Decreased production: aplastic anemia, Fanconi anemia, congenital rubella/parvovirus, leukemia, myelofibrosis, myelodysplastic syndrome, ethanol, gold/chemotherapy, chloramphenicol, benzene, radiation
Increased destruction: ITP, SLE, Heparin induced thrombocytopenia, HIV, DIC, TTP/HUS, HELLP, linezolid
Sequestration: Cirrosis --> Portal HTN --> splenomegaly CXR: Cardiomegaly, cephalization (bat-wing appearance), pleural effusion, kerley B lines
EKG: :LVH, prior MI, widened QRS, lead I p-waves for atrial size
Echo: LV function, valves, pulmonary pressure, ejection fraction (50% is normal)
Labs: BNP, troponins, CRP CNS: Tumor, ischemic/hemorrhagic stroke, trauma, psychosis, infection
Tumor: Small cell, CNS, duodenal, pancreatic, olfactory neuroblastoma
Pulmonary: TB, COPD, pneumothorax, ILD, ventilator dependent respiratory failure
Drugs: SSRI, haldol, tegretol, bromocriptine, oxytocin, NSAIDs, ecstasy, reglan
Other: N/V, pain, emotional stress, surgery, HIV