1. Fever and dyspnea
-The dynamic of diagnostic test is important
-Systems aspects of Diagnosis
-Clinical Expertise

2. Situation
• A 69 year old man with a recent diagnosis of colorrectal
cancer went to the Emergency Department after a
sudden onset of high fever (38 degrees) and an increase
in his basal dyspnea.
• Physical examination: Alert and orientated. No cyanosis.
Normal heart murmurs. Lung: global hypoventilation.
Abdomen: some pain at the examination, no lumps.
Legs: normal.
• Laboratory data: pO2: 95%. No anemic.Normal cardiac
enzymes.

3. Background
• The patient had a previous diagnosis of Chronic
Obstructive Lung Disease, with some episodes of
respiratory infection. Five weeks before this visit he
stayed at the hospital with a diagnosis of Neumonia in
relation to S. pneumoniae. At that time the X-ray showed
no consolidation but an urinary antigen for Streptococus
pneumoniae was positive.Antibiotics were started and
the patient was discharged in good situation.

4. Assesment
• After clinical examination a blood and
urinary sample was collected. The positive
findings were a moderate increase in
white cells, no anemia, and a positive test
for Streptococus antigen in the urine.
• Antibiotics were started with an
improvement in dyspnea but mild
bronchospasm was still present.

5. X-ray at the emergency room

6. Evolution
• The patient had a TAC scan two days before because
the doctor attending him at the oncology clinic felt some
kind of mild respiratory distress.
• The doctor attending the patient at the emergency room
make a consultation to the radiologist, because he was
not confident about the lack of consolidation.
• Two hours later, the radiologist reading the rutine
radiological test, identified the name of the patient and
the TAC scan with an arterial defect, establishing a
diagnosis of pulmonary thrombosis.

7. Pulmonary Thrombus

8. Case analysis (I)
• The initial diagnosis of pneumonia was
established based on the urinary test result. The
doctor in charge has a positive finding not to far
from logic.
• However, the X-ray was normal for a patient with
chronic respiratory disease.
• The patient had a positive urinary test for
S.pneumoniae five weeks before and probably
the present result was in relation with this.

9. Case analysis (II)
• There is concept called “satisfaction of search”
usually related to radiologist, but in this case the
clinician was also “satisfied” to find an
explanation for this patient with fever.
• Fever can be present also in PE.
• Once a patient has a positive urinary test for S.
pneumoniae a new positive test could be
possible at least during the first month after the
first episode. The “system” is also involved in
this case because some kind of “alert” could
help in the clinical reasoning, and better
communication before laboratory and clinician.

10. Some test characteristics (BinaxNOW)
• Urine specimens in standard containers
• Sensitivity: 86%
• Specificity: 94%