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Toronto Notes 2019
Common Presenting Problems
Hematology H11
Lymphopenia
Definition
• absolutelymphocytecount<1.0x109/L
Etiology
• idiopathicCD4+lymphocytopenia
• radiation
• HIV/AIDS,hepatitisB,hepatitisC
• malignancy/chemotherapeuticagents • malnutrition, alcoholism
• autoimmunedisease(e.g.SLE)
Clinical Features
• opportunisticinfections(seeInfectiousDiseases,ID34)
Treatment
• treatunderlyingcause
• treatopportunisticinfectionsaggressivelyandconsiderantimicrobialprophylaxis
(see Infectious Diseases, ID30) Eosinophilia
Definition
• absoluteeosinophilcount>0.5x109/L
Etiology
• primary:duetoclonalbonemarrowdisorder
■ if no primary etiology identified, classified as hypereosinophilic syndrome
◆ 6 mo of eosinophilia (count >1.5 x 109/L) with no other detectable causes and end organ damage
◆ can involve heart, bone marrow, and CNS • secondary
■ most common causes are parasitic (usually helminth) infections and allergic reactions ■ less common causes
◆ collagen vascular diseases (e.g. RA, polyarteritis nodosa, see Rheumatology, RH19)
◆ respiratory causes (asthma, eosinophilic pneumonia, and Churg-Strauss)
◆ cholesterol emboli
◆ hematologic malignancy: see Chronic Myeloid Leukemia, H40 and Hodgkin Lymphoma, H45 ◆ adrenal insufficiency, see Endocrinology, E34
◆ medications (penicillins) ◆ atopic dermatitis
Treatment
• treatunderlyingcause
• ensurestrongyloidesserologyiscollectedtoruleoutinfectionbeforeinitiatingsteroidsforpatientsatrisk
Agranulocytosis
Definition
• severedepletionofgranulocytes(neutrophils,eosinophils,basophils)fromthebloodandgranulocyte precursors from bone marrow
Etiology
• associatedwithmedicationsin70%ofcases:e.g.chemotherapy,clozapine,thionamides(antithyroid drugs), sulfasalazine, and ticlopidine
■ immune-mediated destruction of circulating granulocytes by drug-induced antibodies or direct toxic effects upon marrow granulocytic precursors
Clinical Features
• abruptonsetoffever,chills,weakness,andoropharyngealulcers
Prognosis
• highfatalitywithoutvigoroustreatment
Investigations/Treatment
• discontinueoffendingdrug
• pan-cultureandscreenforinfectionifpatientisfebrile(bloodculturesx2,urineculture,andchestx-ray
as minimum, initiate broad-spectrum antibiotics)
• considerbonemarrowaspirateandbiopsyifcauseunclear
• considerG-CSF
Basophilia and/or Eosinophilia
Can be an indicator of CML or other myeloproliferative neoplasm, associated with pruritus due to excessive histamine production