prothrombin time and elevates the INR. The patient’s INR of 1.9 with a normal platelet count of 260,000/mm³ is the classic pattern of a coagulation-factor defect rather than a platelet or vascular problem.

The combination of a prolonged INR and a normal platelet count points to vitamin K deficiency from fat malabsorption. Platelets are not involved in this pathway, so the normal count does not rule out a bleeding tendency; it helps rule out thrombocytopenia as the cause.

Why the other findings fit the same mechanism

The low serum calcium of 8.2 mg/dL also reflects malabsorption. Vitamin D is another fat-soluble vitamin, and its deficiency reduces intestinal calcium absorption. In addition, vitamin K deficiency can impair bone mineralization over time [1][2]. Therefore, the low calcium is a parallel consequence of fat malabsorption, not the cause of the bruising.

Key point! Calcium participates in the clotting cascade as a cofactor, but hypocalcemia at this mild level does not prolong the INR or cause easy bruising. The INR elevation is specifically explained by reduced vitamin K–dependent clotting factors.

Differential reasoning for the options

| Option | Why it does not fit |
| --- | --- |
| 1. Low serum calcium slowing the clotting cascade | Calcium is a cofactor, but the INR is prolonged by deficient clotting factors, not by mild hypocalcemia. The calcium level reflects vitamin D malabsorption. |
| 2. Poor absorption of a fat-soluble clotting vitamin | Vitamin K is fat-soluble and required for factors II, VII, IX, and X. Malabsorption lowers these factors and raises the INR [1][2]. |
| 3. Platelet loss linked to iron-deficiency anemia | The platelet count is normal, so thrombocytopenia is not present. Iron deficiency does not directly cause bruising through platelet loss. |
| 4. Vitamin C deficiency weakening capillary walls | Vitamin C deficiency causes perifollicular hemorrhage and poor wound healing, but it does not elevate the INR. The INR abnormality points to a coagulation-factor defect. |

Clinical significance in malabsorptive disorders

Chronic gastrointestinal diseases that impair nutrient absorption can produce vitamin K deficiency and bleeding complications [1][2]. In celiac disease, the proximal small intestine is the main site of injury. Vitamin K is absorbed in the small intestine, and when mucosal integrity is lost, oral vitamin K may be only partially effective . In severe cases, parenteral vitamin K may be required because enteral absorption remains unreliable until the mucosa heals .

A high INR with a normal platelet count in a patient with steatorrhea should prompt assessment for vitamin K deficiency. The bleeding manifestations—easy bruising and bleeding gums—are consistent with impaired secondary hemostasis. Watch out! Do not attribute bruising to iron-deficiency anemia alone; iron deficiency affects red cell production, not clotting factor synthesis.References (research sources)

- [1]Old Scars, New Bleeds: Revisiting Coagulopathy in Quiescent Crohn's Disease.Research articlePatel S, Khattak R, Patel R, Kumar SA, Kulkarni AR. (2025) · DOI: 10.12890/2025_005826

- [2]Vitamin K Deficiency in Neonates and AdultsResearch articleDaley SF, Sina RE. (2026)

## 임상 시나리오

Vitamin K Deficiency in Fat MalabsorptionCoagulopathy with normal platelets and prolonged INR
In celiac disease, small-bowel mucosal damage impairs fat absorption, reducing uptake of fat-soluble vitamins including vitamin K. Vitamin K is required for hepatic gamma-carboxylation of clotting factors II, VII, IX, and X.

The classic pattern is a prolonged INR with a normal platelet count. This patient's INR of 1.9 and platelet count of 260,000/mm³ indicate a coagulation-factor defect, not thrombocytopenia.

Low serum calcium of 8.2 mg/dL reflects concurrent vitamin D deficiency from the same fat malabsorption, not the cause of bruising. Mild hypocalcemia does not prolong INR.

CautionDo not attribute bleeding to mild hypocalcemia or vitamin C deficiency when INR is elevated and platelets are normal. Suspect vitamin K deficiency in any patient with steatorrhea and coagulopathy.

## 핵심 개념

- **Vitamin K-dependent clotting factors** — Factors II, VII, IX, and X require vitamin K for hepatic gamma-carboxylation to become functionally active.
- **Fat-soluble vitamins** — Vitamins A, D, E, and K; their absorption depends on dietary fat and bile salts.
- **INR** — International normalized ratio; a standardized measure of the extrinsic and common coagulation pathways.
- **Celiac disease** — Small-bowel mucosal damage from gluten, causing malabsorption of nutrients including fat and fat-soluble vitamins.
- **Steatorrhea** — Pale, bulky, foul-smelling, floating stools due to excess fat in the stool from malabsorption.

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