WBR0966

Author	[[PageAuthor::Mugilan Poongkunran M.B.B.S [1]]]
Exam Type	ExamType::USMLE Step 3
Main Category	MainCategory::Emergency Room
Sub Category	SubCategory::Hematology
Prompt	[[Prompt::A 62 year old woman comes to the emergency department with complaints of shortness of breath and chest pain. She was in her usual state this morning but suddenly developed these symptoms. Her past history is otherwise insignificant and her family history is unremarkable. She is a chronic smoker and smoked two packs of cigarette for the past 25 years. She occasionally consumes alcohol. She attained menopause at the age of 50 and not on any medications. Her vitals are temperature: 36.7 C, blood pressure: 140/80 mmHg, pulse: 80/min and respiration: 15/min. The patients pulse oximetry shows 92 % on 4-litres of oxygen. All system examinations are normal. V/Q scan of the chest shows high probability for pulmonary embolism. Her initial laboratory values are : Hb : 11 g/dl Hct : 37% RBC’s : 3 million/cmm WBC’s : 8000/cmm Platelet’s : 300,000/cmm PT : 13 sec (N 11-15 sec) APTT : 30 sec (N 25-40 sec) BT : 7 min (N 2-7 min) INR : 1.06 You start the patient on unfractionated heparin and warfarin. On the 3rd day, she complaints of pain in the right arm and abdomen. Examination of the right extremity reveals pale, tender arm with erythema in the abdomen that progressed quickly to hemorrhage and necrosis. A repeat CBC reveals Hb : 12 g/dl Hct : 37.5% RBC’s : 2.8 million/cmm WBC’s : 10000/cmm Platelet’s : 260,000/cmm PT : 19 sec (N 11-15 sec) APTT : 60 sec (N 25-40 sec) BT : 11 min (N 2-7 min) INR : 2 What is the most likely cause of her symptoms ?]]
Answer A	AnswerA::Heparin induced skin necrosis
Answer A Explanation	AnswerAExp::''' Correct ''' : This pateint has heparin induced skin necrosis which is not associated with thrombocytopenia.
Answer B	AnswerB::Heparin induced thrombocytopenia
Answer B Explanation	[[AnswerBExp:: Incorrect  : The appearance of otherwise unexplained thrombocytopenia, thrombosis associated with thrombocytopenia, a platelet count which has fallen 50 percent or more from a prior value, or necrotic skin lesions at heparin injection sites should raise the possibility of heparin-induced thrombocytopenia (HIT) in any patient begun on heparin therapy within the preceding 5 to 10 days.]]
Answer C	AnswerC::Warfarin induced skin necrosis
Answer C Explanation	[[AnswerCExp:: Incorrect  : Warfarin induced skin necrosis appears to be mediated by the rapid reduction of protein C levels on the first day of therapy, which induces a transient hypercoagulable state. The skin lesions may occur on the extremities, breasts, trunk, and penis and marginate over a period of hours from an initial central erythematous macule. Warfarin induced skin necrosis is not associated with thrombocytopenia.]]
Answer D	AnswerD::Disseminated intravascular coagulation
Answer D Explanation	[[AnswerDExp:: Incorrect  : The diagnosis of disseminated intravascular coagulation is suggested by the history (eg, sepsis, trauma, malignancy), clinical presentation of bleeding and thrombosis, moderate to severe thrombocytopenia (<100,000/microL) and the presence of microangiopathic changes on the peripheral blood smear. The diagnosis is confirmed by the evidence of both increased thrombin generation (eg, decreased fibrinogen, prolonged PT and aPTT) as well as increased fibrinolysis (eg, elevated FDPs and D-dimer).]]
Answer E	AnswerE::Sub therapeutic anti-coagulation
Answer E Explanation	AnswerEExp::''' Incorrect ''' : Even though in this patient PT/INR are subtherpeutic, the PTT is therapeutic and hence properly anti-coagulated.
Right Answer	RightAnswer::A
Explanation	[[Explanation::Skin necrosis at the site of heparin injections is a well-described complication of treatment with unfractionated heparin or LMWH, and should immediately suggest the presence of HIT. Affected patients have heparin-dependent antibodies but may not develop thrombocytopenia. It usually involves areas rich in fat such as abdomen, although distal extremities can be involved. It presents as an area of erythema that quickly progresses to purpura, hemorrhage and necrosis. Educational Objective: References: ]]
Approved	Approved::Yes
Keyword	WBRKeyword::HIT
Linked Question	Linked::
Order in Linked Questions	LinkedOrder::