Acute Illness and Injury Management in Ambulatory Patients
Start with the dangerous differential
In ambulatory urgent care, most visits begin with an undifferentiated complaint. The candidate must know the common benign diagnoses - viral upper respiratory infection, acute otitis media, streptococcal pharyngitis, uncomplicated cystitis, bronchitis, sprains, and simple lacerations - but the exam rewards recognition of the cannot-miss conditions that mimic them. Anchoring on a benign label before completing vital signs and a targeted examination is the classic error.
Key concepts: triage and red-flag vital signs; sepsis screening; asthma exacerbation severity; anaphylaxis recognition with epinephrine first; chest pain differential including acute coronary syndrome, pulmonary embolism, aortic dissection, and pneumothorax; abdominal pain in women of childbearing age; testicular torsion; ectopic pregnancy; meningitis; and pediatric dehydration. Antibiotic stewardship is tested repeatedly: do not treat viral URI or acute bronchitis with antibiotics; use Centor/McIsaac criteria before rapid strep testing; avoid unnecessary fluoroquinolone use.
Traps: normal vital signs do not exclude serious illness early; a “frequent flyer” can still be acutely ill; pulse oximetry can be normal in early anaphylaxis or carbon monoxide poisoning; elderly and immunocompromised patients present atypically; and children with abdominal pain may have pneumonia or pharyngitis.
Worked example: a 24-year-old woman presents with 6 hours of sharp lower abdominal pain and mild spotting. Before imaging or analgesia decisions, obtain a urine hCG. A positive result converts the differential to ectopic pregnancy until proven otherwise, mandating urgent transfer or gynecologic evaluation. Rule of thumb: any woman of childbearing age with abdominal pain, syncope, or vaginal bleeding gets a pregnancy test before discharge.