surgery - PLASTICS infections

Question 1

what is a skin abscess?

Answer 1

collection of pus within the subcutaneous tissues, lined by a pyogenic membrane

Question 2

how do you differentiate a pyogenic skin abscess to infected sebaceous cyst?

Answer 2

sebaceous cysts are lined with a stratified squamous epithelium

Question 3

what can cause recurrent abscess formation?

Answer 3

perianal fistulae, hidradenitis suppurativa (discussed below), or inflammatory skin conditions

Question 4

pathophysiology of skin abscess?
common organism

Answer 4

S.aureus

Skin abscess of form when there is a breach to the skin’s defensive barrier, leading to inoculation of pathogens in the subcutaneous tissue.

The resultant acute inflammatory response results in non-specific host tissue damage resulting in necrotic tissue and non-viable immune cells forming, termed pus; this becomes surrounded by the pyogenic membrane.

Question 5

what Is Panton-Valentine luecocidin?

Answer 5

Question 6

RF for skin abscess?

Answer 6

diabetes
steroids
immunosuppressive meds
sickle cell disease
IVDU
malnutrition

Question 7

features of skin abscess?

Answer 7

localised erythematous tender swelling
maybe purulent discharge
assoc trauma or localised skin condiiton

tender and fluctuant swelling with surrounding cellulitis
sepsis features if extreme

Question 8

ix for skin abscess?

Answer 8

bloods = FBC, CRP
CT/MRI

Question 9

mx of skin abscess?

Answer 9

empirical abx + analgesia
incision + drainage

Question 10

what is Hidradenitis Suppurativa?

Answer 10

a condition of chronic and recurrent infections affecting the apocrine gland-bearing areas of the body. It is characterised by multiple superficial abscesses, with or without features of chronic sinus formation or ulceration.

Question 11

who does Hidradenitis Suppurativa affect?

Answer 11

adolescent years onwards,
more females

Question 12

features of hidradenitis suppurativa?

Answer 12

recurrent abscess formation regulating in sinus formation
surrounding fibrosis

Question 13

mx of HS?

Answer 13

smoking cessation
weight management
topical = clindamycin + chlorhexidine wash
oral abx long term = tetracycline or clindamycin + rifampicin
retinoids
antimicrobials
immunotherapy
surgical excision

Question 14

what can cause hand infections?

Answer 14

result of trauma, animal bites, human bites, or contaminated lacerations

Question 15

who are hand infections common in?

Answer 15

such as diabetes mellitus, or in current smokers

Question 16

bacteria causing hand infection?

Answer 16

S.aureus or streptococci

Question 17

Answer 17

Question 18

ix for hand infection?

Answer 18

FBC, CRP, WCC and urate
plain film radiograph - exclude foreign bodies, assess for underlying fractures or evidence of osteomyelitis
wound swabs +/ pus culture

Question 19

mx of hand infections?

Answer 19

Areas of erythema should be marked to help determine any rate of spread.

Infectious tenosynovitis, flexor sheath infection, and deep space infections will often require a formal thorough washout in theatre, with subsequent re-looks in order to exclude re-accumulation of infection.

Once complete, patients often require a period of close observation and strict hand elevation to reduce swelling.

Question 20

what is paronychia?

Answer 20

Infection of the perionychium (the soft tissue fold around the nail plate) can occur secondary to contamination with oral flora from nail biting or sucking.

Question 21

features of paronychia?

Answer 21

Pus can track along the perionychium in a horse-shoe shape, producing a characteristic abscess at the skin-nail plate junction*. The fingertip may be swollen, inflamed, and very tender (Fig. 2); pus can collect subungually, even cause necrosis of the nail bed and untreated paronychia can result in osteomyelitis of the distal phalanx.

Question 22

tx of paronychia?

Answer 22

Treatment typically involves antibiotics, however incision and drainage of the pus will be required. Nail plate removal may be necessary to allow for sufficient drainage of pus. Following incision and drainage, a thorough washout with normal saline and antiseptic solution is necessary, with regular dressing changes.

Question 23

what is infection tenosynovitis?
causes

Answer 23

Tenosynovitis is inflammation of tendon sheath, the most common cause of which is infection. Tenosynovitis most often arises from direct inoculation of bacteria (commonly S. aureus) secondary to penetrating trauma*

Question 24

pathophsyiology of infectious tenosynovitis?

Answer 24

The most common type of tendosynovitis are flexor sheath infections. These should be deemed as a surgical emergency, as the raised pressure that occurs within the tendon sheath can impair blood flow and lead to eventual tendon necrosis and rupture.

Question 25

what are Kanavel's signs of flexor sheath infection?

Answer 25

Tenderness along the flexor sheath Flexed finger posture Pain on passive extension Fusiform swelling of the affected digit

Question 26

mx of flexor sheath infection?

Answer 26

A thorough washout of the flexor sheath in theatre followed by strict elevation and close monitoring should be the mainstay of treatment. It is common practice to perform a re-look and further washout in theatre, especially if the clinical features do not resolve.

Question 27

what are felon infections?

Answer 27

A felon infection is a subcutaneous infection of the fingertip pulp, most commonly occur in the thumb or index finger and are caused by S. aureus.

Question 28

how do felon infections present?

Answer 28

Fibrous vertical septae run from the periosteum to the epidermis of the pulp, creating a closed system of microcompartments that are susceptible to rising pressure from inflammation. Felon infections present with swelling of the pulp distal to the distal phalangeal crease and severe pain (Fig. 5). The most common cause is through direct contamination, such as via splinters or garden thorns.

Question 29

mx of felon infections?

Answer 29

simple and will resolve spontaneously after a short period; antibiotics can aid resolution.

Question 30

what are deep hand space infections?

Answer 30

simple and will resolve spontaneously after a short period; antibiotics can aid resolution.

Question 31

what is the thenar space?

Answer 31

The thenar space overlies adductor pollicis and is bound ulnarly by the insertion of the adductor onto the metacarpal; when infected, pus may track dorsally around the adductor and in-between its two heads

Question 32

what is the mid-palmar space?

Answer 32

The mid-palmar space is a continuation of the carpal tunnel, deep to the palmar aponeurosis and superficial to the deep palmar interossei; it has multiple septa distally that separate the space and direct the flexor tendons to their digits

Question 33

what is the hypothenar space?

Answer 33

The hypothenar space is located palmar to the fifth metacarpal and dorsal to the hypothenar fascia

Question 34

what are complications of hand infections?

Answer 34

Tracking cellulitis and subsequent sepsis Damage to local structures, including tendons and joints, are of major concern. Patients can develop impaired function of the hand that may take years of rehabilitation to improve.

Question 35

match the organism to bite animal Pasteurella multocida & Pasteurella cannis Staphylococcus aureus & Streptococci Bartonella henselae Streptobacillicus moniliformis

Answer 35

Question 36

features of bites?

Answer 36

may appear small and uncomplicated superficially, deeper structures may have been affected check neurovasucalr status infection can develop 1-2 days after

Question 37

ix of bites?

Answer 37

plain film radiograph FBC, CRP swab purulent material

Question 38

mx of bites

Answer 38

preventing further bleeding from the bite and wound cleaning apply continuous pressure + gauze dressing tetanus immunisation abxs

Question 39

surgical mx of bites?

Answer 39

wash with saline debridement re-check 24-48hrs later surgical washout

Question 40

what is necrotising fasciitis?

Answer 40

life-threatening rapidly-progressing infection that spreads along the fascial planes and subcutaneous tissue.

Question 41

what is Fournier's gangrene?

Answer 41

a necrotising infection of the perineum.

Question 42

microbial types fo nec fasc?

Answer 42

Type I is a polymicrobial infection, primarily caused by a mixture of anaerobes (e.g. Bacteroides) and aerobes (e.g. S. aureus); it is the more common of the two subtypes, especially in elderly or co-mordid patients Type II is a monomicrobial infection, primarily caused by Streptococcus pyogenes (group A strep), and is more common in healthy individuals with a history of trauma It also can be caused by Panton-Valentine leucocidin (PVL)-positive Staphylococcus aureus infections

Question 43

what is gas gangrene?

Answer 43

form of necrotising fasciitis caused by Clostridium species (most commonly C. perfringens), resulting in gas being produced by the bacteria within the tissue.

Question 44

how does gas gangrene occur?

Answer 44

The clostridial organisms involved produce alpha and beta toxins that lead to extensive tissue damage, alongside producing large volumes of gas within the tissue. It will present in an equally severe clinical state, however tissue crepitus is often present on light palpation of the affected area. Management is the same as with any necrotising fasciitis.

Question 45

RF for nec fasc?

Answer 45

diabetes mellitus, chronic kidney disease, alcohol excess, advanced age or frailty, malnutrition, metastatic cancer, or immunocompromised (e.g. AIDS or recent chemotherapy)

Question 46

features of nec fasc?

Answer 46

precipitating event of skin breach (e.g. recent trauma, animal bite or scratch, or recent surgery) progress rapidly severe pain out keeping with clinical signs haemodynamically unstable multi-organ dysfunction skin erythema oedema skin ischameia skin crepitus vesicles/bullae necrosis

Question 47

ix of nec fasc?

Answer 47

FBC, WCC, CRP blood gas - raised lactate +/- metabolic acidosis worsening renal function, hyponatraemia, impaired liver function, raised glucose, and coagulopathy blood cultures

Question 48

scoring system for nec fasc?

Answer 48

Question 49

grading of severity based on score for nec fasc?

Answer 49

A score ≤5 is low risk, score 6-7 is intermediate risk, and ≥8 is high risk

Question 50

mx of nec fasc?

Answer 50

immediate resus IV fluids + debridement urgent broad spec abx