Platelet
Thrombocytopenia
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Thrombocytopenia
, Low Platelets, Low Platelet Count
Definition
Decreased
Platelet Count
below 100k to 150k
See Also
Thrombocytopenia Causes
Platelet Dysfunction
Purpura
History
Family History
of Thrombocytopenia
Consider congenital
Thrombocytopenia Causes
Comorbid conditions
Liver
disease
Heart Valve Replacement
Pregnancy
Gestational Thrombocytopenia
Preeclampsia
with
HELLP Syndrome
Social history
Alcohol Abuse
Recent
Viral Infection
Immune Thrombocytopenia (ITP) in children follows acute
Viral Infection
by days to weeks
Cytomegalovirus
(CMV)
Epstein Barr Virus
(EBV,
Mononucleosis
)
Varicella Zoster Virus
(VZV,
Chicken Pox
)
Parvovirus B19
HIV Infection
Hepatitis C
Tick Bite
Anaplasmosis
Babesiosis
Rocky Mountain Spotted Fever
Lyme Disease
Recent international travel (especially tropical)
Dengue Fever
Malaria
Rickettsial Disease
Medications
Drug-Induced Thrombocytopenia
Heparin-Induced Thrombocytopenia
Chemotherapy
Radiation Therapy
Immunization
s (MMR, Varicella, H1N1
Influenza Vaccine
)
Transfusion
Transfusion Reaction
Infection (
Hepatitis C
or
HIV Infection
)
Symptoms
Clues to
Thrombocytopenia Causes
Abdominal Pain
HELLP Syndrome
(pregnancy)
Hemolytic Uremic Syndrome
(HUS)
Platelet
Sequestration (
Splenomegaly
)
Bloody
Diarrhea
Hemolytic Uremic Syndrome
(HUS)
Fever
Viral Infection
s (e.g. CMV, EBV, VZV, HIV, HCV,
Parvovirus B19
)
Tick Borne Illness
()
Dengue Fever
Malaria
Rickettsial Disease
Hemolytic Uremic Syndrome
(HUS)
Thrombotic Thrombocytopenic Purpura
(TTP)
Weight loss or
Night Sweats
HIV Infection
Leukemia
Myelodysplastic Syndrome
Exam
Complete exam to identify underlying cause (see below)
Deep bleeding (e.g. hemarthrosis) suggest clotting disorder, not Thrombocytopenia
Signs of bleeding (mucosal and superficial bleeding)
Petechiae
Purpura
Gingival Bleeding
Gastrointestinal Bleeding
Urinary tract bleeding
Signs
Clues to
Thrombocytopenia Causes
Rash
Viral Exanthem
s (VZV,
Parvovirus B19
)
Rickettsia
l infections
Systemic Lupus Erythematosus
Generalized Lymphadenopathy
Viral Infection
s (e.g. CMV, EBV, HIV)
Systemic Lupus Erythematosus
Leukemia
,
Lymphoma
and other hematiologic malignancies
Hepatomegaly
Chronic Liver Disease
Leukemia
Viral Infection
s (CMV, EBV, HCV)
Splenomegaly
Viral Infection
s (CMV, EBV)
Neurologic findings
Thrombotic Thrombocytopenic Purpura
(TTP)
Renal Failure
Thrombotic Thrombocytopenic Purpura
(TTP)
Hemolytic Uremic Syndrome
(HUS)
Causes
See
Thrombocytopenia Causes
Categories of Thrombocytopenia
Decreased
Platelet
production (e.g.
Viral Infection
, medications, radiation,
B12 Deficiency
, marrow infiltration)
Increased
Platelet
destruction (e.g. ITP, TTP, HUS, DIC)
Platelet
loss
Splenic Sequestration
Labs
Platelet Count
Interpretation
Platelet Count
70,000 to 150,000 per uL
Mild Thrombocytopenia
Platelet Count
50,000 to 70,000 per uL
Asymptomatic Moderate Thrombocytopenia
Platelet Count
30,000 to 50,000 per uL
Symptomatic Moderate Thrombocytopenia with excessive bleeding on
Traumatic Injury
Platelet Count
30,000 to 50,000 per uL
Symptomatic Moderate Thrombocytopenia with excessive bleeding on
Traumatic Injury
Platelet Count
10,000 to 30,000 per uL
Severe Thrombocytopenia with excessive bleeding with minimal
Skin Trauma
Platelet Count
5,000 to 10,000 per uL
Severe Thrombocytopenia with risk of spontaneous bleeding,
Bruising
or
Petechiae
Spontaneous bleeding requiring intervention (e.g.
Nasal Packing
for
Epistaxis
) required in 42% of patients
Platelet Count
below 5,000 per uL
Emergent Thrombocytopenia with high risk of major spontaneous bleeding (e.g.
Gastrointestinal Tract
, genitourinary tract)
Labs
Initial Evaluation of Thrombocytopenia
Complete Blood Count
(CBC)
Basic chemistry panel (chem8)
Evaluate for associated
Renal Failure
(e.g. TTP, HUS)
Expand to comprehensive panel in
Hemolysis
Indirect Bilirubin
increased in
Hemolysis
Serum
Lactate Dehydrogenase
and
Haptoglobin
increased in HUS and TTP
Coagulation tests (INR, PTT,
Fibrinogen
)
Normal in isolated Thrombocytopenia, ITP, TTP, HUS
Prolonged in DIC, liver disease,
Massive Transfusion
and
Trauma
Fibrinogen
is decreased in DIC and
Trauma
Peripheral Blood Smear
See
Platelet Morphology
See
Peripheral Blood Smear
Schistocyte
s are present in DIC and
Microangiopathic Hemolytic Anemia
(TTP, HUS), but not ITP
Consider
Parasite
stains (
Tick Borne Illness
,
Malaria
)
Hemolysis
will raise
Indirect Bilirubin
Platelet Count
Rule-out
Pseudothrombocytopenia
Review
Peripheral Smear
to evaluate for clumping (
Pseudothrombocytopenia
)
Repeat
Platelet Count
in non-EDTA
Anticoagulant
(citrate, blue tube)
Repeat
Platelet Count
timing (adjust based on chronicity, stability and bleeding complications)
Repeat immediately for developing bleeding complications
Repeat in days to 1 week if
Platelet Count
<50,000 per uL
Repeat in 2 weeks if
Platelet Count
<100,000 per uL
Repeat in 4 weeks if
Platelet Count
<150,000 per uL
Management
Gene
ral Approach
Red Flag Findings accompanying Thrombocytopenia indicating Hematology Referral
Leukopenia
or
Leukocytosis
Anemia
Peripheral Blood Smear
abnormalities
Symptomatic Thrombocytopenia with
Bleeding Diathesis
,
Petechiae
,
Purpura
or
Ecchymosis
Platelet Count
<50,000 per uL (or persistently below 100,000 per uL on repeat testing)
Conditions requiring emergent management
Heparin Induced Thrombocytopenia
(HIT)
Thrombotic Thrombocytopenic Purpura
(TTP)
Hemolytic Uremic Syndrome
(HUS)
Preeclampsia
with
HELLP Syndrome
Disposition home
Isolated Thrombocytopenia >30,000/mm3 without signs of bleeding in children
Isolated Thrombocytopenia >30,000 to 50,000/mm3 without signs of bleeding in adults
No serious cause suspected of Thrombocytopenia (i.e. not HUS, TTP, HIT, DIC)
Less severe causes include ITP and
Drug induced Thrombocytopenia
Reliable patient or family
No
NSAID
S
Follow activity restrictions as below
Management precautions
Avoid platalet transfusion in
Hemolytic Uremic Syndrome
,
Thrombotic Thrombocytopenic Purpura
Avoid
Corticosteroid
s in suspected malignancy (until cancer evaluation and staging)
Management
Activity and Procedure Limitations
Platelet Count
>50,000 per uL
No limitations to activity or procedures
Use caution in
Collision Sport
s with Thrombocytopenia
Most surgical procedures can be perfromed safely at this
Platelet Count
Epidural Anesthesia
is safe at 50,000 per uL, but >100,000 per uL is preferred
Platelet Count
>20,000 per uL
Bone Marrow Biopsy
, bronchoscopy and endoscopy can be performed
Platelet Count
<10,000 per uL
Avoid
Collision Sport
s and other activities with risk of
Traumatic Injury
References
Merrill and Gillen (2016) Crit Dec Emerg Med 30(3): 3-8
Gauer (2012) Am Fam Physician 85(6): 612-22 [PubMed]
George (2000) Lancet 355(9214):1531-9 [PubMed]
Goldstein (1996) Am Fam Physician 53(3):915-20 [PubMed]
Rizvi (1999) Curr Opin Hematol 6(5):349-53 [PubMed]
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