Bacterial Infections of Bones, Joints and Muscles

Question 1

A 72-year-old HIV patient has a 2 days history of left leg pain, redness and edema. He is admitted to the hospital and gives a history of chest infection and fever for the last 7 days without treatment.

Name the organism

Answer 1

Staphylococci

Question 2

A 72-year-old HIV patient has a 2 days history of left leg pain, redness and edema. He is admitted to the hospital and gives a history of chest infection and fever for the last 7 days without treatment.

Answer 2

Acute osteomyelitis

Question 3

What is the commonest causative organism of osteomyolitis ?

Answer 3

Staph. aureus

Question 4

A 72-year-old HIV patient has a 2 days history of left leg pain, redness and edema. He is admitted to the hospital and gives a history of chest infection and fever for the last 7 days without treatment.

4. What is the route of transmission of this organism in this patient?

Answer 4

Hematogenous on top of bacteremia due to chest infection

Question 5

A 72-year-old HIV patient has a 2 days history of left leg pain, redness and edema. He is admitted to the hospital and gives a history of chest infection and fever for the last 7 days without treatment.

5. What are the main lines of treatment for this patient?

Answer 5

Drain abscess+ antibiotics (oxacillin + Fucidin or Teicoplanin if MRSA) FOR 4-6 WEEKS

Question 6

A 72-year-old HIV patient has a 2 days history of left leg pain, redness and edema. He is admitted to the hospital and gives a history of chest infection and fever for the last 7 days without treatment.

Answer 6

• A: Sequesterm (necrotic isolated bone).

• B: Inflammatory cells.

Question 7

What are the laboratory tests performed to prove an active inflammatory process?

Answer 7

ESR and CRP

Question 8

A 45-year-old African patient has chronic cough, night sweat and night fever for more than one year. He develops severe back pain in the thoracic region. Bone, sputum and blood specimens are collected for investigations

Name the organism

Answer 8

Mycobacterium tuberculosis

Question 9

A 45-year-old African patient has chronic cough, night sweat and night fever for more than one year. He develops severe back pain in the thoracic region. Bone, sputum and blood specimens are collected for investigations.

2. What is your provisional diagnosis?

Answer 9

TB Chronic osteomyelitis (pott’s disease)

Question 10

A 45-year-old African patient has chronic cough, night sweat and night fever for more than one year. He develops severe back pain in the thoracic region. Bone, sputum and blood specimens are collected for investigations.

3. What are the main lines of treatment for this patient?

Answer 10

• rifampicin + isoniazid + pyrazinamide + ethambutol (2 months or more) then rifampicin and isoniazid (up to 10 months)

Question 11

Three days following a right total hip replacement, a 75-year- old woman develops fever and severe hip joint pain. Physical examination reveals swelling and hotness over the right hip joint. A joint aspirate is sent for laboratory examination.

Mention the suspected organism

Answer 11

Strept. pyogenes

Question 12

Three days following a right total hip replacement, a 75-year- old woman develops fever and severe hip joint pain. Physical examination reveals swelling and hotness over the right hip joint. A joint aspirate is sent for laboratory examination.

2. What is your provisional diagnosis?

Answer 12

• Septic arthritis

Question 13

Three days following a right total hip replacement, a 75-year- old woman develops fever and severe hip joint pain. Physical examination reveals swelling and hotness over the right hip joint. A joint aspirate is sent for laboratory examination.

3. What are the main virulence factors of the causitive organism?

Answer 13

• M-protein – adhesin, anti-phagocytic

• Streptokinase

• DN’ase

• Hyaluronidase

• Proteases

Question 14

Three days following a right total hip replacement, a 75-year- old woman develops fever and severe hip joint pain. Physical examination reveals swelling and hotness over the right hip joint. A joint aspirate is sent for laboratory examination.

4. What are the main lines of treatment for this patient?

Answer 14

• Drain the synovial fluid + Bezylpenicillin I.V. then oral for 4-6 weeks

Question 15

A 65-year-old diabetic farmer has left foot pain and darkening of the skin. He is admitted to the hospital. Physical examination reveals, marked edema, blackening of the big toe extended to the foot with bad odour and absence of pulse in the foot but palpable normal pulse at the ankle.

1. What is your provisional diagnosis?

Answer 15

Gangrene

Question 16

A 65-year-old diabetic farmer has left foot pain and darkening of the skin. He is admitted to the hospital. Physical examination reveals, marked edema, blackening of the big toe extended to the foot with bad odour and absence of pulse in the foot but palpable normal pulse at the ankle.

2. What is the commonest causative organism of this condition?

Answer 16

Clostridium perfringens

Question 17

A 65-year-old diabetic farmer has left foot pain and darkening of the skin. He is admitted to the hospital. Physical examination reveals, marked edema, blackening of the big toe extended to the foot with bad odour and absence of pulse in the foot but palpable normal pulse at the ankle.

3. Mention the most important virulence factors of the causitive organism?

Answer 17

Exotoxins (~17 all with Greek letters):

• Alpha toxin :(phospholipase C or Lecithinase)

Question 18

A 65-year-old diabetic farmer has left foot pain and darkening of the skin. He is admitted to the hospital. Physical examination reveals, marked edema, blackening of the big toe extended to the foot with bad odour and absence of pulse in the foot but palpable normal pulse at the ankle.

4. What are the main lines of treatment for this patient?

Answer 18

• Surgery – immediate and all affected tissue must be excised may need amputation.

• Benzylpenicillin is adjunct therapy not an alternative to surgery.

• Hyperbaric oxygen chamber.