Learner Version
Module # 31
Created by Dr. Mary Lacy July 2014
Objectives:
See facilitator version
References:
See facilitator version
Case
You are called by the ER for admission of a 49 year-old man with sepsis. The patient has never been admitted to the hospital but you have access to a few of his outpatient primary care visits from over the years. The records clue you into his history of alcohol and intravenous drug use. Labs performed by his primary care physician showed a platelet count of about 120,000 per μL on several occasions.
What are the major mechanisms of thrombocytopenia?
What signs and symptoms to patients with isolated thrombocytopenia report? When do these signs and symptoms develop?
What are the major considerations in gathering a patient history that could point to a cause for thrombocytopenia?
On further investigation, you realize that your patient had isolated stable thrombocytopenia.HIV and hepatitis panels were negative. B12 and folate levels were normal. Liver function tests including albumin and INR were normal. The cause was presumed to be secondary to his chronic alcohol use causing bone marrow suppression (increased production). No abdominal imaging was performed to assess for splenomegaly (sequestration) or early cirrhosis.
You learn more about his current presentation and suspect sepsis secondary to a soft tissue infection in an area of injection drug use. On examination, he has extreme tenderness as well as erythema of his right thigh. He has no other medical history and is on no medications. You admit him to the hospital and prescribe IV vancomycin. You also prescribe an opiate for his pain and subcutaneous heparin for venous thromboembolism prophylaxis.
Initial Vitals/Labs:
HR 110, BP 110/75, T 388, RR 16
CBC: WBC 16, Hct 35, Plt98
BMP: Na 132, K 3.8, Cl 100, HCO3- 23, BUN 20, Cr 0.8
The degree of thrombocytopenia is acutely worsened from his baseline. What is the differential diagnosis for our acutely ill patient’s thrombocytopenia?
What work up would you pursue for this patient’s thrombocytopenia? What abnormalities would you expect if this patient had DIC?
Whatare the causes and complications of DIC? How do you treat it?
DIC is a condition of thrombocytopenia that can be associated with thrombosis. What other classic causes of thrombocytopenia can result in thrombosis?
Your patient doesn’t have DIC. Unfortunately, his pain continues to escalate and seems out of proportion to your exam. You re-examine him and decide to call general surgery to evaluate for necrotizing fasciitis. His antibiotics are broadened and he is transferred to the general surgery team. On day 7 of his admission you are called by the general surgery team to take the patient back on your service. His last trip to the OR was 3 days prior and he has been narrowed to IV vancomycin for MRSA in his operative cultures. He continues on opiates and subcutaneous heparin for VTE prophylaxis. He was incredibly lucky and his infection has stabilized, but his platelets have dropped to 8,000 (other cell lines are stable). His coagulation studies are normal. He has petechiae in dependent areas and reports a nosebleed that stopped with direct pressure.
Your first thought is HIT secondary prolonged heparin exposure. How would you calculate the probability of HIT in our patient? How do you diagnose and treat HIT?
Our patient has a low probability for HIT, which suggests that you should look for other causes. What is the most likely cause of our patient’s thrombocytopenia?
How would you treat our patient? What if he needed another invasive procedure?
Fortunately, your patient does not need to return to the OR. Over the next week, his platelets recover with withdrawal of vancomycin. He is able to discharge from the hospital.
MKSAP 16 Questions:
Hematology & Oncology: Question 5
Hematology & Oncology: Question 23
Hematology & Oncology: Question 55
Hematology & Oncology: Question 68