Many of the signs and symptoms of aqueductal stenosis are similar to those of hydrocephalus. These typical symptoms include: headache, nausea and vomiting, cognitive difficulty, sleepiness, seizures, balance and gait disturbances, visual abnormalities, and incontinence.

- Headache may be a result of the raised intracranial pressure from the disrupted flow of CSF, and sometimes this symptom may come on suddenly as a “thunderclap headache”.

- In children, cognitive difficulty and developmental delay have been seen in a range of severities. Mild developmental delay is characterized by motor and neurological development that is no greater than 2 standard deviations below average for the age of the child, and moderate delay is characterized by greater than 2 standard deviations below. A child with severe delay may be unable to use spoken language or control movement or interact with others, and can behave abusively towards themselves.

- A patient's level of consciousness may also deteriorate with time, and this can lead to coma or death.

- The visual abnormalities previously mentioned include “upward gaze palsy”, where a person has difficulty looking up.

- Tremors have also been reported as a symptom, but are not as common as these previously mentioned.

Signs of aqueductal stenosis other than those mentioned in “Causes of stenosis” include detection of an enlarged lateral and third ventricle in conjunction with a smaller fourth ventricle. This variation in ventricle size is indicative of a blockage in the aqueduct because it lies between the third and fourth ventricles. Another sign of stenosis is deformation of the midbrain, which can be severe. This is caused by the pressure gradient formed from a blockage in the aqueduct.

Aqueductal stenosis is a narrowing of the aqueduct of Sylvius which blocks the flow of cerebrospinal fluid (CSF) in the ventricular system. Blockage of the aqueduct can lead to hydrocephalus, specifically as a common cause of congenital and/or obstructive hydrocephalus.

The aqueduct of Sylvius is the channel which connects the third ventricle to the fourth ventricle and is the narrowest part of the CSF pathway with a mean cross-sectional area of 0.5 mm in children and 0.8 mm in adults. Because of its small size, the aqueduct is the most likely place for a blockage of CSF in the ventricular system. This blockage causes ventricle volume to increase because the CSF cannot flow out of the ventricles and cannot be effectively absorbed by the surrounding tissue of the ventricles. Increased volume of the ventricles will result in higher pressure within the ventricles, and cause higher pressure in the cortex from it being pushed into the skull. A person may have aqueductal stenosis for years without any symptoms, and a head trauma, hemorrhage, or infection could suddenly invoke those symptoms and worsen the blockage.

This condition is acquired as a consequence of CNS infections, meningitis, brain tumors, head trauma, toxoplasmosis, intracranial hemorrhage (subarachnoid or intraparenchymal) and is usually painful.

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 clinical presentation of hydrocephalus varies with chronicity. Acute dilatation of the ventricular system is more likely to manifest with the nonspecific signs and symptoms of increased intracranial pressure. By contrast chronic dilatation (especially in the elderly population) may have a more insidious onset presenting, for instance, with Hakim's triad (Adams triad).

Symptoms of increased intracranial pressure may include headaches, vomiting, nausea, papilledema, sleepiness or coma. Elevated intracranial pressure may result in uncal or tonsillar herniation, with resulting life-threatening brain stem compression.

Hakim's triad of gait instability, urinary incontinence and dementia is a relatively typical manifestation of the distinct entity normal pressure hydrocephalus (NPH). Focal neurological deficits may also occur, such as abducens nerve palsy and vertical gaze palsy (Parinaud syndrome due to compression of the quadrigeminal plate, where the neural centers coordinating the conjugated vertical eye movement are located). The symptoms depend on the cause of the blockage, the person's age, and how much brain tissue has been damaged by the swelling.

In infants with hydrocephalus, CSF builds up in the central nervous system, causing the fontanelle (soft spot) to bulge and the head to be larger than expected. Early symptoms may also include:

- Eyes that appear to gaze downward;

- Irritability;

- Seizures;

- Separated sutures;

- Sleepiness;

- Vomiting.

Symptoms that may occur in older children can include:

- Brief, shrill, high-pitched cry;

- Changes in personality, memory, or the ability to reason or think;

- Changes in facial appearance and eye spacing;

- Crossed eyes or uncontrolled eye movements;

- Difficulty feeding;

- Excessive sleepiness;

- Headache;

- Irritability, poor temper control;

- Loss of bladder control (urinary incontinence);

- Loss of coordination and trouble walking;

- Muscle spasticity (spasm);

- Slow growth (child 0–5 years);

- Slow or restricted movement;

- Vomiting.

Because hydrocephalus can injure the brain, thought and behavior may be adversely affected. Learning disabilities including short-term memory loss are common among those with hydrocephalus, who tend to score better on verbal IQ than on performance IQ, which is thought to reflect the distribution of nerve damage to the brain. However, the severity of hydrocephalus can differ considerably between individuals and some are of average or above-average intelligence. Someone with hydrocephalus may have coordination and visual problems, problems with coordination, or may be clumsy. They may reach puberty earlier than the average child (see precocious puberty). About one in four develops epilepsy.

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

Babies with this condition usually present any time in the first weeks to months of life with progressively worsening vomiting. The vomiting is often described as non-bile stained ("non bilious") and "projectile vomiting", because it is more forceful than the usual spittiness (gastroesophageal reflux) seen at this age. Some infants present with poor feeding and weight loss but others demonstrate normal weight gain. Dehydration may occur which causes a baby to cry without having tears and to produce less wet or dirty diapers due to not urinating for hours or for a few days. Symptoms usually begin between 3 to 12 weeks of age. Findings include epigastric fullness with visible peristalsis in the upper abdomen from the person's left to right. Constant hunger, belching, and colic are other possible signs that the baby is unable to eat properly.

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.

Laryngotracheal stenosis refers to abnormal narrowing of the central air passageways. This can occur at the level of the larynx, trachea, carina or main bronchi.

In a small number of patients narrowing may be present in more than one anatomical location.

Supravalvular aortic stenosis is a congenital obstructive narrowing of the aorta just above the aortic valve. It is often associated with other cardiovascular anomalies and is one of the characteristic findings of Williams syndrome. The diagnosis can be made by echocardiography or MRI.

A left ventricular outflow tract obstruction (LVOTO) may be due to a defect in the aortic valve, or a defect located at the subvalvar or supravalvar level.

- Aortic valve stenosis

- Supravalvar aortic stenosis

- Coarctation of the aorta

- Hypoplastic left heart syndrome

In mild cases, children may show no signs or symptoms at first and their condition may not be diagnosed until later in life. Some children born with coarctation of the aorta have other heart defects too, such as aortic stenosis, ventricular septal defect, patent ductus arteriosus or mitral valve abnormalities.

Coarctation is about twice as common in boys as it is in girls. It is common in girls who have Turner syndrome.

Symptoms may be absent with mild narrowings (coarctation). When present, they include: difficulty breathing, poor appetite or trouble feeding, failure to thrive. Later on, children may develop symptoms related to problems with blood flow and an enlarged heart. They may experience dizziness or shortness of breath, faint or near-fainting episodes, chest pain, abnormal tiredness or fatigue, headaches, or nosebleeds. They have cold legs and feet or have pain in their legs with exercise (intermittent claudication).

In more severe cases, where severe coarctations, babies may develop serious problems soon after birth because not enough blood can get through the aorta to the rest of their body.

Arterial hypertension in the arms with low blood pressure in the lower extremities is classic. In the lower extremities, weak pulses in the femoral arteries and arteries of the feet are found.

The coarctation typically occurs after the left subclavian artery. However, if situated before it, blood flow to the left arm is compromised and asynchronous or radial pulses of different "strength" may be detected (normal on the right arm, weak or delayed on the left), termed "radio-radial delay". In these cases, a difference between the normal radial pulse in the right arm and the delayed femoral pulse in the legs (either side) may be apparent, whilst no such delay would be appreciated with palpation of both delayed left arm and either femoral pulses. On the other hand, a coarctation occurring after the left subclavian artery will produce synchronous radial pulses, but "radio-femoral delay" will be present under palpation in either arm (both arm pulses are normal compared to the delayed leg pulses).

A right ventricular outflow tract obstruction (RVOTO) may be due to a defect in the pulmonic valve, the supravalvar region, the infundibulum, or the pulmonary artery.

- Pulmonary atresia

- Pulmonary valve stenosis

- Hypoplastic right heart syndrome

- Tetralogy of Fallot

Among some of the symptoms consistent with pulmonary valve stenosis are the following:

- Heart murmur

- Cyanosis

- Dyspnea

- Dizziness

- Upper thorax pain

- Developmental disorders

The most common symptom of laryngotracheal stenosis is gradually-worsening breathlessness (dyspnea) particularly when undertaking physical activities (exertional dyspnea). The patient may also experience added respiratory sounds which in the more severe cases can be identified as stridor but in many cases can be readily mistaken for wheeze. This creates a diagnostic pitfall in which many patients with laryngotracheal stenosis are incorrectly diagnosed as having asthma and are treated for presumed lower airway disease. This increases the likelihood of the patient eventually requiring major open surgery in benign disease and can lead to tracheal cancer presenting too late for curative surgery to be performed.

An overriding aorta is a congenital heart defect where the aorta is positioned directly over a ventricular septal defect (VSD), instead of over the left ventricle. The result is that the aorta receives some blood from the right ventricle, causing mixing of oxygenated and deoxygenated blood, and thereby reducing the amount of oxygen delivered to the tissues.

It is one of the four findings in the classic tetralogy of Fallot. The other three findings are right ventricular outflow tract (RVOT) obstruction (most often subpulmonary stenosis), right ventricular hypertrophy (RVH), and ventricular septal defect (VSD).

Congenital stenosis of vena cava is a congenital anomaly in which the superior vena cava or inferior vena cava has an aberrant interruption or coarctation.

In some cases, it can be asymptomatic, and in other cases it can lead to fluid accumulation and cardiopulmonary collapse.

Supravalvular aortic stenosis is associated with genetic damage at the Elastin gene locus on chromosome 7q11.23. Fluorescent in situ hybridisation techniques have revealed that 96% of patients with Williams syndrome, where supravalvular aortic stenosis is characteristic, have a hemizygous deletion of the Elastin gene. Further studies have shown that patients with less extensive deletions featuring the Elastin gene also tend to develop supravalvular aortic stenosis

Binary restenosis is traditionally defined as a reduction in the percent diameter stenosis of 50% or more (≥50%). It is also known as just "binary stenosis". The term "binary" means that patients are placed in 2 groups, those who have ≥50% stenosis and those who have <50% stenosis. Binary restenosis is an epidemiological method of analyzing percent diameter stenosis for observing not only an individual patient, but also performing statistical techniques on group of patients to determine averages (descriptive measures of central tendency) or as a predictive variable.

Penile Artery Shunt Syndrome (PASS) was initially described in a patient who underwent Penile Revascularization Surgery for isolated left cavernosal artery stenosis in the absence of systemic vascular risk factors. An end-to-end anastomosis of the left inferior epigastric artery to the left dorsal penile artery was created using a previously described technique. After technically successful revascularization surgery, the patient continued to have post-operative erectile dysfunction despite documented patency of the surgical graft by Penile Duplex Ultrasonography. Pelvic angiography was performed on the patient, revealing an aberrant obturator artery originating from the inferior epigastric artery. The study revealed markedly sluggish forward flow visualized through the anastomosis to the left dorsal penile artery, with dominant flow in the left inferior epigastric artery to the obturator artery and its branches. This culminated in reduced blood flow to the penis.

Shone's syndrome (also called Shone's Complex, Shone's Anomaly)is a rare congenital heart disease described by Shone in 1963. In the complete form, four left-sided defects are present:

- Supravalvular mitral membrane (SVMM)

- Parachute mitral valve

- Subaortic stenosis (membranous or muscular)

- Coarctation of the aorta

Of these four defects, supravalvular mitral membrane (SVMM) is the first to occur, and triggers the development of the other three defects. Partial complexes, or form fruste, have also been described. The definition is often expanded to include lesions of the left side of the heart not originally ascribed to Shone's syndrome, including mitral and aortic valvular lesions and supravalvular aortic stenosis.

The term parachute mitral valve stems from the morphological appearance of the valve; that is to say, the mitral valve leaflets appear as the canopy of the parachute, the chordae as the strings and the papillary muscle as the harness.

Pyloric stenosis is a narrowing of the opening from the stomach to the first part of the small intestine (the pylorus). Symptoms include projectile vomiting without the presence of bile. This most often occurs after the baby is fed. The typical age that symptoms become obvious is two to twelve weeks old.

The cause of pyloric stenosis is unclear. Risk factors in babies include birth by cesarean section, preterm birth, bottle feeding, and being first born. The diagnosis may be made by feeling an olive-shaped mass in the baby's abdomen. This is often confirmed with ultrasound.

Treatment initially begins by correcting dehydration and electrolyte problems. This is then typically followed by surgery. Results are generally good both in the short term and in the long term. Some treat the condition without surgery by using atropine.

About one to two per thousand babies are affected. Males are affected about four times more often than females. The condition is very rare in adults. The first description of pyloric stenosis was in 1888 with surgery management first carried out in 1912 by Conrad Ramstedt. Before surgical treatment most babies died.

Restenosis is the recurrence of stenosis, a narrowing of a blood vessel, leading to restricted blood flow. Restenosis usually pertains to an artery or other large blood vessel that has become narrowed, received treatment to clear the blockage and subsequently become renarrowed. This is usually restenosis of an artery, or other blood vessel, or possibly a vessel within an organ.

Restenosis is a common adverse event of endovascular procedures. Procedures frequently used to treat the vascular damage from atherosclerosis and related narrowing and renarrowing (restenosis) of blood vessels include vascular surgery, cardiac surgery, and angioplasty.

When a stent is used and restenosis occurs, this is called in-stent restenosis or ISR. If it occurs following balloon angioplasty, this is called post-angioplasty restenosis or PARS. The diagnostic threshold for restenosis in both ISR or PARS is ≥50% stenosis.

If restenosis occurs after a procedure, follow-up imaging is not the only way to initially detect compromised blood flow. Symptoms may also suggest or signal restenosis, but this should be confirmed by imaging. For instance, a coronary stent patient who develops restenosis may experience recurrent chest pain (angina) or suffer from a minor or major heart attack (myocardial infarction), though they may not report it. This is why it is important that a patient comply with follow-up screenings and the clinician follows through with a thorough clinical assessment. But it is also important to note that not all cases of restenosis lead to clinical symptoms, nor are they asymptomatic.

Stenosis of the pulmonary artery is a condition where the pulmonary artery is subject to an abnormal constriction (or stenosis). Peripheral pulmonary artery stenosis may occur as an isolated event or in association with Alagille syndrome, Berardinelli-Seip congenital lipodystrophy type 1, Costello syndrome, Keutel syndrome, nasodigitoacoustic syndrome (Keipert syndrome), Noonan syndrome or Williams syndrome.

It should not be confused with a pulmonary valve stenosis, which is in the heart, but can have similar hemodynamic effects. Both stenosis of the pulmonary artery and pulmonary valve stenosis are causes of pulmonic stenosis.

In some cases it is treated with surgery.

When pulmonic stenosis (PS) is present, resistance to blood flow causes right ventricular hypertrophy. If right ventricular failure develops, right atrial pressure will increase, and this may result in a persistent opening of the foramen ovale, shunting of unoxygenated blood from the right atrium into the left atrium, and systemic cyanosis. If pulmonary stenosis is severe, congestive heart failure occurs, and systemic venous engorgement will be noted. An associated defect such as a patent ductus arteriosus partially compensates for the obstruction by shunting blood from the left ventricle to the aorta then back to the pulmonary artery (as a result of the higher pressure in the left ventricle) and back into the lungs.