Head pain occurs in 50–75% of all cases of vertebral artery dissection. It tends to be located at the back of the head, either on the affected side or in the middle, and develops gradually. It is either dull or pressure-like in character or throbbing. About half of those with VAD consider the headache distinct, while the remainder have had a similar headache before. It is suspected that VAD with headache as the only symptom is fairly common; 8% of all cases of vertebral and carotid dissection are diagnosed on the basis of pain alone.

Obstruction of blood flow through the affected vessel may lead to dysfunction of part of the brain supplied by the artery. This happens in 77–96% of cases. This may be temporary ("transient ischemic attack") in 10–16% of cases, but many (67–85% of cases) end up with a permanent deficit or a stroke. The vertebral artery supplies the part of the brain that lies in the posterior fossa of the skull, and this type of stroke is therefore called a posterior circulation infarct. Problems may include difficulty speaking or swallowing (lateral medullary syndrome); this occurs in less than a fifth of cases and occurs due to dysfunction of the brainstem. Others may experience unsteadiness or lack of coordination due to involvement of the cerebellum, and still others may develop visual loss (on one side of the visual field) due to involvement of the visual cortex in the occipital lobe. In the event of involvement of the sympathetic tracts in the brainstem, a partial Horner's syndrome may develop; this is the combination of a drooping eyelid, constricted pupil, and an apparently sunken eye on one side of the face.

If the dissection of the artery extends to the part of the artery that lies inside the skull, subarachnoid hemorrhage may occur (1% of cases). This arises due to rupture of the artery and accumulation of blood in the subarachnoid space. It may be characterized by a different, usually severe headache; it may also cause a range of additional neurological symptoms.

13–16% of all people with vertebral or carotid dissection have dissection in another cervical artery. It is therefore possible for the symptoms to occur on both sides, or for symptoms of carotid artery dissection to occur at the same time as those of vertebral artery dissection. Some give a figure of multiple vessel dissection as high as 30%.

Dissections become threatening to the health of the organism when growth of the false lumen prevents perfusion of the true lumen and the end organs perfused by the true lumen. For example, in an aortic dissection, if the left subclavian artery orifice were distal to the origin of the dissection, then the left subclavian would be said to be perfused by the false lumen, while the left common carotid (and its end organ, the left hemisphere of the brain) if proximal to the dissection, would be perfused by the true lumen proximal to the dissection.

Vessels and organs that are perfused from a false lumen may be well-perfused to varying degrees, from normal perfusion to no perfusion. In some cases, little to no end-organ damage or failure may be seen. Similarly, vessels and organs perfused from the true lumen but distal to the dissection may be perfused to varying degrees. In the above example, if the aortic dissection extended from proximal to the left subclavian artery takeoff to the mid descending aorta, the common iliac arteries would be perfused from the true lumen distal to the dissection but would be at risk for malperfusion due to occlusion of the true lumen of the aorta by the false lumen.

Vertebral artery dissection is one of the two types of dissection of the arteries in the neck. The other type, carotid artery dissection, involves the carotid arteries. Vertebral artery dissection is further classified as being either traumatic (caused by mechanical trauma to the neck) or spontaneous, and it may also be classified by the part of the artery involved: extracranial (the part outside the skull) and intracranial (the part inside the skull).

In medical pathology, a dissection is a tear within the wall of a blood vessel, which allows blood to separate the wall layers. By separating a portion of the wall of the artery (a layer of the tunica intima or tunica media), a dissection creates two lumens or passages within the vessel, the native or true lumen, and the "false lumen" created by the new space within the wall of the artery.

The causes of internal carotid artery dissection can be broadly categorised into two classes: spontaneous or traumatic.

The signs and symptoms of carotid artery dissection may be divided into ischemic and non-ischemic categories:

"Non-ischemic signs and symptoms"

- Localised headache, particularly around one of the eyes.

- Neck pain

- Decreased pupil size with drooping of the upper eyelid (Horner syndrome)

- Pulsatile tinnitus

"Ischemic signs and symptoms"

- Temporary vision loss

- Ischemic stroke

About 96% of individuals with aortic dissection present with severe pain that had a sudden onset. The pain may be described as a tearing, stabbing, or sharp sensation; 17% of individuals feel the pain migrate as the dissection extends down the aorta. The location of pain is associated with the location of the dissection. Anterior chest pain is associated with dissections involving the ascending aorta, while interscapular (back) pain is associated with descending aortic dissections. If the pain is pleuritic in nature, it may suggest acute pericarditis caused by bleeding into the pericardial sac. This is a particularly dangerous eventuality, suggesting that acute pericardial tamponade may be imminent. Pericardial tamponade is the most common cause of death from aortic dissection.

While the pain may be confused with the pain of a myocardial infarction (heart attack), aortic dissection is usually not associated with the other signs that suggest myocardial infarction, including heart failure and ECG changes.

Individuals with aortic dissection who do not present with pain have a chronic dissection.

Less common symptoms that may be seen in the setting of aortic dissection include congestive heart failure (7%), fainting (9%), stroke (6%), ischemic peripheral neuropathy, paraplegia, and cardiac arrest. If the individual had a fainting episode, about half the time it is due to bleeding into the pericardium leading to pericardial tamponade.

Neurological complications of aortic dissection (i.e., stroke and paralysis) are due to the involvement of one or more arteries supplying portions of the central nervous system.

If the aortic dissection involves the abdominal aorta, compromise of the branches of the abdominal aorta is possible. In abdominal aortic dissections, compromise of one or both renal arteries occurs in 5–8% of cases, while mesenteric ischemia (ischemia of the large intestines) occurs 3–5% of the time.

The symptoms are often very similar to those of myocardial infarction (heart attack), with the most common being persistent chest pain.

People with an aortic dissection often have a history of high blood pressure; the blood pressure is quite variable at presentation with acute aortic dissection, and tends to be higher in individuals with a distal dissection. In individuals with a proximal aortic dissection, 36% present with hypertension, while 25% present with hypotension. Proximal aortic dissections tend to be more associated with weakening of the vascular wall due to cystic medial degeneration. In those who present with distal (type B) aortic dissections, 60-70% present with high blood pressure, while 2-3% present with low blood pressure.

Severe hypotension at presentation is a grave prognostic indicator. It is usually associated with pericardial tamponade, severe aortic insufficiency, or rupture of the aorta. Accurate measurement of the blood pressure is important. Pseudohypotension (falsely low blood-pressure measurement) may occur due to involvement of the brachiocephalic artery (supplying the right arm) or the left subclavian artery (supplying the left arm).

Aortic rupture is the rupture or breakage of the aorta, the largest artery in the body. Aortic rupture is a rare, extremely dangerous condition. The most common cause is an abdominal aortic aneurysm that has ruptured spontaneously. Aortic rupture is distinct from aortic dissection, which is a tear through the inner wall of the aorta that can block the flow of blood through the aorta to the heart or abdominal organs.

An aortic rupture can be classified according to its cause into one of the following main types:

- Traumatic aortic rupture

- Aortic rupture secondary to an aortic aneurysm

The diagnosis of thoracic aortic aneurysm usually involves patients in their 60s and 70s.

A spontaneous coronary artery dissection (SCAD) (occasionally coronary artery dissection) is a rare, sometimes fatal traumatic condition, with eighty percent of cases affecting women. One of the coronary arteries develops a tear, causing blood to flow between the layers which forces them apart. Studies of the disease place the mortality rate at around 70%.

SCAD is a primary cause of myocardial infarction (MI) in young, fit, healthy women (and some men) with no obvious risk factors. These can often occur during late pregnancy, postpartum and peri-menopausal periods.

Diagnosis is often suspected in patients "in extremis" (close to death) with abdominal trauma or with relevant risk-factors. Diagnosis is confirmed quickly in the Emergency room by ultrasound or CT scan.

A thoracic aortic aneurysm is an aortic aneurysm that presents primarily in the thorax.

A thoracic aortic aneurysm is the "ballooning" of the upper aspect of the aorta, above the diaphragm. Untreated or unrecognized they can be fatal due to dissection or "popping" of the aneurysm leading to nearly instant death. Thoracic aneurysms are less common than an abdominal aortic aneurysm. However, a syphilitic aneurysm is more likely to be a thoracic aortic aneurysm than an abdominal aortic aneurysm.

Familial aortic dissection or FAD refers to the splitting of the wall of the aorta in either the arch, ascending or descending portions. FAD is thought to be passed down as an autosomal dominant disease and once inherited will result in dissection of the aorta, and dissecting aneurysm of the aorta, or rarely aortic or arterial dilation at a young age. Dissection refers to the actual tearing open of the aorta. However, the exact gene(s) involved has not yet been identified. It can occur in the absence of clinical features of Marfan syndrome and of systemic hypertension. Over time this weakness, along with systolic pressure, results in a tear in the aortic intima layer thus allowing blood to enter between the layers of tissue and cause further tearing. Eventually complete rupture of the aorta occurs and the pleural cavity fills with blood. Warning signs include chest pain, ischemia, and hemorrhaging in the chest cavity. This condition, unless found and treated early, usually results in death. Immediate surgery is the best prognosis in most cases. FAD is not to be confused with PAU (penetrating atherosclerotic ulcers) and IMH (intramural hematoma), both of which present in ways similar to that of familial aortic dissection.

Symptoms of myocardial rupture are recurrent or persistent chest pain, syncope, and distension of jugular vein. Sudden death caused by a myocardial rupture is sometimes preceded by no symptoms.

Myocardial rupture is a laceration or t

e ventricles or atria of the heart, of the interatrial or interventricular septum, or of the papillary muscles. It is most commonly seen as a serious sequela of an acute myocardial infarction (heart attack).

It can also be caused by trauma.

The carotid and vertebral arteries are most commonly affected. Middle and distal regions of the internal carotid arteries are frequently involved. Patients with FMD in the carotid arteries typically present around 50 years of age. Symptoms of craniocervical involvement include headaches (mostly migraine), pulsatile tinnitus, dizziness, and neck pain, although patients are often asymptomatic. On physical examination, one may detect neurological symptoms secondary to a stroke or transient ischemic attack (TIA), a bruit over an affected artery, and diminished distal pulses. Complications of cerebrovascular FMD include TIA, ischemic stroke, Horner syndrome, or subarachnoid hemorrhage.

Patients with mesenteric, or intestinal FMD, may experience abdominal pain after eating or weight loss. FMD within the extremities may cause claudication or may be detectable by bruits. If the lower limb arteries are affected, the patient may present with cold legs or evidence of distal embolic disease. FMD present in the subclavian artery may cause arm weakness, parenthesis, claudication, and subclavial steal syndrome.

Since the cause of FAD has not been genetically pinpointed, the only way to diagnose FAD is through the examination of phenotypic variations in the aorta. Usually echocardiography is used to take measurements of the aortic root as well as transesophageal echocardiography. Biomarkers lend a quick way to diagnose dissection when time is of the essence. These have the ability to relay the levels of smooth muscle mysosin heavy chain protein present, which is released from damaged aortic tissue.

There are two types of FAD; groups A and B. Normally if any area of the ascending aorta is involved in the dissection this is considered group A. If the dissection occurs within the descending aorta this is classified in group B. These two groups can than be broken down into three classes of FAD: Type 1, Type 2 and Type 3. Group A consists of Types 1 and 2, whereas Group B consists only of Type 3. Type 1 encompasses dissection in the distal ascending aorta closest to the heart, not including the aortic arch. Type 2 refers to dissection of the ascending aorta, closer to and including the aortic arch. Type 3 refers to the descending thoracic and abdominal aorta.

Group A dissections are the more serious of the two due to the location of the dissection in the ascending aorta, which leads to a higher risk of congestive heart failure and pericardium and/or aortic valve rupture. Individuals also tend to be predisposed to type A if they do have Marfans or Elhers-Danlos syndromes. These contribute to a higher fatality rate in group A dissection if immediate surgery is not performed. The most common corrective surgeries are actual aortic valve replacement and coronary artery bypass. The five year survival rate after surgery is a successful 70.4% due to vigilant monthly physical exams and chest x-rays to monitor progress. Group B dissections typically have a higher surgery mortality rate and are therefore not good candidates. Instead medical management is the common response to treating and keeping dissections of the descending aorta under control.

It is sometimes called "Erdheim cystic medial necrosis of aorta", after Jakob Erdheim.

The term "cystic medial degeneration" is sometimes used instead of "cystic medial necrosis", because necrosis is not always found.

Familial thoracic aortic aneurysm is an autosomal dominant disorder of large arteries.

There is an association between familial thoracic aortic aneurysm, Marfan syndrome and massive baclofen overdose as well as other hereditary connective tissue disorders.

Acute limb ischaemia can occur in patients through all age groups. Patients that smoke and have diabetes mellitus are at a higher risk of developing acute limb ischaemia. Most cases involve people with atherosclerosis problems.

Symptoms of acute limb ischaemia include:

- Pain

- Pallor

- Paresthesias

- Perishingly cold

- Pulselessness

- Paralysis

These symptoms are called "the six P's'"; they are commonly mis-attributed to compartment syndrome. One more symptom would be the development of gangrene. Immediate medical attention should be sought with any of the symptoms.

In late stages, paresthesia is replaced by anesthesia due to death of nerve cells.

In some cases, gangrene can occur within six hours of ischaemia.

Acute limb ischaemia (ALI) occurs when there is a sudden lack of blood flow to a limb.

Acute limb ischaemia is caused by embolism or thrombosis, or rarely by dissection or trauma. Thrombosis is usually caused by peripheral vascular disease (atherosclerotic disease that leads to blood vessel blockage), while an embolism is usually of cardiac origin. In the United States, ALI is estimated to occur in 14 out of every 100,000 people per year. With proper surgical care, acute limb ischaemia is a highly treatable condition; however, delayed treatment (beyond 6 to 12 hours) can result in permanent disability, amputation, and/or death.

The New Latin term "ischaemia" as written, is a British version of the word "ischemia", and stems from the Greek terms "ischein" 'to hold'; and "haima" 'blood'. In this sense, ischaemia refers to the inhibition of blood flow to/through the limb.

Posterior spinal artery syndrome is much rarer than its anterior counterpart as the white matter structures that are present are much less vulnerable to ischemia since they have a better blood supply. When posterior spinal artery syndrome does occur, dorsal columns are damaged and ischemia may spread into the posterior horns. Clinically the syndrome presents as a loss of tendon reflexes and loss of joint position sense