Updated: 11/15/2018

Thrombotic Thrombocytopenic Purpura (TTP)

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https://upload.medbullets.com/topic/120242/images/purpura.jpg
https://upload.medbullets.com/topic/120242/images/ttp.jpg
Snapshot
  • A 24-year-old woman presents to the ED with acute-onset fatigue, fever, and blurry vision. On chart review, it is revealed that she was recently diagnosed with AIDS and was on multiple anti-retroviral medications. On physical exam, her skin is mildly jaundiced. She has multiple purpura over her extremities. Her peripheral smear reveals with schistocytes.
Introduction
  • Thrombotic microangiopathy characterized by a pentad
    • microangiopathic hemolytic anemia
    • acute renal failure
    • thrombocytopenia
    • fever
    • neurologic abnormalities
  • Similar to HUS but with fever and neurologic symptoms
  • Epidemiology
    • female > male
    • most commonly in young adults
    • African-Americans
  • Pathogenesis
    • deficiency or inhibition of metalloproteinase ADAMTS13
      • most commonly disabled by an autoantibody
      • ADAMTS13 degrades vWF multimers
      • deficiency → large vWF multimers → increased platelet adhesion → platelet thrombosis
        • damages brain and kidneys
        • important underlying risk factor, but requires a secondary trigger
    • triggers
      • drugs (quinine, ticlopidine, clopidogrel, and cyclosporine)
      • SLE
      • infections
      • AIDS
      • malignancies
Presentation
  • Symptoms (recall pentad)
    • thrombocytopenia
      • easy bleeding
      • epistaxis
    • neurological symptoms
      • confusion
      • seizures
      • headaches
    • nonspecific symptoms
      • weakness
      • vomiting
      • nausea
    • thrombosis
    • renal dysfunction (less so than HUS)
  • Physical exam
    • fever
    • pallor (from anemia)
    • purpura/petechiae
    • jaundice (from hemolysis)
    • splenomegaly (unlike ITP)
Evaluation
  • Complete blood count
    • anemia
    • thrombocytopenia
  • Peripheral blood smear
    • schistocytes (helmet cells)
  • Serum
    • ↑ LDH
    • ↑ creatinine
    • negative Coomb’s
  • Normal PT/PTT
  • ↑ bleeding time
Differential
  • TTP
  • HUS
  • DIC
  • Other causes of microangiopathic hemolytic anemia:
    • prosthetic valve hemolysis
    • metastatic adenocarcinoma
    • malignant HTN
    • vasculitis


Characteristics
DIC
ITP
TTP
HUS
Fever
  • No
  • No
  • Yes
  • Yes/No
Splenomegaly
  • No
  • No
  • Yes
  • Yes
Platelets
  • Low
  • Low
  • Low
  • Low
Bleeding time
PT
-
-
-
PTT
-
-
-
Shistocytes
  • Yes
  • No
  • Yes
  • Yes
Trauma
  • Yes
  • No
  • No
  • No
 
Treatment`
  • First-line therapy
    • plasma exchange transfusion with fresh frozen plasma  
  • Anecdotal evidence
    • steroids
    • splenetcomy
      • if recurrent
  • Platelet transfusion contraindicated
    • platelet transfusion will worsen disease by feeding the platelet consumption
Prognosis, Prevention, and Complications
  • Prognosis
    • remission with plasma exchange in majority of patients
    • mortality rate 13-15%
  • Complications
    • permanent neurologic sequelae
    • chronic kidney disease
      • especially with quinine-induced TTP
 

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(M2.HE.15.73) A 27-year-old female presents to the emergency department with complaints of acute-onset fatigue, blurred vision, and rash earlier today. Her husband rushed her to emergency department when he noted that she was exhibiting changes in her mental status and had trouble speaking. Her vital signs are as follows: T 38.4, HR 87, BP 110/85, RR 14, and SpO2 96%. Physical examination reveals petechiae, pallor, and left upper extremity weakness. Work-up reveals Hgb 8.5 g/dL, platelets 22,000 cells/uL, normal PT/INR and PTT, absent fibrin split products, elevated fibrinogen, a negative Coombs test, 3.7 mg/dL creatinine, 3.8 mg/dL indirect bilirubin, and LDH 1000 IU/L. Which of the following would be expected on a peripheral blood smear from this patient? Tested Concept

QID: 106575
1

Ovalocytes

4%

(1/25)

2

Spherocytes

4%

(1/25)

3

Atypical lymphocytes

0%

(0/25)

4

Schistocytes

88%

(22/25)

5

Rouleaux formation

0%

(0/25)

M 6 E

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(M2.HE.15.102) A 45-year-old man is brought to the emergency room by his wife because he has been acting confused for the past day. He is febrile, with an oral temperature of 103.6 deg F; vital signs are otherwise stable. His physical exam is significant for the finding shown in Figure A; he has never noticed lesions like these before. He also has subtle right-sided weakness affecting upper and lower extremities. Labs reveal: hemoglobin 7.0 g/dL, hematocrit 21%, white blood count of 10.2 x 10^3 µL, and platelet count of 20 x 10^3 per µL. PT/INR and PTT are normal. A peripheral blood smear is shown in Figure B. What is the most likely diagnosis? Tested Concept

QID: 104742
FIGURES:
1

Idiopathic thrombocytopenic purpura

8%

(2/26)

2

Disseminated intravascular coagulation

8%

(2/26)

3

Thrombotic thrombocytopenic purpura

73%

(19/26)

4

Hemolytic uremic syndrome

8%

(2/26)

5

Evan's syndrome

0%

(0/26)

M 6 C

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Topic COMMENTS (5)
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