DIAGNOSING THE CAUSE DIAGNOSING THE CAUSE OF CHEST PAINOF CHEST PAIN

Dr. Rashidi AhmadEmergentist

MD(USM), MMED(USM), FADUSM

School of Medical Sciences

USM Health Campus

Knowledge is a process of pilling up Knowledge is a process of pilling up facts. Wisdom lies in their simplificationfacts. Wisdom lies in their simplification

Martin Luther King, Jr

Introduction

Chest pain is the chief complaint in about 1-2% of outpatient visits.The cause is often non-cardiac BUT heart disease remains the leading cause of death.Chest pain in ED, > 50% due to CV condition.In outpatient primary: musculoskeletal conditions, GIT disease, stable CAD, pulmonary disease, etc.Unstable CAD is rare.15% never reach a definitive diagnosis.

Buntinx F, et al. Chest pain in general practice or in the hospital emergency department: is it the same? Fam Pract 2001;18:586-9.

Epidemiology of Chest pain in primary care setting & ED

Buntinx F, et al. Chest pain in general practice or in the hospital emergency department: is it the same? Fam Pract 2001;18:586-9.

Chest Pain Origin - Difficult?

Various disease processes in a variety of organs.The severity of pain is often unrelated to its life threatening potential.The location of pain perceived by the patient frequently does not correspond with its source.PE, lab Ix, X-rays are often unavailable or non diagnostic.More than one disease process may be present.

Misdiagnosis of ACS

Young patientAtypical presentation & silent ischemiaPoor documentation & incomplete history & physical examinationECG misinterpretationReliance on laboratory assayInexperience doctorHesitance to admit patients with vague symptoms

History

Chest discomfort ~ 80 - 85% Atypical presentation ~ 20%burning/indigestion ~ > 20%chest ache ~ 13%sharp, stabbing pain ~ 5%pain reproduced by palpation ~ 5%Silent ischemia ~ 23%

History

• Up to 33% of patients (elderly & diabetes), who have AMI do not have pain. Canto et al,. JAMA, vol. 283, p. 3223, 2000

• The presence or absence of risk factors does not change the likelihood of cardiac. Graber & et al. Emergency Medicine April 2001

Accuracy of chest pain diagnosis using the Hx & PE

WILLIAM E. CAYLEY, American family Physician. Volume 72, Number 10 , November 15, 2005

Physical examination

Most often normal

Levine’s sign

"No astute clinician is reassured by chest wall tenderness that reproduces a patient's pain, because 15% of patients with acute MI will have chest wall tenderness on palpation that reproduces their pain"

Rosen and Barkin. Emergency Medicine Concepts and Clinical Practice, St. Louis, Mosby, 1999

Electrocardiogram

NOT a perfect indicator of cardiac diseaseONLY 50% with a proven AMI have positive initial ECG indicating the disorderUp to 76% of ACS – normal an initial ECG, non specific, or unchanged from previous ECG Around 5% of chest pain patients with normal ECG who were discharged from the ED were ultimately found to have ACS

Mc Carthy B, Wong J. Detecting acute ischaemia in ED. J Gen Int Med 1990; 5: 381-8

Relation between time & ECG changes

Time Indication of infarct in ECG

1st to 3 hours 40%

4th to 6th hour 50%

7th to 9th hour 90%

10th to 12th hour Up to 100%

Relation between Cardiac markers & time

Cardiac marker Within time of elevation

Myoglobin

1 – 3 hour

CK-MB/Trop I

Troponin T

4 – 8 hour

6 – 8 hour

•At hours: 4 to 8 and 8 to 12 the CPK level is more sensitive (84% and 94%, respectively) in indicating AMI, than is troponin level (74% and 88%, respectively). •After 12 hours: troponin level is essentially 100% sensitive, whereas the CPK level becomes less sensitive

Graber & et al. Emergency Medicine April 2001

Acute Pulmonary embolism

Diagnosing PE requires a high degree of clinical suspicionSharp chest pain - 59%Dyspnea - 78%Cough - 43%Tachycardia - 30%Syncope 13%

Acute Pulmonary embolism

• Not all patients with pulmonary embolus will be hypoxic or have tachycardia or tachypnea.

• Up to 50% of patients with DVT have a silent, or asymptomatic PE.

• Among PE patients without underlying pulmonary disease, ~ 12% have a PaO2>80 mmHG

Meingnan 7 et al. Archives of Internal Medicine, 2000, Vol 160; 159Stein & et al. Chest .1996, Vol. 109, 78

Chest X Ray

Without infarction, the chest x-ray may be normal, or diminished pulmonary vascular markings in the embolized area may be noted.With infarction, the x-rays frequently shows a peripheral infiltrative lesion, with elevation of the diaphragm & pleural fluid on the affected site.

DIAGNOSING THE CAUSE OF CHEST PAIN

William E. Cayley, Jr., M.D., American Family Physician;Vol. 72/no. 10 (November 15, 2005)

Outpatient Diagnosis of Chest pain

Diagnostic test makes sense

Graber & et al. Emergency Medicine April 2001

Likelihood ratios (LR)& Bayes' nomogramare a useful & practical way of expressing the power of diagnostic tests in increasing or decreasing the likelihood of disease

2 methods of estimating the pre-test probability:

Emergency gut feeling (educated guess) after the history & examination Clinical decision rules.

Accuracy of chest pain diagnosis using the Hx & PE

WILLIAM E. CAYLEY, American family Physician. Volume 72, Number 10 , November 15, 2005

•The Rouan decision rule reliably predicts which patients with chest pain & a normal or nonspecific electrocardiogram are at higher risk for MI

•However, 3% of patients initially diagnosed with a non-cardiac cause of chest pain suffer death or MI within 30 days of presentation.

•Patients with cardiac risk factors warrant close follow-up.

•The Diehr diagnostic rule, uses 7 clinical findings to predict the likelihood of pneumonia .

•Other findings that suggest pneumonia include egophony& dullness to percussion, but their absence does not rule out the diagnosis.

•Well’s clinical decision rules for the diagnosis of PE consists of 7 signs & symptoms.

•The strength of the Wells model is that it does not require a CXR or ABG measurements. It relies on a careful history & physical examination.

Accuracy of chest pain diagnosis

using diagnostic & prognostic tests

D-dimer* testing has become an important part of the evaluation for PE & deep venous thrombosis (DVT).

A low clinical suspicion for PE (Wells score <2) plus a normal quantitative ELISA D-dimer assay safely rules out PE, with a negative predictive value >99.5 %.

If further testing is needed, helical computed tomography (CT), combined with clinical suspicion and other testing such as lowerextremity venous ultrasound, can be used to rule in or rule out PE.

* Quantitative enzyme-linked immunosorbent antibody assay (ELISA) D-dimer assays are more sensitive & have been more thoroughly tested in clinical settings than whole-blood agglutination assays.

DIAGNOSTIC TESTING –PULMONARY EMBOLISM

Summary

Although diagnostic tests are impressive, they should not replace the history & physical examination.Clinician decision rule can be given a point score to arrive at a pre-test probability of a disease & help rule in or out specific diagnoses.After history taking & physical examination, we formulate prior probability of the disease –decide as to whether no test, a screening test, or a definitive test should be performed.

SummaryLikelihood ratios (LR) are a useful & practical way of expressing the power of diagnostic tests.An evidence-based approach tailors the diagnostic strategy to the patient - uses clinical evaluation to guide the selection of tests & their interpretation.

“ Having cross the bridge of understanding, we still must cross the bridge to practice ”

William E. Cayley, Jr., M.D., American Family Physician;Vol. 72/no. 10 (November 15, 2005)

Outpatient Diagnosis of Chest pain