Rheumatology MKSAP || A+ Score Secured.
prosthetic joint infection.
Prosthetic joint infection is the most likely diagnosis. This patient has a prosthetic hip and is
currently undergoing chemotherapy. Malignancy and immunosuppression are risk factors for
prosthetic joint infection, and this patient also has a central venous catheter that increases his risk
for bacteremia. The elevated leukocyte count and erythrocyte sedimentation rate, along with
periprosthetic lucency on radiographs, are all suggestive of prosthetic joint infection. Prosthetic
joint infections are divided into early onset (<3 months after placement), delayed (3 to 24 months
postsurgery), and late onset (>24 months after placement). Early and delayed infections are
usually related to surgical contamination at the time of the implantation, whereas late infections
result from hematogenous seeding of the joint. Early and late prosthetic joint infections typically
present with pain, warmth, ef correct answers A 72-year-old man is evaluated in the emergency
department after falling when his leg gave way as he tried to arise from bed. He has left hip pain,
with the inability to stand and pain at rest. He was recently diagnosed with lymphoma, for which
he is receiving chemotherapy. History is significant for a left hip replacement 7 years ago for
osteoarthritis. His chemotherapy regimen consists of rituximab plus hyperfractionated
cyclophosphamide, vincristine, doxorubicin, and dexamethasone.
On physical examination, temperature is 38.2 °C (100.8 °F); other vital signs are normal. The
right upper chest is implanted with a venous access port. Warmth and tenderness around the left
hip are noted. Pain in the groin is noted. There is limitation of motion in all directions on both
active and passive range of motion of the left hip. There are no other joint abnormalities.
Laboratory studies show an erythrocyte sedimentation rate of 73 mm/h, a leukocyte count of
13,400/µL (13.4 × 109/L), and a serum urate level of 8.2 mg/dL (0.48 mmol/L).
Left hip radiographs show periprosthetic lucency.
Which of the following is the most likely diagnosis?
No additional tests are necessary.
Different criteria have been proposed for the diagnosis of ankylosing spondylitis. Common
requirements include the presence of inflammatory back pain for 3 or more months in a person
younger than age 45 years, limited lumbar spine motion, elevated inflammatory markers, and
evidence of bilateral sacroiliitis on imaging. The patient has a long history of inflammatory back
pain (improves with exercise, worsens with sleep or inactivity), loss of range of motion of the
lumbar spine, and radiographs showing fusion of the sacroiliac joints, one of the typical features
of ankylosing spondylitis. It is important to establish the diagnosis of ankylosing spondylitis to
,assess the risk of further joint fusion and deformity in this patient. correct answers A 32-year-old
woman is evaluated for a 15-year history of low back pain. The pain is worse with rest, improves
with movement, and can awaken her during the night. Family history is notable for three paternal
uncles with back problems. She takes naproxen twice daily with some relief.
On physical examination, vital signs are normal. Joint examination does not reveal any warmth,
erythema, or swelling. Tenderness over the sacroiliac joints bilaterally and reduction in the range
of motion of the lumbar spine are noted.
Laboratory studies are notable for an erythrocyte sedimentation rate of 27 mm/h.
A plain anteroposterior radiograph of the pelvis shows fusion of the sacroiliac joints.
Which of the following is the most appropriate diagnostic test to perform next?
Anakinra.
He has a persistent fever due to a severe acute gouty attack. Synovial fluid analysis permits
definitive diagnosis and can rule out other conditions. Under polarized light, monosodium urate
crystals are needle shaped and negatively birefringent. Whereas extracellular crystals confirm a
chronic gout diagnosis, crystals within neutrophils define active, gout-induced inflammation.
Even in the setting of acute gout, Gram stain and cultures must be obtained to exclude infection
because acute gout and joint infection occasionally coexist. This patient has not responded
favorably to glucocorticoid therapy, which characterizes some severe acute episodes. In a case
such as this, an interleukin-1 inhibitor such as anakinra should be provided as a reliable
(although expensive) off-label treatment. correct answers A 76-year-old man is evaluated for
fever and a swollen, painful left knee. He was hospitalized 7 days ago for heart failure and
appropriately treated. However, he developed fevers up to 38.0 °C (100.4 °F). On examination,
lungs were clear to auscultation. The left knee was hot and swollen; 60 mL of turbid fluid was
drained from the knee. Gram stain of the synovial fluid was negative; microscopy revealed
needle-shaped intracellular crystals. Gout was diagnosed and the knee was drained again,
followed by an injection of 80 mg of methylprednisolone, without improvement. Intravenous
methylprednisolone, 60 mg/d for 3 days, did not improve the knee or the fevers. History is also
significant for hypertension and gout. Other medications are furosemide, lisinopril, metoprolol,
subcutaneous heparin, and morphine as needed.
On physical examination today, temperature is 38.0 °C (100.4 °F), blood pressure is 148/92 mm
Hg, pulse rate is 116/min, and oxygen saturation is 97% on ambient air. The left knee is warm,
swollen, and tender.
Blood, urine, and synovial fluid cultures are negative.
Which of the following is the most appropriate treatment for the knee?
,Physical therapy.
Physical therapy is an effective intervention for the management of pain and reduced functioning
due to OA, with numerous guidelines supporting exercise as an appropriate intervention for all
patients with OA. Evidence is most robust for knee OA. Many patients become sedentary due to
their symptoms, and physical therapy is often a useful starting point to transition patients to
participation in a regular exercise program. Physical therapy can be prescribed at any point in the
course of the disease instead of medication, as a supplement to medication that does not
adequately reduce pain, or prior to surgery to increase strength and potentially influence surgical
outcomes. correct answers A 55-year-old woman is evaluated for an 18-month history of
increasingly severe knee pain with the inability to arise when seated on the floor. She does not
have pain at rest or nocturnal pain. Medications are celecoxib and omeprazole.
On physical examination, vital signs are normal. Bony hypertrophy of both knees is present.
There is no warmth, erythema, or swelling of the joints.
Plain anteroposterior knee radiographs show medial joint space narrowing, peaking of the tibial
spines, and osteophytes; there are no erosions or osteopenia.
Which of the following is the most appropriate management?
MRI of the sacroiliac joints.
This patient has symptoms suggestive of back pain due to inflammation, including young age of
onset, gradual onset, pain during the night, morning stiffness, improvement with motion, no
history of trauma, and no improvement with rest. A single anteroposterior pelvis plain radiograph
to view the sacroiliac joints is an appropriate first diagnostic step in this setting, which may
reveal joint space widening (early) or narrowing (late), erosions, sclerosis, and ankylosis, and
can establish the diagnosis of ankylosing spondylitis. However, plain radiographs may be normal
early in the course of disease, as seen in this patient. MRI of the sacroiliac joints can then be
utilized, which is more sensitive for detecting early spine and sacroiliac joint inflammation. The
finding of bone marrow edema on STIR or T2-weighted images with fat suppression is not
specific for ankylosing spondylitis but do correct answers A 25-year-old man is evaluated for the
gradual onset of bilateral low back pain without radiation to the lower extremities daily, with
increasing severity over the past year. The pain now awakens him during the night 2 to 3 times
per week, with morning stiffness lasting more than an hour. He has improvement with exercise
and no improvement at rest. He takes ibuprofen with some improvement.
On physical examination, vital signs are normal. Limited lateral bending bilaterally and a
reduction in forward flexion at the lumbar spine are noted. The remainder of the examination is
normal.
, An anteroposterior plain radiograph of the pelvis and sacroiliac joints is unremarkable.
Which of the following is the most appropriate diagnostic test to perform next?
Small intestinal bacterial overgrowth (SIBO).
More than 70% of patients with SSc have clinical gastrointestinal involvement. Gastrointestinal
motility is compromised in 40% to 90% of patients with systemic sclerosis, especially those with
diffuse disease. Because of the decrease in motility of the small bowel, bacterial overgrowth
occurs and leads to the symptoms described in this patient history, including diarrhea, bloating,
and pain, and can lead to malabsorption. Patients with SSc can also develop chronic pancreatic
insufficiency and develop symptoms similar to SIBO, which must be considered in the
differential diagnosis. Diagnosis of SIBO can be confirmed with glucose hydrogen breath testing
or jejunal aspirate cultures. Treatment is with rotating antibiotics to try to reduce the overgrowth
using agents with both aerobic and anaerobic coverage. Probiotics may have some benefit in
such patients. It is important t correct answers A 45-year-old woman is evaluated for a 4-month
history of diarrhea and a 4.5-kg (10-lb) weight loss. She reports explosive episodes of loose
stools that follow most meals. There is a feeling of bloating and pain with the episodes. She has a
10-year history of diffuse cutaneous systemic sclerosis (DcSSc) complicated by Raynaud
phenomenon with occasional digital ulceration and gastroesophageal reflux disease. Her only
medication is omeprazole.
On physical examination, vital signs are normal. BMI is 21. Skin changes associated with DcSSc
involve the arms, forearms, and hands. The abdominal examination reveals active and loud
bowel sounds but is otherwise unremarkable.
Which of the following is the most likely diagnosis?
Serologic testing for Borrelia burgdorferi.
The most likely diagnosis is Lyme arthritis, which can be confirmed by serologic testing for
detection of Borrelia burgdorferi-specific antibodies using a two-tiered approach: enzyme-linked
immunosorbent assay (ELISA) followed by Western blot. This patient is a park ranger in an area
of emerging risk for Lyme disease; thus the diagnosis should be strongly suspected, especially
given a monoarthritis of the knee that is not overly painful, which is typical for Lyme arthritis.
Lyme arthritis is a late manifestation of Lyme disease; after the first month of infection, at least
5/10 bands should be present on Western blot testing for IgG antibodies to different B.
burgdorferi proteins. It is not uncommon for patients to be unaware of or experience
manifestations of early stages of disease, such as erythema migrans or constitutional symptoms.
correct answers A 49-year-old man is evaluated a 3-month history of right knee swelling without
significant pain. He does a lot of physical activity as a park ranger in Michigan but does not
prosthetic joint infection.
Prosthetic joint infection is the most likely diagnosis. This patient has a prosthetic hip and is
currently undergoing chemotherapy. Malignancy and immunosuppression are risk factors for
prosthetic joint infection, and this patient also has a central venous catheter that increases his risk
for bacteremia. The elevated leukocyte count and erythrocyte sedimentation rate, along with
periprosthetic lucency on radiographs, are all suggestive of prosthetic joint infection. Prosthetic
joint infections are divided into early onset (<3 months after placement), delayed (3 to 24 months
postsurgery), and late onset (>24 months after placement). Early and delayed infections are
usually related to surgical contamination at the time of the implantation, whereas late infections
result from hematogenous seeding of the joint. Early and late prosthetic joint infections typically
present with pain, warmth, ef correct answers A 72-year-old man is evaluated in the emergency
department after falling when his leg gave way as he tried to arise from bed. He has left hip pain,
with the inability to stand and pain at rest. He was recently diagnosed with lymphoma, for which
he is receiving chemotherapy. History is significant for a left hip replacement 7 years ago for
osteoarthritis. His chemotherapy regimen consists of rituximab plus hyperfractionated
cyclophosphamide, vincristine, doxorubicin, and dexamethasone.
On physical examination, temperature is 38.2 °C (100.8 °F); other vital signs are normal. The
right upper chest is implanted with a venous access port. Warmth and tenderness around the left
hip are noted. Pain in the groin is noted. There is limitation of motion in all directions on both
active and passive range of motion of the left hip. There are no other joint abnormalities.
Laboratory studies show an erythrocyte sedimentation rate of 73 mm/h, a leukocyte count of
13,400/µL (13.4 × 109/L), and a serum urate level of 8.2 mg/dL (0.48 mmol/L).
Left hip radiographs show periprosthetic lucency.
Which of the following is the most likely diagnosis?
No additional tests are necessary.
Different criteria have been proposed for the diagnosis of ankylosing spondylitis. Common
requirements include the presence of inflammatory back pain for 3 or more months in a person
younger than age 45 years, limited lumbar spine motion, elevated inflammatory markers, and
evidence of bilateral sacroiliitis on imaging. The patient has a long history of inflammatory back
pain (improves with exercise, worsens with sleep or inactivity), loss of range of motion of the
lumbar spine, and radiographs showing fusion of the sacroiliac joints, one of the typical features
of ankylosing spondylitis. It is important to establish the diagnosis of ankylosing spondylitis to
,assess the risk of further joint fusion and deformity in this patient. correct answers A 32-year-old
woman is evaluated for a 15-year history of low back pain. The pain is worse with rest, improves
with movement, and can awaken her during the night. Family history is notable for three paternal
uncles with back problems. She takes naproxen twice daily with some relief.
On physical examination, vital signs are normal. Joint examination does not reveal any warmth,
erythema, or swelling. Tenderness over the sacroiliac joints bilaterally and reduction in the range
of motion of the lumbar spine are noted.
Laboratory studies are notable for an erythrocyte sedimentation rate of 27 mm/h.
A plain anteroposterior radiograph of the pelvis shows fusion of the sacroiliac joints.
Which of the following is the most appropriate diagnostic test to perform next?
Anakinra.
He has a persistent fever due to a severe acute gouty attack. Synovial fluid analysis permits
definitive diagnosis and can rule out other conditions. Under polarized light, monosodium urate
crystals are needle shaped and negatively birefringent. Whereas extracellular crystals confirm a
chronic gout diagnosis, crystals within neutrophils define active, gout-induced inflammation.
Even in the setting of acute gout, Gram stain and cultures must be obtained to exclude infection
because acute gout and joint infection occasionally coexist. This patient has not responded
favorably to glucocorticoid therapy, which characterizes some severe acute episodes. In a case
such as this, an interleukin-1 inhibitor such as anakinra should be provided as a reliable
(although expensive) off-label treatment. correct answers A 76-year-old man is evaluated for
fever and a swollen, painful left knee. He was hospitalized 7 days ago for heart failure and
appropriately treated. However, he developed fevers up to 38.0 °C (100.4 °F). On examination,
lungs were clear to auscultation. The left knee was hot and swollen; 60 mL of turbid fluid was
drained from the knee. Gram stain of the synovial fluid was negative; microscopy revealed
needle-shaped intracellular crystals. Gout was diagnosed and the knee was drained again,
followed by an injection of 80 mg of methylprednisolone, without improvement. Intravenous
methylprednisolone, 60 mg/d for 3 days, did not improve the knee or the fevers. History is also
significant for hypertension and gout. Other medications are furosemide, lisinopril, metoprolol,
subcutaneous heparin, and morphine as needed.
On physical examination today, temperature is 38.0 °C (100.4 °F), blood pressure is 148/92 mm
Hg, pulse rate is 116/min, and oxygen saturation is 97% on ambient air. The left knee is warm,
swollen, and tender.
Blood, urine, and synovial fluid cultures are negative.
Which of the following is the most appropriate treatment for the knee?
,Physical therapy.
Physical therapy is an effective intervention for the management of pain and reduced functioning
due to OA, with numerous guidelines supporting exercise as an appropriate intervention for all
patients with OA. Evidence is most robust for knee OA. Many patients become sedentary due to
their symptoms, and physical therapy is often a useful starting point to transition patients to
participation in a regular exercise program. Physical therapy can be prescribed at any point in the
course of the disease instead of medication, as a supplement to medication that does not
adequately reduce pain, or prior to surgery to increase strength and potentially influence surgical
outcomes. correct answers A 55-year-old woman is evaluated for an 18-month history of
increasingly severe knee pain with the inability to arise when seated on the floor. She does not
have pain at rest or nocturnal pain. Medications are celecoxib and omeprazole.
On physical examination, vital signs are normal. Bony hypertrophy of both knees is present.
There is no warmth, erythema, or swelling of the joints.
Plain anteroposterior knee radiographs show medial joint space narrowing, peaking of the tibial
spines, and osteophytes; there are no erosions or osteopenia.
Which of the following is the most appropriate management?
MRI of the sacroiliac joints.
This patient has symptoms suggestive of back pain due to inflammation, including young age of
onset, gradual onset, pain during the night, morning stiffness, improvement with motion, no
history of trauma, and no improvement with rest. A single anteroposterior pelvis plain radiograph
to view the sacroiliac joints is an appropriate first diagnostic step in this setting, which may
reveal joint space widening (early) or narrowing (late), erosions, sclerosis, and ankylosis, and
can establish the diagnosis of ankylosing spondylitis. However, plain radiographs may be normal
early in the course of disease, as seen in this patient. MRI of the sacroiliac joints can then be
utilized, which is more sensitive for detecting early spine and sacroiliac joint inflammation. The
finding of bone marrow edema on STIR or T2-weighted images with fat suppression is not
specific for ankylosing spondylitis but do correct answers A 25-year-old man is evaluated for the
gradual onset of bilateral low back pain without radiation to the lower extremities daily, with
increasing severity over the past year. The pain now awakens him during the night 2 to 3 times
per week, with morning stiffness lasting more than an hour. He has improvement with exercise
and no improvement at rest. He takes ibuprofen with some improvement.
On physical examination, vital signs are normal. Limited lateral bending bilaterally and a
reduction in forward flexion at the lumbar spine are noted. The remainder of the examination is
normal.
, An anteroposterior plain radiograph of the pelvis and sacroiliac joints is unremarkable.
Which of the following is the most appropriate diagnostic test to perform next?
Small intestinal bacterial overgrowth (SIBO).
More than 70% of patients with SSc have clinical gastrointestinal involvement. Gastrointestinal
motility is compromised in 40% to 90% of patients with systemic sclerosis, especially those with
diffuse disease. Because of the decrease in motility of the small bowel, bacterial overgrowth
occurs and leads to the symptoms described in this patient history, including diarrhea, bloating,
and pain, and can lead to malabsorption. Patients with SSc can also develop chronic pancreatic
insufficiency and develop symptoms similar to SIBO, which must be considered in the
differential diagnosis. Diagnosis of SIBO can be confirmed with glucose hydrogen breath testing
or jejunal aspirate cultures. Treatment is with rotating antibiotics to try to reduce the overgrowth
using agents with both aerobic and anaerobic coverage. Probiotics may have some benefit in
such patients. It is important t correct answers A 45-year-old woman is evaluated for a 4-month
history of diarrhea and a 4.5-kg (10-lb) weight loss. She reports explosive episodes of loose
stools that follow most meals. There is a feeling of bloating and pain with the episodes. She has a
10-year history of diffuse cutaneous systemic sclerosis (DcSSc) complicated by Raynaud
phenomenon with occasional digital ulceration and gastroesophageal reflux disease. Her only
medication is omeprazole.
On physical examination, vital signs are normal. BMI is 21. Skin changes associated with DcSSc
involve the arms, forearms, and hands. The abdominal examination reveals active and loud
bowel sounds but is otherwise unremarkable.
Which of the following is the most likely diagnosis?
Serologic testing for Borrelia burgdorferi.
The most likely diagnosis is Lyme arthritis, which can be confirmed by serologic testing for
detection of Borrelia burgdorferi-specific antibodies using a two-tiered approach: enzyme-linked
immunosorbent assay (ELISA) followed by Western blot. This patient is a park ranger in an area
of emerging risk for Lyme disease; thus the diagnosis should be strongly suspected, especially
given a monoarthritis of the knee that is not overly painful, which is typical for Lyme arthritis.
Lyme arthritis is a late manifestation of Lyme disease; after the first month of infection, at least
5/10 bands should be present on Western blot testing for IgG antibodies to different B.
burgdorferi proteins. It is not uncommon for patients to be unaware of or experience
manifestations of early stages of disease, such as erythema migrans or constitutional symptoms.
correct answers A 49-year-old man is evaluated a 3-month history of right knee swelling without
significant pain. He does a lot of physical activity as a park ranger in Michigan but does not
