Thrombocytopenia

Brief HPI:

A middle-aged female with no known medical history is brought to the emergency department with altered mental status. Her family notes worsening confusion over the past 2-3 days associated with vomiting and yellow discoloration of skin and eyes.

Initial vital signs were normal, though with borderline hypotension (99/64mmHg). Examination demonstrated an alert, but lethargic patient with jaundice and scleral icterus, no skin lesions were appreciated. Laboratory studies were obtained:

CBC

  • WBC: 21.3 (N: 83%, Bands: 11%)
  • Hb: 5.5
  • Plt: 6k
  • Marked schistocytes

Coagulation Panel

  • INR: 1.26
  • PTT: Normal
  • Fibrinogen: Normal
  • FDP: Normal
  • D-dimer: >9,000 (normal 250)
  • Haptoglobin: Undetectable
  • LDH: 1493

CMP

  • Creatinine: 1.1
  • AST/ALT: Normal
  • TB: 4.3, DB: 0.8

Imaging:

CT Head: No acute intracranial process.

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CT Abdomen/Pelvis with Contrast

Moderate free intra-abdominal fluid, heterogeneous liver with periportal edema, dense right middle lobe consolidation.

ED Course:

The patient developed worsening respiratory failure with hypoxia and tachypnea requiring endotracheal intubation. Thrombotic thrombocytopenic purpura was suspected and while awaiting emergent plasma exchange transfusion, the patient arrested and resuscitation efforts were unsuccessful.

The patient’s ADAMTS13 activity level was <3%. Autopsy demonstrated consolidation of the right middle lobe with possible lymphoproliferative mass, and lung petechial hemorrhages from microvascular thrombi.

Differential Diagnosis of Thrombocytopenia 1-7

Differential Diagnosis of Thrombocytopenia

Algorithm for the Evaluation of Thrombocytopenia 8

Algorithm for the Evaluation of Thrombocytopenia

Definition 9

  • Mild: <150k
  • Moderate: 100-150k
  • Severe: <50k
    • 10-30k: bleeding with minimal trauma
    • <10k: increased risk spontaneous bleeding

History 9,10

  • Prior platelet count
  • Family history bleeding disorders
  • Medications
    • Heparin
    • Quinine, quinidine
    • Rifampin
    • Trimethoprim-sulfamethoxazole
    • Vancomycin
  • Alcohol use
  • Travel-related infections

Physical Examination 9,10

  • Splenomegaly (liver disease)
  • Lymphadenopathy (infection, malignancy)

Workup 10,11

Schistocytes

Red blood cell fragments (schistocytes) 11

  • hCG
  • Repeat CBC
    • Detect spurious measure
    • Neutrophil-predominant leukocytosis: bacterial infection
    • Immature leukocytes (blasts): leukemia, myelodysplasia
  • Peripheral smear
    • Schistocytes: microangiopathic process (DIC, TTP, HUS)
    • Atypical lymphocytes: viral infection
    • Intracellular parasites: malaria
    • Hypersegmented neutrophils: nutritional deficiency
  • Infectious features: HIV, HCV, EBV, H.pylori, blood cultures
  • Autoimmune features: ANA, APL-Ab
  • Suspected occult liver disease: LFT, PT/PTT/INR
  • Suspected thrombotic microangiopathy: PT/PTT/INR, haptoglobin, LDH, fibrinogen, FDP, d-dimer

Specific Conditions 2-6,9,12-20

Disease Cause Presentation Laboratory Findings Treatment
DIC Sepsis
Trauma
Burn
Malignancy
Bleeding
Multi-organ failure
Shock
INR
Fibrinogen
FDP
D-dimer
Directed at underlying cause
Transfusion thresholds for hemorrhage:
FFP for INR >1.5
Platelets if <50k
Cryoprecipitate of fibrinogen <100mg/dL
TTP Insufficient ADAMTS-13 activity Non-specific constitutional symptoms (ex. weakness)
Neuro: headache, AMS, focal neuro deficit
GI: abdominal pain, nausea/vomiting
LDH
Reticulocyte
Unconjugated bilirubin
Haptoglobin
Plasma exchange
HUS Shiga-toxin-producing bacteria, E. coli O157:H7 Bloody diarrhea, anuria, oliguria, and hypertension Aggressive supportive care
HELLP Spectrum of eclampsia Hypertension
Visual symptoms
Headache
RUQ abdominal pain
AST/ALT
Uric acid
Unconjugated bilirubin
LDH
Reticulocyte
Haptoglobin
Delivery, MgSO4
ITP Primary ITP

Secondary ITP
– Drug
– Autoimmune
– Infection
– Malignancy

Usually asymptomatic, may have petechiae or easy bruising Isolated thrombocytopenia Steroids
HIT Exposure to heparin or LMWH Thrombocytopenia or a 50 percent reduction in platelet count between 5-10d exposure
New thrombosis or skin necrosis
4 T’s score
Platelet factor 4 antibodies Withdraw heparin

References

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  3. Leslie SD, Toy PT. Laboratory hemostatic abnormalities in massively transfused patients given red blood cells and crystalloid. Am J Clin Pathol. 1991;96(6):770-773.
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