Laura Goyack MD, Rachel Skains MD, Robert Buckingham MD
Department of Emergency Medicine, University of Alabama at Birmingham
Introduction
Hematologic emergencies are rare and often difficult to diagnosis due to nebulous presentations that can lead to acute life-threatening conditions and severe hemodynamic compromise. A comprehensive knowledge of prompt diagnostic evaluation with immediate therapeutic intervention is critical in EM practice. The case below highlights the importance of developing a rapid, systematic approach to the diagnosis and treatment in a patient with suspected hematologic emergency.
Case Description
Case: 36yo AAF with no significant PMHx presented to the ED with acute blurry vision and SOB x10 days. Pt was evaluated by an Ophthalmologist and diagnosed with retinal vasculitis. She was referred to the ED for further evaluation because she was noted to be tachycardic and dyspneic. Pt was in USOH until 5mo prior when she developed urticaria, unintentional wt loss, and facial swelling. She was previously evaluated by multiple providers, but workup for autoimmune conditions was inconclusive. She was started on colchicine, metoprolol and prednisone after recent hospitalization for pericarditis and PNA.
Vitals: HR 116, BP 110/70, RR 20, O2 Sat 99% RA, Temp 98.2F
PE: PERRL-EOMI, no scleral icterus/jaundice, S1/S1, no m/r/g, lungs CTAB, 2+ BL LE pitting edema
Labs: WBC 11.74 (Neu 67%, Eos 25%), H&H 9.5/30, (MCV 80), Plts 129.2, LDH 1074,
(+) schistocytes, haptoglobin <30, retic wnl, LFTs wnl, Tbili wnl. Direct coombs (-), Cr 8.3, HCO3 20, CRP 29.41
Imaging: MRI brain/orbits: no acute abnormalities
Discussion
Initially, an autoimmune condition was suspected, as well as acquired hemolytic anemia, as she had renal, ophthalmologic, and hematologic abnormalities. Differential diagnosis included: vasculitis, RPGN, TTP-HUS, DIC, and infection (e.g., HIV).
Hospital Course: On admission she was found to have ATN (muddy brown urine casts), chronic DIC (fibrinogen 152, D-dimer 3,049) and low complements (C3 85, C4 20). A renal biopsy confirmed diagnosis of thrombotic microangiopathy (TMA), most likely primary in the setting of complement-mediated atypical HUS. Ophthalmology diagnosed Purtscher’s retinopathy, which is also consistent with atypical HUS. Pt was started on eculizumab; however, she developed oliguria and was started on iHD. Unfortunately, she developed seizures, suffered PEA arrest and support was withdrawn after tonsillar herniation.
Conclusion
TMA are a group of disorders characterized by endothelial cell injury in the terminal arterioles and capillaries(1). It is distinguished by thrombocytopenia, microthrombi, and microangiopathic hemolytic anemia (MAHA), leading to ischemic tissue injury(2). Primary forms of TMA include: HUS and TTP. However, other causes of thrombotic microangiopathies include: drugs, infection, autoimmune disease, DIC, malignant hypertension and cancer. Early recognition is based on clinical history and focused laboratory studies. Immediate treatment therapies include plasma exchange, steroids and directed biologic therapy as untreated TMA portends a poor prognosis with high mortality with rates up to 72-94% in the absence of effective treatment(3).
- Learning Points:
• TMA = thrombocytopenia, MAHA, schistocytes –> ischemic tissue injury
• Acquired hemolytic anemia laboratory findings: RBC hemolysis, Hgb breakdown, reticulocytosis(4)
• Evaluation for TMA:- Clinical features: non-specific symptoms (weakness, fatigue), abdominal pain, diarrhea, N/V, CNS manifestations (headache, aphasia, diplopia)
- Evidence of end-organ damage (e.g., ARF, seizure, CVA, pulmonary hemorrhage)
- Labs: CBC w/ diff, CMP, retic count, peripheral smear, LDH, haptoglobin, bilirubin
- Treatment: plasma exchange, prednisone, rituximab, eculizumab1
- TMA has a high mortality rate if untreated