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Flashcards in Infections Deck (67):

What is this?

What is its pathology?

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Herpetic Whitlow

Viral infection of the finger by Herpes Simplex 1- HSV1


Who is hepetic whitlow common in?

What is its pathphysiology?

Dental / medical personnel

Commonly effects toddlers and preschool children

viral shedding occurs with vesicles forming bullae


What are the symptoms and signs of someone with herpetic whitlow?

Intense burning then erytherma, malaise

O/e= erytherma then small vesicular rash

over 2 weeks vesicles may merge to -> bullae 

Fever and lymphadenitis

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How is hepetic whitlow confirmed?

TZANK smear

Diagnosis confirmed by culture, antibody titers or Tzank smear


How is this treated?

What are the complictions?

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1) Non operative and Acyclovir

standard tx- resolution 7-10 days

acyclovir may reduce time of symptoms

2) Operative = AVOID as- associated with superinfections, encephalitis and death!!

Complications include SUPERINFECTIONS- may require further antibiotics oral- pencillinase resistance for 7-10 days


What is this?

What is its incidence?

What is it's pathology?

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Most common hand infection- children and women (3:1 cf males)

Most commonly affects the thumb

Break in seal between nail fold and plate allows bacteria to gain entry- result of nail biting or manicures


What is the common organism in acute and chromic paronychia?


Adults- Staphyloccus aureus

Children/ Diabetics-mixed oropharyneal 


Candida albicans- common diabetics, often unresponsive to antibiotics




What are the causes of acute paronychia?

Nail biting


Thumb sucking


What are the causes of Chronic paronychia?

What are the risk factors for developing chronic paronychia?


Occupational exposure to water and irrants acid/alkali

RF= Diabetes



Retroviral drugs- Indinavir= HIV +ve pts.* 

*Resolves on withdraw of medication




What is the role of the nail organ?

Adds Stability to finger tip as counterforce to finger pulp

Thermoregulation- glomus bodies of nail/ nail bed

Extended Percision Grip- opposing thumb/index nails to remove a splinter



What is the nail plate made of and how much does it grow?

Where does it grow from

Made of keratin

Grows 3mm/ month, faster in summer

fingernails row faster than toes ( finger nails 3-6 months to regrow, toes 12-18 months)


Growth part is under eponychium

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What are the symptoms of acute paronychia?


Nail fold tenderness



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What are the symptoms of chronic paronychia?

RECURRENT Boats of low grade inflammation


What do you find on examination of

1) acute paronychia and 2) chronic paronychia?

1) acute= Fluctuant

Nail plate discolouration- green= pseudomonas

2) Chronic ( see pic)- Nail plate hypertrophy- fungal infection

Nail fold blunting and retraction after rpt boats of inflammation

Prominent transverse ridges on nail plate

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What are your differential diagnosis of a person with acute paronychia?

Herpetic whitlow




Glomus tumour

Mucous cyst


How do you tx acute paronychia?

Non operative- > Swelling but no fluctation= Warm soaks, oral antibiotics ( augmentin/clindamycin) and avoid nail biting

Operative= fluctuation=  Incision and drainage with partial or total nail bed removal



How do you tx chronic paronychia?

Non operative- warm soaks, avoid finger sucking, topical antifungals ( miconazole)- rarely antibiotics effective

Operative = Marsupialization ( See pic)= Excision of 3mm dorsal eponychrium crescent shape down to level of Germinal matrix ) combine with nail plate removal  =Heal by secondary intention 

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Decribe your operative teachnique for incision and drainage of an acte paronychia with partial nail removal?

Incision into sulcus between lateral nail plate and lateral nail fold


preserve Eponychial fold by placing materials (removed nail) between skin and nail bed

If abscess extends proximally over eponychium (eponychia), a separate counterincision is needed over the eponychium

Obtain gram stain and culture



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What are the complications of paronychia?

Eponychia- spreads to eponychium

Run around infection- both lateral folds involved

Felon- spreads to volar pulp- I& D required

Flexor tenosynovitis- volar spreads to felxor sheath

Subungual abscess- floating nail


What is this?

How does it occur?

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A Felon

Infection of the volar pulp of the fingertip

Local spread from paronychia


Penetrating injury/ needle stick


Describe the anatomy of the pulp?

multiple small compartments of subcutaneous fat separated by fibrous septae between the distal phalanx and dermis

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What is the pathology of a felon?

Swelling and pressure within micro-compartments, leading to "compartment syndromes" of the pulp


What are the causative organisms?

Staphylococcus aureus- most common

Gram negative organism- immunosupressed

Eikenella corrodens- in diabetics



What are the symptoms of a felon?

What are the signs ?

Pain and swelling of the finger pulp

Tenderness on palpation of the pulp


How do you tx a Felon?

Operative- incision and drainage

Due to risk of finger tip compartment syndrome


Can you describe the technique of incision and drainage of a Felon?


Keep incision distal to DIP crease -T
o prevent DIP flexion crease contracture and prevent extension into flexor sheath.

Mid lateral approach - see picture below- Indicated for deep felons with no foreign body and not discharging.

Incision on ulnar side for digits 2,3 and 4 and radial side for thumb and digit 5 (non-pressure bearing side of digit)

Longitudinal approach ( see pic) most direct)

Indicated for superficial felons, foreign body penetration or visible drainage .

AVOID FISH MOUTH INCISIONS-> unstable fonger pulp

DOUBLE LONGITUDINAL or transverse incision - injury to digital nerve and artery



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Can you describe the technique drainage of a Felon and what to avoid?

Avoid violating flexor sheath or DIP joint to avoid spread into these spaces

Aim to Break up septa to decompress infection and prevent compartment syndrome of fingertip 

don't forget gram stain and cultures

Leave wound open to allow drainage!

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What are the complications of a felon?

Finger digitial tip necrosis

Finger tip compartment syndrome

Flexor tenosynovitis




What types of bites are common? Which cause infection?

How does the patient present?

Dog and cat bites

Cat bites more frequently -needle like teeth -> deep penetration wound so high suspicion required



Wound to arm/ hand

local or systemic sepsis

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What are the common pathogens?

Pasterella Multicoida- 80% pt with cat bites

Staph aureus

Streptococcus alpha haemolytic





What is the pathology of dog and cat bites?

Dog bites- 

Cause crush, puncture, avulsion, tears and abrasions 
large dogs' jaws exert >450lbs/ square inch  
more likely to cause structural damage to nerves, vessels, joints

Cats have fine sharp teeth-> pentrating joints.

Puncture wounds that close immediately-> septic arthritis and osteomyelitis


What is the treatment of a cat/dog bite?

Thorugh cleaning of wound with saop or iodine - shown to dramatically reduce  the devlopement of rabies in those bitten by infected animals

Non op Copious irrigation, appropriate antibiotics, tetanus and rabies prophylaxis

Antibiotics- amoxicillin/clavulanic acid effective against Pasteurella multocida, 

ce furoxime or 


Surgical debridment if crush/devitialised tissue, abscess,  bites to pup space, flexor tendon, joinspace, deep space of hand, septic arthritis.




What is rabies?

Caused by a rhabdovirus
common animal carriers include dogs, raccoons, bats, foxes

Increased risk with open wounds, scratches/abrasions, mucous membranes

fatal bites associated with large aggressive dogs, small children, head and neck bites

prophylaxis is = human diploid cell vaccine and human rabies immunoglobulin

Immobilise limb and elevate



What is the incidence of human bites?

Males more affcted then females

Often occur around 3/4th MC after a fight- from direct punch another individual

Actual human bite



What is the pathology of a fight bite?

Tooth pentrated capsule of MCPJ

bacteria flora from mouth enter joint->infection

Bacteria get trapped in joint as it is flexed and caught unde extensor tendon


What organisms are common in human bites?

Alpha haemolytic strep *

Staph aureus*

Eikonella corrodens in 7-29%

*= most common



What other pathology is associated with fight bites?

Extensor tendon lacerations


What are the signs and symptoms of a fight bite?

What invetsigations would be orderd?

1) Pain, swelling to hand with puncture wound to 3/4 MC

Purulent discharge

Pain with passive and active rom

Test flexor and extensor tendons

2) xray hand to exclude any foreign bodies- teeth!

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What is the TX for fight bites?

Operative- Incision and drainage

Debridement of wound

Open capsule

Leave wound open for drainage

Gram stain and culture

Iv antibotics for 48 hrs then change to oral for 5-7 days -target organism - amoxicillin/clavulanic acid (augmentin)



What is this ?

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Pyogenic flexor tenosynovitis

Infection of the synovial sheath that surrounds the flexor tendon


What is the pathology of flexor sheath infections?

1) Penetrating injury

2) Spread from felon, deep space infection, septic arthritis


What are the organims involved in flexor sheath infections?

Staphylococcus aureus- most common

Gram negative/ Anaerobic bacteria= assoc HIV/ diabetic/ MRSA infections/ farmyard/ animal bites


What are flexor sheath infections commonly associated with?

Horseshoe abscess

Many individuals have a connection between the sheaths of the thumb and little fingers at the level of the wrist   I

nfection in one finger can lead to direct infection of the sheath on the opposite side of the hand resulting in a condition known as a "horseshoe abscess' 


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Can you draw the flexor tendon sheaths?

Can you describe their role

See pic below

Tendon sheaths function to allow glide of tendons, provide nutrtion by bathe in synovial fluid and protect the flexor tendons

They extend DIPJ-  midpalm in index, middle and ring fingers

From DIPJ to wrist ( ulna bursa) in little finger

from IPJ to wrist ( radial bursa) in thumb

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What are the signs of a flexor sheath infection?

Kanavel signs - 4 signs in total

1) Flexed position of  involved digit 

2) Fusiform swellling of digit 

3) Tenderness to palpation over tendon sheath

4) Marked Pain on passive stretch/extension


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What are the normal sypmtoms of a flexor sheath infection?

Increase pain 48 hrs- localised to palmar aspect of digit



Is imaging helpful in flexor tenosynovitis?

Xrays no use

MRI cannot distinguish infectious flexor tenosynovitis from inflammatory but may help determine the extent of the ongoing process


What is the treatment of flexor tenosynovitis?

Non op: in early intervention= Admit, elevation and iv antibiotics, close obeservation- surgery if no improvement in 24hrs

Surgery= incision and drainage of flexor sheath iv antibiotics following op to avoid ADHESIONS in flexor tendons


Describe the technique for closed drainage of flexor tenosynvoitis?

Palmar incision
- transverse incision is made just proximal to distal palmar crease, over the infected tendon; 

- spread thru the palmar aponeurosis; 
- make incision just proximal to A1 pully and enter into sheath; 
Distal incision: 
- finger incision may be made either dorslateral at level of middle phalanx or directly on palmar surface at this level; 
- incision can also be made in the distal flexor crease of digit; 
- distal sheath is exposed thru ulnar midaxial incision & opened; 
- enter sheath between annular pulleys, insert small paeds feeding catheter-  (size no. 5 Fr) or 16 gauge catheter and irrigate +++

Iv antibiotics for 48 hrs then oral 2 weeks

Hand physio post to prvent adhesions


What is the treatment if need to open tendon sheath?

Brunner lines in finger to open skin then incise tendon sheath prox A1 pulley and annular pulleys distally

According to Hand Surgery Update 3 2003, Trumble states, open sheath irrigation has been replaced largely by closed sheath irrigation. These authors cite a retrospective study that showed no statistical difference in resolution of infection using open sheath irrigation or closed sheath irrigation, however, there was a trend towards more frequent complications and reoperations in the open drainage group.


What is this?

Where can these be located?

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possibly a Deep space infection

Hypothenar, Thenar and Midpalmar space

other DD not in this picture

Collar button infection- ( abscess in webspace between fingers)



Can you describe the thenar, midpalmar and hypothenar spaces?

Thenar= A bursa (potential space) just palmar to adductor pollicis and dorsal to flexor tendons. 

Separated from midpalmar potential space by a fascial septum 

Midpalmar= dorsal and radial to hypothenar space 

Hypothenar space= palmar to 5th MC, dorsal and radial  to hypothenar fascia, ulnar to hypothenar septum

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Which space is commonly infected in deep infections?

What are the signs and symtpoms?


hx of penetrating injury to hand

Worsening swelling and pain

O/E pain on  thumb flexion- thenar space finger 

pain on little finger flexion- hypothenar

pain on flexion middle, ring index- midpalmar


What is the treatment of deep palmar infection?

Operative- incision and drainage

Use volar and dorsal incisions for collar button abscesses

Avoid skin in actual web space

Thenar space release-

dorsal incision (can spread to involve 1st dorsal interossei) or palmar incision

Midpalmar releasetransverse incision across palm

webspace infection- incisions dorsal and volar to alow adequate drainage. Not transverse -> contractures





Who do Atypical mycobacterium infections affect?

What is the location of the infection?

Marine workers

Hand and wrist in 50% of cases

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What is the pathophysiology of atypical mycobacterium?

Incubation period 2 weeks to 6 months

Average time to diagnosis and tx is 1 year


What are the types of organism causing atypical myocbacterium infections?

Mycobacterium marium*- injuries in marine environments/aquariums

mycobacterium avium-intracellulare*

*most common

M. kansasii - i soil



Describe the signs and symptoms of atypical mycobacterium infection?

How is it diagnosed?


Symptoms:cutaneous rash with discomfort

signs: papules, ulcers and nodules- indistinguishable to tuberculous mycobacterial infection

Dx by Culture requiring Lowenstein-Jensen culture agar at 30-32 degrees


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How is atypical mycobacterium treated?

NON OP If diagnosed early  with 

ethambutol, tetraycline, trimethoprim-sulfamethoxazole, clarithromycin, azithromycin 

add rifampin if osteomyelitis present 

surgical debridement and antibiotics for later disease 


What is this?

What is the incidence?

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Fungal infection

serious in immunocompromised patients

Rare but common to have it in areas of macerated skin.


Fungal infectsions can be divided into 3 caterogeries, what are they?

Cutaneous - involving nail bed-Onychomycosis 

Subcutaneous - sporothrix schenckii from rose thorn prick

Deep-orthopaedic manifestation= tenosynovial 

septic arthritis, 





What is this? 

What causes it?

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A Superficial fungal infection of the nail

Trichophyton rubrum=>a destructive nail plate infection


Candida=>chronic infection of nail fold



How is Onychomycosis treated?

Topical antifungals 

Nail plate removal

systemic griseofulvin or ketoconazole if retractible disease

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What is this infection?

What causes it ?


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Sporothrix schenckii

A common soil bacteria 

Rose thorn in classic mechanism of subcutaneous transmission



What are the signs of Sporothrix schenckii?

How is diagnosis confirmed?


A small papule where pentration of skin made then additional lesions in region of lymphatic tissue ( see pic)

S schenckii is isolated at room temperature on Sabouraud dextrose agar

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How is Sporothrix schenckii treated ?

Oral itraconazole for 3 to 6 months


Can you name any fungi that cause deep infections?

Histoplasmosis-> sublclnical symptoms/ tenosynoval - found in rivers-tx amphotercin B, surgical debridment and tenosynovectomy

Coccidiomycosis- > arthritis/synovitis/ periarticular arthritis

tx with amphocterin B and surgical debridement