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Metabolic (scurvy, gout, cppd, fluorosis) sayid

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A long-term deficiency of dietary vitamin C (ascorbic acid) results in scurvy.

Today its being found almost exclusively in infants between the ages of 8 and 14 months who are fed on pasteurized or boiled milk preparations (infantile scurvy) because process of heating the milk leads to disruption of vitamin C and the appearance of clinically apparent disease develops after deficiency of the vitamin has existed for 4 to 10 months.

Occasionally the elderly are affected, when the diet is compromised (adult scurvy).

Vitamin C is essential to the formation of intercellular substances such as collagen, osteoid, and endothelial linings.

In small blood vessels, the deficiency of intercellular cement promotes vascular fragility, as evidenced by the increased occurrence of tissue hemorrhages.

Cartilage cells do not proliferate at their normal rate but will still mineralize.

Bone cells are also inhibited in their activity, producing generalized osteopenia.

Petechial hemorrhages, swollen, red, and ulcerated gums, palatal petechiae, hematuria, melena, hematemesis, and secondary infections, when combined with characteristic radiographic changes and depressed levels of serum ascorbic acid (< 0.6 mg/100 mL), ensures accurate diagnosis.

Osteopenia: A generalized decrease

in bone density will be evident in combination with thinning of the cortex and loss of trabecular definition.

Dense zone of provisional calcification (white line of Frankel): Enhancement of the

dense metaphysealzone of calcified cartilage occurs owing to delayed conversion into bone.

Ring epiphysis (Wimberger’ssign): The peripheral margin of the

epiphysis appears dense, whereas the central portion is more radiolucent.

Corner (angle) sign: Irregularity of the metaphyseal

margins frequently occurs secondary to infractions of the epiphyseal-metaphyseal junction.

Pelken’s spurs: These bony protuberances occur

at the metaphyseal margins and extend at right angles away from the shaft axis.

Scorbutic zone (Trümmerfeld’szone):

Directly beneath the zone of provisional calcification a radiolucent band may be visible, representing disordered osteoid formation.

Subperiosteal hemorrhage:

Extensions of extravasatedblood frequently lift the periosteum away from the bone and will later calcify, especially during healing.

The identification of radiodense lines at the metaphysis and about the epiphysis, metaphyseal fractures, osseous beaks, epiphyseal displacements, and diaphyseal periostitis allows an accurate diagnosis of scurvy.

Leukemia can lead to periostitis and diaphysealdestruction in combination with bandlike metaphysealradiolucency, but fracture and epiphyseal separation are not identified.

Syphilis produces symmetric destructive foci in the metaphyses, particularly in the proximal tibia, but the distinctive findings are not confused with those of scurvy.

Gout (podagra) results from an inborn error of purine metabolism that causes hyperuricaemia and deposition of monosodium urate (MSU) crystals in joints and soft tissues resulting in recurrent episodes of acute arthritis.

Primary gout: Transmitted as an autosomal dominant condition with low penetrance

in women. Only 5–10% of cases occur in women, in whom it usually occurs post-menopausally. Symptomatically primary gout usually begins in the third decade of life, but can occur earlier.

Secondary hyperuricaemia: Associated with either excessive breakdown of nuclear proteins

(e.g. blood dyscrasias, leukaemia, lymphoma, myeloma, collagen storage diseases)

Or decreased renal excretion of uric acid (e.g. chronic renal disease, diuretics, low-dose salicylates).

Characterized by acute inflammatory monoarticular or oligoarticular arthritis, usually in the early hours of the morning.

Most common sites of involvement are in the lower extremity, especially at the first metatarsophalangeal and intertarsal joints, and knees.

Up to 60% of the initial attacks will occur at the first metatarsophalangeal joint.

Distinctively, the affected joint is swollen and hot, but dry, in contrast to other arthritides, which are usually moist.

Tophi characteristically have a predilection for relatively avascular tissues: Tendons and subcutaneous layers

of the elbow, forearm, hand, knee, foot, helix of the ear, synovium, periarticular soft tissues, and subchondral bone.

Tophi close to the skin surface may ulcerate and extrude their contents to the exterior.

The effects on bones and joints are often severely destructive and deforming and may require surgery.

Rarely, tophi may deposit within the spinal canal and act as a space-occupying mass, resulting in various neurological complications.

A tophus may gradually erode an adjacent bone, producing a protruding lip of bone.

Soft Tissue Changes: In acute attacks evidence of joint

effusion may be visible; however, the most important and readily identifiable finding is the presence of tophi.

Tophi are manifested as a localized increase in soft tissue density from 5 mm up to as large as 5 cm in size.

Distinctively, they are eccentric; are usually, but not always, periarticular; and occur in predictable locations such as the forearm, elbow, dorsum of the hand, knee, ankle, and forefoot.

Occasionally, peripheral calcification within the tophusmay be apparent.

Bone Erosions:

Marginal: Intra-articular loss of the cortex and underlying bone up to 2-3 mm in size may be apparent. These may further enlarge and spread to involve the central articular region.

Periarticular: Occur within the metaphysis or diaphysis; are eccentric; have a dense, sclerotic margin; and often have a protruding lip of bone extending away from the bone into the soft tissues (overhanging margin sign). Occasionally, extension of a marginal erosion may have this overhanging edge of bone at its periphery.

Intraosseous: Accumulations of tophi within bone will be visible as well-circumscribed, oval, or round punched out radiolucencies usually within the medullary cavity.

Metatarsal Head:

Sharp, excavated defect flanked by a distinctive bony projection, referred to as the overhanging margin sign.

Great Toe and Tarsus:

Multiple defects in multiple bones, with overhanging margins

Severe erosive changes, loss of joint space, and large tophi.

T1-Weighted MRI, Coronal Foot.

T1-Weighted MRI, Sagittal Foot. The low signal intensity in the area of the tophi erosion of the bony structures, which correlates with the plain film findings.

The signal intensity in gouty tophi is low on T1- and T2-weighted images.

Hand:

Multiple areas of bone destruction owing to the presence of tophi.

A large intraosseoustophus is seen in the second digit.

Numerous erosions are also visible in the carpal bones, creating the spotty carpal sign.

Spotty Carpal Sign:

Multiple carpal erosions have resulted in this appearance.

Radioulnar Erosion:

Large erosive excavations at the distal radius and ulna.

The outline of the adjacent tophus can be seen

ELBOW: Tophus within the olecranon bursa, which has created an extrinsic erosion of the olecranon process.

SACROILIAC & PUBIC ARTICULATIONS:

Severe erosive and destructive changes at both sacroiliac and pubic articulations.

Of incidental note is the radiopaque contrast material present in colonic diverticulae.

Calcium pyrophosphate dihydrate (CPPD) crystal deposition disease is an articular disease characterized by the production of gout-like symptoms (pseudo-gout) in the presence of these crystals.

The most common form of presentation is similar to DJD, with chronic progressive joint pain, intermittent swelling, reduced range of motion, and crepitus.

Usually > 30 years of age, with a peak at 60 years; equal sex distribution.

Can be acute or chronic and may be asymptomatic.

Acute presentations (20%) may simulate gout or rheumatoid arthritiswith swollen, hot, tender joints; usually affects knees, wrists, and hands, with attacks lasting 1-7 days.

Chronic presentations (60%) simulate DJD, with bony swelling, crepitus, and stiffness.

Asymptomatic cases (20%) exist in which the only sign is radiographic chondrocalcinosis.

Other diseases are associated with CPPD deposition diabetes mellitus, degenerative joint disease, gout, hyperparathyroidism, hemochromatosis, Wilson’s disease, neuroarthropathy, and ochronosis. In addition, there is a hereditary factor in Czechoslovakian, Chilean, and Dutch populations..

Laboratory signs include a raised ESR with synovial fluid crystal evaluation diagnostic.

Involves predominantly the peripheral joints, especially the knees, wrists, hands, ankles, hips, and elbows, in approximate order of decreasing frequency.

In recent years, increasing emphasis has been placed on local tissue damage as a cause of crystal deposition which may be age-related, secondary to trauma, or disease-induced.

Cartilage damage may alter proteoglycan concentrations and inhibitory factors, increase PPi (Inorganic Pyrophosphate) turnover, or effect some other change that predisposes susceptible persons to CPPD crystal formation.

Aging and associated metabolic disease independently may enhance this susceptibility.

The pathogenesis of acute synovitis in this disease may relate to a process of crystal shedding, in which cartilaginous deposits are cast into the articular cavity

Signs of arthropathyinclude osteopenia, chondrocalcinosis(arrow), cysts(arrowheads), irregular cortex, osteophytes, and ossicles.

Patellofemoral joint narrowing, a key indication of an underlying crystal-induced arthropathy.

Bilateral Hands: Arthropathy in the second and third metacarpophalangeal and radiocarpal joints

Chondrocalcinosis can be seen in either the fibrocartilage (FC) or hyaline cartilage (HC)

Calcification:

In the meniscus (arrow), hyaline cartilage (arrowhead), and synovial membrane (crossed arrow).

Chondrocalcinosis:

Calcification within the triangular cartilage (arrows) and intercarpal hyaline cartilage (arrowhead).

Subchondral Cysts: Cysts within the lunate and scaphoid, with associated chondrocalcinosis.

Scapholunate Dissociation (Terry Thomas’ Sign):

Scapholunate space is widened (arrow)

Scapholunate Advanced Collapse Deformity:

The large subchondralcysts within the radius and carpus (arrow).

The lunate has rotated anteriorly, as noted by its triangular shape (pie sign) (arrowhead).

There is widening of the scapholunate space (crossed arrow)

A. Chondrocalcinosis. Curvilinear calcification paralleling the articular surface of the humeral head (arrow).

B. Degenerative Joint Disease. Changes secondary to CPPD are typical of degenerative change, including non-uniform loss of joint space, osteophytes, and sclerosis.

Chondrocalcinosis within the fibrocartilage disc of the pubic symphysis (arrowhead)

Chronic ingestion of fluorine (fluorosis) has the potential to produce a spectrum of toxic effects.

At 1 ppm the incidence of dental caries may be reduced; 2 ppm or more can precipitate mottled tooth enamel; 8 ppm results in osteosclerosis in 10% of individuals; and > 100 ppm causes growth disturbances, kidney damage, or death.

It is most commonly the result of drinking contaminated water in certain geographic areas, especially India and China (endemic fluorosis).

Other causes include industrial and laboratory exposure, fluorine medications, and habitual intake of fluorine-containing wine (wine fluorosis).

Generalized increase in bone density.

Diffuse calcification of multiple ligaments, including the sacrotuberous (arrows) and sacrospinous ligaments (arrowhead).

The key findings are initial osteopenia followed by sclerosis, growth arrest lines, exuberant vertebral hyperostosis, ligamentous calcification, and periostitis.

The combination of diffuse osteosclerosis and ligamentous calcifications is virtually diagnostic of fluorosis.