When the Script Doesn’t Fit J Gen Intern Me d. 2017 Mar 23

1. DIAGNOSTIC SCHEMA JGIM EXERCISES IN CLINICAL REASONING Teaching Slides by: Rabih Geha, MD & Denise M. Connor, MD • When the Script Doesn’t Fit • J Gen Intern Med. 2017 Mar 23 • Daniel J Wheeler, MD; Thomas Cascino, MD; Bradley A Sharpe, MD; Denise M Connor, MD

2. Diagnostic Schema • A diagnostic schema is a cognitive tool that provides a structured approach to a complex clinical problem. • Schemas convert lists (e.g. specific diagnoses) into mental flowcharts organized by clinically meaningful variables.

3. Volume Overload Causes of lower extremity edema include: • Congestive heart failure • Medications • Chronic kidney disease • Venous stasis • Cirrhosis • Hypothyroidism

4. Diagnostic Schema: • Volume Overload Volume Overload Urgent Non-urgent • Venous Stasis • Congestive Heart Failure • Medications • Liver Disease • Lymphedema • Renal Disease • Hypothyroidism

5. Diagnostic Schema: • Volume Overload Volume Overload Urgent Non-urgent Pitting JVP: elevated JVP: normal Non-pitting • Congestive Heart Failure • Liver disease • Venous stasis • Lymphedema • Hypothyroid • Medications • Renal Disease

6. A Case • Chief Complaint: Pleuritic chest pain • HPI • A 31-year-old man presented to an urgent care clinic with 1 day of left-sided pleuritic chest pain and non-productive cough. • He had no fever, chills, night sweats, or dyspnea. There was no recent travel or immobilization.

7. Pause • Outline your approach to chest pain

8. PMH None PSH None Family History No significant FH • More History • More History • Medications • None • Social History • Lives in California • One female partner • Works in office setting • Modest alcohol use • No tobacco or recreational drugs

9. T 99FBP 117/90 HR 70 RR 19 Sat 96% RA Young man in no acute distress Chest: clear to ausculatation, normal percussion CV: regular rate and rhythmwith no murmurs Abdomen: Soft, non-tender, non-distended Skin: No rashes Remainder of the exam is normal • Physical Exam

10. Imaging

11. Pause • What is your problem representation at this point?

12. Pause • What is your schema for infiltrates on CXR?

13. Diagnostic Schema: • CXR infiltrates CXR infiltrate Pus Water Blood • Pneumonia • Pulmonary edema • ARDS • Aspiration • Alveolar hemorrhage • Pulmonary embolism

14. Pause • What would your next steps be and why?

15. Case Continued • The patient was diagnosed with community acquired pneumonia and started on doxycycline. • One week later he presented to the emergency department with worsening cough, fatigue, fevers and chills. • He was taking the doxycycline as prescribed. • Vials were unchanged.

16. Pause • What is your problem representation so far?

17. Pause • How do you approach the causes of CAP treatment failure?

18. Diagnostic Schema: • CAP treatment failure CAP treatment failure Wrong bug Wrong diagnosis Wrong drug Wrong host • Congestive • Heart • Failure • Doxycycline resistant S. Pneumo • Endemic mycoses • Immuno- • compromised

19. 16 • Eosinophil: 600 (nl: < 500) • 132 • 102 • 22 • Labs • 304 • 12 • 102 • 50 • 4.3 • 23 • 0.9

20. Pause • What do you think about these labs?

21. Imaging • Chest X-Ray • Unchanged

23. Imaging • CT chest with contrast • Scattered centrilobular nodules in the left lung with associated ground glass. • Consolidation in the lingula, left hilar adenopathy and a small left-sided pleural effusion. • No pulmonary embolism.

24. Pause • How would you incorporate these findings into a updated problem representation?

25. Pause • What is your schema for pulmonary disease with peripheral eosinophilia?

26. Diagnostic Schema: • Pulmonary Infiltrates with Eosinophilia Pulmonary Infiltrates+ eosinophilia Hypersensitivity Idiopathic Autoimmune Dx Infection • Acute • eosinophilic • pneumonia • Parasites • Eosinophilic • granulomatosis • with polyangiitis • Drug • reactions

27. Case Continued • The patient was diagnosed with a non-resolving pneumonia and started on Levofloxacin. • Four days later, he returned to the ED with worsening pleuritic pain, cough, night sweats and multiple new, painful, red lesions on his right lower extremity.

28. Physical Exam

29. Case Continued: Further History • After additional history was asked, the patient mentioned that two weeks prior to symptom onset, he had participated in a 10-mile outdoor race near San Diego, California that involved scrambling through an obstacle course of dust, dirt, and mud.

30. Pause • What is your updated problem representation? • What is your prioritized differential diagnosis?

31. Case Continued • A diagnostic test was performed

32. Case Continued • Coccidioides immunodiffusion was positive with a complement fixation titer of 1:4 • The patient was started on Fluconazole with resolution of his symptoms over the next month.

33. Coccidiomycosis • Coccidiomycosis is caused by C. imminitisand C. posadasii, dimorphic fungi endemic to the South Western United States. • Broad spectrum of disease from self-limited flu-like illness to severe disseminated disease in less than 1% of infections. • Other manifestations include rash (erythema nodosum, erythema multiforme) and peripheral eosinophilia. • A travel history is important in making the diagnosis.

34. Diagnostic Schema: Recap • Provides a systematic approach for expanding the DDx (helps to avoid anchoring) • Helps manage cognitive load and maximize problem-solving • abilities • Unique to individual clinicians; enhanced by deliberate practice

35. Acknowledgements • We thank Mark Henderson MD, Jeff Kohlwes MD, and Reza Manesh MD for their critical review of this material

36. Additional Information: Approach to Erythema Nodosum • Lymphoma • OCPs • Post-Strep • Tuberculosis • Endemic myocoses • IBD • Sarcoidosis • Pregnancy