Osteomyelitis, Septic Arthritis (Masumoto) & Crystal Arthropathies (Vogelgesang)

Question 1

An open pressure ulcer with wound drainage in a diabetic patient is an example of what pathogenic mechanism of osteomyelitis?

A. Contiguous spread of infection with both gram positive cocci and gram negative rods

B. Trauma related wound infection with streptococcus

C. Hematogenous spread of infection with staph aureus

D. Contiguous spread of infection with staph aureus or streptococcus

E. Trauma related wound infection with both gram positive cocci and gram negative rods

Answer 1

A

Continguous spread of infection is usually polymicrobial, with staph aureus being the most common of the infecting microbes.

Hematogenous spread of infection is associated with central lines and IV drug use.

Surgical/trauma wound infections can be serious, as in the case of an open fracture, because of the high morbidity associated with bone infection under these conditions; early antibiotic administration and washout are critical.

Question 2

what is the most frequent pathogen in osteomyelitis?

Answer 2

staph aureus

Question 3

the picture below shows chronic or acute osteomyelitis?

Answer 3

Chronic osteomyelitis, such as a non-healing ulcer. Acute osteomyelitis has a much more angry look with redness, fever, and pus.

Question 4

devitalized bone acting as a foreign body that is not easily reached by antibiotics is known as what?

Answer 4

sequestrum

Question 5

A 46 yo male with schizophrenia and dental carries has dental pain for several years. The x-rays show a lytic lesion, suggestive of osteomyelitis. Which is the likely mechanism of pathogenesis?

A. Contiguous spread

B. Hematogenous spread

C. Surgical/trauma wound infection

Answer 5

A. And it is likely due to a polymicrobial infection with oral microbes (Streptococcus, anaerobes).

Question 6

signs and symptoms of this disease are red, hot, painful joints that are usually mono-arthralgiac, and systemic symptoms like fever and chills

Answer 6

septic arthritis (or crystal arthritis)

Question 7

type of migratory polyarthritis resulting from a gram negative, sexually transmitted infection, and is diagnosed via joint fluid and urethra/cervix/throat cultures

Answer 7

gonococcal arthritis

Question 8

what is the most frequent pathogen in septic arthritis?

Answer 8

staph aureus

Question 9

what is the organism that can cause septic polyarthritis in a sexually active patient?

Answer 9

neisseria gonorrhoeae

Question 10

All of the following favor diagnosis of septic arthritis EXCEPT:

A. WBC of 50,000

B. Neutrophils > 50% of WBC

C. Elevated protein

D. Gram + cocci in clusters on culture

E. No crystals

Answer 10

B. Should be a higher percentage of PMNs, like > 90%

Question 11

Which of the following treatments are important for septic arthritis?

A. Washout

B. Antibiotics (3-4 week course for non-gonococcal, 2 weeks for gonococcal)

C. Joint ROM exercises

D. All of the above are important treatments

Answer 11

D

Question 12

recurrent attacks of acute arthritis caused by monosodium urate crystals in the synovium and elevated serum uric acid > 7.0 mg/dl

Answer 12

gout

Question 13

aggregated deposits of urate crystals are known as ______

Answer 13

tophi

Question 14

Describe the asymptomatic hyperuricemia stage of gout with respect to duration, onset, and likelihood of advancement to acute gout.

Answer 14

• 10-20 years
• Onset: men - during puberty; women - during menopause
• only 1-10% with hyperuricemia develop acute gout (+ correlates with level of uric acid)

Question 15

• abrupt onset of pain, usually at night
• no constitutional symptoms
• self-limited to one week with complete resolution of symptoms

Answer 15

acute gout

Question 16

skin sloughing is a clinical feature seen in what stage of gout?

Answer 16

acute gout stage

Question 17

Which of the following statements regarding acute gout is FALSE?

A. MTP is the most commonly affected joint

B. Prepatellar and olecranon bursae are commonly affected

C. Uric acid is almost always largely elevated during an acute attack

D. Potential triggering events include trauma, dietary/alcohol excess, and diuretic use or change

E. Almost all of the time, presentation is monoarticular

Answer 17

C. Uric acid is normal in 1/2 of patients having an acute attack

Question 18

T/F: 50% of people who experience an acute attack of gout will have no recurrence.

Answer 18

False. Only 7% have no recurrence. 60% recur within the 1st year.

Question 19

Which of the following is not descriptive of chronic gout?

A. Monoarticular with systemic features

B. Radiography shows punched out erosions with surrounding radiodensity

C. Affects the ulnar surface of forearms among other sites

D. When aspirated looks like toothpaste

E. Joint spaces are preserved and normal mineralization

Answer 19

A. This is one main way it differs from acute - it tends to be polyarticular.

Question 20

T/F: Current understanding of gout is that it is the precipitation of uric acid crystals that causes chronic kidney disease.

Answer 20

False. Studies in lab animals have showed that raising the serum uric acid induces glomerular hypertension and tubular interstitial fibrosis, despite the absence of renal crystals.

Question 21

T/F: Less than 10% of patients with gout also have kidney stone disease.

Answer 21

True.

Question 22

Which of the following is NOT considered to be part of the pathophysiology of hyperuricemia?

A. Cold and decreased oxygen tension may trigger an attack of gout

B. WBCs that have attempted to phagocytose precipitated crystals are lysed and this triggers an inflammatory resopnse

C. Activation of the innate immune response leads to recruitment of cytokines and neutrophils

D. Diet is thought to make very little contribution to the pathophysiology of hyperuricemia, as there is a strong familial predisposition

Answer 22

D. Diet high in purines, alcohol, and sugar are all thought to contribute to the formation of hyperuricemia.

Question 23

gout is yellow or blue when parallel to the plane of polarization on microscopy, and negatively or positively birefringent?

Answer 23

yellow; negatively birefringent

*in “pseudo gout” crystals are blue and weakly or positively birefringent, with more of a rhomboid rather than needle shape.

Question 24

Which of the following would NOT be an acute therapy for the treatment of gout?

A. Colchicine

B. NSAID

C. Prednisone

D. Aspirin

E. Joint injection

Answer 24

D

Question 25

Which of the following pairs is incorrectly matched?

A. Febuxostat: stop purine metabolism

B. Probenecid: increase renal exretion of uric acid

C. Uricase: converts uric acid to allantoin

D. Allopurinol: prevents the formation of uric acid

E. Pegloticase: contraindicated with Azathioprine

Answer 25

E. Allopurinol and Febuxostat, the xanthine oxidase inhibitors, are contraindicated with Azathioprine.

Pegloticase is a uricase for really bad gout that is resistant to other treatments, and also is an IL-1 antagonist that blocks inflammatory response to crystal phagocytosis.

Question 26

In which of the following groups would allopurinol be the most appropriate therapy for lowering uric acid levels?

A. A 50 year old man with normal renal function

B. A 55 year old Korean woman with chronic kidney disease

C. A 70 year old man with history of urolithiasis

D. A 65 year old woman being treated with Azathioprine for rheumatoid arthritis

Answer 26

C

A: should treat with probecenid (a uricosuric that increases renal excretion of urate in people under 60 who don’t tolerate XOIs)

B: Allpurinol contraindicated in this population, also with specific HLA mutations and in Thai/Chinese subpopulations.

D: Along with Febuxostat, NOT for use with azathioprine

Question 27

this disease behaves like gout, is associated with aging, and presents with acute/subacute monoarthritis, most often in the knee

Answer 27

Acute CPP (calcium pyrophosphate - different crystals than gout)

Question 28

polyarticular, symmetric arthritis involving the small joints of hands and feet and used to be called “pseudo-rheumatoid”

Answer 28

chronic CPP

Question 29

what radiographic feature shown here is associated with CPPD?

Answer 29

cartilage calcification (chondrocalcinosis)

*occurs in wrists more often than knees

Question 30

All of the following radiographic signs are seen in both osteoarthritis and CPPD EXCEPT:

A. Osteophytes

B. Joint space loss

C. Large and small joints affected

D. Cartilage calcification

Answer 30

D. Cartilage calcification is a unique feature of CPPD.

Unlike OA, CPPD shows uniform joint space loss, normal mineralization of the bone, and no erosion.

Question 31

What medication used for RA seems to work for CPPD when NSAIDs and Colchicine are inadequate?

Answer 31

hydroxychloroquine or methotrexate