Test 1.1 Flashcards
1
Q
What are the characteristics of a dysplastic nevus?
A
A dysplastic nevus is characterized by irregular borders, variable pigmentation, and atypical melanocytes. >5mm, elevated and flat areas
Dysplastic nevi may indicate an increased risk of melanoma.
2
Q
What is the most common mutation associated with melanoma?
A
BRAF (V600E) is the most common mutation associated with melanoma.
This mutation is typically found in non-chronic sun-damaged sites, particularly in superficial spreading melanomas.
3
Q
True or False: Melanoma is the most rapidly rising cancer in Caucasians.
A
True
There is a trend toward early detection, leading to thinner melanomas.
4
Q
What are the primary risk factors for melanoma?
A
Risk factors include:
* Genetic factors (e.g., inherited CDKN2A mutations)
* Environmental factors (e.g., UV exposure)
* Immunological response
Cumulative and short intermittent bursts of UV exposure are significant.
5
Q
Fill in the blank: The most common subtype of melanoma is _______.
A
Superficial spreading
This subtype may arise de novo or in association with a nevus.
6
Q
What is the typical age range for melanoma onset?
A
Mostly fourth decade onward
Peak onset for superficial spreading melanoma is between 40 to 60 years old.
7
Q
What is FAMMM syndrome associated with?
A
Inherited CDKN2A mutations
FAMMM stands for Familial Atypical Multiple Mole Melanoma syndrome.
8
Q
What type of melanoma is associated with chronic sun-damaged skin?
A
Nodular melanoma
NRAS mutations are commonly found in this type of melanoma.
9
Q
Which gene is linked to an increased risk of cutaneous melanoma and uveal melanoma?
A
BAP-1 (BRCA1-Associated Protein 1)
Germline loss-of-function mutations in BAP-1 are associated with worse prognosis.
10
Q
What are the characteristics of superficial spreading melanoma during its growth phases?
A
Irregularly shaped/variably pigmented macule during radial growth phase, becomes papulonodular during vertical growth phase.
This subtype has a predilection for the trunk in men and legs in women.
11
Q
True or False: Melanomas are more common in dark-skinned individuals.
A
False
Melanomas are most common in Caucasians; rare cases occur in dark-skinned individuals.
12
Q
What mutations are associated with acral and mucosal melanomas?
A
C-KIT and amplifications of CCND1/CDK4
These mutations are commonly found on chronic sun-damaged skin sites.
13
Q
A
14
Q
A
15
Q
A
16
Q
A
17
Q
A
18
Q
What is contact dermatitis?
A
Allergic or irritant acute or chronic skin rash related to substances to which the skin comes into contact.
19
Q
Define irritant contact dermatitis (ICD).
A
Chemical/irritant induced skin inflammation which is dose dependent, occurs immediately after exposure and occurs in all individuals exposed to the irritants.
20
Q
What percentage of all occupational skin diseases does irritant contact dermatitis account for?
A
80%.
21
Q
What is the pathogenesis of irritant contact dermatitis?
A
involves three main steps: irritation and disruption of the skin barrier, stimulation of the epidermal cells, and cytokine release leading to inflammation and skin changes.
Acute phase - tnf alpha/IL-6
Chronic phase - hardening affect with tolerance + hyperkeratosis
ICD occurs via a non-immunlogic
way + require no prior sensitisation
Atopic eczema is at risk.
22
Q
List common occupational risks associated with irritant contact dermatitis.
A
- Housekeeping
- Hairdressing
- Medical, dental, and veterinary services
- Cleaning
- Floral arranging
- Car maintenance
- Construction
23
Q
What are the clinical features of irritant contact dermatitis?
A
- Erythema
- Vesicles
- Erosions
- Crusting
- more sharply circumscribed compared to ACD
*more localised to area of contact than with ACD
24
Q
What is the commonest site for irritant contact dermatitis?
A
Hands.
25
What is the onset time for irritant contact dermatitis after exposure?
Onset within minutes, maximum a few hours.
26
What are other presentations of irritant contact dermatitis?
* Follicular and acneiform eruptions
* Miliaria
* Pigmentary changes (hypo- and hyperpigmentation)
* Granulomatous reactions
* Alopecia
27
What symptoms are typically associated with irritant contact dermatitis?
Pain and burning rather than itching.
28
True or False: Irritant contact dermatitis develops constitutional symptoms.
False.
29
Name some common agents that cause irritant contact dermatitis.
* Soaps
* Detergents
* Waterless hand cleaners
* Acids and alkalis (e.g., hydrofluoric acid, chromic acid)
* Industrial solvents (e.g., acetone, DMSO)
* Plants (e.g., Euphorbiaceae, Urticaceae)
30
What is the primary method for diagnosing irritant contact dermatitis?
History and examination.
31
What histological findings are associated with acute irritant contact dermatitis?
* Epidermal necrosis
* Neutrophils
* Vesiculation
* Necrosis
(Similar to ACD but no/rare eosinophils)
32
What is the treatment approach for irritant contact dermatitis?
* Identify and remove cause
* Wet dressings with Burow’s solution
* Topical or oral corticosteroids
* Topical calcineurin inhibitors
* Emollients
33
What does allergic contact dermatitis (ACD) signify?
Allergic (type IV) mediated immune response to inciting agent in sensitized individuals resulting in an eczematous skin rash.
34
What is the epidemiology of allergic contact dermatitis?
Under-reported; accounts for 7% of occupational dermatitis.
35
Describe the pathogenesis of allergic contact dermatitis.
Type IV immunologic response.
Hapten binding phase (initial step)
Contact allergen (hapten) penetrates skin barrier
Hapten is bound to a skin protein carrier
Sensitization (afferent) phase
Antigen presenting cells (including Langerhans cells) present the hapten protein complex to priming T cells
Generates hapten specific memory / effector T cells
Elicitation (efferent phase) (Allergy 2009;64:1699)
Repeat exposure to hapten elicits hapten specific memory / effector T cells
Elicits an inflammatory / cytokine response
Leads to tissue damage - clinical manifestation of allergic contact dermatitis (ACD), 48 - 72 hours after repeat exposure
36
What is the typical onset time for allergic contact dermatitis after initial exposure?
1 to 2 weeks. ?48-72hr
37
What are the clinical features of acute allergic contact dermatitis?
* Erythema
* Papules
* Vesicles
* Erosions
* Crusts
* Scaling
38
List common agents that cause allergic contact dermatitis.
* Nickel sulfate
* Balsam of Peru
* Fragrance mix 1
* Quaternium-15
* Neomycin sulfate
* Formaldehyde
* Cobalt chloride
* Thiuram mix
39
What histological findings are associated with acute allergic contact dermatitis?
* Spongiosis
* Intraepidermal intercellular edema
* Lymphocytes
* Eosinophils
40
What is the procedure for performing patch tests?
A series of allergens are applied, - to the back, on special tapes fitted with small aluminium discs (Finn chambers) that hold the individual allergens
Ideally the patch tests are applied when the dermatitis is inactive, but if the back skin is inflamed, the arms or abdominal skin can be used for application.
After carefully marking the position of the patch test panels, they are removed at 48 hours, and the skin inspected then and at D4-D7
During patch testing, it is best to:
Be taking less than 10 mg of oral prednisolone a day
Not be on an immunosuppressive agent that will reduce the reaction
Avoid potent topical steroids to the application site for three days before patch testing is commenced
Avoid bathing or showering the test area which will wash off the panels or the identification marking
Avoid excessive exercise that may dislodge the allergen tapes.
41
What are the types of patch tests available?
* European Standard Series: 52 allergens
* TRUE patch test: 28 allergens
* Other specialized series
42
What is the treatment for allergic contact dermatitis?
* Avoidance of allergens
* Soap replacement
* Emollients
* Topical corticosteroids
* Oral corticosteroids
* Other immunosuppressants
43
What is bacillary angiomatosis?
A bacterial infection caused by gram negative Bartonella henselae or Bartonella quintana
## Footnote
It is an emerging opportunistic infection often seen in HIV patients.
44
When was bacillary angiomatosis first described in the context of HIV?
1983
## Footnote
It was first noted as an opportunistic infection in HIV patients.
45
Who first described bacillary angiomatosis in South Africa?
Dr. Levy and Naylar in 1993
46
What is the epidemiological significance of bacillary angiomatosis?
It is a rare condition with increasing cases associated with the HIV epidemic
## Footnote
The mean CD4 count in associated cases is around 20.
47
What is the commonest form of Bartonella infection?
Cat scratch disease
## Footnote
It affects approximately 1 in 10,000 people in the US.
48
What type of organism is Bartonella?
An aerobic gram negative rodbacillus
49
Name four significant species of Bartonella affecting humans.
* Henselae
* Quintana
* Bacilliformis
* Clarigea (occasionally)
50
How is Bartonella infection transmitted to humans?
Either directly from a reservoir or via a vector
## Footnote
Common reservoirs include cats, humans, dogs, rats, and mice.
51
What is the reservoir and vector for Bartonella henselae?
Reservoir = cats; Vector = fleas
52
What is the reservoir and vector for Bartonella quintana?
Reservoir = humans; Vector = body lice
53
What are the clinical presentations of cat scratch disease?
* Erythematous papule/nodule (innoculation site)
* fever
* Localized lymphadenopathy
* May suppurate but often heals spontaneously
54
What are the symptoms of trench fever caused by Bartonella quintana?
* Fever (1 week)
* Headache
* Neck and back pain
* Endocarditis
55
What is oroya fever and how is it transmitted?
Acute disease caused by Bacilliformis transmitted via sandfly vector
## Footnote
Associated with a high mortality rate if untreated.
56
What characterizes verruga peruana?
Angiomatous, PG-like lesions that heal spontaneously, occurring weeks to months post acute infection
57
What percentage of bacillary angiomatosis cases is due to Quintana and henselae?
* 47% due to Quintana
* 53% due to henselae
58
What conditions are associated with bacillary angiomatosis?
* HIV
* Transplant
* Leukaemia
59
Describe the mechanism by which Bartonella affects the body.
Directly infects erythrocytes (by forced endocytosis) and endothelial cells, increasing production of VEGF leading to endothelial proliferation
60
What are the clinical appearances of bacillary angiomatosis?
* Pyogenic granuloma-like lesions
* Subcutaneous masses
* Plaques
* Ulcerations
*Papules and nodules, range in size from pinpoint to 10cm
Purple, violaceous, or bright red in colour
Single/multipre
Any skin or mucosal site can be involved, although rarely the palms and soles
(Extra cut sites can also be involved)
*polypoid with epidermal collarette
61
What is a common complication of bacillary angiomatosis in HIV patients?
*Bacteraemia affecting 50% of HIV+ patients
*tumour-like masses in other organs including the brain, bone, gastrointestinal tract, and respiratory tract with airway obstruction.
Liver involvement is called 'peliosis hepatis' or 'bacillary peliosis
*bleeding
62
What histological features are seen in bacillary angiomatosis?
*
1. Lobular proliferation of capillaries with ectatic vessels lined by prominent endothelial cells in edematous stroma
2. Neutrophils, lymphocytes and histiocytes are frequently present
3. Purplish grey bacterial colonies may be seen, especially near neutrophils
4. Peripheral collarette may be seen (low power histologic image mimics pyogenic granuloma)
5. Warthin-Starry special stain will highlight Bartonella organisms
63
What stain is used to identify bacillary angiomatosis?
Warthin Starry Stain
64
Why is culture not generally used for diagnosing bacillary angiomatosis?
It is very difficult and can take 4-8 weeks
65
What is the treatment for cutaneous bacillary angiomatosis?
Doxycycline 100mg bd or erythromycin 500mg qid for 3 months
66
What is the treatment approach for systemic involvement of bacillary angiomatosis?
IV therapy with gentamycin and/or rifampicin
67
What general preventative measures can be taken against bacillary angiomatosis?
* De-flea cats
* Avoid cat scratches or bites
* Human hygiene to avoid lice
68
Fill in the blank: Ongoing _______ is preventative for bacillary angiomatosis but not currently recommended.
rifampicin
69
True or False: Bacillary angiomatosis can be caused by both Bartonella henselae and Bartonella quintana.
True
70
71
72
73
74
75
76
77
Diagnostic methods for bacillary angiomatosis?
1)Culture: 2-6 week incubation, isolation is often unsuccessful in patients without systemic disease.
2) PCR-enzyme immunoassay is a quick identification method.Variable sensitivity and the need for highly specialized equipment and personnel make PCR somewhat impractical.
3) Serology for Bh is more practical than PCR. The two major diagnostic methods are indirect fluorescence assay (IFA) and enzyme immunoassay (EIA). Positive IgM EIA indicates acute disease.
*IgM antibodies do not last long (3 months), negative results do not exclude acute disease.
IgG antibodies also decrease with time,
Disadvantages of serology include variable sensitivity and specificity,not able to tell if active and previous infection, and occasional cross-sensitivity with other Bartonella species.
In immunosuppressed patients, there are often no detectable antibodies.
The diagnosis of BA is thus mainly based on clinical assessment and histopathologic findings; laboratory evaluation is used to confirm initial suspicion.
78
79
What is relapsing polychondritis?
A rare autoimmune disorder characterised by recurrent episodes of inflammation and destruction of cartilaginous tissues.
80
Which areas of the body are most commonly affected by relapsing polychondritis?
* Cartilage in the ears
* Nose
* Trachea
* Joints
81
What are the common symptoms of relapsing polychondritis?
* Pain
* Swelling
* Stiffness
82
What is the estimated incidence of relapsing polychondritis?
3.5 cases per million people per year.
83
At what age is relapsing polychondritis most prevalent?
Between the ages of 40 and 60.
84
Is there a gender or ethnic predilection for relapsing polychondritis?
No.
85
What are the autoimmunity factors involved in relapsing polychondritis?
* T lymphocytes
* B lymphocytes
86
What do T lymphocytes produce that contributes to inflammation in relapsing polychondritis?
* Tumour necrosis factor-alpha (TNFα)
* Interleukin 1 (IL-1)
87
What is auricular chondritis?
Inflammation of the cartilage of the ears.
88
What percentage of patients experience auricular chondritis?
Up to 90%.
89
What is nasal chondritis?
Inflammation of the cartilage of the nose.
90
What percentage of patients experience nasal chondritis?
Up to 50%.
91
What deformity can result from nasal chondritis?
Saddle nose deformity.
92
What are common ocular complications associated with relapsing polychondritis?
* Scleritis
* Episcleritis
* Conjunctivitis
* Iritis
93
What complications can arise from respiratory involvement in relapsing polychondritis?
* Airway obstruction
* Chronic bronchitis
94
What are the complications of relapsing polychondritis?
* Respiratory: airway obstruction, chronic bronchitis
* Cardiovascular: valvulopathies, aortopathies
* Ocular: scleritis, episcleritis
* Auditory: hearing loss, vertigo, tinnitus
* Neurological: spinal cord compression
* Musculoskeletal: arthritis, joint deformities
* Renal: glomerulonephritis, kidney failure
95
What tests are used to diagnose relapsing polychondritis?
* Clinical features
* Blood tests (autoantibodies, inflammatory markers)
* Imaging (MRI or CT)
* Tissue biopsy
96
What are the McAdam's diagnostic criteria for relapsing polychondritis?
At least 3 of the following: * Bilateral auricular chondritis
* Nasal chondritis
* Ocular inflammation
* Respiratory tract chondritis
* Vestibulocochlear dysfunction
* Seronegative inflammatory polyarthritis
97
Name two alternative diagnostic criteria for relapsing polychondritis.
* Positive histopathological confirmation
* Steroid or dapsone-responsive chondritis at 2 or more different anatomical sites
98
What is the primary treatment for relapsing polychondritis?
Systemic corticosteroids.
99
What are some immunosuppressive agents used in treatment?
* Dapsone
* Colchicine
* Azathioprine
* Methotrexate
* Cyclophosphamide
* Hydroxychloroquine
* Ciclosporin
* Infliximab
100
What is the general outcome for relapsing polychondritis?
Variable prognosis depending on severity and organ involvement.
101
What is a major cause of death in patients with relapsing polychondritis?
Respiratory failure.
