Hand Infections Flashcards
How do you classify hand infections
- Acute vs chronic
- By anatomic site
- skin, subcut, deep space, tendon, muscle,
- By organism
- bac, viral, fungal, parasitic, protozoal
- By etiology
- trauma, human/animal bute, IVDU, immunocompromise, post-op
What special tests are used for identification of fungal, mycobacteria and HSV infections?
- Fungal: KOH, Giemsa, Silver stains
- Hyphae, spores, mycelia
- Mycobacteria/Nocardia: Ziehl-Niessen stain
- HSV: Tzank smear
What are treatment principles of hand infection
- Debridement
- I&D
- Splint, Elevation, Rest
- Antibiotics
- Early rehab
- For surgical Tx
- dont exsanguinated for tourniquet
- local takes longer to work
- plan for extension of incisions not over NV bundles
- plan for multiple washouts
- cultures from intraop samples
- Joints - avoid aspiration over area of cellullits
- Send joint fluid for cell count, C&S, Glc, protein
What are approaches to joints for washout of infection
- Radio carpal jt - b/w 3/4 compartments
- MCP jt - dorsal and split extensor
- PIP jt - midaxial, split TRL, protect central slip
- DIP jt - H or Y incision, protect TT
What are mimickers of infection to keep on DDX
- Gout/Pseudogout
- sent jt aspirate for crystals, Rheum referral
- Acute calcific tendonitis
- NSAIDs, Rheum referral
- FB
- Pyogenic granulosum
- excise and cauterize base
- Pyoderma gangrenosum
- macult->papule w raise violaceous borders, associated w UC.
- Do not excise - treat w steroids and wound care
- Spider bite
- brown recluse spider leads to ST necrosis
- Metastatc or 1’ tumor
- SCC BCC melnaoma KA
- DP primary site for bone mets (source thyroid, prostate, breast, lung, kidney, colon
What are the 3 potential spaces for infections in the hand and forearm
- Hand
- thenar
- hypothenar
- midpalm
- Forearm
- Paronas space
What are the 9 spaces (includes 4deep and 5 superficials)
DEEP
- thenar
- hypothenar
- midpalm
- Paronas
Superficial
- dorsal subcutaneous
- dorsal subaponeurotic
- interdigital webspace
- radial bursa
- ulnar bursa
Define boundaries of thenar space deep infection, symptoms/signs and treatment
THENAR SPACE
- Roof: D2 flexor sheath and palmar fascia
- Floor: Adductor fascia
- ulnar border: D3 MC vertical septum to palmar fascia
- radial border: confluence of AddP fascia and muscle at insertion to PP
Findings: thumb abducted, pain w opp/abd
Tx:
I&D across thenar crease and dorsal webspace
Define boundaries of midpalm space deep infection, symptoms/signs and treatment
MIDPALM - deep to flexors
Floor - Volar IO and MC 3,4,5
Roof - flexor sheaths 3,4,5 and palmar aponeurosis
Radial - vertical septum at D3 MC
Ulnar - hypothenar septum at D5 MC
Finding - loss of palmar concavity
Tx
I&D with incisoin from D3 webspace to pisiform
Define boudaries of Paronas space, findings and Treatment
- volar wrist b/w PQ and long flexors
- communicates w radial and ulnar bursa - horseshoe abscess-
- proximal extend to FDS insertion
What are complications of a hand infection
EARLY
- skin slough
- extension to adjacent structures - OM, SA, tendon rupture, vessel thrombosis
- amputation
LATE
- recurrence
- stiffness
- degenrative arthritis
What is your management of a felon
= subcutaneous abscess of the finger pulp
Compx: OM, skin/pulp necrosis
Tx - I&D - incise on non-dominent side, break apart septae, keep intact flexor sheath, Abx, pack tid
–> can also consider longitudinal incision over most pointing aspect of felon
What is your management of a herpetic whitlow
= vesicles 2’ to HSV1 (oral) HSV2 (genital)
Dx: Tzank smear of vesicle media or IF anti-HSV Ab
Tx: no I&D, dry gauze, topicla pancyclovir if immunocompromised, acyclovir if prodrome
What is your DDX of acute suppurative flexor tenosynovitis
- gout/psudogout
- inflammatory tenosynovitia
- herpetic whitlow
- felon
- abscess
What is your management of acute flexor tenosynovitis suppurativa
Early
- IV abx, splint elevate observe and reqeunt reassessment
Late
- Catheter irrigation - incise prox to A1 distal to A4, irrigate w tid dressing change
- ABX: ???
- Early ROM
What is your management of a dog/cat bite
History
tetanus
Rabies immunization
Culture
copious irrigation
delayed 1 wound healing
Xray to r/o FB
Abx: amox-clav (clavulin) OR if pen allergy, clindamycin + septra
What bacteria are associated w dog and cat bites?
DOG
- s. aureus, s. viridans
- bacteroides
- pasteurella multicoda GNB
- capnocytphaga canimorsus
CAT
- Pasteurella multicoda most common
plus similar to above
- cat scratch - rochalimaea henselea
What is your management of a human bite/fight bite
History
Tetanus
Culture
Xray for air in jt/FB
Clavulin OR if pen allergy, clindamycin + septra
I&D if joint involved, packing, delayed extensor repair
* most common pathogens
- aerobics: s. aureus, epidermidis, strep
- anaerobic: bacteroides, peptococcus, peptosctreptococcus, Eikenella corrodens GNR,
What is your management of a necrotizing fasccitis
- ABCs, ICU consult
- Culture wound/blood
- CBC, lytes Cr, LFT, CK, INR/PTT, lactate
- Or - debridement devitalized tissue, repeat OR 24-48hrs later
- IV abx - vanco+piptazo+clinda. Use 900mg IV q8h clinda for anaerobe, 4mu q4h penicillin for GAS
What are complications of septic arthritis
- Stiffness, adhesions
- OM
- degenerative arthritis
- boutonniere, mallet (pus erodes dorsally)
- amputation
What will you send from sample for chronic wound to determine etiology
- 1/2 in formalin (histo)
- 1/2 not in formalin for 8pack micro diagnostic work-up:
- Smears and stains:
- Gram stain
- AFB (ziehl neelsen)
- Fungal stain (KOH)
- Culture and sensitivity
- aerobic
- anaerobic
- tuberculous mycobacteria at 37’
- non-tuberculous mycobacteria at 30’ (M.marinum) and at 42 (M.xenopi)
- Mycotic culture media (Sabouraud dextrose agar) for sporotrichosis
What is your management of cat scatch disease?
- Bartonella
- Inoculation 1-3wks
- lymphangitis, regional LAD
- Self limiting
What is your management of Actinomycosis?
- Actinomycosis Israelii
- H&N, oral lesion ->abscess, + sinuses +sulfur yellow granules expressed, INVASIVE
- Biopsy, Penicillin 6-12mths
What is your management of Tularemia?
- Francisella Tularensis
- Hx of animal bite non responisve to regular treatment w clavulin - >papule to ulceration/necrosis/lymphangitis
- Tx: streptomycin/gentamycin
What necrotizing infection occurs from seawater contact/contamination?
- Vibrio vulnificans -> necrotizing soft tissue infection - GN anaerobic rod
- Tx: surgical debridement, +/- fasciotomies, DOXYCYCLINE
What is your treatment of onychomycosis?
- Tinea infection - Trichophytan
- nail thickening/seperation - occurs in DM/immunosuppressed/scleroderma
- Dx: KOH of scrapings
- Tx: antifungals topical, removal nail if persistent
What is your differential of a ulcerated verrucous nodule with lymphangitis wks-mths post injury, Hx of farming/gardening?
DDX
- nocardiosis (dirt/soil)
- tularemia (animla contact)
- atypical mycobacteria
- sporotrichosis schenckii (gardening)
What is your management of sporotrichosis?
- sporothrix schenkii (fungal)
- ulcerated raised verrucous nodule with lymphangitis, wks to months post injury while gardening
- Dx: culture in Sabourard media
- Tx: I&D of abscess if present, + amphotericin or itraconazole
What is your management of aspergillosis
- Aspergillosis funigatis (hyphae)
- necrotizing ulcer - usually at IV site - in immunocomp.
- DDx nocardia, mucor
- Dx: KOH prep
- Tx - debridement w clear margins and amphotericin B
What is your management of mucormycosis
- Mucorales rhizopus/rhizomucor
- Triad: DM, gangrene, thrombosis + black discharge
- Dx: biopsy
- Tx:debridement + IV amphotericin
What is your management of mycobacterial infection?
- MOST COMMON CHRONIC HAND INFECTION
- TYPICAL: M. tuberculosis, bovis
- ATYPICAL: M. marinum, Kansaii
- Chronic granuloma + caseation
- Dx: biopsy, culture (ZIehl Niessen stain)
- Tx: Isoniazid, Rifampin, Ethambutal, Pyrazinamide
Where can tuberculosis infection occur and how does tx differ?
- Cutaneous TB (most common site)
- M. marinum, tuberculosis
- TB tenosynovitis
- M. Marinum most common
- TB arthritis
- M. Marinum most common
- TB osteomyelitis
What is your management of cutaneous TB?
- M. tuberculosis/marinum - Typical Myco infx
- Hx of fresh water exposure
- pustules on digits, LAD
- Dx: skin biiopsy for ZN stain (AFB), C&S for mycobac
- Tx:
- Anti-tb Tx with Isoniazid, Rifampin, Ethambutal, Pyrazinamide
What is your management of TB tenosynovitis
- M. Marinum most common
- mimicks RA synovitis, commonly on flexors
- Dx. biopsy for AFB, C&S
- Tx: Synovectomy, Anti TB Tx: isoniazid, rifampin, ethambutal, pyrazinamide
What is your management of TB arthritis and osteomyelitis?
- M. Marinum most common
- WRIST most common for arthritis- with little pain, mainly swelling and decreased ROM - subchondral erosions draining sinuses
- MC and Phalanges most common for OM - bone loss, cystic lesions, pathologic fractue
- Tx arthritis: control infection with antiTB meds then arthrodesis or arthorplasty
- Tx OM: Anti TB meds
How do you classify fungal infections of the hand
By location
- cutaneous (skin, nail)
- Subcutaneous (sporotrochosis, chronic paronychia)
- deep (mucomycosis)
What are three cardinal signs of Hansen’s Diseasae (HD) - leprosy
- Anesthetic skin patch
- Nerve thickening
- hypopigmented skin lesions (nodules)
What is the pathophysiology of HD?
- Mycobacteria leprae, nasal droplet transmission
- invade and proliferate in Schwann cells
- causes mononeuritis multiplex
- ulnar>median>radial
- infectious neuropathy, immune neuropathy, compressive neuropathy
- immune sys eradicates bacteria and repalces neural tissue with hyalinized fibrous tissue = nerve thickening
- incubation 2-3yrs
How do you classify and diangose HD?
According to hosts immune response to M. leprae
- Tuberculoid (high immunity)
- Lepromatous (low immunity)
- borderline (unstable/intermediate immunity)
Skin biopsy for dx
- granulomas, thickened nerves
- stain AFB
How do you treat HD
- Eradicate M. leprae - Multidrug therapy - dapsone, rifampin, clofazinime x1yr
- pain management - n. decompression, NSAIDS, gabapentin
- prevention further nerve damage- steroids
- restore sensation - n. transfer
- restore function - ulnar n defomrity - claw hand - most common
- psychiatric support
How do you define osteomyelitis?
def. inflammation of bone secondary to pyogenic organism, leading to bone destruction and subsequent new bone formation
What is an involucrum, a sequestrum, osteitis and brodies abscess
- Involucrum: layer of newly formed living bone over area of necrotic bone
- Sequestrum: area of necrotic bone - defines chronic OM
- Osteitis: infected bone cortex
- Brodies abscess: localized focus of infected bone following a subperiosteal infection
How do you classify OM
By etiology
- hematogenous spread (peds)
- contiguous spread form ST (vascular insufficiency - DM.PVD)
- inoculation (post trauma/iatrogenic)
By chronicity
- acute: within 2wks of disease and before sequestrae develop
- subacute - 1-2 months
- chronic >3months
What bacteria are associated with different OM etiologies?
- Post-trauma = s. aureus, epidermidis
- Open F# = GNB, anaerobes
- Fresh water/pool - m.marinuum
- Sickle cell = salmonella
- soil = sporotrichosis, enterobacter
- foot - pseudomonas
List 4 factors protective against development of OM in post traumatic patient
- adequate debridement
- stabilization
- dead space obliteration
- early soft tissue coverage (5-7days)
What is your work-up for dx of OM?
- Bone biopsy - before abx or 48hrs after stopping
- Blood work - wbc, crp, esr,
- Investigations
- Xray 1st - need 50% bone loss to see abnormality
- CT
- MRI - more sensitive butmust be >12mth and no hardware
- scintigraphy - can distinguish healing fractue from infected non union, subclincial OM
What are features of OM on Xray and CT?
Xray
- periostitis
- involucrum formation
- cortical lucency
CT
- cortical defects
- sequestra
- fistula
What are your treatment goals and principles for OM?
GOALS
- Eradicate infection
- Dead space obliteration
- SST coverage
- Fracture union
- Function
PRINCIPLES
- Sugical debridement of all infected/devitalized tissue/bone + removal of hardware if fractur healed
- Reconstruction of bone and ST
- ST: Muscle flap - deadspace/vascular
- Bone - exfix/1’ graft or 2’ graft
- <1.5cm defect - 1’ graftw cancellous bone
- if 2’, wait 3-6mths and place PMMA Abx beads
- IV abx 6wks and until all clinical signs improve
- if hardware in place, and s. aureux infection -> rifampin + ciprofloxacin
- Amputation - if all tx fails and cannot restore fx
What is your treatment algorith for acute infection after ORIF
- Bone not healed, hardware stable
- Abx and leave hardware until union and clinically improved, then remove hardware
- Bone not healed, hardware unstable
- Abx, remove hardware and externally stabilize and plan for 2’ recon once infx clear
- Bone healed, hardware stable
- Abx, remove hardware, control dead space
