امراض نظري 6.docx

Oesophagus Anatomy: The oesophagus is a fibromuscular tube that connects the pharynx in the neck to the stomach in the abdomen. It begins at the level of C6. As it descends through the mediastinum, it passes posterior to the aortic arch, the left main bronchus and the left atrium, each of which c...

Oesophagus Anatomy: The oesophagus is a fibromuscular tube that connects the pharynx in the neck to the stomach in the abdomen. It begins at the level of C6. As it descends through the mediastinum, it passes posterior to the aortic arch, the left main bronchus and the left atrium, each of which causes an impression. At the diaphragm the oesophagus passes through the diaphragmatic hiatus at T10; it ends at the gastric cardia at the level of T11. The oesophagus is therefore composed of a [short cervical], a [long thoracic] and a [short abdominal] segment. The wall of the oesophagus is made up of five layers: the mucosa, the muscularis mucosa, the submucosa, the muscularis propria and the adventitia. Function: The oesophagus actively moves ingested material from the pharynx to the stomach and thus prevents reflux of stomach contents. Passage of a food bolus is regulated by the upper and lower oesophageal sphincters. Unlike the upper and lower oesophageal sphincters, the oesophagus between these high-pressure zones is relaxed in the resting state. The swallowing reflex induces so-called primary peristaltic waves that travel at [3 to 4 cm/s]. Secondary peristalsis occurs when oesophageal sensory receptors are activated by material persisting in the oesophagus after primary peristalsis. Tertiary contractions are [nonpropulsive] and are seen in a variety of motility disorders. EXAMINATION The oesophagus can be examined with any of the commonly used imaging techniques: 1)The initial test of choice is usually endoscopy. 2\) fluoroscopy ([reserved for frail patients or those who have had recent] [surgery]). 3)Computed tomography (CT) is often the first-line test in the context of trauma. 4)Imaging is extensively used in the staging of oesophageal malignancy, particularly CT, positron-emission tomography--CT (PET-CT) and endoscopic ultrasound (EUS).  Plain Radiography =================== In most circumstances, plain radiographs reveal little useful information regarding the oesophagus except in the context of foreign body ingestion~.~  Foreign bodies tend to lodge at one of the following oesophageal constriction points: - Cricopharyngeus - Aortic arch - Left main bronchus - Diaphragmatic hiatus  Ultrasound ============ Most of the oesophagus is inaccessible to conventional ultrasound examination (but see 'Endoscopic Ultrasound', later). The short cervical and abdominal segments are amenable to imaging in this way, but this is rarely used in clinical practice.  Fluoroscopy ============= Fluoroscopic examination of the oesophagus is performed for a wide variety of indications. If possible, double-contrast images should be obtained using an effervescent agent, usually with the patient in the erect position. These are complementary to prone single-contrast images. NOTE:Water-soluble contrast medium is used when a tear, perforation or anastomotic leak is suspected.  Endoscopy =========== Oesophagogastroduodenoscopy (OGD/endoscopy) is the initial investigation of choice for most indications, particularly dysphagia. It permits the direct visualisation of the mucosa and, crucially, biopsies can be taken. In addition to a detailed diagnostic assessment of the mucosa, a wide variety of therapeutic manoeuvres may be carried out endoscopically. These include : - The treatment of upper gastrointestinal (GI) haemorrhage. - Balloon dilatation and/or stenting of strictures. - Radiofrequency ablation (RFA) of dysplastic epithelium. - Injection of botulinum toxin for motility disorders. Computed Tomography ------------------- In the context of oesophageal disease, CT is most widely used in the staging of oesophageal cancer. A CT of the thorax, abdomen and pelvis should be acquired. Good oesophageal and gastric distension is important: the patient should be given 1--1.5 L of water to drink as well as effervescent granules and should be imaged in the prone position. Intravenous contrast medium should be used whenever possible, with the upper abdomen imaged in both the arterial and portal venous phases. Magnetic Resonance Imaging ========================== In current clinical practice, magnetic resonance imaging (MRI) is not used for imaging the oesophagus. Image quality is hampered by motion artefacts from cardiac motion, breathing and peristalsis. Whole-body MRI is under evaluation as an alternative to PET-CT for the staging of metastatic disease in oesophageal cancer but has not yet entered clinical practice. Endoscopic Ultrasound ===================== - EUS is generally used to characterise abnormalities identified using other imaging techniques, in particular the staging of oesophageal cancer. - Less frequently, EUS is used for the assessment of submucosal lesions of the oesophagus. [The high frequency and close proximity of the ultrasound probe allow the] [delineation of five layers of the oesophageal wall: mucosa, muscularis] [mucosa, submucosa, muscularis propria and] adventitia. The muscular layers are hypoechoic; hence, there is a fivelayered alternating pattern. - Endoscopic ultrasound/fine-needle aspiration (EUS-FNA) enables the sampling of structures deep to the oesophageal mucosa, particularly thoracic and upper abdominal lymph nodes. Radionuclide Radiology Including Positron-Emission Tomography--Computed Tomography: For patients with oesophageal cancer, 18F-fluorodeoxyglucose (FDG) PET-CT is now the standard of care if radical treatment is intended~.~ Technetium-based radionuclide imaging of the oesophagus can be used for the identification of oesophageal motility disorders and gastrooesophageal reflux disease (GORD). PATHOLOGICAL FEATURES  Oesophageal Cancer ==================== Oesophageal cancer is the sixth most common cause of death from cancer in the United Kingdom. There are two major histological types: - squamous cell carcinoma. - adenocarcinoma. Accurate [preoperative] staging of oesophageal cancer is difficult due to: 1. The mobility of the oesophagus. 2. Its proximity to other organs make the assessment of local invasion problematic. 3. Malignant lymph nodes are usually not enlarged and may first arise some distance from the tumour. 4. Furthermore, unsuspected metastases may be present in up to 30% of patients at diagnosis. The patient with oesophageal cancer can face a whirlwind of tests, including endoscopy, CT, EUS and PET-CT. This combination is crucial for determining appropriate therapy. The vast majority of patients will go on to CT as their initial staging investigation. Although less sensitive than EUS and PET-CT, it is relatively specific for identifying locally advanced or metastatic disease.  Computed Tomography for Oesophageal Cancer The normal oesophagus when adequately distended should have a wall thickness of less than 5 mm on CT. Tumours are seen as regions of wall thickening, which may be circumferential or asymmetric. CT is rather limited in the local staging of oesophageal tumours because it is unable to delineate the layers of the oesophageal wall and is therefore useful only for distinguishing between T1--3 and T4 (invasion of other structures). For [nodal staging] of oesophageal cancer, CT is relatively insensitive, as [the majority of] [involved nodes are not enlarged]. NOTE:1 cm are considered involved on CT. Common sites of regional nodal disease include : The supraclavicular lymph nodes, which are metastatic. [The most frequent sites for oesophageal cancer metastases are nonregional] [lymph nodes such as] the supraclavicular and retroperitoneal abdominal lymph nodes. [Visceral metastases] are seen in the liver, the lungs,bones, muscles and the adrenal glands.  Endoscopic Ultrasound for Oesophageal Cancer EUS is superior to CT and PET-CT for T staging. The sensitivity and specificity for identifying the various T stages of oesophageal cancer is high. In some patients with advanced tumours, the stricture is too tight to permit passage of the standard radial echoendoscope. An [endobronchial ultrasound] (EBUS) scope can be used in most of these cases if required. For nodal disease, EUS has a sensitivity higher than that of PET-CT or CT, but it is less specific.  Positron-Emission Tomography--Computed Tomography for Oesophageal Cancer -------------------------------------------------------------------------- In T1 tumours of the oesophagus, it is usually not possible to identify the tumour with PET, which should therefore be omitted if this stage is suspected endoscopically. If a tumour is not detectable by PET-CT, it will be T2 or less in 70% of cases. PET-CT otherwise suffers the same limitations as CT in terms of depth of mural invasion; EUS is therefore the preferred technique for T staging. PET-CT is the technique of choice for identifying metastases to nonregional lymph nodes and other tissues such as the liver and skeletal muscle.  Treatment of Oesophageal Cancer --------------------------------- Treatment for oesophageal cancer involves a broad range of interventions that are dependent on : - The stage of tumour. - Type of tumour. - Fitness of the patient and local availability. 1. EMR (endoscopic mucosal resection). 2. Oesophagectomy. 3. Palliative treatment(like in case (T4b) or metastatic disease). Palliative treatment include: - manoeuvres for maintaining oesophageal patency, most commonly stenting - palliative chemotherapy is used in patients with a [good performance] [status]. - Radiotherapy has an important role, particularly for the more radiosensitive squamous cell carcinoma. The oesophagus is almost always substituted with a gastric conduit. Both fluoroscopy and CT play an important role in the detection of [postoperative complications]. If there is necrosis of the gastric conduit, a colonic interposition may be used, usually after an interval of several months, to allow the patient to recover before further surgery.  Other Oesophageal Neoplasms ----------------------------- Other than adenocarcinoma and squamous cell carcinoma, true neoplasms of the oesophagus are [uncommon]. They can be categorised as benign or malignant and according to whether they are mucosal or submucosal. ###  Benign Lesions 1. Glycogenic acanthosis,(sequamous epithelial pllaqua with abundant intracellular glycogen deposit)mural nodule which present in up to 30% of normal individuals. 2. Papillomata are uncommon benign tumours of the oesophagus biopsy is required to distinguish a papilloma from an early adenocarcinoma or squamous cell carcinoma. (DDX: a congenital foregut duplication cyst which give a simple cyst feature on MRI or EUS ). 4.Fibrovascular polyps are very rare pedunculated submucosal lesions They are notable for their potentially unusual clinical presentation: regurgitation into the mouth, which can sometimes result in death by asphyxiation. 5.Other submucosal lesions---such as schwannoma, neurofibromata ###  Malignant Lesions Nearly all oesophageal malignant tumours are adenocarcinomas and squamous cell carcinomas. A number of rare malignancies are encountered, each representing around 1% of all oesophageal tumours. These include: - - - - - 1.Hiatus Hernia =============== A hiatus hernia exists when abdominal organs pass through the oesophageal hiatus into the chest. Usually the herniated organ is the abdominal segment of the oesophagus with part of the stomach, although greater omentum, colon, spleen, pancreas and small intestine are sometimes involved. Hiatal hernias are divided into: 1.Sliding The majority of hiatal hernias are of the sliding type (approximately 90%). The diagnosis of a sliding hiatal hernia is made on fluoroscopy when gastric rugae are seen traversing the diaphragm, or when the oesophageal B ring (representing the squamo-columnar junction) is seen above the diaphragm(GEJ above the diaphragm). It also called type 1 hiatal hernia gold standard. CT, endoscopy and fluoroscopy are sufficient for diagnosing large sliding hiatal hernias 2.Rolling type(paraesophageal hernia): When there is a part of stmach above the diaphragm [without GEJ(called type 2]) or [with GEJ(called type 3)]  2.Gastro-Oesophageal Reflux Disease =================================== The term GORD covers a spectrum of disorders including reflux oesophagitis and non-erosive reflux disease (where the patient has symptoms but the oesophagus is endoscopically normal). A variety of causative factors: - including dysfunction of the lower oesophageal sphincter. - hiatus hernia. - Obesity. - alcohol consumption and smoking---have been identified. The gold standard test for establishing it: - presence is 24-hour pH monitoring - Endoscopy is the most accurate method for identifying the consequences of gastro-oesophageal reflux, as reflux oesophagitis and columnar-lined oesophagus may be occult fluoroscopically. Complications of Gastro-Oesophageal Reflux Disease  Reflux oesophagitis***.***  Columnar-lined oesophagus***.*** Columnar-lined oesophagus (also known as Barrett oesophagus). 3.Oesophageal Diverticula ------------------------- It is out pouching of oesophageal wall,it is three types: 4.Motility Disorders -------------------- - Fluoroscopic examination of the oesophagus is used in preference to endoscopy as the first-line test for suspected case. - high-resolution manometry is the gold standard ###  Achalasia dysphagia for solids and liquids coupled with regurgitationand chest pain are suggestive. Radiological investigation: - - - - - ####  Jackhammer Oesophagus Chest pain is usually a more prominent symptom than dysphagia. (muscle contraction more than the normal and discoordinated in compare with normal contraction) Radiological investigation: - fluoroscopy, with a corkscrew appearance of the oesophagus. - EUS may show thickening of the muscularis propria. - At high-resolution manometry, simultaneous non-propulsive contractions of the lower oesophagus are interspersed with normal peristaltic waves. ####  Systemic Disorders Scleroderma (progressive systemic sclerosis) preferentially involves the oesophagus over the rest of the GI tract. The loss of smooth muscle from the muscularis propria results in fluoroscopic findings of reduced peristalsis, a patulous GOJ and gastrooesophageal reflux with its various complications. - Manometry or fluoroscopy is used for the diagnose oesophageal Involvement~.~ - endoscopy is used to assess for complications. ###  Neuromuscular Disorders A wide variety of neuromuscular disorders may result in dysphagia, including : - Stroke. - Parkinson disease. - myasthenia gravis.  multiple sclerosis. - motor neurone disease. Miscellaneous Conditions ------------------------ ###  Schatzki Ring Treatment is generally non-operative with PPIs unless symptoms are severe. ###  Dysphagia Aortica The acquired equivalent of dysphagia lusoria is compression of the posterior wall of the lower oesophagus by a tortuous or dilated aorta: ###  Trauma The rib cage shields the oesophagus from blunt and penetrating injuries in most cases of external trauma. The commonest injury to the oesophagus is at endoscopy, with a perforation. The classic clinical picture is of severe chest pain and surgical emphysema in the neck following vomiting, although these features may be absent in up to 50% of cases. [The technique of choice is usually CT, given its availability]. Thank =====