Dual Process Theory: Clinical Reasoning and Chorea in a 60-Year-Old Woman

1. DUAL PROCESS THEORY • JGIM EXERCISES IN CLINICAL REASONING • Teacher’s Guide: • Gabrielle Berger MD, Juan Lessing MD A 60-Year-Old Woman with Chorea and Weight Loss J Gen Intern Med. 2012 Jun;27(6):747-51. Amanda Vick, MD, Ryan R. Kraemer, MD, Jason L. Morris, MD, Lisa L. Willett, MD, Robert M. Centor, MD, Carlos A. Estrada, MD, MS, and J. Martin Rodriguez, MD. University of Alabama and Veterans Affairs Medical Center, Birmingham

2. Objectives Define Dual Process Theory. Describe the application of System 1 and System 2 thinking to clinical reasoning.

3. Dual Process Theory • Cognitive psychology framework adapted for clinicians to organize complex information Acad Med. 2009; 84:1022-28.

4. Dual Process Theory • Experienced clinicians activate System 1 or System 2 thinking depending on clinical scenario

5. The Case Chief Complaint: abnormal movements and weight loss HPI • A 60-year-old woman was transferred to tertiary care for further evaluation of choreiformmovements and weight lossFor the past 6 months she endorsed: • Progressive clumsiness and chorea • Difficulty speaking and eating due to involuntary movements of the mouth • Intermittent progressive abdominal pain and nausea • Documented unintentional weight loss (60lbs)

6. Discussion What do you know/remember about chorea? What diagnoses come to mind (System 1)? What organizational approach would help you broaden your differential diagnosis (System 2)?

7. Dual Process Theory System 1: The Intuitive Approach • Relatively quick • Implicit, uses first impressions • Based on pattern recognition • Requires little cognitive effort • Experienced clinicians use more often • Example: • “Common disorders associated with chorea are Sydenham chorea and Huntington disease.”

8. Dual Process Theory System 2: The Analytical Approach • Commonly used by novice clinicians or by experienced clinicians when confronted with diagnostic dilemmas • Slow process, less susceptible to bias • Explicit, based on knowledge and logic • Requires considerable cognitive work Example: “Possible etiologies of chorea include metabolic disorders, nutritional deficiencies, infections, immune-mediated disorders, vascular ischemia, toxins and medication side effects.”

9. Clinical Teaching Point • Chorea • An uncommon symptom, especially in older adults • Hyperkinetic movement disorder • Rapid, semi-purposeful, non-patterned involuntary movements involving distal or proximal muscle groups • video: http://www.edge-cdn.net/video_900389?playerskin=37016

10. Clinical Teaching Points

11. PMH Afib HTN Hypothyroidism Vitamin B12 deficiency Social History Widowed 30 pack-year history of tobacco use, quit 6 months ago No alcohol or illicit drug use More History More History Medications • Atorvastatin • Digoxin • Furosemide • Levothyroxine • Vitamin B12 • Warfarin • Family History • No known history of neurodegenerative disease or malignancy

12. T 98.6 °F BP 108/62 HR 114 Sat 97% RA General: cachectic, chronically ill appearing, in no distress. Alert and oriented CV: heart rhythm irregularly irregular, no murmur Pulmonary, gastrointestinal and integumentary systems normal Physical Exam

13. Physical Exam cont’d: Neurological Exam Mental Status: Alert and oriented to name, place, date Cranial Nerves: Oral dyskinesias and severe dysarthria. Motor: moderate generalized muscle atrophy consistent with cachexia and paratonia in both upper extremities (involuntary variable resistance during passive movement). Choreiform movements in upper extremities. 4/5 strength in all extremities. Sensory: decreased vibratory sensation below both knees. Reflexes: 1+ in upper extremities, absent in lower extremities. Flexor plantar responses. Coordination: finger-to-nose task impaired due to upper extremity chorea Gait: not tested as patient unable to stand.

14. Discussion What studies do you want and why?

15. Labs and Additional Studies TSH: normal INR: 2.3 electrolytes normal CBC normal Electromyelogram • Mild distal motor neuropathy • CT head/chest/abdomen/pelvis with and without contrast • No significant findings

16. Additional Imaging • MRI brain • T1 hyperintensity within the basal ganglia with thalamic sparing. • No areas of ischemia or hemorrhage.

17. Discussion • Based on this new information, what is your problem representation* for this patient? Use your problem representation to refine your differential diagnosis. • Are you using intuitive (System 1) or analytical (System 2) reasoning? • What would you do next? • *Problem representation: a summary sentence that highlights the defining features of a case

18. Case Continued • Neurology was consulted. The constellation of abnormal neurologic exam findings, hyperintensity of the basal ganglia, and normal labs raised suspicion for a paraneoplastic neurologic syndrome. • Paraneoplastic antibody tests were performed and returned positive for anti-CRMP-5 IgG at a level of 1:3,840 (normal < 1:240). • Malignancy has been reported in greater than 90% of cases with anti-CRMP-5 antibody.

19. Case Continued

20. Patient underwent 4 cycles of chemotherapy, lung radiation therapy and prophylactic whole brain radiation therapy. One year following treatment, she had gained weight, was eating well, and was no longer wheelchair-bound. Most recent CRMP-5 antibody titer was negative. Patient Outcome

21. Recap: Dual Process Theory • Dual Process Theory describes how expert clinicians think. • System 1 is fast and relies on pattern recognition, while System 2 is slower and relies on an effortful attempt to organize and structure knowledge. • Incorporating Dual Process Theory into clinical problem-solving helps clinicians consciously slow down and avoid cognitive biases when faced with diagnostic dilemmas.

22. Teaching Point • Underlying malignancy with paraneoplastic syndromes should be considered for patients with clinical syndromes that do not fit with common illness scripts. • The CRMP-5 antibody can produce chorea and seems to be associated with malignancy in greater than 90% of cases.

23. Acknowledgements • Teaching slides are based on: Vick A, Kraemer RR, Morris JL, Willett LL, Centor RM, Estrada CA, Rodriguez JM. A 60-Year-Old Woman with Chorea and Weight Loss. J Gen Intern Med. 2012;27(6):747-51. • This work, assisted by editorial group Drs. Carlos Estrada, Amanda Vick and Jeff Kohlwes, is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License

24. References • Bhatnagar D, Morris JL, Rodriguez M, Centor RM, Estrada CA, Willett LL. A middle-age woman with sudden onset dyspnea. J Gen Intern Med. 2011;26:551-4. • Dhaliwal G. Going with Your Gut. J Gen Intern Med 26:107–109. • Henderson MC, Dhaliwal G, Jones SR, Culbertson C, Bowen JL. Doing what comes naturally. J Gen Intern Med. 2010;25:84-7. • Croskerry P. A universal model of diagnostic reasoning. Acad Med. 2009; 84:1022–1028. • Norman G. Dual processing and diagnostic errors. Adv Health SciEduc Theory Pract. 2009. Suppl 1:37-49. • Eva KW, Hatala RM, LeBlanc VR, Brooks LR. Teaching from the clinical reasoning literature: combined reasoning strategies help novice diagnosticians overcome misleading information. Med Educa 2007; 41: 1152–1158. 10.1111/j.1365-2923.2007.02923.x • Bowen, JL. Educational Strategies to Promote Clinical Diagnostic Reasoning. N Engl J Med 2006;355:2217-2225. • Gozzard P, Maddison P. Which antibody and which cancer in which paraneoplastic syndromes? Pract Neurol. 2010;10:260-70. • Pellacia T, Tardif J, Triby E, Charlin B. An analysis of clinical reasoning through a recent and comprehensive approach: the dual process theory. Med Educ Online 2011; 16:5890. doi: 10.3402/meo.v16i0.5890.