Bacterial and Viral Infections Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

What are commensal bacteria and give some examples of commensals?

A

Commensal bacteria are bacteria that are found on the skin but not normally causing disease.

Staphylococci

Micrococci

Cornyebacteria

Propionbacteria

Note Staph aureus is considered pathogenic but it can be commensal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the two most common causative bacterias in skin disease.

A

Staph. aureus

Group A Streps (Strep. Pyogenes) this is always considered to be pathogenic. Causes an acute onset and spreads rapidly.

S. aureus and strep. pyogenes cause similar infections and can cause co-infections.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What does the following image show, what is the likely causative organism, how does it present and how would you treat?

A

Folliculitis: infection of hair follicles.

Characterised by follicular pustules.

S. Aureus

Treat with flucloxacillin or if unresponsive a longer course of tetraccyclines.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What does the following image show, what is the likely causative organism, how does it present and how would you treat?

A

Impetigo.

Usually caused by s.aureus but can be caused by strep.pyogenes or can a dual infection.

Contagious superficial pyogenic (pus) skin infection. Characterised by a golden crust.

Can be treated with topical (fucidic acid) or oral antibiotics (flucloxacillin).

Also patient shouuld soak off the golden crust with soap and water.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What does the following image show, what is the likely causative organism, how does it present and how would you treat?

A

Ecthyma.

Start off as pustule or blister but become indurated (hardenned).

Signifys a deeper infection again caused by staph or strep.

It is more common in diabetics or those with immunosupression.

Needs a long course of oral antibiotics.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What does the following image show, what is the likely causative organism, how does it present and how would you treat?

A

Cellulitis

Staph or strep (mixed)

Gross oedema, erythema, tender, pain, heat. Poorly demarcated. Systemic signs: fever, malaise, systemic upset

Systemic antiobiotics oral or IV - benzylpenicillin/Fluclox

Worth checking for tinea pedis as this is a common portal of entry.

Bilateral cellulitis is very rare and therefore you should consider alternative diagnoses if the oedema is bilateral.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What does the following image show, what is the likely causative organism, how does it present and how would you treat?

A

Erysipelas

Usually caused by Grp A Strep or Haemophilus Influenzae (<2yrs)

Well demarkated, erythematous plaque on one side of the face. Tender, fever, malaise.

Again treat with systemic antibiotics - High dose IV/oral benzylpenicillin 10-14 days

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What does the following image show, what is the likely causative organism, how does it present and how would you treat?

A

Scalded Skin Syndrome

Fever and redness followed by peeling causing erosions on the face and body.

Caused by Staphylococcal toxins.

Identify the underlying cause may be something as trivial as simple impetigo.

Treatment is with IV flucloxacillin, fluids, analgesia and emollients.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe erythema nodosum, and state which infection it is associated with?

A

Red tender nodules on the shins.

Streptococcal infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Which infections are erythema multiforme associated with?

A

HSV and Streptococcal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What infections is a purpuric rash associated with?

A

Post streptococcal in which case it is known as Henoch Schonlein Purpura

Meningococcal sepsis

Hepatitis C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the different hypersensitivity reactions to the streptococcal antigen?

A

Erythema Nodosum

Erythema Multiforme

Vasculitis and Glomerulonephritis

Guttate Psoriasis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What does the following image show, what is the likely causative organism, how does it present and how would you treat?

A

Necrotising Fasciitis

S.aureus and strep.

Very unwell, high fever, severe pain in the affect area, with the rash progressing rapidly over a few hours.

Emergency debridement involvement of plastics and a long course of IV antibiotics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What does the following image show, what is the likely causative organism, how does it present and how would you treat?

A

Cold sore

HSV

Vesicles usually on the lip but reappears at the same point.

Topical aciclovir can help if it is give immediately but it is a self limiting infection.

Note HSV 1 usually affects lips

HSV 2 usually affects the genitals but there is crossover

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What does the following image show, what is the likely causative organism, how does it present and how would you treat?

A

Eczema herpeticum

HSV infection superimposed on eczema

Monomorphoc vesicles which crust or become eroded.

Treated with systemic aciclovir, IV if severe.

Carrys a mortality risk.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What does the following image show, what is the likely causative organism, how does it present, how is it transmitted and how would you treat - include incubation period?

A

Chicken Pox

Varicella Zoster Virus

Widespread vesicular rash, leading on to crusted papules as well as high fever.

Virus is transmitted in respiratory droplets and has an incubation of 14-17 days. Patients are contagious for one week from 2 days prior to the onset of the eruption.

In children mild and self limiting.

Internal organ involvement can happen in adults or immunosupressed in this group treat with systemic aciclovir.

17
Q

What does the following image show, what is the likely causative organism, how does it present and what are the complications?

A

Shingles

VZV

VZV lies dormant in the dorsal root ganglion following primary infection. It may later reemerge causing an eruption of vesicles in a dermatomal distribution.

Usually settles on its own, but it can become superimposed with infection.

Also be wary of shingles on the nose as this implies involvement of the nasocilliary nerve these patients are likely to cause ocular involvement which can be sigt threatenning. (hutchingson’s sign)

Also be wary of shingles around the external auditory meatus or pinnearas it may indicate the ramsay hunt syndrome (facial palsy, hearing loss and vertigo)

Other complications of shingles include post herpetic neuralgia and encephalitis.

18
Q

What is the lesion, the causative organism and treatment?

A

Common Wart

Human Papilloma Virus 2

Cryotherapy

But also topical paints (salicylate and lactic acid), C and C, Formalin soaks

19
Q

What is the lesion, the causative organism and treatment?

A

Mosaic Warts

Human Papilloma Virus

Curratage (difficult to treat)

20
Q

What is the lesion, the causative organism and treatment?

A

Plain Warts (flatter and often coalesce)

Human Papilloma Virus 3

Cryotherapy

Face and Back of hands

21
Q

What is the lesion, the causative organism and treatment?

A

Filliform Wart (finger like projections)

Human Papilloma Virus

Cryotherapy or curratage

Note all warts are self limting although they are often treated as they take a long time to spontaneously heal.

22
Q

What is the lesion, the causative organism, how does it present and what is the treatment?

A

Molluscum Contagiosum (Pox Virus)

Molluscipox virus type 1 or 2 that affects skin

Umbilicated papules on trunk, inflammation suppuration and intense erythema around indiviual lesions

common in children + young infants

It is self limiting and therefore not usually treated (although cryotherapy/topical podophylin in adults)