DVT & Cellulitis Flashcards
What is cellulitis?
A bacterial infection that affects the dermis and deeper subcutaneous tissue.
What causes cellulitis?
A break in the skin barrier that allows entry for bacteria:
- Skin trauma
- Skin conditions e.g. eczema, chronic venous ulcers, psoriasis
- Venous insufficiency and peripheral vascular disease
- Obesity
- Skin breaks (such as recent cuts or insect bites)
- Lymphoedema
- Previous cellulitis
- Surgery to the lower limb including saphenectomy
- Tinea pedis
- T2DM
- IVDU
- Alcoholism
- Immunosuppression
- Pregnancy
What are the 3 most common organisms causing cellulitis?
1) Staph. aureus
2) Group A Strep. (mainly streptococcus pyogenes)
3) Group C Strep. (mainly streptococcus dysgalactiae)
What should be considered as the causative organism of cellulitis in patients with repeated hospital admissions and antibiotics?
MRSA
Clinical features of cellulitis?
Unilateral:
- swelling
- erythema
- warmth
- tenderness
- bullae (fluid-filled blisters)
- systemic upset e.g. fever, malaise, nausea (SEPSIS red flag)
Where does cellulitis usually occur?
On the shins
A golden-yellow crust in cellulitis indicates which causative organism?
Staph. aureus
Is cellulitis a rapid or slow onset?
Rapid
A rapidly progressive and blistering rash should prompt consideration of what?
Necrotising fasciitis
What classification system is used to guide management of cellulitis?
Eron classification
Describe the Eron classification
Class I - no systemic toxicity or comorbidity
Class II - systemic toxicity or comorbidity
Class III - significant systemic toxicity or significant comorbidity
Class IV - sepsis or life-threatening infection
What Eron classification indicates admission for IV Abx?
Class III and IV
N.B. Admission is also considered for frail, very young or immunocompromised patients and those with facial, periorbital or orbital cellulitis
Give some indications for admission for IV Abx in cellulitis
1) Has Eron Class III or Class IV cellulitis.
2) Has severe or rapidly deteriorating cellulitis (for example extensive areas of skin).
3) Is very young (under 1 year of age) or frail.
4) Is immunocompromised.
5) Has significant lymphoedema.
6) Has facial cellulitis (unless very mild) or periorbital cellulitis.
Investigations in cellulitis?
Consider sepsis 6.
1) FBC:
- leucocytosis or neutrophilia
- N.B. only half of patients presenting with cellulitis have a raised WCC
2) U&Es
- assess for AKI
3) CRP or ESR
4) Consider blood cultures
Differentials for cellulitis?
1) DVT
2) Varicose or venous stasis eczema
3) Superficial thrombophlebitis
4) Necrotising fasciitis
What is typical 1st line Abx for mild/moderate cellulitis?
Oral flucloxacillin
1st line Abx for mild/mod cellulitis in pregnancy?
Oral erythromycin
1st line Abx for mild/mod cellulitis in penicillin allergy?
oral clarithromycin, erythromycin or doxycycline
What can you do to assess whether cellulitis is spreading?
mark the area of erythema to detect spreading cellulitis
What is usually the 1st choice Abx for cellulitis near the eyes or nose?
Co-amoxiclav
1st line Abx in severe cellulitis?
Oral/IV co-amoxiclav, oral/IV clindamycin, IV cefuroxime or IV ceftriaxone
Complications of cellulitis?
- systemic infection
- subcutaneous abscess formation
- myositis
- fasciitis
- death
What is orbital cellulitis?
Orbital cellulitis is an infection around the eyeball involving the fat and muscles behind the orbital septum.
What is orbital cellulitis usually caused by?
A spreading URT infection from the sinuses.
Is orbital celluliti dangerous?
Yes - carries a high mortality rate.
Risk factors for orbital cellulitis?
- Childhood
- Previous sinus infection
- Lack of Haemophilus influenzae type b (Hib) vaccination
- Recent eyelid infection/ insect bite on eyelid (Peri-orbital cellulitis)
- Ear or facial infection
Clinical features of orbital cellulitis?
1) Pain
- throbbing or deep ache
- worse on eye movement
2) Proptosis (exophthalmos)
3) Periocular swelling (oedema)
4) Pupillary involvement and visual changes
5) Palsy (ophthalmoplegia)
What is proptosis (exophthalmos)?
Forward displacement or protrusion of the eyeball due to inflammation and oedema of the orbital contents, or in severe cases, formation of an abscess.
How can periocular swelling in orbital cellulitis present?
- swollen eyelids
- chemosis (swelling of conjunctiva)
- erythema
What visual changes may be seen in orbital cellulitis?
- blurred vision
- decreased visual acuity
- diplopia
- loss of vision (severe cases)
What pupillary defect may be seen in orbital cellulitis?
A relative afferent pupillary defect (RAPD) may be present, indicating optic nerve involvement.
What causes palsy (ophthalmoplegia) in orbital cellulitis?
Due to the inflammation and swelling in the orbit, there can be restriction or paralysis of the extraocular muscles, leading to impaired eye movements (ophthalmoplegia).
Management of orbital cellulitis?
Orbital cellulitis requires emergency admission under ophthalmology and IV antibiotics. Surgical drainage may be needed if an abscess forms.
What is the main differential for orbital cellulitis?
Periorbital cellulitis (less serious)
What is periorbital cellulitis?
Periorbital cellulitis (also known as preseptal cellulitis) is an eyelid and skin infection in front of the orbital septum (in FRONT of the eye).
How does periorbital cellulitis present?
It presents with swollen, red, hot skin around the eyelid and eye.
Management of periorbital cellulitis?
1) Exclude orbital cellulitis
2) Systemic antibiotics (oral or IV).
reorbital cellulitis can develop into orbital cellulitis, so vulnerable patients (e.g., children) or severe cases may require admission for monitoring.
What is necrotising fasciitis (NF)?
A severe and rapidly progressive soft tissue infection that causes necrosis of the subcutaneous tissues and fascia, sometimes also affecting the muscle.
It needs rapid management and it has a high mortality rate of around 32%.
What are the main risk factors for developing necrotising fasciitis?
1) diabetes mellitus
2) CKD
3) alcohol excess
4) advanced age or frailty
5) malnutrition
6) metastatic cancer
7) immunocompromised (e.g. AIDS or recent chemotherapy)
Cause of NF?
The large majority of cases of NF are related to some form of trauma, either an external injury or a surgical wound.
How can NF be categorised?
Depending on the causative organism.