Diagnosis is via a careful history and physical examination, often supplemented by radiographic imaging studies. Pyloric stenosis should be suspected in any young infant with severe vomiting. On physical exam, palpation of the abdomen may reveal a mass in the epigastrium. This mass, which consists of the enlarged pylorus, is referred to as the 'olive', and is sometimes evident after the infant is given formula to drink. Rarely, there are peristaltic waves that may be felt or seen (video on NEJM) due to the stomach trying to force its contents past the narrowed pyloric outlet.

Most cases of pyloric stenosis are diagnosed/confirmed with ultrasound, if available, showing the thickened pylorus and non-passage of gastric contents into the proximal duodenum. Muscle wall thickness 3 millimeters (mm) or greater and pyloric channel length of 15 mm or greater are considered abnormal in infants younger than 30 days.

Although somewhat less useful, an upper GI series (x-rays taken after the baby drinks a special contrast agent) can be diagnostic by showing the narrowed pyloric outlet filled with a thin stream of contrast material; a "string sign" or the "railroad track sign". For either type of study, there are specific measurement criteria used to identify the abnormal results. Plain x-rays of the abdomen sometimes shows a dilated stomach.

Although UGI endoscopy would demonstrate pyloric obstruction, physicians would find it difficult to differentiate accurately between hypertrophic pyloric stenosis and pylorospasm.

Blood tests will reveal low blood levels of potassium and chloride in association with an increased blood pH and high blood bicarbonate level due to loss of stomach acid (which contains hydrochloric acid) from persistent vomiting. There will be exchange of extracellular potassium with intracellular hydrogen ions in an attempt to correct the pH imbalance. These findings can be seen with severe vomiting from any cause.

Infantile pyloric stenosis is typically managed with surgery; very few cases are mild enough to be treated medically.

The danger of pyloric stenosis comes from the dehydration and electrolyte disturbance rather than the underlying problem itself. Therefore, the baby must be initially stabilized by correcting the dehydration and the abnormally high blood pH seen in combination with low chloride levels with IV fluids. This can usually be accomplished in about 24–48 hours.

Intravenous and oral atropine may be used to treat pyloric stenosis. It has a success rate of 85-89% compared to nearly 100% for pyloromyotomy, however it requires prolonged hospitalization, skilled nursing and careful follow up during treatment. It might be an alternative to surgery in children who have contraindications for anesthesia or surgery, or in children whose parents do not want surgery.

On chest radiography, a retrocardiac, gas-filled viscus may be seen in cases of intrathoracic stomach, which confirms the diagnosis. Plain abdominal radiography reveals a massively distended viscus in the upper abdomen. In organoaxial volvulus, plain films may show a horizontally oriented stomach with a single air-fluid level and a paucity of distal gas. In mesenteroaxial volvulus, plain abdominal radiographic findings include a spherical stomach on supine images and 2 air-fluid levels on erect images, with the antrum positioned superior to the fundus.

- Upper GI contrast studies:

The diagnosis of gastric volvulus is usually based on barium studies; however, some authors recommend computed tomography (CT) scanning as the imaging modality of choice.

Upper gastrointestinal (GI) contrast radiographic studies (using barium or Gastrografin) are sensitive and specific if performed with the stomach in the "twisted" state and may show an upside-down stomach. Contrast studies have been reported to have a diagnostic yield in 81–84% of patients.

Often performed for an evaluation of acute abdominal pain, a computed tomography (CT) scan can offer immediate diagnosis by showing two bubbles with a transition line. Proponents of CT scanning in the diagnosis of gastric volvulus report several benefits, including:

1. the ability to rapidly diagnose the condition based on a few coronal reconstructed images,

2. the ability to detect the presence or absence of gastric pneumatosis and free air,

3. the detection of predisposing factors (i.e., diaphragmatic or hiatal hernias), and

4. the exclusion of other abdominal pathology.

- Endoscopy:

Upper gastrointestinal (GI) endoscopy may be helpful in the diagnosis of gastric volvulus. When this procedure reveals distortion of the gastric anatomy with difficulty intubating the stomach or pylorus, it can be highly suggestive of gastric volvulus. In the late stage of gastric volvulus, strangulation of the blood supply can result in progressive ischemic ulceration or mucosal fissuring.

The nonoperative mortality rate for gastric volvulus is reportedly as high as 80%. Historically, mortality rates of 30–50% have been reported for acute gastric volvulus, with the major cause of death being strangulation, which can lead to necrosis and perforation. With advances in diagnosis and management, the mortality rate from acute gastric volvulus is 15–20% and that for chronic gastric volvulus is 0–13%.

The differential diagnosis of gastric outlet obstruction may include: early gastric carcinoma hiatal hernia, gastroesophageal reflux, adrenal insufficiency, and inborn errors of metabolism.

The most confirmatory investigation is endoscopy of upper gastrointestinal tract.

Laboratory

- Individuals with gastric outlet obstruction are often hypochloremic, hypokalemic, and alkalotic due to loss of hydrogen chloride and potassium. High urea and creatinine levels may also be observed if the patient is dehydrated.

Abdominal X-ray

- A gastric fluid level may be seen which would support the diagnosis.

Barium meal and follow through

- May show an enlarged stomach and pyloroduodenal stenosis.

Gastroscopy

- May help with cause and can be used therapeutically.

Diagnosis is achieved mainly by plain and contrasted radiographical and ultrasound imaging. Colonic marker transit studies are useful to distinguish colonic inertia from functional outlet obstruction causes. In this test, the patient swallows a water-soluble bolus of radio-opaque contrast and films are obtained 1, 3 and 5 days later. Patients with colonic inertia show the marker spread throughout the large intestines, while patients with outlet obstruction exhibit slow accumulations of markers in some places. A colonoscopy can also be used to rule out mechanical obstructive causes. Anorectal manometry may help to differentiate acquired from congenital forms. Rectal biopsy is recommended to make a final diagnosis of Hirschsprung disease.

l-TGA can sometimes be diagnosed in utero with an ultrasound after 18 weeks gestation. However, many cases of simple l-TGA are "accidentally" diagnosed in adulthood, during diagnosis or treatment of other conditions.

The diagnosis of pulmonary valve stenosis can be achieved via echocardiogram, as well as a variety of other means among them are: ultrasound, in which images of the heart chambers in utero where the tricuspid valve has thickening (or due to Fallot's tetralogy, Noonan's syndrome, and other congenital defects) and in infancy auscultation of the heart can reveal identification of a murmur.

Some other conditions to contemplate (in diagnosis of pulmonic valvular stenosis) are the following:

- Infundibular stenosis

- Supravalvular pulmonary stenosis

- Dysplastic pulmonic valve stenosis

Heyde's syndrome is now known to be gastrointestinal bleeding from angiodysplasic lesions due to acquired vWD-2A deficiency secondary to aortic stenosis, and the diagnosis is made by confirming the presence of those three things. Gastrointestinal bleeding may present as bloody vomit, dark, tarry stool from metabolized blood, or fresh blood in the stool. In a person presenting with these symptoms, endoscopy, gastroscopy, and/or colonoscopy should be performed to confirm the presence of angiodysplasia. Aortic stenosis can be diagnosed by auscultation for characteristic heart sounds, particularly a crescendo-decrescendo (i.e., 'ejection') murmur, followed by echocardiography to measure aortic valve area (see diagnosis of aortic stenosis). While Heyde's syndrome may exist alone with no other symptoms of aortic stenosis, the person could also present with evidence of heart failure, fainting, or chest pain. Finally, Heyde's syndrome can be confirmed using blood tests for vWD-2A, although traditional blood tests for von Willebrand factor may result in false negatives due to the subtlety of the abnormality. The gold standard for diagnosis is gel electrophoresis; in people with vWD-2A, the large molecular weight von Willebrand factors will be absent from the SDS-agarose electrophoresis plate.

In terms of treatment for pulmonary valve stenosis, valve replacement or surgical repair (depending upon whether the stenosis is in the valve or vessel) may be indicated. If the valve stenosis is of congenital origin, balloon valvuloplasty is another option, depending on the case.

Valves made from animal or human tissue (are used for valve replacement), in adults metal valves can be used.

Diagnosis of angiodysplasia is often accomplished with endoscopy, either colonoscopy or esophagogastroduodenoscopy (EGD). Although the lesions can be notoriously hard to find, the patient usually is diagnosed by endoscopy. A new technique, pill enteroscopy, has been a major advance in diagnosis, especially in the small bowel which is difficult to reach with traditional endoscopy. With this technique a pill that contains a video camera and radio transmitter is swallowed, and pictures of the small intestine are sent to a receiver worn by the patient. Recently, multiphase CT angiography (without positive oral contrast) has been shown to play a promising role in the diagnoses of small and large bowel angiodysplasia, especially when associated with active hemorrhage

Angiodysplasiae in the small bowel can also be diagnosed and treated with double-balloon enteroscopy, a technique involving a long endoscopic camera and overtube, both fitted with balloons, that allow the bowel to be accordioned over the camera.

In cases with negative endoscopic findings and high clinical suspicion, selective angiography of the mesenteric arteries is sometimes necessary, but this allows for interventions at time of the procedure. An alternative is scintigraphy with red blood cells labeled with a radioactive marker; this shows the site of the bleeding on a gamma camera but tends to be unhelpful unless the bleeding is continuous and significant.

The main diagnostic tools are blood tests, X-rays of the abdomen, CT scanning, and/or ultrasound. If a mass is identified, biopsy may determine the nature of the mass.

Radiological signs of bowel obstruction include bowel distension and the presence of multiple (more than six) gas-fluid levels on supine and erect abdominal radiographs.

Contrast enema or small bowel series or CT scan can be used to define the level of obstruction, whether the obstruction is partial or complete, and to help define the cause of the obstruction.

According to a meta-analysis of prospective studies by the Cochrane Collaboration, the appearance of water-soluble contrast in the cecum on an abdominal radiograph within 24 hours of oral administration predicts resolution of an adhesive small bowel obstruction with a pooled sensitivity of 97% and specificity of 96%.

Colonoscopy, small bowel investigation with ingested camera or push endoscopy, and laparoscopy are other diagnostic options.

A color flow and doppler imaging is used to help confirm the presence as well as evaluate the severity of ASD and MS.

A chest x-ray will be given to determine the size of the heart and the blood vessels supplying blood to the lungs.

Various modalities of diagnosis are available:

- Cystoscopy

- Colonoscopy

- Poppy seed test

- Transabdominal ultrasonography

- Abdominopelvic CT

- MRI

- Barium enema

- Bourne test

- Cystogram

A definite algorithm of tests is followed for making the diagnosis.

For diagnosis, measures of liver biochemistry and pancreatic enzymes are performed. Along with ruling out structural abnormalities, normally by performing an abdominal ultrasound and endoscopic retrograde cholangiopancreatography (ERCP). Measurements of bile transit when performing ERCP are taken to help evaluate different treatment options.

Sphincter of Oddi dysfunction is best diagnosed using manometry-an internal test done to measure the pressures within surrounding ducts to determine whether or not the muscle is functioning normally.

Subglottic stenosis is a congenital or acquired narrowing of the subglottic airway. Although it is relatively rare, it is the third most common congenital airway problem (after laryngomalacia and vocal cord paralysis). Subglottic stenosis can present as a life-threatening airway emergency. It is imperative that the otolaryngologist be an expert at dealing with the diagnosis and management of this disorder. Subglottic stenosis can affect both children and adults.

Subglottic stenosis can be of three forms, namely congenital subglottic stenosis, idiopathic subglottic stenosis (ISS) and acquired subglottic stenosis. As the name suggests, congenital subglottic stenosis is a birth defect. Idiopathic subglottic stenosis is a narrowing of the airway due to an unknown cause. Acquired subglottic stenosis generally follows as an after-effect of airway intubation, and in extremely rare cases as a result of gastroesophageal reflux disease (GERD).

Subglottic stenosis is graded according to the Cotton-Meyer classification system from one to four based on the severity of the blockage.

Grade 1 – <50% obstruction

Grade 2 – 51–70% obstruction

Grade 3 – 71–99% obstruction

Grade 4 – no detectable lumen

Treatments to alleviate the symptoms of subglottic stenosis includes a daily dose of steroids such as prednisone, which reduces the inflammation of the area for better breathing. Other medications such as Methotrexate is also being tested by patients but results are pending.

Differential diagnoses of bowel obstruction include:

- Ileus

- Pseudo-obstruction or Ogilvie's syndrome

- Intra-abdominal sepsis

- Pneumonia or other systemic illness .

Simple l-TGA has a very good prognosis, with many individuals being asymptomatic and not requiring surgical correction.

In a number of cases, the (technically challenging) "double switch operation" has been successfully performed to restore the normal blood flow through the ventricles.

Stenoses of the vascular type are often associated with unusual blood sounds resulting from turbulent flow over the narrowed blood vessel. This sound can be made audible by a stethoscope, but diagnosis is generally made or confirmed with some form of medical imaging.

The resulting syndrome depends on the structure affected.

Examples of vascular stenotic lesions include:

- Intermittent claudication (peripheral artery stenosis)

- Angina (coronary artery stenosis)

- Carotid artery stenosis which predispose to (strokes and transient ischaemic episodes)

- Renal artery stenosis

The types of stenoses in heart valves are:

- Pulmonary valve stenosis, which is the thickening of the pulmonary valve, therefore causing narrowing

- Mitral valve stenosis, which is the thickening of the mitral valve (of the left heart), therefore causing narrowing

- Tricuspid valve stenosis, which is the thickening of the tricuspid valve (of the right heart), therefore causing narrowing

- Aortic valve stenosis, which is the thickening of the aortic valve, therefore causing narrowing

Stenoses/strictures of other bodily structures/organs include:

- Pyloric stenosis (gastric outflow obstruction)

- Lumbar, cervical or thoracic spinal stenosis

- Subglottic stenosis (SGS)

- Tracheal stenosis

- Obstructive jaundice (biliary tract stenosis)

- Bowel obstruction

- Phimosis

- Non-communicating hydrocephalus

- Stenosing tenosynovitis

- Atherosclerosis

- Esophageal stricture

- Achalasia

- Prinzmetal angina

- Vaginal stenosis

With early intervention, morbidity and mortality of cases of intestinal obstruction is low. The outcome is in part dependent upon congenital comorbidities and delays in diagnosis and management.

Medical diagnosis of the two forms of congenital dextrocardia can be made by ECG or imaging.

Medication (to prevent spasms) or Sphincterotomy (surgical procedure to cut the muscle) are the standard treatments for sphincter of Oddi dysfunction. One or the other may be better based on the classification of the condition.

Technical dextrocardia refers to an ECG reading that has no basis in the patient's anatomy. This apparent presentation is typically caused by the accidental lead placement of the left and right arm electrodes. Usually this would show as an extreme axis deviation.