Hepatosplenic T-cell lymphoma (HSTCL) is an aggressive T-cell lymphoma with characteristic clinicopathologic features. This chapter highlights the key immunophenotype of HSTCL and underscores the distinct differences between HSTCL and its mimickers, such as γδ T-LGLL and aggressive NK-cell neoplasm.

Congenital pyloric stenosis is a form of gastric outlet obstruction that occurs most often in babies under six months of age. Symptoms include projectile emesis and no loss of appetite. A small olive-sized mass may be palpated on exam, and is pathognomonic if found. Labs may reveal hypochloremic hypokalemic metabolic alkalosis, and will improve with fluid resuscitation. Congenital pyloric stenosis is corrected surgically and prognosis is excellent.

This is an emergency medicine oral board-style case of a transplant patient with a fever. A patient with a history of a renal transplant presents to the emergency department with fever and is found to have sepsis secondary to cellulitis. As transplant patients are immunosuppressed and susceptible to septic shock, successful completion of the case requires the administration of IV fluid bolus, broad-spectrum antibiotics, obtaining blood and urine cultures, consulting the transplant specialist, and appropriately admitting the patient to the ICU.

This chapter describes normal megakaryocytic maturation and the dynamic antigenic changes associated with megakaryocytic differentiation. Common markers used to define the megakaryocytic lineage are highlighted. For acute megakaryoblastic leukemia (AMKL), three distinct clinical groups are discussed, and common chromosomal translocations associated with AMKL are described. The immunophenotypes associated with each AMKL subtype are addressed in detail. For the differential diagnosis, non-neoplastic (such as platelet adhesion) and neoplastic processes (such as acute erythroid leukemia and non-hematopoietic tumors) are included.

This is an emergency medicine oral board-style case of severe facial trauma. An intoxicated patient presents to the emergency department with facial swelling and bleeding after trauma and is found to have a Le Fort III fracture with significant facial swelling, ecchymosis, missing teeth, and bleeding from the oropharynx. Successful completion of the case includes suctioning the airway, repositioning the patient, opening the airway, intubating the patient using an awake or facilitated look technique, and obtaining CTs of the head, C-spine, and facial bones. The patient’s final diagnosis is Le Fort III fracture and facial hemorrhage. The oropharynx continues to bleed, requiring packing and emergent otolaryngology or oral maxillofacial surgery consultation. This chapter discusses specific considerations for difficult airway management in the setting of significant facial trauma.

A 78-year-old male with a history of Parkinson’s disease and hypertension is sent to the ED from his skilled nursing facility for one week of worsening abdominal pain. He is nauseous and has vomited once in the past 24 hours. His pain is worse with eating. He has a history of constipation and has not had a bowel movement in over a week. On exam, he appears uncomfortable. His vital signs are notable for mild tachycardia with a heart rate of 98, and mild tachypnea with a respiratory rate of 22. His abdomen is soft but distended and diffusely tender to palpation. Given the patient’s use of anticholinergic medication and chronic constipation, he is at elevated risk of an abdominal emergency. While awaiting CT, abdominal x-rays are obtained that show massively dilated bowel loops confirming the diagnosis of sigmoid volvulus. After decompression by sigmoidoscopy, the patient is taken to the OR for sigmoid resection to prevent recurrence. This life-threatening diagnosis is not to be missed; maintain a high index of suspicion among bedbound elderly patients despite a sometimes indolent presentation.

Cat bites can lead to infection and therefore should be treated with appropriate wound care, irrigation, and prophylactic antibiotics. Left untreated, some of these infections can spread hematogenously and cause septicemia. IV antibiotics may be considered for high-risk bites. Though rare, cat bites can be associated with rabies; providers should ask the patient about the cat’s vaccination status, if known. Consider administering the rabies vaccine in high-risk cases. Tetanus immunization should also be administered if it has been more than 5 years since the patient received their last tetanus vaccine. X-ray can be helpful to check for foreign bodies, especially with puncture wounds. Puncture wounds to the hands should be closely examined for possible tendon injury. Though most infections are polymicrobial, the most common species isolated from cat bites are Staphylococcus, Streptococcus, and Pasteurella multocida. All patients with cat bites should be instructed to follow up in 24−48 hours for a reevaluation, given the possibility for worsening infection.

This case is a presentation of a 56-year-old female with a history of diabetes, hypertension, hepatitis C, and cirrhosis presenting with massive hematemesis. She is hypotensive and tachycardic. Learners should identify these vital sign abnormalities and begin fluid resuscitation and blood product administration. Nuances of managing presumed variceal bleeding such as antibiotic administration, esophageal balloon tamponade with intubation in case of airway compromise, and prompt GI consultation should be considered.

This chapter presents a case of a 66-year-old male with severe heart failure with a left ventricular assist device (LVAD) emergency. The candidate will be able to recognize and manage one of the common issues that affect these patients. The candidate will also be able to evaluate the LVAD device and learn some basics of how to handle the management of these patients.

This chapter includes the diagnosis of T-lymphoblastic leukemia/lymphoma (T-ALL/LBL) and measurable disease detection (MRD) post therapy. Flow cytometry immunophenotyping is essential in establishing a diagnosis of T-ALL/LBL and subclassifying by their maturation into early T-phenotype (ETP), near ETP, cortical thymic T-, and mature T-ALL/LBL. Recent advancement in genetic classifications of T-ALL/LBL shows high-risk genetic alterations are highly associated with ETP-ALL. T-ALL/LBL show overlap features with acute undifferentiated leukemia, mixed phenotype T/myeloid, T/B leukemia, indolent T-lymphoblastic proliferation, and mature T-cell lymphoma/leukemia. The features pertinent for differential diagnosis are illustrated. For MRD, the discussion includes the principles and strategies, analysis and interpretations, mimics and common pitfalls. The pros and cons of flow cytometry MRD are compared with molecular MRD, including NGS sequencing (Clonoseq). Although currently there is no FDA-approved CAR T-therapy for T-ALL, promising products such as CD7-CAR and CD5-CAR have been used in clinical trials. Strategies in MRD and challenges in the era of targeted therapy are discussed.

A retropharyngeal abscess is a serious infection of the soft tissue behind the pharynx, which can in severe circumstances lead to airway obstruction or sepsis. They typically occur in children ages 2−4 years old and are associated with symptoms such as drooling, fever, sore throat, trismus, and neck stiffness with extension. Early interventions include airway evaluation, IV access, broad-spectrum antibiotics, and ENT consultation. Plain films can be suggestive of a retropharyngeal abscess, but a CT of the neck is often needed for diagnosis. Retropharyngeal abscesses often need surgical drainage, especially if they do not respond promptly to antibiotics.

This is an emergency medicine oral board-style case of an exacerbation of chronic obstructive pulmonary disease (COPD). A patient with a history of COPD presents with respiratory distress and requires treatment. Successful completion of the case includes the administration of β-agonists such as albuterol, anticholinergic agents such as ipratropium bromide, steroids, and antibiotics. Oxygen use, steroid use, antibiotic use, use of BiPAP and CPAP, and mechanical ventilation are discussed in the context of COPD exacerbation.

Pediatric patients frequently present with musculoskeletal pain to the emergency department. Slipped capital femoral epiphysis (SCFE) is a common cause of hip pain and disability in adolescents. It is caused by slipping of the epiphysis of the femur on the metaphysis. The incidence is highest in obese males during the time of adolescent growth spurt. Pain and limp may be insidious, causing a worsening chronic limp, though an acute injury may exacerbate the condition, prompting presentation to the emergency department. Patients may present with knee pain due to referred hip pain. The hip should always be examined in pediatric patients presenting with knee pain. X-rays are diagnostic for the condition. Treatment is non-weight-bearing and percutaneous pinning. Early treatment is critical to avoid complications that can lead to permanent disabilities.

This chapter describes a case of a 33-year-old male who was found unconscious. The patient was initially unresponsive and had no apparent obstruction or trauma. Naloxone was administered in titrated doses as the patient had a history of working as a home health aide for a client with advanced cancer and had access to fentanyl patches and oxycodone tablets. The patient responded to the treatment and was observed for 12 hours. The chapter highlights the importance of early actions, including administering naloxone incrementally, monitoring and observing patients after naloxone administration, and performing a fingerstick glucose test. The chapter also provides pearls to manage opioid overdose, including the use of titrated doses of naloxone and the consideration of naloxone prescription for patients being discharged after opioid overdose.

This chapter provides the learner with the skills and knowledge for cases that involve a patient who comes in with undifferentiated right-sided back pain who is later found to have pyelonephritis. However, the case is complicated by the patient being a pregnant 30-year-old female who is allergic to penicillin and therefore the critical actions would be to determine her pregnancy and allergy, and then to prescribe the most appropriate antibiotics for a pregnant female.

This chapter briefly describes the clinicopathologic features of mycosis fungoides and Sezary syndrome. We focus on their immunophenotype as well as the differential diagnosis, which includes T-prolymphocytic leukemia, adult T-cell leukemia/lymphoma, T follicular helper cell lymphoma, and reactive T cells.

Mixed-phenotype acute leukemia (MPAL) comprises acute leukemias with discrete admixed populations of myeloid and lymphoid blasts (bilineal or mixed lineage) or with coexpression of lymphoid and myeloid markers in a single blast population (biphenotypic or mixed phenotype). However, the distinctions between mixed-lineage and mixed-phenotype MPAL are not always clear-cut. This chapter focuses on explaining the diagnostic criteria for MPAL and lineage-defining markers, summarizing its biological and genetic features, and addressing common diagnostic pitfalls of these unusual leukemias as part of the differential diagnostic considerations.

This emergency medicine oral boards case describes the diagnosis and appropriate management of LVAD (left ventricular assist device) thrombosis. The case presents an older male patient with an LVAD who presents to the emergency department in respiratory distress. The history reveals that the patient has advanced heart failure and received surgery for an LVAD implantation 2 years prior. He has been compliant with his medication, but his LVAD has been showing higher power readings and lower flow rates than usual. His exam shows that he is in respiratory distress, has a low MAP (mean arterial pressure) and has signs of volume overload. His diagnostic studies indicate thrombosis and hemolysis, as well as pulmonary edema. These studies raise high suspicion of a thrombus in the LVAD pump causing LVAD dysfunction and cardiogenic shock. A heparin infusion should be initiated and the LVAD team and cardiothoracic surgery should be consulted in order to expeditiously treat the LVAD thrombus and restore adequate perfusion to the patient. LVADs, although lifesaving and life-prolonging, are associated with numerous complications. As LVAD utilization increases, emergency physicians must be well versed in their management.

The chapter describes the case of a 55-year-old male with severe abdominal pain, nausea, and vomiting, who presents with worsening abdominal distension, pain, and two episodes of vomiting. The patient has a history of hypertension, diabetes, and asthma, and has had swelling in the groin before, but it has gotten worse, more painful, and has become “hard.” The physical examination reveals a distended, diffusely tender abdomen, bowel sounds absent, and a large right inguinal hernia that is not reducible, with overlying skin that is dusky. The patient is diagnosed with an incarcerated hernia with bowel obstruction. Critical actions include recognition of the hernia, large-bore IV access and fluid bolus, upright chest x-ray, CT abdomen pelvis with IV contrast, pain management and antiemetics, nasogastric tube placement if symptoms are not controlled, broad-spectrum antibiotics, and surgery consult. The chapter provides several pearls, including the importance of fluid resuscitation, recognition of peritoneal signs, and avoiding reduction of a strangulated hernia, which can lead to perforation and sepsis.