MCQs in Rheumatology:
Infections and arthritis
Contributors:
These MCQs were written by Dr Frances Rees, Dr Roshan
Amarasena and Dr Dipti Patel; and were reviewed by Dr Adrian Jones, Dr Marian
Regan, Dr Philip Courtney, and Prof. Michael Doherty. The MCQs were edited by Dr
A Abhishek who also facilitated the review process.
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Question 1
A 22year-old previously healthy university student is evaluated for fever, joint pain,
and rash for last 48 hours. She denies any preceding infections like diarrhoea,
urethral discharge, or sore throat. There is no history of travel, tick bite, or prior joint
symptoms. She is sexually active, and the last menstrual period a week ago.
On examination, the temperature is 38.8oC and had a petechial skin rash with
pustules over her arms. There is no erythroderma. There is tenosynovitis in flexor
tendons of the wrist.
Investigations: Hb 13.6g/l, WBC count 13.4, Neutrophils 7.6, platelets 437, ANA
negative, renal and liver function tests normal. CRP 318 and ESR 96.
What should be your working diagnosis?
1.
2.
3.
4.
5.
Gonococcal arthritis
Meningococcal septicaemia
Pustular psoriasis
Reactive arthritis
Sweet’s syndrome
Question 2
A 30 year old female presents to MAU with fatigue, fever and arthritis She had
noticed a rash on her left leg which had been getting worse. Two weeks ago she
went camping in the New Forest. On examination she had a left knee effusion. She
had a 10cm diameter red macule on her left shin with central clearing. Joint aspirate
No organisms, no crystals.
What is the most appropriate first line therapy?
1. Amoxicillin
2. Cefalexin
3. Ciprofloxacin
4. Metronidazole
5. Nitrofurantion
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Question 3
A 43 year old woman presents with a 3 week history of cough, malaise, weight loss,
and low grade fever. She emigrated from Nigeria 7 years ago, and has sickle cell
trait. On examination, the temperature was 37.8oC, BP 95/55 mmHg, pulse 115
beats/minute. She has a cold right knee effusion. Systemic examination is otherwise
unremarkable.
Initial investigations
Hb 9.6g/dl
WCC 4.3 x109/l
Plts 135 x109/l
MCV 67fL
CRP 110 mg/L
ANCA, ANA, rheumatoid factor, anti-CCP – negative
Urine dipstick 1+ protein
Right knee aspirate – no organisms. Few white cells. No growth at 24hours.
Extended culture pending.
CXR infiltrate with cavitation in the right upper lobe
What is the most likely diagnosis?
1.
2.
3.
4.
5.
ANCA associated vasculitis
Lung abscess
Lung cancer
Tuberculosis
Reactive arthritis
Question 4
A 40 year old Indian man is admitted with weight loss, fevers and night sweats. He
has a 2 month history of low back pain for which he has been prescribed Naproxen.
He emigrated from India 10 years ago.
Observations: temperature 37.8 degrees, pulse 99bpm, BP 130/70.
On examination he had localised tenderness of the L1 vertebra. There was no
neurological deficit.
Initial investigations
C-reactive protein 104mg/L
White cell count 17x109/L
What is your next investigation of choice?
1.
2.
3.
4.
5.
Blood culture
Chest radiograph
MRI lumbar spine
Sputum for acid fast bacilli
T Spot test
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Question 5
A 39 year old Nigerian woman presents to clinic with an oligoarthritis affecting her
right ankle, right knee, and both wrists. She is known to be HIV positive and is
currently on anti-retroviral therapy. Four weeks ago she had a flu-like illness with a
sore throat. On examination she is afebrile. She has effusions of her right ankle, right
knee and both wrists.
Initial investigations
WCC 3.5 x109/l
CRP 92 mg/L
Right knee aspirate – no organisms. Moderate white cells. No growth.
What is the most likely diagnosis?
1.
2.
3.
4.
5.
AIDS
Infectious mononucleosis
Lymphoma
Reactive arthritis
Tuberculosis
Question 6
An 18-year-old female is referred from the medical admission unit with swelling of
the knees. Yesterday her ankles were painful, stiff, swollen, but have resolved
completely. She has no past history of joint problems. She is in a stable relationship.
Two weeks ago she saw her GP with a sore throat. A throat swab was performed
which grew Streptococcus, and she was treated with oral penicillin V. On
examination she has a temperature of 38.2oC, small knee effusions bilaterally, and a
soft pansystolic murmur.
Initial investigations show
C-reactive protein 89mg/L
White cell count 14x109/l
Blood cultures pending. A routine ECG done in the MAU shows a PR interval of 0.24
seconds.
What is the most likely diagnosis?
1.
2.
3.
4.
5.
Acute rheumatic fever
Acute sarcoid arthritis
HIV seroconversion
Reactive arthritis
Septic arthritis
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Question 7
You are asked to see a 30 year old man on the medical admissions unit. He
presents with a 2 week history of fever and joint pains. He has a past history of
intravenous drug use. On examination he has a right knee effusion and a petechial
rash over his toes. The admissions team have performed some initial investigations
White cell count 19.5 x 109/l (4.0-11.0)
C reactive protein 89 mg/l (<10)
Anti-neutrophil cytoplasmic antibodies c ANCA positive
Blood cultures : pending
Joint aspirate : pending
Which of the following investigations would you do next?
1.
2.
3.
4.
5.
Anti-nuclear antibody
ENA
Echocardiogram
Skin biopsy
Urinalysis
Question 8
A previously fit and well 26 year nursery school teacher presented to her GP with an
acute onset symmetrical polyarthritis affecting the MCPJs, and wrists. She was
commenced on diclofenac, and referred to the rheumatology clinic. She was seen in
the clinic 2 weeks later and had significantly less discomfort and no stiffness in the
joints. There was no family history of arthritis. On examination there was minimal
synovial thickening in the PIP joints of the right 4th finger. The other joints were not
involved. Investigations show a normal FBC, ESR, U&E, CRP, and serum urate. The
RF and anti-CCP antibodies were negative. ANA was positive (homogeneous, 140).
X-rays of hands were normal. IgM antibody for parvovirus B19 was positive.
What is the most appropriate course of action?
1.
2.
3.
4.
5.
Continue analgesia and review
Give an intra muscular corticosteroid injection
Repeat ANA
Request an urgent ultrasound scan of hands
Start disease modifying anti-rheumatic drug
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Question 9
A 30 year old fit and well male student presents with a 2 day history of painful
swollen right knee. On enquiry, he gives a history of sore throat, malaise and rigors.
On examination he appears unwell, T 38.8 oC, P 100/min, BP 110/70 mm Hg. Septic
arthritis is suspected and following investigations are planned.
Which of the following is of least diagnostic value in diagnosis of septic arthritis?
1. Blood cultures
2. CRP
3. ESR
4. Synovial fluid analysis
5. X ray
Question 10
A 65 year old lady with a 20 year history of deforming seropositive RA, on long term
low dose corticosteroids presents with a 3 week history of gradually worsening
painful swollen left knee, and fever. An arthrocentesis is performed which confirms
septic arthritis.
Which of the following organism account for >90% of septic arthritis in the above
clinical setting?
1.
2.
3.
4.
5.
Gram negative bacilli
Mycobacterim tuberculosis
Pseudomonas spp
Staphylococous aureus
Streptococcus pneumonia
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Answers
Q1.
2. Meningococcal septicaemia
Meningococcal septicemia is the working diagnosis. Gonococcal arthritis may
present in a similar manner but is extremely rare in the UK, as the prevalent strains
in UK are not as arthritogenic as those in the USA. Pustular psoriasis does not have
such a florid onset, and is usually accompanied by underlying erythrodrema.
Reactive arthritis is unlikely given the clinical feature, and the absence of a
preceding illness. Sweet’s syndrome is a not unreasonable differential diagnosis;
however, meningococcal septicemia should be excluded first.
Q2.
1. Amoxicillin
This patient has Lyme disease. For skin disease first line therapy is either Amoxicillin
(500mg tds po for 3 weeks), Doxycycline or Cefuroxime for 3 weeks.
Q3.
4. Tuberculosis
This woman has pulmonary TB with systemic spread. She has septic arthritis of her
right knee due to TB. Although the 24hour culture is negative, extended culture is
likely to reveal the diagnosis as Mycobacterium tuberculosis is relatively slow
growing. If TB is suspected microscopic examination for acid-fast bacilli should be
specifically requested.
Q4.
3. MRI lumbar spine
This gentleman is most likely to have spinal TB. Imaging of the lumbar spine would
be the next most helpful investigation to assess the extent of the disease, and
localize an appropriate target for bone biopsy.
Q5.
5.Reactive arthritis
The common arthropathies affecting HIV-infected individuals are the same as those
affecting the general population, in this case reactive arthritis is the most likely
diagnosis. If the CD4 count is very low then consider opportunistic infections such as
atypical mycobacteria, fungi or parasites.
Q6.
1. Acute rheumatic fever
This patient meets the criteria for diagnosis of acute rheumatic fever. Reactive
arthritis would be possible, but is less likely due to the new murmur. Septic arthritis
would be unusual to present in multiple joints, however, it remains a reasonable
differential diangosis. Revised Jones’ criteria for diagnosis of acute rheumatic fever
2 major or 1 major and 2 minor plus evidence of Streptococcus pyogenes infection.
Major criteria
 polyarthritis a temporary migrating inflammation of the large joints, usually
starting in the legs and migrating upwards.
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
carditis inflammation of the heart muscle which can manifest as congestive
heart failure with shortness of breath, pericarditis with a rub, or a new heart
murmur.
 subcutaneous nodules painless, firm collections of collagen fibers over bones
or tendons. They commonly appear on the back of the wrist, the outside
elbow, and the front of the knees.
 erythema marginatum a long lasting rash that begins on the trunk or arms as
macules and spreads outward to form a snake like ring while clearing in the
middle. This rash never starts on the face and it is made worse with heat.
 sydenham's chorea (St. Vitus' dance) a characteristic series of rapid
movements without purpose of the face and arms. This can occur very late in
the disease.
Minor criteria
 fever of 38.2–38.9 °C
 arthralgia Joint pain without swelling (Cannot be included if polyarthritis is
present as a major symptom)
 raised erythrocyte sedimentation rate or C reactive protein
 leukocytosis
 ECG showing features of heart block, such as a prolonged PR interval
(Cannot be included if carditis is present as a major symptom)
 previous episode of rheumatic fever or inactive heart disease
Q7.
3. Echocardiogram
The most likely diagnosis (or the working diagnosis) in this case is infective
endocarditis causing a septic arthritis, neutrophilia, and a raised CRP. As blood
cultures and a joint aspirate have already been sent, an echocardiogram is most
likely to reveal the diagnosis. cANCA may be raised in infection, however, typically,
the anti-PR3, and anti-MPO antibodies are negative.
Q8.
4. Continue analgesia and review
This is the typical history of a viral arthritis - most likely to be parvo virus B19. The
clues are that it was sudden onset, symmetric arthritis in a person with close contact
with young children. The fact that the arthritis is resolving is reassuring. An
ultrasound would not change management if the patient is improving. The ANAs are
sometimes transiently positive and without other features of connective tissue
disease are of little value.
Q9.
5. X ray
Initial radiographs should be obtained to exclude adjacent osteomyelitis and to be a
baseline. However, plain radiologic changes consistent with septic arthritis may take
several days to 2 weeks to develop.
The earliest change on plain radiograph of septic arthritis is soft tissue swelling and a
widened joint space from joint effusion. With progression of disease joint space
narrowing occurs and bone destruction develops. Superimposed features of
osteomyelitis may develop e.g. periosteal reaction, bone destruction, and
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sequestrum formation. Bone scan is usually positive in 24-48 hours but not specific
for septic arthritis.
Q10.
4. Staphylococcal aureus
Patients with damaged joints secondary to RA, and on immunosuppressive agents
are at increased risk of septic arthritis. Symptoms may be mistaken for flare of RA.
Increased age, RA, immunosuppressive treatment is all predictors of poor outcomes.
Gram positive organisms, especially S. aureus accounts for 90% of infections.
Other organisms seen most commonly with following conditions
Alcoholism- gram negative bacilli, streptococci pneumoniae
Diabetes mellitus –gram negative bacilli, gram positive cocci
Drug abuse- Pseudomonas aeruginosa, serratia marcescens
Hemoglobinopathies- streptococcus pneumoniae, salmonella
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