The Virtual Hospital: ElectricPE: The Diagnosis of Pulmonary Embolism: Osteosarcoma and Back Pain

ElectricPE: The Diagnosis of Pulmonary Embolism: Case Study 27

Osteosarcoma and Back Pain

Jeffrey R. Galvin, M.D. and James J. Choi, B.S.
Peer Review Status: Internally Reviewed

This case was 64 year old male who presented to the emergency room ten days after an above the knee amputation for a left lower extremity osteosarcoma. He complained of severe, left sided, chest pain that had started the night before as a mild soreness in the his lower left ribs. The symptoms progressed to severe pain with inspiration. This discomfort radiated around to his back and was associated with shortness of breath and cough. His arterial blood gases on admission were: PH 7.47, PCO2 35 and PO2 76 on room air.

Cardiac enzymes and an EKG were unremarkable. The chest x-ray demonstrated a left lower lobe density that was not present on a chest radiograph done 2 weeks earlier.

The V/Q scan showed a large segmental area of decreased perfusion in the left lower lobe that matched a similar area of abnormality on the chest x-ray. The ventilation scan was read as normal. The V/Q scan was originally read as high probability for pulmonary embolus.

A chest CT done to rule out metastases from the patients osteosarcoma showed a pleural based density in the posterior segment of the left lower lobe. The mediastinal views showed clot in a segmental artery.

Case Assessment
This was a 64 year old man who was 10 days post-op and presented with pleuritic chest pain, dyspnea, cough, and respiratory alkalosis.

1. This is a classic presentation for pulmonary embolus. The diagnosis is not difficult when the patient presents with this constellation of symptoms and a predisposition such as prior surgery. As you will see from the other cases, the manifestations of pulmonary embolus are protean and the clinician must have a high index of suspicion.

2. The case illustrates the variability of V/Q scan reading. This scan could have read this as an indeterminate (Non-diagnostic) scan because of matched perfusion and chest radiograph abnormalities.

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