Fever and dyspnea-The dynamic of diagnostic test is important -Systems aspects of Diagnosis -Clinical Expertise
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.
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.
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.
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.
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.
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.
Some test characteristics (BinaxNOW)• Urine specimens in standard containers• Sensitivity: 86%• Specificity: 94%