Magnetic resonance imaging (MRI) is widely used as a non-invasive imaging modality for a wide variety of diseases and disorders. A patient placed in the MR machine for scanning is subjected to a powerful static magnetic field, rapidly varying gradient magnetic field, and radiofrequency field -in addition to the risk factors associated with gadolinium-based MR contrast agents. At present, there is no conclusive evidence for adverse biological effects in patients undergoing MRI. However, a clear understanding of the various bioeffects associated with MRI diagnostics is necessary to ensure the safety of patients as well as to justify its clinical use.
The thalassemias are a heterogenous group of inherited disorders of hemoglobin (Hb) synthesis characterized by a lack of or decreased /defective synthesis of globin chains. The name Mediterranean anemia, which Whipple introduced, is misleading because the condition can be found in any part of the world. In ά-thalassemia, ά-globin chain synthesis is reduced, whereas in β-thalassemia, β-globin chain synthesis is defective. Their clinical severity varies widely, ranging from asymptomatic forms to severe or even fatal entities. Like most anemias, erythropoietin production and erythropoiesis is increased in thalassemia causing erythroid marrow hyperplasia as well as extramedullary haematopoiesis which is a common compensatory mechanism for chronic anemia found in patients with hemoglobinopathies such as thalassemia, sickle cell anemia, and hereditary spherocytosis. These patients are usually asymptomatic. Extramedullary hematopoiesis (EMH) usually manifests in the liver, spleen, kidneys and as paravertebral masses. Extramedullary hematopoietic tissue occurring within the spinal canal and causing cord compression is an unusual but well-described entity. Total surgical excision is usually not feasible because of the diffuse spread of extramedullary hematopoietic tissue and the possibility of recurrence, but acute neurological impairment does require emergency surgery. Extramedullary hematopoiesis is radiosensitive so radiation therapy is widely accepted as a very effective mode of therapy. Repeated blood transfusion and cytostatic agents are also recommended for treatment.We report a case of a 35-year-old man with underlying beta thalassemia intermedia who developed pain in lower back and progressive paresthesia and weakness of both lower limbs due to multifocal extramedullary epidural hematopoietic tissue occurring within the spinal canal with compression over the cord.
Case presentationA 73-year-old male presented to the emergency department (ED) with worsening shortness of breath (SOB) and cough over two weeks. One week ago, he was seen in clinic for similar symptoms and was prescribed amoxicillin. His symptoms got worse and he came to the ED next week. Physical examination was significant for dullness on percussion and decreased breath sounds on the left side of chest. His oxygen saturation was 70% by pulse oximetry on ambient air; was started on oxygen via non-rebreather mask at flow of 11 L/min with improvement to 88%. Chest radiograph (CXR) showed large left-sided pleural effusion with mediastinal shift to the right (Fig. 1A). He underwent placement of a pigtail catheter on the left under ultrasound guidance for pleural fluid removal. Over 1 h, a total of 2.5 L were removed. His SOB improved and oxygen requirement decreased to 2 L/ min. Repeat CXR confirmed expansion of the left lung ( Fig. 1B). Two hours later, patient developed tachypnea, tachycardia, and respiratory distress, resulting in the need for BiPAP with FIO2 of 100%. CXR showed severe left sided pulmonary congestion (Fig. 1C).What is the diagnosis for worsening shortness of breath after thoracentesis? DiscussionRe-expansion pulmonary edema (REPE) is a complication that occurs after rapid re-expansion of a collapsed lung within 1 to 24 h. It has been reported < 1% in most studies [1] with variable mortality rate even up to 20% in one study. Risk factors associated with REPE include: age < 40, lung collapse for > 7 days, degree of lung collapse, rapid reexpansion of collapsed lung, and presence of large hydrothorax or pneumothorax. The pathophysiologic mechanism of REPE is unknown [1]. Clinical features vary from cough and chest tightness to acute respiratory failure [3]. Treatment is usually supportive and includes continuous non-invasive positive pressure ventilation or mechanical ventilation in severe cases; some patients also require vasopressors, steroids and diuretics [2].It remains uncertain how much fluid can be safely drained since occurrence of REPE does not correlate well with the volume of fluid removed after thoracentesis [1]. Studies have shown that pleural pressure (Ppl) monitoring during thoracentesis helps to prevent REPE. In cases where Ppl is not being monitored, consensus is to terminate thoracentesis after removal of 1 L of fluid [1].Our case highlights the importance of identifying risk factors for development of REPE during large volume thoracentesis. It also highlights the importance of considering usage of pleural manometry during thoracentesis and having a heightened awareness of development of new symptoms during the fluid removal. Ethics approval and consent to participateNot applicable.
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