A 30-year-old woman comes to the physician for a follow-up evaluation after a recent hospitalization. She was admitted to the hospital two weeks ago with abdominal pain and bloody diarrhea, and she improved markedly with antibiotics and intravenous hydration. She was told to follow-up with her physician regarding abnormal laboratory results obtained during her hospitalization. She currently has no symptoms and denies prior chronic medical problems. She does not smoke or drink alcohol.
Examination shows no abnormalities.
Today's laboratory results are as follows:

The laboratory studies at the time of hospital discharge showed similar results.
Which of the following is the most appropriate next step in management?

Question

A 30-year-old woman comes to the physician for a follow-up evaluation after a recent hospitalization.  She was admitted to the hospital two weeks ago with abdominal pain and bloody diarrhea, and she improved markedly with antibiotics and intravenous hydration.  She was told to follow-up with her physician regarding abnormal laboratory results obtained during her hospitalization.  She currently has no symptoms and denies prior chronic medical problems.  She does not smoke or drink alcohol.
Examination shows no abnormalities.
Today's laboratory results are as follows:

The laboratory studies at the time of hospital discharge showed similar results.
Which of the following is the most appropriate next step in management?

Quizplus · Accepted Answer

11ec193a_982f_0acf_853d_69a4f9a8f31a_MD0002_00 Prolonged aPTT and normal PT (INR) suggest an intrinsic pathway defect. Deficiencies of factor XII, prekallikrein, or high molecular weight kininogen all cause a prolonged aPTT without clinical bleeding. Prolonged aPTT with bleeding can occur in congenital or acquired von Willebrand disease and isolated deficiencies of factors VIII, IX, and XI. Antiphospholipid antibodies (lupus inhibitor) cause prolonged aPTT with thromboses rather than bleeding. Mixing studies that mix the patient's plasma in a 1:1 ratio with normal plasma can help differentiate between a factor deficiency and an inhibitor as the cause of the prolonged aPTT. Factor deficiencies are corrected during a mixing study, resulting in normalization of the clotting time; while the presence of an inhibitor will prevent correction of the clotting time. This patient's bloody diarrhea resolved quickly with antibiotic therapy and is unlikely to have caused her prolonged aPTT. She should have a mixing study performed with further evaluation based on the results. (Choice A) Factor VIII and IX deficiencies cause hemophilia with prolonged PTT, but they usually present with recurrent bleeding episodes that are not seen in this patient. In addition, a mixing study should be performed first to confirm factor deficiency. (Choice B) Chronic liver disease causes decreased synthesis of all vitamin K dependent clotting factors (II, VII, IX, X), and can prolong both PT and aPTT. However, this patient's prolonged PTT and normal PT makes this consideration less likely. (Choice C) Antiphospholipid syndrome may present with thrombosis and prolonged aPTT, but this patient first needs a mixing study to see whether or not her aPTT will correct before testing for lupus anticoagulant. (Choice E) Vitamin K deficiency usually prolongs the PT more than the PTT due to deficient factors II, VII, IX, and X. Antibiotics can cause vitamin K deficiency by affecting intestine bacteria that synthesize vitamin K, and by vitamin K inactivation. However, this patient's normal PT makes vitamin K deficiency unlikely. Educational objective: Prolonged aPTT or PT can be evaluated by using mixing studies. Factor deficiency will result in a normal clotting test after plasma mixing, while an inhibitor will cause persistent prolongation of the aPTT or PT. __________ References: Perioperative evaluation of bleeding diathesis (http://www.ncbi.nlm.nih.gov/pubmed/17124099)

A 30-Year-Old Woman Comes to the Physician for a Follow-Up