++
A 34-year-old woman presented to the ED with dyspnea that began
three hours earlier.
++
The ambulance call report clearly
captures the essence of the patient’s clinical presentation
(Figure 1).
++++
Her chief complaint was: “I can’t breathe.” She
had dull substernal chest pain. The ambulance crew noted that she
was “hysterical and hyperventilating” and that
she was taking birth control pills. During the previous month, she
had had episodes of shortness of breath and dull chest pain.
++
She appeared ill, and the presumptive diagnosis was “rule-out
myocardial infarction.”
++
On arrival in the ED, she was anxious
and in mild respiratory distress. Her vital signs were: blood pressure
120/80 mm Hg, pulse 104 beats/min, respiratory
rate 24 breaths/min, and she was afebrile. Her oxygen saturation
by pulse oxymetry was 88% on room air and 94% on
4 L/min oxygen administered by nasal cannula.
++
On examination, her lungs were clear to auscultation and her
heart was rapid and regular without murmur, pericardial friction
rub, or gallop. Her abdomen was not tender and there was no lower extremity
edema or tenderness. She was overweight.
++
Blood tests, EKG, and chest radiographs were obtained. The EKG
revealed sinus tachycardia and nonspecific T-wave flattening.
++
The chest radiographs were interpreted as being “normal” (Figure
2).
++++
A bolus and infusion of heparin was administered by intravenous
catheter.
+
- Should you order a chest radiograph in this
patient?
- What are you looking for?
++
(There are three significant radiographic findings.)
++
++
Pulmonary embolism (PE) was the primary diagnostic consideration
in this patient. Although the radiograph was initially interpreted
as normal, there are three significant findings: (1) blunting of the
right costophrenic sulcus; (2) relatively increased opacity at the
left lung base; and (3) an enlarged left hilum (Figure 3).
++++
Blunting of a costophrenic sulcus is
most often due to a small pleural effusion, a finding that is sometimes
seen in patients with PE (Figure 3, arrowhead).
However, on the lateral view, the posterior costophrenic sulci are
sharp rather than fluid-filled, as would be expected with a pleural
effusion (Figure 4, arrow). In addition,
pleural fluid generally creates a meniscus with a concave-up contour
rather than convex, as seen on this patient's AP view. The opacity
is therefore not a pleural effusion, but instead represents a peripheral
region of airspace filling, i.e., an ...