Percussion: You Remember?

Introduction

Physical examination has long been a cornerstone of clinical practice, and inadequacies in physical examination are a preventable source of medical error.1 Yet, with the growth of advanced diagnostic technologies, essential bedside skills like percussion are being neglected in everyday practice. Percussion allows clinicians to distinguish between normal, fluid-filled, or air-filled body cavities. Historically, it has been critical for diagnosing pleural effusions, pneumothorax, hydro pneumothorax, mild ascites, and organomegaly; especially splenomegaly.

Training in medicine, even a couple of decades ago, involved a systematic approach with a thorough history and an elaborate physical examination, including inspection, palpation, percussion, and auscultation, after which one would shortlist the differential diagnoses. Diagnostic tests were useful in confirming or ruling out a diagnosis. This process lent our practice a certain charm and excitement that may have been lost over the years

Today, when a clinician sees a patient, they are often already equipped with a large ‘file’ with multiple test reports, either confirming a diagnosis or informing further tests. They are seldom required to perform a traditional physical examination. For example, how often do we now see a pleural effusion or thickening diagnosed using percussion? How often do we perform a percussion exam to diagnose ascites?

In this age of super specialists, and of course, social media and generative artificial intelligence (AI), clinicians spend significant time and effort answering highly specific questions about particular organs or diseases, often to the extent of having to justify their approach. This has also become important in preventing potential medico-legal issues. Thus, a heavy dependence on investigations has crept into practice.

Historical Perspective

Leopold Auenbrugger introduced percussion to clinical medicine in 1761, revolutionising the way physicians approached the diagnoses of internal diseases.2 For over two centuries, percussion, coupled with inspection, palpation, and auscultation, were the mainstay of chest and abdominal assessments, providing diagnostic clues long before X-rays or computed tomography (CT) scans became available.

Case Report

A 52-year-old male, non-smoker, with hypertension, presented to the emergency department with breathlessness and left-sided chest heaviness. There was no history of trauma, fever, or cough. On presentation, his vital signs were as follows: respiratory rate 34/min, blood pressure 90/70 mmHg, SpO2 79% on room air, and pulse rate 112/min. The differential diagnoses considered were pulmonary embolism, acute coronary syndrome, and pleural pathology (effusion or pneumothorax). Due to an unforeseen technical failure, and anticipated delay in imaging, the physician proceeded with a detailed bedside examination.

Relevant clinical findings included tracheal shift to the right, and reduced chest expansion on the left. On percussion, there was a stony dullness over the left hemithorax, with the upper border at the 4th intercostal space, midclavicular line. On auscultation, breath sounds were absent over the dull area of the left hemithorax.

Based on percussion and auscultation, a massive leftsided pleural effusion was diagnosed clinically. Once the technical issue was resolved, a chest X-ray confirmed the diagnosis, validating the bedside findings. Emergency thoracentesis was performed, draining 1.5 litres of strawcoloured fluid, resulting in immediate symptom relief.

Discussion

Mechanisms and techniques of percussion

Percussion assesses tissue density based on sound transmission:

1. Resonant: Normal lung
2. Dull: Consolidation or mass
3. Stony dull: Pleural effusion
4. Hyper-resonant: Pneumothorax or emphysematous bullae

The technique highlights the use of the non-dominant hand as a pleximeter, with the middle finger of the dominant hand (the plexor finger) used to tap briskly on the pleximeter. Both sides should be compared systematically to ensure accurate interpretation.

Clinical applications

1. Thoracic pathologies: Pleural effusion, consolidation, pneumothorax and specially hydropneumothorax
2. Abdominal assessment: Hepatomegaly, splenomegaly, bladder distension, ascites (including demonstration of shifting dullness)
3. Cardiac borders: Pericardial effusion (rarely performed today but still valuable in certain situations) and cardiomegaly

Evidence-based utility

This involves emphasising the most important physical signs needed to determine an underlying medical condition or disease.3 Sapira also emphasised the role of percussion in bedside diagnosis.4

Why has percussion been forgotten?

• Overreliance on imaging (X-ray, ultrasound, CT scan)
• Fear of medico-legal cases
• Fear of missing diagnoses
• Decline in confidence in physical examination3

When percussion can save lives

• Emergency triage when imaging is delayed
• Mass casualty situations or disasters
• Resource-limited or rural settings
• Rapid bedside diagnosis during acute deterioration
• Lack of importance given to medical sign

Limitations

• Operator-dependent; requires practice and experience
• Less effective for early pathology especially small effusions, minimal pneumothorax or mild organomegaly
• May miss subtle pathology without complementary techniques

Educational implications

Percussion should be actively taught and demonstrated during bedside rounds. Senior clinicians must role-model its use to ensure transfer of skills. It should be included in Objective Structured Clinical Examination (OSCEs) and clinical competency assessments. Studies have shown that pulmonary physical examination skills among medical students vary significantly and are often inadequate, highlighting the need for focused training.5