September 11, 2015 - Blood Podcast

Question 1

Essential Thrombocythemia

Answer 1

Diagnosis of exlusion.

Platelets >450 for a prolonged period of time.

All patients need ASA, and high risk (over 60 or platelets >1000) need hydroxyurea.

Question 2

Polycethemia Vera

Answer 2

Typically associated with increased red cell mass or elevated hemoglobin. Also often associated with both thrombocytosis and leukocytosis.

Presence of JAK2 V616F mutation or other functionally similar JAK2 mutation.

Often accompanied by splenomegaly and low erythropoietin levels.

Question 3

Chronic Myelogeous Leukemia

Answer 3

Presents with splenomegaly, leukocytosis, with or without thrombocytosis.

Diagnosed by the presence of the Philadelphia chromosome and/or the presence of BCR-ABL1 fusion product.

Question 4

Lyonization

Answer 4

X-chromosome inactivation in early embryogenesis.

Question 5

Hemophilia: Clinical Severity

Answer 5

Mild (5-40%)

Moderate (1-5%)

Severe (<1%)

Question 6

Schistocytes

Answer 6

An indication of MAHA. Broken fragments of red blood cells.

Question 7

Laboratory Testing for MAHA

Answer 7

1. Schistocytes on PBS
2. Anemia and thrombocytopenia in CBS
3. Negative DAT
4. Increased LDH
5. Increased bilirubin
6. Decreased haptoglobin

Question 8

Thrombotic Thrombocytopenic Purpura (TTP)

Answer 8

Normally, ADAMTS-13 cleaves unusually large multimers of VWF.

In patients with TTP, adhesion and aggregation of platelets to the large multimers of VWF renders ADAMTS-13 unable to cleave them. This results in MAHA, thrombocytopenia, acute kidney injury, neurologic deficits, and fever.

In the lab, you will see anemia, schistocytes, increased LDH, increased bilirubin, decreased haptoglobin, thrombocytopenia, increased creatinine, and decreased ADAMTS13.

TTP is a hematological emergency with a 90% fatality rate if untreated. Patients need a daily plasma exchange until platelets >150 and LDH is normal and will need steroids/immunosuppressive therapy if acquired TTP.

Question 9

Hemolytic Uremic Syndrome (HUS)

Answer 9

Is caused by a systemic ADAMTS-13 deficiency. Shigatoxin from E. coli disables the enzyme which results in similar symptoms to TTP.

Antibiotic use is avoided unless the patient is septic as it may cause further toxin release. Hemodialysis may be required as kidney failure is more common.

Question 10

Disseminated Intravascular Coagulation (DIC)

Answer 10

1. Excess TF release activating F7/extrinsic pathway
2. Excessive thrombin production and defective anticoagulant mechanisms
3. Suppression of fibrin clot degradation

Question 11

When to Transfuse Platelets

Answer 11

<50

Question 12

HELLP Syndrome

Answer 12

Hemolysis, elevated liver enzymes, and low platelets.

Seen between 28-36 weeks gestation.

Delivery is the only effective treatment.

Question 13

Thrombosis Threshold

Answer 13

A “line” that needs to be crossed to develop thrombosis. It increases with age always but can be influenced by genetic risk and transient (or environmental) factors.

Cancer and surgery can increase it.

Question 14

Virchow’s Triad

Answer 14

1. Venous stasis
2. Hypercoagulable state
3. Vessel injury or abnormalities

Question 15

Protein C and Protein S

Answer 15

Downregulate F8 and F5

Question 16

Antithrombin

Answer 16

Downregulates F2 and F10

Question 17

Classical Symptoms of DVT

Answer 17

1. Swelling
2. Pain
3. Redness
4. Warmth
5. Edema

Question 18

Classical Symptoms of PE

Answer 18

1. Dyspnea
2. Chest pain
3. Cough
4. Hemoptysis
5. Palpitations
6. Syncope (loss of consciousness)
7. Sudden death

Question 19

D-Dimer

Answer 19

Best used for a negative predictive value for a blood clot.

Question 20

CT Pulmonary Angiography (CTPA)

Answer 20

95% sensitivity and specificty when used in conjunction with D-dimer. Very good at detecting PE.

Question 21

Heparin

Answer 21

Mimics antithrombin and inhibits Factor 10a and Factor 2.

Safe in pregnancy.

May cause Heparin-Induced Thrombocytopenia in 1-5% of people.

Question 22

Heparin-Induced Thrombocytopenia

Answer 22

Occurs with Heparin sometimes.

Antibodies form against the complex of heparin and platelets, which causes their destruction. Stop heparin and switch to an alternative anticoagulant.

Question 23

Therapeautic INR of Warfarin

Answer 23

Between 2.0 and 3.0

For mechanical heart valves between 2.5 and 3.5