Infections

Question 1

What organism causes cellulitis

Answer 1

B-haemolytic streptococci usually group A strep (progenies)

Others include staph aureus

Question 2

Describe the clinical presentation of cellulitis

Answer 2

infected area is painful, hot and oedematous usually with lymphangitis

Question 3

What si the treatment for cellulitis

Answer 3

antibiotics - amoxicillin

necrotising fasciitis may require surgery

Question 4

What is the curative treatment for an abscess

Answer 4

drainage

Question 5

What organism is responsible for the tetanus infection

Answer 5

C. tetani bacillus (anaerobic)

Question 6

Where is tetanus more often seen

Answer 6

tropics

Question 7

How long is the incubation period of tetanus

Answer 7

2 days to 3 weeks

Question 8

What can cause tonic and clonic muscle contracture in a tetanus infection
What muscles are often affected

Answer 8

a powerful neurotoxin which is produced at site of infection and then the facial and jaw muscles producing lockjaw.
Gradual muscle involvement spreads and leads to respiratory arrest

Question 9

What causes gas gangrene

Answer 9

Anaerobic bacillus C perfringens

Question 10

Where does gas gangrene occur

Answer 10

in wounds contaminated by soil and manure especially if necrotic tissue is present

Question 11

What is often associated with wound botulism

Answer 11

IV drug usage where spew contaminated batches of heroin have been injected directly into tissues (skin popping)

Question 12

What is the classical presentation of wound botulism

Answer 12

Bilateral cranial neuropathies associated with symmetrical descending weakness
absence of fever
normal heart rate
blurred vision

Question 13

What is the treatment for wound botulism

Answer 13

Soft tissue debridement
appropriate antibiotics (metronidazole)
anti-toxin administration
Supportive care - ITU and intubation

Question 14

What is acute osteomyelitis

Answer 14

a common condition that is usually caused by Staph progenies

Question 15

Who is most commonly affected by acute osteomyelitis

Answer 15

children

Question 16

What may predispose to acute osteomyelitis

Answer 16

poor living conditions

Question 17

What bones are most commonly affected by acute osteomyelitis

Answer 17

Lower end of the femur
upper end of the tibia
either end of humerus, radius and ulna
vertebral bodies

Question 18

What actually happens in acute osteomyelitis

Answer 18

Usually a preceding injury
confined space and tension results in tissue necrosis
abscess may form within the bone
plus breaks out under the periosteum penetrating a point on the surface of the skin

Question 19

What are some of the clinical features of acute osteomyelitis

Answer 19

fever 
pain
swelling 
tenderness
oedema and pus 
Swelling of nearby joint due to a sympathetic effusion
failure to thrive
cries when limb is moved

Question 20

What is the management fro acute osteomyelitis

Answer 20

Blood culture 
Broad spectrum antibiotics 
Surgical drainage is pus is suspected 
Change of antibiotics depending on the microbiology result 
6 weeks of antibiotic therapy

Question 21

What is a guide to the rate of recovery of acute osteomyelitis

Answer 21

ESR levels

Question 22

How is a diagnosis of osteomyelitis of the spine sometimes made

Answer 22

blood culture and aspiration or drainage of pus from a paravertebral abscess

Question 23

How does osteomyelitis of the spine occur

Answer 23

usually secondary to bacteraemic spread; common sources include skin and soft tissue infections, cannula/ line associated infections
UTI
endocarditis
RTI

Question 24

How can acute suppurative arthritis occur

Answer 24

from progression of osteomyelitis
from haematogenous spread
in rheumatoid joints
following penetrating injuries

Question 25

What joints affected by osteomyelitis are more likely to cause acute suppurative arthritis

Answer 25

Hip and upper end of the radius (elbow)

Question 26

Describe the radiological changes in acute suppurative arthritis

Answer 26

may be none in the early stages | later, sub-periosteal new bone may become visible with generalised periarticular porous

Question 27

How can a diagnosis of acute suppurative arthritis be made

Answer 27

aspiration and identification of organisms by blood culture

Question 28

What is the management for acute suppurative arthritis

Answer 28

infected joint must be surgically washed out

Question 29

What is chronic paronychia

Answer 29

a persistent nail-fold infection usually caused by a fungus or by repeated irritation e.g. detergents

Question 30

What is the usual causative organism of chronic paronychia

Answer 30

Herpes simplex

Question 31

How might chronic pyogenic osteomyelitis arise

Answer 31

After trauma to bone (open fracture, penetrating injury, bullet wounds) Haematogenous spread Inadequately treated acute osteomyelitis Complication of surgery particularly when foreign material is implanted

Question 32

Describe the clinical course of chronic pyogenic osteomyelitis

Answer 32

Flares of infection with pain and swelling and often pus alternating with periods of quiescence sometimes lasting several years

Question 33

What investigations should be performed for chronic pyogenic osteomyelitis

Answer 33

X Rays - demonstrate the abnormal bone texture with thickening and diffuse cavity formation Culture of the pus from a persistent sinus usually yields mixed organisms from secondary infection

Question 34

What is involved in treating chronic pyogenic osteomyelitis

Answer 34

Acute episodes - appropriate antibiotic and surgical drainage if necessary Eradication- long term antibiotics combined with excision of sequestra and opening up or poorly draining cavities Open a wound widely, scrape out cavities and close the defect with muscle on a vascular pedicle or a split-skin graft Amputation may occasionally be required

Question 35

What are the prominent features of TB of bones and joints

Answer 35

Destruction of bone and articular cartilage by TB granulation tissues Thickening of synovial membrane - destroys the articular cartilage Abscess formation - in spinal tuberculosis - pus tracks along tissue planes Fibrosis - occurs in the healing phase

Question 36

What are the Xray features of TB of bones and joints

Answer 36

Osteoporotic changes around the joint Erosion of the joint surfaces and loss of joint space Destruction of bone Soft tissue shadows representing abscesses (BIRD'S NEST SHADOW)

Question 37

What are the investigations for TB of bones and joints

Answer 37

``` ESR Moderate lymphocytosis Tuberculin test may be positive Biopsy of lymph glands may show TB - biopsy of bone or synovium usually more reliable Bacilli may be cultures from sputum ```

Question 38

What is the treatment of TB of bone and joints

Answer 38

Rifampicin Isoniazid Pyrazinamide Ethambutol

Question 39

What are the 4 reasons for formation of a sinus

Answer 39

congenital - persistance of an embryological structure Foreign body - often a problem with infected prostheses Chronic infection - TB or fungal infection may produce a chronic sinus after the abscess has discharged or been drained Neoplasia - a sinus may communicate with a neoplastic mass