following implantation. SUBASH KC/NMC-15TH/2014 ECTOPIC PREGNANCY 245 Information for the radiologist \200 Salient history and examination \201 ndings. \200 Last menstrual period important. \200 B hCG level if known. Fig. 16.15 calipers) inseparable from the right ovary. This was con \201 rmed at surgery t o be a tubal ectopic pregnancy, and the patient underwent a salpingo-oophorectomy. Image from a TV ultrasound showing a complex mass (indicated by SUBASH KC/NMC-15TH/2014 246 CHAPTER 16 Genitourinary conditions Endometriosis This is the presence of endometrial glands and stroma outside the uterine cav ity and musculature. Ectopic endometrial material responds to hormonal stimuli causing cycl ical hemorrhage. Common sites for endometrial deposits include the ovaries and pelvic perit oneum. Deep endometriosis describes endometriosis that in \201 ltrates the peritoneum > 5m m. These deposits are found in the subperitoneal pelvic space, the uterosacral ligaments, r ectovag- inal septum, and also in the bladder and bowel wall. Clinical presentation Many patients are asymptomatic. It commonly presents with infertility or pelvic pain. Imaging Ultrasound and MRI are the most useful tests. Occasionally the diagnosis may be uns uspected, and suggests following other imaging, such as barium enema showing endometrial se rosal deposits on the bowel wall, typically at the rectosigmoid. Ultrasound \200 Endometriomas ( \200\230chocolate cysts \200\231) appear as complex cysti c ovarian mass with homogeneous low level echoes and a thick wall (Fig. 16.16 ). Hydrosalpinx maybe present. \200 Assessment of super \201 cial peritoneal deposits, ovar ian foci and deep endometriosis is less accurate with ultrasound. MRI \200 Typical MRI features of endometriomas include high signal intensity on T1-weighted sequences due to blood products in the cyst. There may be layering of \202 ui d within the cyst due to blood products of different ages. Features of deep endometriosis depend on whether it is in \201 ltrative small implants, vi sceral implants, or solid deep lesions in the posterior cul-de-sac. Secondary complications of adhesions, such as bowel obstruction may be seen. Information for the radiologist Detailed clinical symptoms and examination \201 ndings wi ll help the radi- ologist identify endometriotic deposits accurately particularly when the deposits are small and subtle. SUBASH KC/NMC-15TH/2014 ENDOMETRIOSIS 247 Fig. 16.16 Ultrasound showing endometrioma within the right ovary. SUBASH KC/NMC-15TH/2014 248 CHAPTER 16 Genitourinary conditions Ovarian torsion \200 The abnormal rotation of the ovary on its vascular pedicle, compromising the venous and arterial blood supply to the ovary. Predisposing factors include: ovarian cyst ( > 5cm) or cystic neoplasm, cystic ovaries associated with ovarian hyperstimulation syndrome and polycystic ovaries. Initially the venous out \202 ow and lymphatic drainage are compromised, with maintenance of arterial in \202 ow. The ovary enlarges and becomes oedematous causing arterial thrombosis, leading to ovarian ischaemia and infarction. Highest prevalence is in women of reproductive age. 17 \200\22320 % of cases occur in pregnant women. Clinical presentation Symptoms may be non-speci \201 c iting associated with tenderness/pe ritonism, be intermittent. \200\224 lower abdominal pain, nausea and vom- a palpable mass. Pain may Imaging Ultrasound First-line investigation. Both TA and TV ultrasound should be performed. \200 A unilateral enlarged ovary \200 Peripheral ovarian follicles ( \200\230string of pearl \200\231 sign) as the follicles are a coexistent ovarian mass. displaced by the oedematous stroma. Free \202 uid in pelvis. \200 Arterial and venous blood \202 ow can be maintained des pite a twisted vascular pedicle; however, absence of blood \202 ow is highly suggestive o f the diagnosis. CT (Fig. May be performed prior to ultrasound, as CT is commonly used as the \201 rst-lin e investigation for non-speci \201 c abdominal and pelvic pain. \200 An adnexal mass whi ch may be displaced to the midline. \200 Ascites or haemoperitoneum. \200 Reduced centr al enhancement of the ovary. \200 Hemorrhage and gas in the ovary if necrotic. \200 Str anding and in \202 ammatory changes in the adjacent fat. 16.17a ) MRI (Fig. May be required when pelvic ultrasound inconclusive. 16.17b ) Information for the radiologist \200 Last menstrual period \200\224 is the patient pregn ant? \200 Is there any relevant gynecological history? \200 Is the woman taking inferti lity drugs? \200 Are there any other symptoms to suggest other diagnoses, e.g. diverticulitis, appendicitis? SUBASH KC/NMC-15TH/2014 OVARIAN TORSION 249 (a) (b) Fig. 16.17 a) CT and b) MRI in a patient with left-sided ovarian torsion. The CT shows a bu lky, high attenuation left ovary, in keeping with hemorrhage. MRI showing enlarged, low sig nal intensity infarcted left ovary (long arrow), showing no enhancement compared to the nor mal right ovary (short arrow). SUBASH KC/NMC-15TH/2014 250 CHAPTER 16 Genitourinary conditions Pelvic in \202 ammatory disease \200 Infection of the upper genital tract, commonly sexu ally transmitted Chlamydia trachomatis or Neisseria gonorrhoeae . Less commonly occurs as a result of second ary infection from appendicitis or diverticulitis. Peak incidence rate is in women aged 20 \200\22324 years. Long-term sequelae include infertility, ectopic pregnancy, and chronic pain if left untreated. Clinical presentation Abdominal pain, raised temperature, vaginal discharge, abdominal tend er- ness, cervical and adnexal tenderness. Imaging Ultrasound (Fig. TA and TV ultrasound are the \201 rst-line investigations, looki ng for: \200 An enlarged and indistinct uterus. Adjacent fat may be in \202 amed and of 16.18 ) increased echogenicity. Free \202 uid in the pouch of Douglas. \200 Evidence of salpingitis which occurs in the early stages of pelvic in \202 ammatory disease (PID). A tubo-ovarian complex/abscess. \200 Perihepatitis: Fitz \200\223Hugh \200\223Curtis synd rome occurs when in \202 ammatory exudates spread to the liver via the right paracolic gutter from the pelvis, causing RUQ pa in. CT This may be the \201 rst investigation if symptoms are non-speci \201 c. Advantages o f CT over US are that \201 rstly, it is easier to appreciate the effects of pelvic in \202 ammation on adjacent structures, e.g. bowel ileus, hydroureter, or appendicitis. Secon dly, subtle signs of in \202 ammation are easier to appreciate on CT, e.g. there may be ha ziness in the pre-sacral fat, thickening of the uterosacral ligaments, peritoneal enhanceme nt or periovarian stranding in adjacent fat. Classic features of PID are also appreciated o n CT such as dilated fallopian tubes, adnexal abscesses, enlarged ovaries, and free \202 uid. MRI MRI has a higher sensitivity and speci \201 city in depicting PID compared with TV ult rasound. However, ultrasound is a relatively low cost and more readily accessible compared to MRI. MRI should only be used in dif \201 cult cases as a problem solver. Information for the radiologist Relevant history and examination \201 ndings. SUBASH KC/NMC-15TH/2014 PELVIC INFLAMMATORY DISEASE 251 Fig. 16.18 is seen to contain debris. Ultrasound showing dilated, \202 uid \201 lled fallopian tube (arrow). The \202 uid SUBASH KC/NMC-15TH/2014 252 CHAPTER 16 Genitourinary conditions Epididymitis May be acute or chronic. Usually acute, secondary to infection, resolving with antibiotic therapy. The role of imaging is to con \201 rm the diagnosis and exclude compl ications. Clinical presentation \200 Acute epididymitis: presentation is with acute pain and scrota l in \202 ammation. Secondary to ascending UTI, sexually transmitted infection, or haemato genous infection. Recent instrumentation can be a factor. Numerous bacteria are associated, e.g. Pseudomonas , gonorrhea, Chlamydia , and TB. \200 Chronic epididymitis: pain and te nderness for Escherichia coli , > 6 weeks, often unclear etiology. Associations: previous infection, scrotal surgery, or systemic in \202 ammatory conditions. Investigate for infection especially Treatment is with antibiotics and anti-in \202 ammatories. Role of imaging is limited. Chlamydia . Investigations FBC (increased WCC) and urine sample. culture and may require prostatic mass age or direct epididymal sampling. Chlamydia can be dif \201 cult to Differential diagnosis \200 Orchitis: if present without epididymitis is likely mumps. \200 Sperm granuloma (post vasectomy). \200 Torsion (younger age group). \200 Tumor: e specially in young children an extra-testicular mass in the scrotum may represent a rhabdomyosarcoma. Imaging Ultrasound (Fig. Performed with a high-frequency probe. In acute epididymitis the e ntire epididymis is enlarged, occasionally only the head. The echogenicity is either low du e to oedema or heterogeneous. Blood \202 ow is mostly increased. Complications include sc rotal abscesses. The collection should demonstrate increased through transmission of sound (picture looks brighter behind) \200\224 an important ultrasound imaging sign. Alternative pathology can be demonstrated such as tumor or orchitis. 16.19 ) In chronic epididymitis the imaging can be normal or a more subtle swelling of the epididymis may be seen. Information for the radiologist Clinical history, in particular any surgical procedures. SUBASH KC/NMC-15TH/2014 EPIDIDYMITIS 253 Fig. 16.19 with epididymitis. Ultrasound showing oedematous hyperaemic epididymitis in a patient SUBASH KC/NMC-15TH/2014 254 CHAPTER 16 Genitourinary conditions Testicular torsion \200 Male <30 years, peak 10 \200\22314 years. \200 Associated with bell clapper insertion of the testis within the tunica vaginalis, allowing the spermatic cord to wind around with resultant vascular compromise. Clinical presentation Presentation is with pain severe enough to inhibit mobility and cause nausea. The testis can occasionally un-tort and re-tort, giving an episodic history of pai n. The differential diagnosis is of a torted hydatid of Morgagni (testicular appendage) and infection (epididymitis/orchitis). History and examination help differentiate. Typically t he torted testis will be exquisitely tender and have a high horizontal lie in an in \202 a med scrotum. Boys at the younger end of the spectrum can present with abdominal pain and na usea. 1 Acute torsion of the testis is a surgical emergency which requires urgent operative explo ration with bilateral orchidopexy (if viable) or orchidec- tomy and contralateral orchidope xy (if non-viable). Do not waste time requesting an ultrasound or nuclear scan to assess fo r viability. Early restoration of blood supply is the aim. Imaging Ultrasound (Fig. Performed when other causes of scrotal pain are suspected such as epidiymo- orchitis or when the history of torsion is of such chronicity that the test is to con \201 rm the presence of a non-viable testis. 16.20 ) If scanned in acute torsion the affected testis will be swollen, of low echogenicity, and a reactive hydrocoele may be present. There may be no Doppler blood \202 ow seen, or react ive hyperaemia. The presence of peripheral \202 ow around the testis is a poor prognostic indicator and increases over time. In the non-viable testis no central blood \202 ow wil l be detected and peripheral \202 ow is usually identi \201 ed. The echogenicity will be heterogeneous. False negative and false positive results are not uncommon. Clinical acumen is of the highest importance. Nuclear perfusion scan Technetium-99m pertechnitate IV injection has a role in determining the presence of non-viable testis in cases with a suggestive chronicity of symp- toms, but not in the acute setting. Information for the radiologist Clinical history, especially length of symptoms. SUBASH KC/NMC-15TH/2014 TESTICULAR TORSION 255 (a) (b) Fig. 16.20 The \201 rst image a) is from the normal testis, showing normal echogenicity ( brightness) and color \202 ow. The second image b) is from the symptomatic side, showing the torted testicle that is swollen, hypoechoic (darker), with no color \202 ow compared to the normal side. Two ultrasound images from a patient with unilateral testicular torsion. SUBASH KC/NMC-15TH/2014 This page intentionally left blank SUBASH KC/NMC-15TH/2014 257 Chapter 17 Musculoskeletal differential diagnosis Moth-eaten bone Osteopenia 258 Increased uptake on bone scans Scoliosis 258 258 258 SUBASH KC/NMC-15TH/2014 258 CHAPTER 17 Musculoskeletal differential diagnosis Moth-eaten bone \200 Neoplastic: Metastases. \200 Multiple myeloma. \200 Leukemia. \200 Primary bone tumors, e.g. sarc oma. \200 Langerhans cell histiocytosis. Infection: Acute osteomyelitis. Osteopenia \200 Osteoporosis. \200 Osteomalacia. \200 Hyperparathyroidism. \200 Dif fuse in \201 ltrative bone disease. Increased uptake on bone scans \200 Metastases. \200 Joint disease. \200 Traumatic fr actures. \200 Post surgery: up to 1 year. \200 Infection. \200 Paget \200\231s diseas e. \200 Superscan. \200 Metabolic bone disease. Scoliosis \200 Idiopathic. \200 Congenital. \200 Neuropathic. \200 Neuromuscular di sorders. \200 Neuroectodermal diseases. \200 Post radiotherapy. \200 Leg-length discr epancy. SUBASH KC/NMC-15TH/2014 259 Chapter 18 Musculoskeletal presenting syndromes Bone pain Swollen joint 261 Soft tissue lump 262 Bony lesions 263 260 SUBASH KC/NMC-15TH/2014 260 CHAPTER 18 Musculoskeletal presenting syndromes Bone pain This may be local or general. Pain may also be referred, and a non-speci \201 c symptom. Certain features may be more worrying, e.g. pain causing the patient to wake up fr om sleep. Causes \200 Skeletal: Fracture/trauma. \200 Primary bone tumor (benign or malignant). \200 Infection. \200 Metastases. \200 Joint disease. Soft tissue: Infection. \200 Trauma. \200 Tumor. \200 Foreign body. Imaging This depends on the history and location of symptoms. For bony pathology, plain rad iographs are the \201 rst-line imaging modality. For investi- gation of soft tissue patho logy, ultrasound is better, and if non-conclusive, MRI as second line. Plain \201 lm Good for detection of fractures, bony lesions, and established osteomyeliti s. (Radiographs may be normal in early osteomyelitis.) Ultrasound For identi \201 cation of collections within the soft tissues, identi \201 cat ion of certain foreign bodies, and traumatic soft tissue injuries. MRI Most sensitive investigation, but expensive and limited availability. Good for bony pat hology and soft tissues tumors, injury, and infection. Nuclear medicine Bone scan can be useful if pain is persistent and initial investigations u nhelpful, or if multifocal pathology. SUBASH KC/NMC-15TH/2014 SWOLLEN JOINT 261 Swollen joint In the acute presentation, it is important to exclude septic arthritis, as th is can lead to joint destruction if left untreated. Causes \200 Trauma: Effusion/haemarthrosis. Infection: Septic arthritis. \200 Osteomyelitis. In \202 ammation: \200 Synovitis. \200 Bursitis. \200 Rheumatoid arthritis. \200 G out. \200 Osteoarthritis. Tumor: Primary bone tumors. \200 Metastases. Hematological conditions: \200 Sickle call anemia. \200 Hemophilia. Imaging Plain \201 lm Plain \201 lms are usually the \201 rst-line investigation. The y may be normal in infection, and joint aspiration may be needed to exclude or prove joint infection. Ultrasound This is used to identify effusions, to guide aspiration in certain cases, and ca n show synovial hypertrophy. MRI Good for identi \201 cation of effusions, ligament and tendon disruption, frac- tures. Also sensitive in assessment of bony tumor extension, synovial hypertrophy, and marrow abn ormalities. SUBASH KC/NMC-15TH/2014 262 CHAPTER 18 Musculoskeletal presenting syndromes Soft tissue lump Common benign causes \200 Lipoma. \200 Lymphadenopathy (commonly norma l prominent nodes). \200 Haematoma. \200 Haemangioma/AVM. \200 Neuro \201 broma. \200 Abscess. \200 Ganglion cyst (close to joint). Common malignant causes \200 Metastatic soft tissue deposits. \200 Lymphadenopathy (lym phoma/malignant involvement). \200 Sarcomatous lesions. Imaging Plain \201 lm May detect associated bony destruction, or calci \201 cation withi n the soft tissues. Ultrasound Most valuable imaging modality in soft tissue pathology. Allows identi \201 ca- tion and characterization of mass and, if indicated, image-guided biopsy. Deeper lesions m ay be dif \201 cult to see. MRI The most sensitive modality. Good for characterization, and can look at enhancement usi ng gadolinium. SUBASH KC/NMC-15TH/2014 BONY LESIONS 263 Bony lesions The patient \200\231s age, symptoms, and past medical history are the primary clues in the assessment of bone tumors. Benign bone tumor \200 Bone cyst. \200 Non-ossifying \201 broma. \200 Giant cell tu mor. \200 Infection. Malignant bone tumor \200 Metastases. \200 Multiple myeloma/plasmocytoma. \200 Sarcom a (Ewing \200\231s, osteosarcoma, chondrosarcoma). \200 Lymphoma/leukemia. Imaging The role of imaging is to decide if the lesion has benign or aggressive fea- tures. If malignant in appearance, imaging can show the local extent, assess for distant metastas es, and aid biopsy, if indicated. Biopsy of primary bone tumors is performed only after dis cussion with radiologists, and may involve the patient being refereed to a tertiary bone re ferral center. Plain \201 lm \200 Identify bony lesions, associated fractures and marrow involvement. Ultrasound \200 Limited use in bony pathology. CT \200 Used sometimes in characterization of lesions, and if malignant for detection of distant metastases. MRI \200 Show local extent of tumor, and characteristics. Nuclear medicine \200 Bone scan used to detect other foci of bony involvement. SUBASH KC/NMC-15TH/2014 This page intentionally left blank SUBASH KC/NMC-15TH/2014 265 Chapter 19 Musculoskeletal conditions Osteoarthritis Rheumatoid arthritis 268 Crystal deposition Ankylosing spondylitis 272 Degen erative disc disease Cord compression 276 Osteomyelitis 278 Discitis 280 Psoas abscess Sept ic arthritis Swollen diabetic foot 286 Loose (painful) joint replacement Primary bone tumor s 290 Bone metastases 292 Myeloma 294 Benign bone lesions 296 Diaphyseal benign bone tumors Sclerotic bone lesions 300 Paget \200\231s disease 302 Avascular necrosis 304 Osteoporosis 306 Osteomalacia 308 266 270 274 282 284 288 298 SUBASH KC/NMC-15TH/2014 266 CHAPTER 19 Musculoskeletal conditions Osteoarthritis A chronic disease characterized by cartilage degeneration in synovial joints . Affects 80 \200\22390 % of people over the age of 65 years. by \200\230wear and tear \200\231 but may also result from: \200 Normal forces on abnormal joints, e.g. slipped up per femoral 1 Usually caused epiphyses. Abnormal forces on normal joints, e.g. obesity causing osteoarthritis (OA) of the knees. Clinical presentation Patients present with joint pain. On examination, they have stiff joi nts with reduced range of movement and bony deformity around the joints. Unlike rheumatoid arthritis, there is often asymmetry between sides. Imaging Plain \201 lm This is the preferred imaging modality. The cardinal features are: \200 Loss of joint space. \200 Subchondral sclerosis. \200 Subchondral cysts. 19.1 ). \200 Osteophytes (bone spurs) (Fig. The disease distribution can be useful to distinguish OA from other the arthritides: \200 Hands: distal interphalangeal joints (DIPJs) > proximal interphalangeal joint (PIPJs), thumb carpometacarpal joints (CMCJs), metacarpophalangeal jo ints (MCPJs), and the trapezio-scaphoid joint. Feet: similar to hand. \200 Hip: superior joint space narrowing at the maximum weight-bea ring joint area. Knee: medial compartment most commonly affected due to weight distribution. Spine: apophyseal joints, narrowing of intervertebral disc spaces. \200 Sacroiliac joints (SIJs): contralateral SIJ to the arthritic hip joint. MRI This can be used as a specialist investigation to look for early loss of joint cartilag e, usually in the hips or knees. Information for the radiologist \200 Site, duration, and severity of patient \200\231s sy mptoms. \200 Predisposing factors to OA, e.g. obesity, acromegaly, avascular necrosis, sl ipped upper femoral epiphyses, previous trauma, or joint infections. SUBASH KC/NMC-15TH/2014 OSTEOARTHRITIS 267 (a) (b) Fig. 19.1 loss of joint cartilage, and subchondral sclerosis. Images a) and b) show severe OA of the knee with marginal osteophytes, Reference 1 Roberts J , Burch Vital Health Stat 1 TA . Osteoarthritis prevalence in adults by age, sex, race, and geographic area . . 1966 ; 11 ( 15 ): 1 \200\223 27 . SUBASH KC/NMC-15TH/2014 268 CHAPTER 19 Musculoskeletal conditions Rheumatoid arthritis This is a chronic systemic disorder causing a bilateral symmetrical in \202 am- matory joint disease. Affects women > men, usually aged between 40 \200\22360 at diagnosis. Synovial joints are affected with synovial hyperaemia and prolif- eration (pann us) leading to bone erosions and cartilage destruction. Clinical presentation The American Rheumatism Association decree that at least 4 of the fol lowing criteria are required, lasting at least 6 weeks, for diagnosis: \200 Early morning joint stiffness, which lasts 1 hour before improvement. \200 Simultanous joint swelling in at least 3 joints. \200 Symmetrical arthritis involving in particular the PIPJs, MCPJs , or wrist. \200 Subcutaneous nodules. th percentile). \200 Positive rheumatoid factor (above 95 \200 Typical radiographic changes of erosions and periarticular osteopenia. 1 Imaging Plain \201 lm Appearances may be normal. Early signs include periarticular osteop enia, subcortical synovial cysts, soft tissue swelling, and widened joint spaces due to syn ovial in \202 ammation. Later signs include erosions, reduction in joint space secondary t o cartilage destruction, joint subluxation, ankylosis and loose bodies. \200 Hand (Fig. 1 9.2 a): affects MCPJs and PIPJs > DIPJs. Characteristic deformities include: \200 Ulnar deviation at the wrist. \200 Ankylosis of the carpal bo nes. \200 Boutonniere: hyper \202 exion at PIPJ, hyperextension at DIPJ. \200 Swan-nec k: hyperextension at PIPJ, hyper \202 exion at DIPJ. \200 Mallet \201 nger: droopy dis tal phalanx. \200 Feet: similar appearances to the hands. \200 Cervical spine: erosions of the odontoid peg and atlanto-axial subluxation. Shoulder: involves the glenohumeral and acromioclavicular joints (Fig. 19.2 b). Knees: bilateral and symmetrical. Osteoporosis and erosions. \200 Chest: pleural or peric ardial effusions, rheumatoid nodules which may cavitate and occasionally lower zone \201 brosis. Ultrasound May demonstrate synovitis, joint effusions and tendon rupture. MRI Demonstrates synovitis, erosive changes, and pannus. Information for the radiologist \200 Distribution and duration of symptoms. \200 Rheuma toid factor if known. SUBASH KC/NMC-15TH/2014 RHEUMATOID ARTHRITIS 269 (a) (b) Fig. 19.2 A 55-year-old patient with severe right hand and left shoulder deformity. a) Demo nstrates severe erosive disease primarily affecting the radio-carpal, carpal and metacarpal phalangeal joints. b) Shows complete loss of the humeral head as well as severe erosive dis ease to the acromio-clavicular joint. Reference Arnett F , 1 criteria for the classi \201 cation of rheumatoid arthritis . Edworthy S , Bloch DA , et al. The American Rheumatism Association 1987 revised Arthritis Rheum 1987 ; 31 ( 3 ): 315 \200\223 24 . SUBASH KC/NMC-15TH/2014 270 CHAPTER 19 Musculoskeletal conditions Crystal deposition \200 Gout: deposition of monosodium urate crystals in and around joint s or in the urinary tract. Predominantly affects middle aged/elderly men. Serum uric acid i s often raised. Calcium pyrophosphate deposition disease (CPPD): deposition of calcium pyrophosphate crystals in and around joints. Commonly associated with gout. Alkaptonuria: rare autosomal recessive disorder causing excess homogentisic acid deposition in connective tissues, cartilage and bone. Clinical presentation \200 Gout: usually monoarticular and may be asymptomatic in the ear ly stages. Acute presentations are with a hot, swollen, painful joint, typically the \201 rs t MCPJ. Chronic presentations are with repeated bouts of arthritis in the same joint. Less common presentations are with urinary calculi (radiolucent), tendon rupture or paraesthesia due to nerve paralysis. CPPD: presentation may be similar to gout (pseudogout), OA or rheumatoid arthritis. Can be monoarticular or polyarticular and most commonly affects the knees, wrist, MCPJs, and PIPJs . Alkaptonuria: back pain, skin and sclera pigmentation, dark urine, heart failure, or renal failure. Imaging Plain \201 lm In the early stages often normal. \200 Gout: affects feet > hands and small joints > large joints. Soft tissue swelling, \200\230punched-out \200\231 erosi ons with overhanging edges, subchondral cysts and soft tissue crystal deposition which may calcify (gouty tophi) (Fig. 19.3 ). CPPD: resembles OA with osteophyte formation, joint space narrowing, subchondral cysts, and sclerosis. Cartilage calci \201 cation (chondrocalcinosi s) is characteristic, especially around the knee, pubic symphysis, and triangular \201 br ocartilage of the wrist. Alkaptonuria: calci \201 cation of intervertebral disks, vertebral ankylosis and osteophytosis. Early onset OA is also a feature. Ultrasound May identify soft tissue calci \201 cation, synovitis, nerve compression, tendo n rupture or renal calculi. CT Used to identify radiolucent urinary calculi. MRI Not commonly used. Will show erosions, soft tissue calci \201 cation, synovitis and bo ny ankylosis. Information for the radiologist \200 Site, duration and frequency of symptoms. \200 Ser um urate if known. SUBASH KC/NMC-15TH/2014 CRYSTAL DEPOSITION 271 Fig. 19.3 exquisitely painful, red great toe with no history of preceding trauma. There is widespread degenerative change with multiple punched out para-articular erosions (arrow) an d marked soft tissue swelling. These \201 ndings are typical for gout. Single foot radiograph taken after a 45-year-old presented with an SUBASH KC/NMC-15TH/2014 272 CHAPTER 19 Musculoskeletal conditions Ankylosing spondylitis This is an autoimmune seronegative disease, affecting ligamentous in ser- tions, synovial and cartilaginous joints. It causes a chronic arthritis eventu- ally l eading to bony ankylosis and enthesopathy, classically involving the spine, pelvis, proxima l femur, and calcaneus. Clinical presentation The typical patient is a young Caucasian adult male (15 \200\22335 ye ars). They present with insidious onset of lower back pain and stiffness, usually worse in the mornings. As ankylosis progresses, the range of movement reduces. Complications include fractures, pulmonary \201 brosis, and respiratory com- promise. Other associations inclu de aortic valve incompetence, iritis, and ulcerative colitis. Imaging Plain \201 lm (Fig. These are good for monitoring progression. \200 SIJs: indis tinct joint margins are followed by sclerosis and later 19.4 a) ankylosis. Usually bilateral and symmetrical. Spine: changes usually begin in the lumbar spine: \200\230Bamboo spine \200\231 ( \202 owing syndesmophytes on the AP radiograph). \200 O ssi \201 cation of spinous ligaments. \200 Squaring of anterior vertebral end-plates (Ro manus lesions). \200 \200\230Shiny corner \200\231 of vertebral bodies secondary to scle rosis. \200 Apophyseal erosions and ankylosis. \200 Disc calci \201 cation. \200 Kyp hosis. \200 Atlanto-axial subluxation. Hands: osteophytes, osteoporosis, joint space narrowing and erosions affecting the MCPJ, PIPJ, DIPJ \200\231s. Chest: upper lobe \201 brosis, occasional bullae and cavitation. \200 Other: periostiti c \200\230whiskering \200\231 at sites of ligamentous insertions, e.g. greater femoral trochanter, iliac crest, ischial tuberosity, calcaneum. CT HRCT chest may show upper lobe \201 brosis, peripheral interstitial lung disease, and bronchiectasis. MRI (Fig. This has an expanding role in the early detection of ankylosing spondylitis. The earliest \201 ndings are of low-grade oedema to the SIJs and the corners of the vertebral bodies (the entheses). 19.4 b) Information for the radiologist \200 Presenting symptoms including sites of pain/tenderne ss. \200 HLA-B27 status if available (95 % of patients are carriers). \200 Any history or clinical signs indicating UC, aortic valve disease, iritis, or pulmonary \201 brosis. SUBASH KC/NMC-15TH/2014 ANKYLOSING SPONDYLITIS 273 (a) (b) Fig. 19.4 graph showing smooth fusion of all the lumbar vertebral bodies. b) T1-weighted sa cral MRI showing complete ankylosis of the SIJs consistent with ankylosing spondylitis. A 40-year-old male with stiffness in the back. a) Lateral lumbar spine radio- SUBASH KC/NMC-15TH/2014 274 CHAPTER 19 Musculoskeletal conditions Degenerative disc disease Degenerative disc disease is mechanical degeneration of the inter vertebral disks of the spine. This can lead to a prolapsed or herniated disc. About 90 of a ll disc prolapses occur at the L4/L5 and L5/S1 levels although the cervical spine can also be affected. % Clinical presentation \200 Non-speci \201 c back pain. \200 May present with radiation to the side of the disc prolapse if there is nerve root compression. Motor symptoms develop as the disc compresses the nerve further. \200 Cauda equine syndro me is a combination of saddle (perineal anesthesia), para-paresis, loss of bowel and bladder control due to a central disc prolapse compressing the cauda equine. Imaging Plain \201 lm \200 Plain radiographs are often the \201 rst modality used, al though they are of limited value. They may show a reduction in disc height and degenerative changes affecting the facet joints. CT \200 CT is only used where MRI is contraindicated such as patients with aneurysm clips or severe claustrophobics. CT may show a disc prolapse on careful review but it is of more value showing degenerative facet joints. De \201 nitive diagnosis can be made by instilling contrast into the CSF \200\224 known as a CT myelogram. This de \201 nes the prolapsed disc. MRI \200 MRI is the modality of choice for imaging of suspected disc prolapse. \200 The prolapsed disc can be visualized and any compression of the nerve can be seen. Standard sets of images include sagittal and axial T1 and T2 sequences. \200 The nomencla ture for disc prolapse has been standardized (Table 19.1 ). Information for the radiologist \200 The dermatome, myotomes, and side of affected areas. \200 Any associated neurology. \200 Any signs of cauda equine syndrome. \200 History of previous trauma, surgery to the spine or malignancy. SUBASH KC/NMC-15TH/2014 DEGENERATIVE DISC DISEASE 275 Table 19.1 in 2001 Nomenclature de \201 ned by North American Spine Society Name Meaning Disc herniation Localized displacement of disc material beyond the intervertebral disc space Bulge Disc between 50 \200\223100 % circumferentially beyond the edges \200\224 not a form of he rniation Broad-based disc Disc displaced between 25 \200\22350 % circumferentially beyond the edges Focal Disc displaced <25 % of the circumference Protrusion Disc material is focally displaced Extrusion Displaced disc material has a greater length than width Sequestration Disc material has lost continuity with the parent disc (a) (b) Fig. 19.5 a) Sagittal T2-weighted image showing extrusion of the L4/5 intervertebral disc. b) Axial T2-weighted image showing the full extent of this (arrowhead). A 35-year-old patient with sudden onset severe left sided sciatica. SUBASH KC/NMC-15TH/2014 276 CHAPTER 19 Musculoskeletal conditions Cord compression This is a surgical emergency secondary to compression of the spinal cord b y tumor, pus, blood, bone, or disc material. This requires decompres- sion to prevent a lon g-term neurological de \201 cit. Clinical presentation Patients complain of back pain, paralysis below the level of compress ion, urinary and fecal incontinence. Imaging Timing of imaging Urgent imaging is indicated as once complete paralysis has been p resent for > 24 hours then the chance of any reasonable recovery decreases dra- matically. However, there is no reason to scan someone in the middle of the night unless a surgeon is available who can operate immediately. It is much more appropriate to get the scan done \201 rst thing in the morning in time for the day-time emergency lists. Plain \201 lm These are helpful in showing areas of vertebral collapse or fracture but th ey cannot show what is causing the cord compression. MRI (Fig. Other imaging modalities may provide useful information about trauma and vertebra l collapse but MRI is the investigation of choice. This demon- strates what is causing the compression and over how much of a distance. Cord signal change is helpful and in trauma th e presence of blood within the cord is a bad prognostic sign. In addition this will provide detail about other abnormalities in the region and give the surgeon a road-map for any pla nned surgery. 19.6 ) CT myelography In patients who have contraindications for MRI then this is an alternative. Iodine dye is introduced into the dural sac using \202 uoroscopic control. CT is then use d to look for indirect evidence of obstruction i.e. is there a level where the dye cannot p ass through. Information for the radiologist \200 Does the patient have any known malignancy? \200 H as the patient had any recent surgery \200\224 the risk of spinal infection is much higher where there has been recent thoracic or abdominal surgery? Is the patient on any form of anticoagulation? SUBASH KC/NMC-15TH/2014 CORD COMPRESSION 277 Fig. 19.6 of the L3 vertebral body secondary to tumor replacement of the body. This is impi nging upon the cauda equina and leading to severe nerve compression. A 66-year-old male with sudden urinary incontinence. This shows collapse SUBASH KC/NMC-15TH/2014 278 CHAPTER 19 Musculoskeletal conditions Osteomyelitis Osteomyelitis is a debilitating condition with a considerable morbidity. It a ffects both children and adults, albeit differently. In children, the commonest route is by haematogenous spread. Infection typically localizes to the metaphysis with the lower limbs usually affected. The most commo n organism is Staphylococcus aureus can lead to a Brodie \200\231s abscess. . Chronic infection In adults the commonest causes are direct inoculation or pre-existing conditions such as diabetes. Staphylococcus aureus the most commonly isolated organisms. Jo int involvement is common. Chronic osteomyelitis in adulthood is usually due to a foreign b ody, chronic underlying disease, or previous trauma. and streptococci are Clinical presentation \200 Fever, malaise, lethargy, and weight loss. \200 In children, there may be a history of recent infection. \200 In adults, there may be a previous hist ory of surgery or IV drug abuse. Imaging Plain \201 lm \200 Plain \201 lms can be insensitive in the early phase (ther e has to be 50 % loss of bone before there is an appreciable radiographic change). Ill de \201 ned lucency at the site of infection. In children this is usually at the metaphysis of the bone. Periosteal elevation is seen later. \200 Chronic osteomyelitis is often characterized by necrotic bone termed a \200\230sequestrum \200\231. Bone scintigraphy \200 Osteomyelitis causes increased osteoblastic activity, which shows up as an area of increased uptake. Scintigraphy can therefore be used to con \201 rm areas of active infection and identify if there are multiple foci. CT CT is useful in identifying periosteal elevation, sequestra, or foreign bodies. MRI (Fig. \200 MRI is the modality of choice for further investigation of osteomyelitis. \200 It can identify early oedema, periosteal reaction, soft tissue collections, 19.7 ) and sequestra at the site of infection. Information for the radiologist \200 Area of concern. \200 Past history of immunosuppre ssion, chronic disease, IV drug abuse, surgery, and trauma. In \202 ammatory markers. SUBASH KC/NMC-15TH/2014 OSTEOMYELITIS 279 (a) (b) Fig. 19.7 Figures 19.7a and 19.7b are T1-weighted gadolinium axial images of the hindfoot s howing osteomyelitis of the calcaneus (arrowheads) and soft tissue pus (arrow). A 20-year-old patient admitted with red and grossly swollen hindfoot. SUBASH KC/NMC-15TH/2014 280 CHAPTER 19 Musculoskeletal conditions Discitis Discitis is infection of the intervertebral disks. It accounts for 2 \200\2234 all skeletal infection with a male:female ratio of 3:1. There are 2 distinct affected age grou ps: children and adults aged > 50. The infection may be con \201 ned to a single disc spac e or multiple levels with the lumbar spine commonly affected. The most commonly isolated pa thogen is Staphylococcus aureus always be considered. The three main routes of infection ar e: haematog- enous (commonest), direct inoculation (iatrogenic), or contiguous spread. Disc itis may progress to give vertebral body osteomyelitis. % of (60 % ) although other organisms including TB should Clinical presentation \200 Red \202 ag signs (see Box 19.1 ) for spinal pathology. \200 Acute, non-traumatic localized pain. \200 Non-speci \201 c symptoms including feve r, weight loss, and malaise. \200 Chronic illnesses such as diabetes and immunosuppressio n predispose to it. Box 19.1 Red \202 ag signs for spinal pathology Age of onset <20 or > 50 years \200 Thoracic pain \200 Fever and unexplained with loss \200 Bladder and bowel dysfunction \200 History of carcinoma \200 Ill health or previ ous medical illness \200 Progressive neurological de \201 cit \200 Disturbed gait or s addle anesthesia. Imaging Plain \201 lm \200 This is relatively insensitive for early infection. \200 L oss of disc space. \200 Indistinct end plates. \200 Chronic changes include end-plate s clerosis or collapse. \200 Gradual disc obliteration and vertebral fusion. CT \200 CT is not routinely used in the initial work-up. \200 It has a role in assessme nt of the bony anatomy, to guide biopsies, and where the patient cannot tolerate an MRI. MRI \200 MRI is the initial modality of choice. \200 Standard sequences include T1-weig hted, STIR and T1-weighted post-contrast sagittal and axial planes (Fig. 19.8 ). T1 images will show low signal intensity changes to the disc and vertebral body with loss of disc height. STIR images show high signal in the disc, adjacent vertebral end plates, and paravertebral soft tissues. SUBASH KC/NMC-15TH/2014 DISCITIS 281 Post-contrast T1 images show ring enhancement of pus and can be used to differentiate pus from oedema. Information for the radiologist \200 Predisposing factors such as recent surgery? \200 What are the in \202 ammatory markers? \200 Is there any evidence of sepsis? (a) (b)