ACUTE INFLAMMATION

Acute inflammation displays typical features:

Causes of acute inflammation include:

CHRONIC INFLAMMATION

Chronic inflammation differs from acute inflammation in the cell types present (fewer neutrophils and more lymphocytes) and the increased amount of granulation tissue (new capillaries and fibrous tissue) formed.

Causes of chronic inflammation include:

CONSEQUENCES OF INFLAMMATION

There are a variety of potential outcomes for inflamed tissue.

CANCER INCIDENCE

Cancer incidence increases with age (Fig. 21.1). The transformation of a normal cell into a cell that will form a tumour is primarily a genetic event, but this may be triggered by environmental factors. Cells from older people have had more time to experience the environmental factors that can lead to carcinogenesis and this may explain the increasing incidence with age. Table 21.2 gives details of some commonly seen cancers.

Figure 21.1 Incidence of cancer in different age groups in the UK.

TUMOUR BEHAVIOUR

CANCER TREATMENT

Cancer treatment is usually simpler when the tumour is confined to a discrete area, and may be removable by surgery. Infiltration of adjacent tissues or metastasis may require radiotherapy or systemic treatments such as chemotherapy.

DELAYED FRACTURE HEALING

The speed of fracture healing is highly variable, depending on their complexity and the age of patient, but an uncomplicated fracture in a child may show complete healing within 8 weeks. On occasions the normal process of reunification of bone fragments may be delayed or not occur at all. The following factors may be responsible:

Failure of a fracture to mend is called non-union. This may result in prolonged pain (e.g. non-union of the scaphoid) and loss of normal function such as the ability to weight bear (e.g. the tibia).

OSTEOPOROSIS

Osteoporosis is primarily a condition of old age caused by loss of the bone connective tissue matrix. Mineralisation of the matrix is normal. This distinguishes it from the condition, osteomalacia, where the matrix is normal but undermineralised.

The loss of bone mass in osteoporosis weakens the bones so that fractures become more likely – wrist and hip fractures are common. Weakening of the vertebral bodies causes gradual height reduction and often wedge-shaped compression fractures.

The causes of osteoporosis are:

Osteoporosis is seen radiographically as a loss of bone density (osteopaenia) when greater than 30% of the bone mass is lost. Vertebral body height reduction and wedge fractures are typical appearances in the spine.

ARTHRITIS

Arthritis is a disease of the synovial joints. Pain and loss of mobility results from damage to the hyaline cartilage articular surfaces. In the healthy joint, the articular cartilage is smooth, facilitating the sliding of one bone against the other. In arthritis, the cartilage is thinned and loses its smooth surfaces, increasing friction between the articulating bones. Two important forms of arthritis are osteoarthritis and rheumatoid.

Osteoarthritis affects mainly the elderly and is primarily a condition of the weight-bearing joints, though other joints are also affected. Common presentation includes:

As a result of these changes, those with osteoarthritis may experience pain on movement, stiffness and joint instability. If this becomes severe it may be necessary to perform a total joint replacement (Fig. 21.2).

Figure 21.2 Radiograph of the pelvis showing advanced osteoarthritis in the right hip joint, with sclerotic bone growth in the femoral head and acetabulum and loss of the joint space. The left side has a total hip replacement.

Rheumatoid arthritis may affect the young as well as the old, though it commonly begins between the ages of 30 and 50. It differs from osteoarthritis in that it is fundamentally an inflammatory condition. Common changes are as follows:

Figure 21.3 Radiograph of the hands showing severe erosions of the metacarpophalangeal and interphalangeal joints, due to rheumatoid arthritis.

OSTEOMYELITIS

Osteomyelitis is an infection of the bone by bacteria, most often Staphylococcus aureus. The infecting organisms gain access to the bone through a wound, such as an open fracture, or via the blood stream. Infection via the blood stream is referred to as haematogenous osteomyelitis, the bacteria entering the bone marrow through the nutrient artery.

The bone is painful and the overlying soft tissue swollen. There may also be a generalised fever, as is typical of many infections. If the infection becomes chronic some of the bone may die. There is also the possibility of sinus formation, which drains pus to the skin surface.

Osteomyelitis can be difficult to eradicate. The treatment is by antibiotic therapy and, sometimes, surgical removal of the infected bone.

PAGET’S DISEASE

Paget’s is a fairly common disease affecting the elderly, arising from a disordering of normal bone turnover. Affected bones are characterised by an increase in bone synthesis, resulting in a thickened and sclerotic ‘cotton wool’ appearance radiographically. Paget’s usually affects the pelvis, skull and long bones, often progressing from one end towards the centre. Weight-bearing bones affected by Paget’s, such as the femur and tibia, can become bowed (Fig. 21.4). When the skull is affected there may be encroachment on the cranial nerve foramina, causing various neurological symptoms including vertigo, blindness and deafness.

Figure 21.4 Deformity of the weight-bearing long bones occurs due to weakening of the bone structure through Paget’s disease.

BONE TUMOURS

Figure 21.5 Osteosarcoma in the proximal tibia, showing spiculated reactive bone growth under the periosteum.

Secondary bone tumours

• Secondary bone tumours resulting from metastasis from other malignant primary cancers are far more common (Fig. 21.6).

• Cancers typically metastasising to bone are breast, prostate, lung, kidney and thyroid.

• Appear lytic (destruction of bone) or sclerotic (increased bone density).

• Bone metastases are often painful and may be associated with pathological fractures due to weakening of the bone structure.

Figure 21.6 Radionuclide bone scan showing areas of increased tracer uptake representing metastases.

ISCHAEMIA AND INFARCTION

The main cause of ischaemia and infarction is atherosclerosis. This is the gradual accumulation of fatty deposits (atheroma) on the inner surface of an artery, which will cause narrowing (stenosis) and ultimately block it (occlusion) (Fig. 21.7). Atherosclerosis is associated with high levels of cholesterol and other lipids (fats) in the blood, smoking and elevated blood pressure. Arteries that have atherosclerosis are more prone to developing blood clots and this may cause a stenosed vesselto become occluded. Figure 21.8 shows possible complications of atherosclerosis.

Figure 21.7 Digital subtraction angiogram demonstrating complete occlusion at the origin of the right common iliac artery due to atherosclerosis.

Figure 21.8 The complications of atherosclerosis.

Ischaemia and infarction may occur anywhere in the body. They are most immediately life-threatening when they occur in the heart or brain.

THROMBOSIS

One of the normal protective mechanisms of the body is blood clotting, which occurs in response to vascular damage to limit blood loss. A blood clot can also occur pathologically when there is no vascular damage, and this is referred to as a thrombus.

ISCHAEMIC HEART DISEASE (IHD)

Ischaemia of the myocardium often results in severe chest pain referred to as angina pectoris. It is caused by increased oxygen demand, such as during exertion, in myocardium that is supplied by diseased coronary arteries. The arteries are unable to supply blood rapidly enough to the myocardium because they are stenosed, and the muscle suffers oxygen starvation.

Myocardial infarction (MI) occurs when the myocardium is starved of oxygen long enough for the cells in a particular region to die, usually due to occlusion of a coronary artery. The occlusion may occur suddenly if a thrombus forms on an area of atherosclerotic vessel. If a sufficiently large portion of the heart muscle becomes infarcted the patient may die as the heart will be unable to pump blood adequately, or it may stop – a cardiac arrest. Non-lethal MIs cause severe chest pain and the patient’s heart will be damaged. The infarcted muscle will be replaced with scar tissue that lacks the ability to contract and therefore the heart’s pumping efficiency is reduced.

Signs and symptoms of MI:

Patients with suspected MI need urgent hospitalisation to receive treatment that minimises the risk of further damage to the heart or death.

HEART FAILURE

When the pumping capacity of the heart does not meet the needs of the body it is said to be in failure. Heart failure may affect the left, right or both ventricles and usually leads to their enlargement and accumulation of fluid in the tissues that feed blood to them (Fig. 21.9).

Figure 21.9 Chest radiograph demonstrating enlargement of the heart, and lung oedema due to failure. Enlargement of the heart occurs due to dilatation and ventricular hypertrophy.

HEART VALVE DISEASE

The heart valves should ensure the efficient progress of blood through the heart from atrium to ventricle, and then into the aorta and pulmonary trunk. Diseased valves may either:

These effects are caused by hardening of the valve leaflets as a result of calcification, or scarring from rheumatic fever, a bacterial infection in childhood. The growth of bacterial vegetations on the valves may also worsen valve disorders – this is called infective endocarditis.

The greatest clinical significance is attached to disease of the mitral and aortic valves:

ANEURYSM

An aneurysm is an abnormal enlargement of the diameter of an artery, usually associated with atherosclerosis. The vessel wall may become thin, weakened and more liable to rupture. Common sites for aneurysm are the aorta and other large arteries (Fig. 21.10). Rupture of a large artery is very serious because of the possibility of fatal haemorrhage.

Figure 21.10 This axial computed tomography scan through the abdomen shows gross enlargement of the abdominal aorta due to an aneurysm.

Aneurysms found in the arterial supply of the brain are often congenital. They are usually small in size, but serious in outcome as their rupture will compromise the brain’s blood supply and the leaked blood can cause pressure on it.

DIABETES MELLITUS

The hormone insulin causes cells to take up and store glucose and lipids. In diabetes mellitus the levels of glucose and lipids within the blood are elevated because of insufficient insulin, or inability of the cells to respond to it. The high levels of lipids cause an increase in atheroma within the blood vessels and hence reduced blood flow. There are also changes to the capillary vessels, with development of microaneurysms (especially within the retina, renal glomeruli and nerves). Blood flow to certain regions such as the kidneysand peripheral vasculature can be severely compromised in diabetes mellitus. Individuals with poorly controlled diabetes are prone to foot ulcers and gangrene, and damage to the kidney tissue and retina. Even in well-controlled diabetes, stroke is twice as likely, and myocardial infarction 3–5 times more likely than in the non-diabetic population.

PNEUMONIA

Pneumonia is the inflammation of the distal airways and alveoli, usually in response to an infection. The infective agent is often bacterial but may also be viral, such as influenza, or fungal (e.g. Pneumocystis carinii). It presents as an acute illness with fever, cough and purulent sputum. It is a major cause of death in those over 70 years old.

As part of the inflammatory process, exudate accumulates in the airspaces. This is called consolidation and is evident on the chest radiograph as opacification.

Pneumonia may be classified according to its anatomical distribution:

CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD)

COPD is a term describing the presence of chronic bronchitis and emphysema simultaneously. A diagnosis of chronic bronchitis is made on clinical grounds when a chronic productive cough exists for at least 3 months of the year over two consecutive years. It has the following features:

Emphysema is also present to a variable degree in COPD. In emphysema:

The appearances of COPD on chest radiography are only obvious in severe cases where it is possible to see hyperinflation of the lungs, with flattening of the diaphragm, and increased lucency of the lung fields due to increased X-ray transmission.

BRONCHIECTASIS

Bronchiectasis is characterised by permanent abnormal dilatation of the bronchi (Fig. 21.11). Patients experience a chronic cough, producing large amounts of sputum and having difficulty in breathing (dyspnoea). It is caused by severe, recurrent or chronic infection. Associated inflammation leads to scarring and destruction of the airways, which become permanently enlarged.

Figure 21.11 Permanent dilation of the bronchi, known as bronchiectasis.

TUBERCULOSIS (TB)

Infection by the bacterium Mycobacterium tuberculosis may affect any tissue of the body but is most often found in the lungs, the bacteria normally gaining entry to the body via the airways. Infection is usually through close contact with someone infected with TB in an active stage. Individuals whose immune systems are compromised are at much greater risk of developing infection; those infected with HIV are therefore at greater risk. TB infection often presents with low-grade fever, cough, weight loss, fatigue and night sweats.

The primary focus of infection is normally the mid/upper zone of the lungs where pulmonary lesions known as Ghon complexes form. In this primary stage of infection the disease is usually clinically silent, as the bacteria are walled off within a granuloma. The bacteria may migrate from theinitial infection site to the lung apices (secondary tuberculosis) or become widely disseminated throughout the lungs and other organs (miliary tuberculosis).

PNEUMOTHORAX

Normally, the visceral pleura of the lungs adhere to the parietal pleura of the thoracic cavity or the mediastinum by the surface tension created by a thin layer of pleural fluid. In a pneumothorax, air is introduced into the pleural space and the lung in that region no longer adheres to the parietal pleura and falls away. This may occur due to a leak of air from the outer surface of the lung, either spontaneously in healthy individuals, or as a result of pre-existing lung disease.

Depending on its size a pneumothorax will result in tachycardia, difficulty in breathing and pain on the affected side. Whilst small ones will normally spontaneously resolve, larger ones will need the insertion of a chest tube to allow the air within the pleural space to escape.

A tension pneumothorax describes a situation where air is pulled into the pleural space on inspiration that cannot escape on expiration. This is often associated with an injury penetrating the thoracic wall. The result is a steadily increasing compression of the lung on the affected side causing it to collapse, and the mediastinum is pushed away from the midline (Fig. 21.12). This obstructs venous return to the heart and decreases cardiac output. It is a medical emergency that requires urgent placement of a chest drain.

Figure 21.12 Chest radiograph with air in the pleural cavity on the right, which has compressed the lung. Note the increased lucency of the thoracic cavity from where the lung tissue has receded.

PLEURAL EFFUSION

In certain pathological conditions the amount of serous fluid secreted into the pleural space increases. These include heart failure, bacterial pneumonia, lung cancer and tuberculosis. In the erect position the fluid accumulates at the lung bases and may be identified on the chest radiograph when the volume exceeds 300 ml. If the volume of pleural effusion is very large it will interfere with respiration and must be removed via a chest drain (Fig. 21.13).

Figure 21.13 Chest radiograph showing a very large pleural effusion on the right side of the chest.

LUNG CANCER

Primary lung tumours

Lung cancer is the most common malignant tumour (Fig. 21.14). There are different types of lung cancer, as the tumour may arise from different cell types, though they are usually cells within the bronchi. The prognosis and treatments options are dependent on whether it is a non-small cell lung cancer (85%) or small cell lung cancer (15%).

Figure 21.14 Chest radiograph demonstrating a large lung tumour in the right upper lobe.

Typical signs and symptoms are:

• chronic cough

• dyspnoea

• haemoptysis

• weight loss

• mass on chest X-ray

• hoarse voice.

The prognosis is poor for small cell lung cancer because, at the time of presenting, the disease is usually already well advanced and not suitablefor surgical resection, which is the procedure offering the best chance of cure. The outlook is slightly better for the non-small cell type, as 20% present when the tumour is still resectable. Primary lung tumours metastasise to the brain, liver and bone. There may be direct invasion of the ribs adjacent to the tumour, and if the primary lesion is situated in the apex (Pancoast tumour), there may be involvement of the brachial nerve plexus, causing severe pain in the shoulder and arm. Another complication is superior vena cava obstruction as a result of compression by the tumour. Restriction of venous return results in marked oedema of the face and upper extremities.

Secondary lung tumours

Carcinoma of the breast, bone, kidney and gastrointestinal tract commonly form lung metastases (Fig. 21.15). They are usually found within the lung parenchyma and may initially be relatively asymptomatic.

Figure 21.15 Chest radiograph showing extensive metastatic disease within the lungs.

INFLAMMATORY BOWEL DISEASE

Inflammatory bowel disease (IBD) refers to the separate diseases of ulcerative colitis and Crohn’s disease. Both are chronic illnesses that begin most often in childhood or young adulthood. The primary cause is not well understood in either case. They display a pattern of increased disease activity, including acute flare-ups followed by periods of remission. IBD is well-demonstrated by barium contrast studies and will account for a significant proportion of the gastrointestinal work of a radiology department.

Crohn’s disease

Crohn’s disease may occur anywhere in the alimentary tract but is most common in the terminal portion of the ileum (Fig. 21.16). Abdominal pain is often present. Deep linear ulcers form, which may extend through the full thickness of the wall, and this may result in the formation of fistulae between adjacent bowel loops or between the bowel and the skin surface, particularly around the anus. Whereas ulcerative colitis forms a continuous zone of diseased bowel, Crohn’s may affect several separate portions, hence the term ‘skip lesions’. The bowel develops a thickened and fibrosed wall whilst the lumen becomes stenosed, which may lead to bowel obstruction.

Figure 21.16 Radiolabelled white cell scan. White cells labelled with technetium-99 m migrate to areas of inflammation as well as to bone marrow. This scan shows normal marrow appearances and an intense focus of activity in the terminal ileum.

INTESTINAL OBSTRUCTION

Abdominal radiographs are commonly requested for investigating suspected intestinal obstruction. Obstruction may be complete or partial. The bowel proximal to the obstruction accumulates fluid and gas, causing the typical radiographic appearance of dilated bowel loops. Deciding whether the obstruction is in the large or small bowel can be made on the basis of the distribution, diameter and shape of the gas pattern (Fig. 21.17).

Figure 21.17 Abdominal radiograph showing dilated and gas-filled bowel due to obstruction.

Intestinal obstruction is a serious condition because it results in congestion, oedema and eventual death of the proximal bowel. There may be migration of faecal bacteria into the bloodstream from the damaged bowel wall, or it may perforate, resulting in peritonitis (a severe infection and inflammation of the peritoneal cavity).

Causes of intestinal obstruction:

DIVERTICULAR DISEASE

Diverticula are blind-ended pouches of bowel mucosa on the outside of the bowel wall. It is thought that they form where the muscular wall of the bowel is penetrated by blood vessels and therefore potentially weakened. There is an association with a low-fibre diet and increased age.

As they are open-ended towards the bowel lumen, diverticula are filled with faeces, which can become stagnant and inflamed (Fig. 21.18). The presence of diverticula is called diverticulosis; when one or more are inflamed the condition is called diverticulitis. This is experienced as abdominal pain and fever. Complications of diverticulitis include abscess formation and perforation.

Figure 21.18 Double contrast barium enema, showing diverticular disease.

PEPTIC ULCER DISEASE (PUD)

A peptic ulcer is found in the stomach or duodenum. It may present with upper abdominal pain that is relieved by food, or be clinically silent. This disease is commonly investigated in the radiology department by barium meal, where it will be demonstrated as a cratered area of the mucosal lining. Ulceration of the gastric or duodenal mucosa is dependent on excess gastric acid secretion.

Bleeding from peptic ulcers may result in sufficient blood loss to cause anaemia, and may also be evidenced by digested blood in the stool (melaena). Peptic ulcers may be sufficiently severe to perforate the bowel wall, allowing bowel contents and gas to escape into the peritoneal cavity. Erect chest X-rays are often requested in suspectedpeptic ulcer perforation to identify gas collected beneath the diaphragm, which is indicative of this condition.

COLORECTAL CANCER

There is an association of colorectal cancer with high dietary intake of saturated fats and low intake of dietary fibre, which may explain its high incidence in developed countries. The risk of developing colorectal cancer increases significantly after the age of 40.

The majority of bowel cancers are carcinomas, which are thought to arise from sporadic polyps that develop from the bowel mucosa. Initially these are benign, but there is an increasing association with malignant transformation as they get larger. Approximately 50% are found in the rectum, 30% in the sigmoid and the remainder in the rest of the colon.

Bowel cancers may appear as a fungating mass with an ulcerated centre or as a complete ring of tumour growth. The latter is associated with marked fibrosis that causes the bowel to constrict, forming an annular stricture. This type gives the typical apple core appearance shown by barium enema (Fig. 21.19).

Figure 21.19 Barium enema demonstrating an annular stricture in the transverse colon representing an adenocarcinoma.

Tumour cells breaking away into the bloodstream are directed expressly to the liver via the hepatic portal system where they will be captured and may develop into secondary deposits. Infiltration of the tumour into the numerous lymphatic channels draining the bowel leads to involvement of the lymph nodes. Cases with liver and lymph node involvement have a poor long-term prognosis; however colorectal cancer has a good chance of cure if it is detected and treated at an early stage. Alterations of bowel habit, especially with evidence of blood in the stool, should always be investigated thoroughly at the earliest opportunity.

PYELONEPHRITIS

Pyelonephritis is infection of the kidney tissue. In the acute phase there is pus formation associated with typical symptoms of infection, such as fever, nausea and rigors. If recurrent infections occur, the kidney may become damaged through scar formation, which replaces the functioning tubular tissue. This is most likely to occur in children where there is reflux of urine from the bladder into the ureters due to incompetent ureteral valves.

UROLITHIASIS

Urolithiasis is the formation of stones (calculi) within the renal tract. Renal calculi may form anywhere but most often occur in the renal pelvis. Stone formation may result from disturbances of normal physiology, such as change in urine pH, or excessive levels of certain substances within the urine, which are then more likely to precipitate out of solution.

Figure 21.20 Intravenous urogram following intravenously administered iodinated contrast agent showing a dilated right renal pelvis and calyces due to obstruction at the pelvi-ureteric junction. The left side shows a staghorn calculus completely filling the pelvicalyceal system.

Renal calculi are associated with an increased likelihood of urinary tract infection. Their presence may also cause dull loin pain or renal colic, an exceptionally painful condition produced by the passage of the stone along the ureter.

OBSTRUCTIVE UROPATHY

Obstructive uropathy refers to renal tract disease resulting from the obstruction of urinary outflow. The obstruction may be complete or partial and can be caused as a result of calculi, tumours or congenital abnormalities.

Calculi may become lodged within the ureter, causing obstruction of the urine flow out of the kidney. Common sites of calculi obstruction are where the ureter narrows at the pelvi-ureteric junction, the pelvic brim and where it enters the bladder (vesico-ureteric junction). Ureteric obstruction needs to be resolved as soon as possible as the increasing backpressure will cause damage to the kidney. Obstruction results in enlargement of the kidney and dilation of the renal pelvis and calyces (hydronephrosis) and of the ureter proximal to the obstruction (hydroureter).

Radiology plays an important role in the identification of the cause of obstruction and also in therapeutic procedures. Intravenous urography, unenhanced helical CT and ultrasound are all commonly employed diagnostic procedures.

Some stones are suitable for disintegration using shockwaves – a procedure called lithotripsy. The stones are targeted with fluoroscopic imaging, which guides the shockwave device to the correct position on the flank. If the obstruction is due to a tumour or some other kind of stricture, it may be necessary to employ interventional radiological procedures such as nephrostomy. This refers to percutaneous access to the renal pelvis with placement of an externally sited drain, or positioning of an internally deployed tube, called a stent, to re-establish drainage of the kidney to the bladder.

RENAL TUMOURS

Renal tumours may manifest with obstructive symptoms, and haematuria (blood in urine). Radiology plays an important role in their diagnosis and staging.

CEREBROVASCULAR EVENT (STROKE)

Stroke results from a severe disruption in blood supply to the brain, resulting in damage to the brain tissue. Neurological effects ensue which may be from very mild through to more severe effects including paralysis, visual and speech disturbances. Strokes affecting the critical centres of the brain result in death. Risk factors are similar to other cardiovascular diseases and include smoking, hypertension, elevated lipid levels, diabetes and old age. Stroke may be due to infarction or haemorrhage.

Haemorrhage

Bleeding may occur within the brain tissue and is called intracerebral haemorrhage, or from the arteries at the base of the brain, including the circle of Willis, which is referred to as subarachnoid haemorrhage (SAH).

Intracerebral haemorrhage results in a haematoma that takes up space within the brain matter, causing increased intracranial pressure and distortion of the brain structure. In SAH blood accumulates inside the arachnoid layer of the meninges, giving rise to increased intracranial pressure (Fig. 21.21). As with intracerebral haemorrhage there is distortion of the brain structure. Irritation of the arteries by the free blood may also cause arterial spasm and infarct.

Figure 21.21 Computed tomography of the brain demonstrating high attenuation (white) areas within the brain due to the presence of freshly leaked blood from a subarachnoid haemorrhage.

Both types of haemorrhage are closely associated with hypertension, which promotes the formation and rupture of aneurysms.

SPINAL CORD AND NERVE COMPRESSION

Physical compression of the spinal cord and the spinal nerve roots can cause a range of pain and neurological deficit from paraesthesia (tingling) to paralysis. The severity of the effects is dependent on the degree of compression and how much damage is caused to the nerve tissue.

Causes of compression

Intervertebral disc herniation

The intervertebral disc consists of a tough outer ring of dense connective tissue (the annulus fibrosus) surrounding a soft jelly-like centre (the nucleus pulposus). It allows flexibility in the spine and acts as a shock absorber. Sometimes the outerring may be damaged and part of the nucleus pulposus herniates through the weakness in the annulus fibrosus. This herniation can cause compression of the spinal cord or the spinal nerve roots. Depending on its severity, the disc may need surgery to remove the parts that are compressing the nerve. This condition is shown very well by magnetic resonance imaging but not radiography.

Cervical spondylosis

Osteophyte formation around the margins of the intervertebral foramina and disc degeneration in the neck is called cervical spondylosis. It can lead to chronic pain and stiffness in the neck that may also radiate to the upper extremities (radiculopathy). It is often demonstrated by cervical spine radiography.

Tumour infiltration

Metastases to the vertebral column are usually the cause of the most severe neurological effects (Fig. 21.22). Infiltration of the vertebral bodies leads to severe weakening and collapse. The fragments extrude posteriorly and cause compression of the cord.

Figure 21.22 Sagittal MRI of the thoracic spine showing collapse due to tumour infiltration of T11 with cord compression.

Cancers most commonly leading to cord compression:

• Lung

• Breast

• Prostate

• Multiple myeloma

• Non-Hodgkin’s lymphoma.

MENINGITIS

The brain and spinal cord are covered in three layers of membrane, which make up the meninges. Infection of the meninges either by bacteria or viruses causes inflammation called meningitis.

The infection occurs by direct extension from the nasopharynx or via the blood. Bacterial meningitis is the most serious form, and even with the best care about 15% of patients will die. The bacteria responsible for approximately two-thirds of all cases are Neisseria meningitidis and Streptococcus pneumoniae.

Classical symptoms are:

Infection with Neisseria meningitidis leads to a specific form of the disease called meningococcal meningitis. It is often accompanied by a generalised septicaemia typified by a non-blanching rash. Immediate treatment of suspected cases with intravenous antibiotics is essential to avoid death or severe after-effects, such as neurological damage and limb loss.

MULTIPLE SCLEROSIS

Multiple sclerosis (MS) is a disabling neurological disorder resulting from damage to the myelin coating of nerve cells in the central nervous system. It usually presents between the ages of 20 and 40. Patients with MS suffer from loss of normal function in certain parts of the body due to disruption of the nerve signals to and from the brain. These symptoms may be episodic, only presenting during a relapse, or permanent. The damaged areas of the nerves form scar tissue called plaques; these are well shown by MRI.

The course of MS is variable, depending on the individual and the age of onset, but usually patients suffer progressive levels of debilitation, with each relapse leaving them in a worse state.

BRAIN TUMOURS

Primary brain tumours

Primary brain tumours may arise from the neuroglial cells. The general term for tumours derived from neuroglial cells is glioma, or more specifically astrocytoma and oligodendroglioma, depending on the cell type of origin.

These tumours may grow slowly or rapidly and spread by local extension into surrounding tissues. They do not metastasise to other organs. The effect they have on the individual is dependent on where they are located in the brain (Fig. 21.23). Tumours in the frontal lobe may affect personality and mood; those in the temporal lobe may affect coordination speech and memory. The precise effect depends on the function of the brain tissue damaged and the size of the tumour. Because they arise from the brain tissue itself, they are referred to as intrinsic tumours.

Figure 21.23 Computed tomography showing an enhancing brain tumour within the left cerebral hemisphere.

Extrinsic tumours develop from the tissues covering the brain and spinal cord. A meningioma is a tumour of the meninges. They may grow large and cause considerable distortion and compression of the brain; however, they are usually benign and do not infiltrate the brain tissue. Surgery is usually the first option for removal, and this is often completely curative (Fig. 21.24).

Figure 21.24 Meningioma causing cerebral compression.

Brain tumours are well shown by CT and MRI, especially when contrast agents are used. In intrinsic tumours the breakdown of the blood–brain barrier allows penetration of the contrast into the tumour, which then shows enhancement.