DVT & Cellulitis Flashcards
1
Q
What is cellulitis?
A
A bacterial infection that affects the dermis and deeper subcutaneous tissue.
2
Q
What causes cellulitis?
A
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
3
Q
What are the 3 most common organisms causing cellulitis?
A
1) Staph. aureus
2) Group A Strep. (mainly streptococcus pyogenes)
3) Group C Strep. (mainly streptococcus dysgalactiae)
4
Q
What should be considered as the causative organism of cellulitis in patients with repeated hospital admissions and antibiotics?
A
MRSA
5
Q
Clinical features of cellulitis?
A
Unilateral:
- swelling
- erythema
- warmth
- tenderness
- bullae (fluid-filled blisters)
- systemic upset e.g. fever, malaise, nausea (SEPSIS red flag)
6
Q
Where does cellulitis usually occur?
A
On the shins
7
Q
A golden-yellow crust in cellulitis indicates which causative organism?
A
Staph. aureus
8
Q
Is cellulitis a rapid or slow onset?
A
Rapid
9
Q
A rapidly progressive and blistering rash should prompt consideration of what?
A
Necrotising fasciitis
10
Q
What classification system is used to guide management of cellulitis?
A
Eron classification
11
Q
Describe the Eron classification
A
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
12
Q
What Eron classification indicates admission for IV Abx?
A
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
13
Q
Give some indications for admission for IV Abx in cellulitis
A
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.
14
Q
Investigations in cellulitis?
A
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
15
Q
Differentials for cellulitis?
A
1) DVT
2) Varicose or venous stasis eczema
3) Superficial thrombophlebitis
4) Necrotising fasciitis
16
Q
What is typical 1st line Abx for mild/moderate cellulitis?
A
Oral flucloxacillin
17
Q
1st line Abx for mild/mod cellulitis in pregnancy?
A
Oral erythromycin
18
Q
1st line Abx for mild/mod cellulitis in penicillin allergy?
A
oral clarithromycin, erythromycin or doxycycline
19
Q
What can you do to assess whether cellulitis is spreading?
A
mark the area of erythema to detect spreading cellulitis
20
Q
What is usually the 1st choice Abx for cellulitis near the eyes or nose?
A
Co-amoxiclav
21
Q
1st line Abx in severe cellulitis?
A
Oral/IV co-amoxiclav, oral/IV clindamycin, IV cefuroxime or IV ceftriaxone
22
Q
Complications of cellulitis?
A
- systemic infection
- subcutaneous abscess formation
- myositis
- fasciitis
- death
23
Q
What is orbital cellulitis?
A
Orbital cellulitis is an infection around the eyeball involving the fat and muscles behind the orbital septum.
24
Q
What is orbital cellulitis usually caused by?
A
A spreading URT infection from the sinuses.
25
Is orbital celluliti dangerous?
Yes - carries a high mortality rate.
26
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
27
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)
28
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.
29
How can periocular swelling in orbital cellulitis present?
- swollen eyelids
- chemosis (swelling of conjunctiva)
- erythema
30
What visual changes may be seen in orbital cellulitis?
- blurred vision
- decreased visual acuity
- diplopia
- loss of vision (severe cases)
31
What pupillary defect may be seen in orbital cellulitis?
A relative afferent pupillary defect (RAPD) may be present, indicating optic nerve involvement.
32
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).
33
Management of orbital cellulitis?
Orbital cellulitis requires emergency admission under ophthalmology and IV antibiotics. Surgical drainage may be needed if an abscess forms.
34
What is the main differential for orbital cellulitis?
Periorbital cellulitis (less serious)
35
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).
36
How does periorbital cellulitis present?
It presents with swollen, red, hot skin around the eyelid and eye.
37
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.
38
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%.
39
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)
40
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.
41
How can NF be categorised?
Depending on the causative organism.
42
What are the 4 types of NF?
Type I: polymicrobial
Type II: monomicrobial (caused by Streptococcus pyogenes)
Type III: monomicrobial (caused by the Clostridium species most commonly)
Type IV: fungal NF, mainly Candida species
43
What is the most common type of NF?
Type I (70-90%)
44
Where is type I NF typically found?
On the drunk or perineum
45
Which organism causes type II NF?
Streptococcus pyogenes
46
Who does Type II NF typically occur in?
Younger patients, healthy individuals with a history of trauma
47
Where is type II NF typically found?
Limbs
48
What organism causes type III NF?
Clostridium species
49
Who is type III NF typically found in?
IVDU
50
What organism is type IV NF caused by?
Mainly Candida
51
Who is type IV NF typically seen in?
Mainly found in immunocompromised patients, and is particularly aggressive and extensive.
52
Pathophysiology of NF?
1) Bacteria produce enzymes that result in necrosis of the fascia and fat
2) Bacteria also cause thrombosis in the vessels leading to ischaemia which further promotes necrosis
N.B. This ischaemia originally produces intense pain for the patient but, as the disease progresses, can result in hypoesthesia/anaesthesia.
53
What is gas gangrene?
A form of NF caused by clostridium specicies (C. perfringens), resulting in gas being produced by the bacteria within the tissue.
54
What bacteria causes gas gangrene?
C. perfringens
55
How do the Clostridium species cause gas gangrene?
The organisms produce alpha and beta toxins that lead to extensive tissue damage, alongside producing large volumes of gas within the tissue.
56
Presentation of gas gangrene?
- same as NF
- tissue crepitus is often present on light palpation of affected area
57
Clinical features of NF?
- Swelling (80%)
- Pain (79%) - patients will complain of severe pain, often out of keeping with the overt clinical signs.
- Erythema (70%)
- Induration
There may be history of skin breach.
There will be rapid progression to skin crepitus, vesicles / bullae, and obvious skin necrosis.
58
Investigations in NF?
1) FBC:
- raised WCC
2) CRP: raised
3) U&Es:
- signs of worsening renal function
- hypnatraemia
4) lactate: raised
5) ABG: metabolic acidosis
59
Management of NF?
1) Surgical emergency - needs immediate resuscitation and debridement.
2) Urgent broad spectrum Abx
3) Resuscitation IV fluids (and catheterise patient)
4) Mark and time denote any area of redness or discolouration
60
What is the only definitive management of NF?
Surgical debridement
61
What is a DVT?
The formation of a thrombus (blood clot) in a deep vein, which partially or completely obstructs blood flow.
62
Give some risk factors for a DVT
1) male
2) increasing age
3) immobilisation e.g. hospitalisation, long haul flight
4) inflammatory state e.g. vasculitis, sepsis
5) malignancy
6) medication e.g. chemo, HRT, COCP
7) obesity
8) pregnancy
9) thombophilia
10) smoking
11) varicose veins
63
Why is pregnancy a prothrombotic state?
As there is venous stasis from the gravid uterus obstructing venous return, cardiovascular changes associated with pregnancy affect the endothelium and changes in the clotting cascade favour hypercoagulability.
64
What is a thrombophilia?
Thrombophilias are conditions that predispose patients to develop blood clots.
65
Give some examples of thrombophilias?
1) antiphospholipid syndrome
2) Factor V Leiden
3) antithrombin deficiency
4) protein C or S deficiency
5) hyperhomocysteinaemia
6) prothrombin gene variant
7) activated protein C resistance
66
What condition is antiphospholipid syndrome often associated with?
Recurrent miscarriage
67
What is Virchow's triad?
Virchow's triad encompasses the 3 changes that contribute to the formation of venous thromboses:
1) hypercoagulability of blood e..g factor V Leiden, malignancy, COCP
2) stasis of blood e.g. immobilisation
3) changes to endothelium e.g. smoking, HTN
68
Clinical features of a DVT?
- unilateral leg pain and swelling
- commonly found in lower leg
- pain exacerbated by exertion
- swelling usually confined to calves; may be pitting oedema
- skin changes e.g. dilated superficial veins
69
What may examination of the affected leg in DVT reveal?
- increased temp
- tender calf that is more solid in consistency
- tenderness on palpation
- difference in size of calves
70
How can leg swelling be investigated in a DVT?
Measure the circumference of the calf 10cm below the tibial tuberosity.
71
What size difference between calves in significant?
More than 3cm difference between calves is significant.
72
What is the key complication of a DVT?
PE (co-exists in 40-50% of patients).
73
If a patient is suspected of having a DVT, what is next step?
Wells score
74
What Wells score indicates that a DVT is likely?
2 or more
75
If the Wells score indicates that a DVT is likely (i.e. 2 points or more), what is next step?
Proximal leg US should be carried out within 4 hours.
76
How quickly should a leg US be done in a suspected DVT if the Wells score is 2 or more?
within 4 hours
77
If the proximal leg US is positive for a DVT, what is next step?
Anticoagulation
78
If the proximal leg US is negative for a DVT, what is next step?
D-dimer test.
A negative scan and negative D-dimer makes the diagnosis unlikely and alternative diagnoses should be considered.
79
After a positive Wells score (≥2), if if a proximal leg vein US scan cannot be carried out within 4 hours, what should you do?
Perform a d-dimer test and interim therapeutic anticoagulation administered whilst waiting for the proximal leg vein US scan (which should be performed within 24 hours)
80
What interim therapeutic anticoagulation is given in a suspected DVT whilst waiting for an US (if waiting time is >4 hours)?
DOAC e.g. apixaban
81
If the US is negative but the d-dimer is positive in a DVT, what is next step?
1) stop interim therapeutic anticoagulation
2) offer a repeat proximal leg vein ultrasound scan 6 to 8 days later
82
If the Wells score indicates that a DVT is unlikely (i.e. ≤1 point), what is next step?
Perform a d-dimer test (within 4 hours).
83
If the Wells score was ≤1 and the d-dimer is negative, what is next step?
if the result is negative then DVT is unlikely and alternative diagnoses should be considered
84
If the Wells score was ≤1 and the d-dimer is positive, what is next step?
proximal leg US scan within 4 hours
85
What is the cornerstone of VTE management?
anticoagulant therapy
86
1st line anticoagulant in confirmed DVT?
DOAC e.g. apixaban or rivaroxaban
87
1st line anticoagulant in suspected DVT whilst waiting for confirmation?
DOACs
88
1st line DOACs in DVT?
apixaban or rivaroxaban
89
2nd line anticoagulant in DVT if DOACs are not suitable?
LMWH
90
1st line anticoagulation in DVT if patient has severe renal impairment (e.g. < 15/min)?
LMWH
91
1st line anticoagulation in DVT if patient has antiphospholipid syndrome?
LMWH
92
What are the options for long term anticoagulation in DVT?
1) DOACs
2) LMWH
3) Warfarin
93
What is the anticoagulant of choice in DVT in pregnancy?
LMWH
94
How long should patient be anticoagulated for following a DVT?
Depends on whether it was provoked or unprovoked.
Provoked --> 3 months (3 to 6 months for people with active cancer)
Unprovoked --> 6 months
95
What are the 2 main complications of a DVT?
1) PE
2) post thrombotic syndrome
96
What is post thrombotic syndrome?
Complications following a DVT --> venous outflow obstruction and venous insufficiency result in chronic venous hypertension.
The resulting clinical syndrome is known as post-thrombotic syndrome.
97
What features may be seen in post-thrombotic syndrome?
1) painful, heavy calves
2) pruritus
3) swelling
4) varicose veins
5) venous ulceration
98
What are the 2 main methods of VTE prophylaxis in hospital?
1) mechanical
2) pharmacological
99
What are the 2 methods of mechanical thromboprophylaxis?
1) Antiembolic stockings (AES)
2) Intermittent pneumatic compression (IPC, more commonly used in theatre)
100
What is the typical pharmacological VTE prophylaxis?
LMWH
101
What is the typical pharmacological VTE prophylaxis in renal impairment (eGFR <30)?
UH
102
Who are anti-embolic stockings contraindicated in?
1) suspected or proven peripheral arterial disease
2) periipheral arterial bypass grafting
3) peripheral neuropathy or other causes of sensory impairment
4) any local conditions in which anti-embolism stockings may cause damage e.g. fragile 'tissue paper' skin, dermatitis, gangrene or recent skin graft
5) severe leg oedema
103
