Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Clin Med III - Heme/Onc > Thrombocytopenia > Flashcards

Thrombocytopenia Flashcards

1
Q

What are thrombocytes and where are they produced?

A
  • Platelets
  • Small cell fragments w/o nucleus
  • Produced in BM
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Avg lifespan of a platelet?

A

5-9 days

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Where are reserve platelets stored?

A

Spleen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Where are old platelets destroyed?

A

Spleen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Normal platelet range

A

150-450,000

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

30,000 - 50,000 platelets may manifest as:

A

Purpura

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

10,000 - 30,000 platelets may cause:

A

Bleeding (w/minimal trauma)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Platelets less than 5,000 may cause:

A

Spontaneous bleeding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Define primary hemostasis

A
  • Occurs instantly after a blood vessel endothelium injury

- Platelet plug is formed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Define secondary hemostasis

A
  • Occurs simultaneously w/primary hemostasis
  • Exposure to TF to Factor 7 and other clotting factors
  • Fibrin strands to strengthen platelet plug
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Define prothrombin time (PT) and what it tests

A
  • Time to clot in presence of tissue thromboplastin

- Tests EXTRINSIC and common pathways (factors 5, 7, 10, prothrombin, fibrinogen)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Define partial thromboplastin time (PTT) and what it tests

A
  • Time to clot in presence of kaolin (activates factor 12) and cephalin (substitute platelet phospholipid)
  • Tests INTRINSIC and common pathways (factors 5, 8, 9, 10, 11, 12, prothrombin, fibrinogen)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Define bleeding time and what it tests

A
  • Time required to stop bleeding from a standardized skin puncture
  • Tests primary hemostasis (platelet number and function)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

General causes of thrombocytopenia

A
  • Decreased production (not enough platelets made in BM)
  • Increased destruction (breakdown of platelets in bloodstream, spleen or liver)
  • Med induced
  • Other
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What conditions cause decreased production of platelets?

A
  • Aplastic anemia
  • Leukemia
  • Cirrhosis
  • Folate/B12 deficiency
  • Infections of BM
  • MDS
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What conditions cause increased destruction of platelets?

A
  • ITP
  • TTP
  • DIC
  • HIT
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Define idiopathic thrombocytopenic purpura (ITP)

A
  • Autoimmune
  • Antibodies against several platelet surface antigens (present in 60% of cases)
  • Results in destruction of platelets (thrombocytopenia)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Who is MC affected by ITP?

A
  • Children (50% of cases)
  • Adults are diagnosed 56-60 yo
  • In adults, females MC
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How do adults with ITP typically present?

A

With a chronic condition (idiopathic, lasts longer than 6 months)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How do children with ITP typically present?

A

With an acute condition (usually follows an infection, spontaneous resolution within 6 months)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Pathophys of ITP

A

IgG autoantibodies attack platelet membrane glycoproteins and megakaryocytes (precursor platelets)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Clinical s/s of ITP

A
  • Petechiae, purpura, gingival bleeding
  • Isolated thrombocytopenia
  • NORMAL blood smear
23
Q

When is BM testing indicated in ITP workup?

A
  • Pts w/unexplained cytopenias
  • Pts over 60 yo
  • Pts who do not respond to therapy
24
Q

What is Evans syndrome?

A

ITP with co-existent autoimmune hemolytic anemia

25
Treatment of ITP
- Only if plt count is under 20-30,000 OR significant bleeding - Steroids, IVIG - Platelet transfusion is CONTRAINDICATED
26
Describe thrombotic thrombocytopenic purpura (TTP)
- Rare disorder of blood coagulation system | - Causes extensive microscopic clots to form in small blood vessels throughout the body
27
Who is MC affected by TTP?
Females 3:2 | AAs
28
Etiology of TTP
- Autoimmune (antibody that inhibits ADAMTS13 enzyme activity) - Secondary - Inherited (Upshaw-Schulman Syndrome)
29
What is Upshaw-Schulman Syndrome?
- Inherited type of TTP | - Deficiency of ADAMTS13
30
Pathophys of TTP
- Spontaneous aggregation of platelets, platelets are consumed (decreasing platelet count) - Circulating platelet-vWF complexes are unopposed by ADAMTS13 resulting in microthrombi - Microthrombi cause obstruction and shearing/fragments of RBCs (schistocytes)
31
What is the main defect of autoimmune TTP?
Severely decreased ADAMTS13 activity
32
What is the main defect of secondary TTP?
- Poorly understood - Develop TTP in situations w/increased vWF (e.g. infection) - ADAMTS13 activity is generally normal
33
Activity of ADAMTS13 in autoimmune TTP vs. secondary TTP?
- Decreased activity in autoimmune | - Normal activity in secondary
34
What is ADAMTS13?
- Metalloproteinase responsible for breakdown of UL-vWF | - Without proper cleavage of vWF by ADAMTS13, coagulation occurs at a higher rate (e.g. TTP)
35
Clinical presentation of TTP?
Pentad 1. Thrombocytopenia 2. Microangiopathic hemolytic anemia 3. Neuro symptoms 4. Renal insufficiency 5. Fever
36
What is the pentad?
- Clinical presentation of both TTP and Hemolytic Uremic Syndrome (HUS) - Thrombocytopenia, microangiopathic hemolytic anemia, neuro symptoms, renal failure, fever
37
When a patient presents with the pentad s/s, how to tell TTP vs. HUS?
- If renal failure dominates, it is usually called HUS | - MC in children
38
What is the MC cause of acquired renal failure in childhood?
HUS
39
What are TTP and HUS known as?
Systemic thrombotic microangiopathy (TMA) - leads to thrombotic events, organ damage, death
40
Lab findings of TTP
- Microangiopathic hemolytic anemia with thrombocytopenia | - Schistocytes on blood smear
41
Treatment of autoimmune TTP
Plasmapheresis and steroids
42
Treatment of refractory/relapsing TTP
- Immunosuppressive and steroids | - Possible splenectomy?
43
Treatment of hereditary TTP (Upshaw-Schluman Syndrome)
Prophylactic plasma every 2-3 wks (maintains adequate levels of functioning ADAMTS13)
44
Tranfusion in TTP?
Transfusion is CONTRAINDICATED (fuels coagulopathy)
45
Describe disseminated intravascular coagulation (DIC)
- Acquired clinical syndrome - Widespread activation of coagulation and fibrinolysis - Thrombi formation and bleeding
46
Etiology of DIC
- Severe trauma - Sepsis - Malignancy - Pregnancy complications - Liver disease
47
Pathophys of DIC
- Release of TF triggers over clotting within the body | - This disrupts clotting elsewhere in the body causing abnormal bleeding
48
Clinical presentation of DIC
- Bleeding - Renal and hepatic dysfunction - Respiratory dysfunction - Shock
49
Lab findings of DIC
- Thrombocytopenia - Reduced fibrinogen - Prolonged PT/bleeding time - Elevated D-dimer
50
Treatment of DIC
- Treat underlying condition - Heparin - FFP (temporary/may result in thrombosis) - Platelet replacement if under 5-10,000 and hemorrhaging (temporary/may result in thrombosis)
51
Clinical presentation of HIT
- 5-14 days after starting Heparin - Thrombocytopenia - Thrombosis
52
Pathophys of HIT
- Antibodies against heparin are formed when it is bound to platelet factor 4 (PF4) - Results in platelet activation and formation of clots, dropping platelet count
53
Treatment of HIT
- STOP heparin, replace with DTI therapy | - AVOID platelet transfusion

Clin Med III - Heme/Onc (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions