Endoscopy

Endoscopy is a medical procedure used to directly visualise the interior of the human body, particularly hollow organs and cavities, by means of an instrument known as an endoscope. Unlike external imaging techniques such as X-rays, ultrasound, or magnetic resonance imaging, endoscopy involves inserting the viewing instrument into the body, allowing real-time inspection, diagnosis, and, in many cases, treatment. It has become an essential tool across numerous medical specialties due to its diagnostic accuracy, minimally invasive nature, and therapeutic versatility.
In common clinical usage, the term endoscopy most frequently refers to examination of the upper gastrointestinal tract, known as oesophagogastroduodenoscopy, but the term encompasses a broad family of procedures applied throughout the body.
Endoscopy may be performed while a patient is fully conscious, sedated, or under general anaesthesia, depending on the type of procedure, the body site examined, and the clinical indication.

Historical development

The origins of endoscopy date to the nineteenth century. Adolf Kussmaul, a German physician, was inspired by sword swallowers who could pass long objects into the oesophagus without triggering gag reflexes. This observation led him to attempt internal visualisation of the upper digestive tract using rigid tubes.
One of the earliest challenges was illumination. Early endoscopists relied on candles or oil lamps, which limited both safety and visibility. The term endoscope was first formally used on 7 February 1855 by the engineer-optician Charles Chevalier, referring to instruments developed by Antonin Jean Desormeaux, who later adopted the same terminology.
A major technological advance occurred in the late nineteenth century with the advent of electricity. The first self-illuminated endoscope was developed at the Glasgow Royal Infirmary by John Macintyre between 1894 and 1895. This innovation marked a turning point, enabling clearer visualisation and expanding the diagnostic potential of endoscopy.
Subsequent developments, including fibre optics, video imaging, and flexible materials, transformed endoscopy into a cornerstone of modern medicine.

Medical uses

Endoscopy serves both diagnostic and therapeutic purposes. It is commonly used to investigate symptoms affecting internal organs, particularly within the digestive system. These symptoms include nausea, vomiting, abdominal pain, difficulty swallowing, unexplained weight loss, and gastrointestinal bleeding.
From a diagnostic perspective, endoscopy allows:

• direct visual inspection of mucosal surfaces
• identification of inflammation, ulcers, strictures, and tumours
• performance of biopsies for histological examination

Biopsies obtained during endoscopy are critical in diagnosing conditions such as anaemia due to bleeding, inflammatory disorders, and neoplasms of the digestive system.
Therapeutically, endoscopy enables minimally invasive interventions, including:

• cauterisation of bleeding vessels
• dilation of narrowed segments of the oesophagus
• removal of polyps
• extraction of foreign bodies
• banding of oesophageal varices

Professional medical organisations emphasise appropriate use of endoscopy. For example, patients with Barrett’s oesophagus without cancerous changes are advised not to undergo excessive surveillance endoscopies, as unnecessary procedures expose patients to avoidable risks without proportional benefit.

Types and applications of endoscopy

Endoscopy can be applied to a wide range of anatomical regions. Common procedures include:
Gastrointestinal tract

• Oesophagogastroduodenoscopy (oesophagus, stomach, duodenum)
• Enteroscopy (small intestine)
• Colonoscopy and sigmoidoscopy (colon)
• Anoscopy and rectoscopy (anus and rectum)
• Endoscopic retrograde cholangiopancreatography (ERCP)
• Cholangioscopy and pancreatoscopy

Respiratory tract

• Rhinoscopy (nose)
• Laryngoscopy (upper airway)
• Bronchoscopy (lower airways)

Ear

• Otoscopy

Urinary system

• Cystoscopy (urinary bladder)
• Ureteroscopy (ureters)

Female reproductive system

• Colposcopy (cervix)
• Hysteroscopy (uterus)
• Falloposcopy (fallopian tubes)

Closed or surgically accessed cavities

• Laparoscopy (abdominal or pelvic cavity)
• Arthroscopy (joints)
• Thoracoscopy and mediastinoscopy (chest organs)

Pregnancy-related procedures

• Amnioscopy (amnion)
• Fetoscopy (fetus)

Combined procedures

• Panendoscopy or triple endoscopy, combining laryngoscopy, bronchoscopy, and upper gastrointestinal endoscopy

Endoscopy is also integral to many surgical procedures, such as anterior cruciate ligament reconstruction, epiduroscopy, bursectomy, and peripheral nerve decompression.

Endoscopic instruments and technique

An endoscope typically consists of a flexible or rigid tube equipped with:

• a light source
• a camera or optical system
• channels for air, water, suction, and instruments

Modern endoscopes use video technology to display high-resolution images on monitors. Accessories such as forceps, snares, or cutting tools can be passed through the endoscope to perform biopsies or minor surgical procedures.
To improve visibility, air or carbon dioxide is often insufflated to distend the examined cavity. This can lead to temporary sensations of bloating or pressure after the procedure.

Applications outside medicine

In non-medical contexts, similar instruments known as borescopes are used for internal inspection of mechanical and structural systems. These are employed in engineering, aviation, and industrial maintenance.
Endoscopes are also used by:

• architects and planners for visualising scale models of buildings and urban layouts
• bomb disposal units to inspect improvised explosive devices
• law enforcement agencies for surveillance through confined spaces

These applications rely on the same fundamental principle of remote visual access to otherwise inaccessible areas.

Risks and complications

Endoscopy is generally considered safe, but like all medical procedures it carries some risks. The most significant potential complications include:

• infection
• oversedation
• bleeding, particularly after biopsy or polyp removal
• perforation of the oesophagus, stomach, or intestinal wall

Perforation is rare but may require surgical intervention, though some cases can be managed conservatively with antibiotics and intravenous fluids. Minor bleeding often resolves spontaneously or can be controlled endoscopically.
Other possible risks include adverse drug reactions and complications related to pre-existing medical conditions. Patients are therefore advised to disclose allergies, medications, and relevant health issues prior to the procedure. Temporary inflammation or tenderness at the sedative injection site may occur but is usually mild.

Recovery and aftercare

After an endoscopy, patients are monitored until the effects of sedation have substantially worn off. Common temporary after-effects include a mild sore throat and a sensation of abdominal bloating due to insufflated air. These symptoms are typically short-lived and self-resolving.
Most patients can resume a normal diet within a few hours. When sedation has been used, patients are generally required to:

• be accompanied home by another person
• avoid driving or operating machinery for the remainder of the day