Background: Lassa fever could precipitate a condition of hypercoagulable state with multiple organ involvement. We report an unusual presentation of cerebral vasospasm, intracardiac clot, Wellens syndrome, and popliteal vein aneurysm in a case of Lassa fever. We demonstrate the use of noninvasive imaging in the diagnosis and management of hypercoagulable state in a first case presentation in Lassa fever. Methods: We present a 53-year-old Nigerian woman, with a high-grade fever (39°C) that was associated with chills, headaches, insomnia, anxiety, chest pain, diaphoresis, palpitation, general weakness, muscle aches in all extremities, muscle cramps, dizziness spells, hyperacusis, nausea, vomiting, diarrhea, hematochezia, and abdominal pain. She admitted that her home is infested with rodents. Physical examination revealed severe anemia. Laboratory tests including blood sample analysis and biochemistry were conducted. Lassa fever was confirmed using Lassa virus-reverse transcription-polymerase chain reaction tests. Electrocardiography (ECG), two-dimensional echocardiography, venous duplex ultrasound of the leg veins, and transcranial Doppler ultrasound were performed. Results: Blood tests showed electrolyte imbalance and hypertriglyceridemia. Ultrasound tests revealed intracardiac clots with dyskinetic apical septal wall motion abnormality, saccular aneurysm with popliteal venous thrombosis of the right leg popliteal vein, and cerebral vasospasm of the right internal carotid artery due to cardiogenic microemboli. ECG demonstrated Wellens syndrome. The patient was successfully treated with intravenous ribavirin, whole blood transfusion, broad-spectrum antibiotics, isosorbide dinitrate, pentoxifylline, metronidazole, antimalarial, dexamethasone, erythropoietin, anticoagulants (low-molecular-weight heparin and warfarin), and supportive care. Conclusion: Noninvasive ultrasound modalities were useful for early detection and treatment of hypercoagulable state in Lassa fever.