Nodules (Marsella) Flashcards
1
Q
Nodules
A
Solid elevations that extend deep into the dermal or subcutaneous tissue (inflammatory or neoplastic)
2
Q
DDX for nodules: Fungal
A
- Cryptococcus
- Histoplasma
- Coccidiodomycosis
- Sporotrichosis
- Kerion
- Mycetoma/pseudomycetoma
- Phaeohyphomycosis
- Oomyces (pythiosis)
3
Q
DDX for nodules: Bacterial
A
- Deep pyoderma
- Acral lick dermatitis
- Cutaneous bacteral granuloma
- Botryomycosis
- Abscess
- Staphylococcus furunculosis
- Opportunistic/atypical mycobacteria
- Actinomyces
- Actinobacillus
- Leprosy
4
Q
DDX for nodules: non-infectious/sterile
A
- Allergy (cats)
- Eosinophilic granuloma
- Mosquito hypersensitivity
- Sterile nodular panniculitis
- Sterile nodular granuloma/pyogranuloma
- Plasma cell pododermatitis (cats)
- Neoplastic
5
Q
Nodule diagnostic approach
A
- FNA
- Biopsy for histopath & culture
- R/O other infectious causes
6
Q
Systemic fungal infections
A
- Cryptococcosis
- Histoplasmosis
- Blastomycosis
- Coccidiodomycosis
7
Q
Subcutaneous fungal infections
A
- Sporotrichosis
- Phaeohyphomycosis
- Mycetoma
- Kerion
8
Q
Sporotrichosis (general info)
A
- Sporothrix schenckii
- Thermally dipmorphic (yeast in tissues)
- In soils and decaying organic matter
- Spread by inoculation (contaminate wound) or inhalation (rare)
- ZOONOTIC
9
Q
Infection of sporotrichosis from cats (to humans)
A
- Large number of organisms in feline exudate
- No immune suppression necessary
- Wear gloves
- Wash hands in chlorohexidine and povidone iodine
10
Q
Feline sporotrichosis
A
- Draining nodules (head, distal limb, tail)
- Hx of poor response to abx
- Autoinoculation in other parts by grooming
- Most cats develop disseminated dz
11
Q
Sporotrichosis diagnosis
A
Easiery in cats due to large number of organisms
- Cytology
- Culture
- Histopath
12
Q
Sporotrichosis treatment
A
- Itraconazole
- Ketoconazole
- Iodides
- Treat at least 1 month past resolution of clinical signs
13
Q
Iodism
A
- Oral iodine treatment not tolerated well
- Vomit, anorexia, depression
- Twitching, hypothermia
- Ocular & nasal discharge
- Dry coat, excessive scaling
14
Q
Kerion
A
- Exudative nodular lesions
- Reaction to dermatophytic infection
- M. gypseum
- T. mentagrophytes
- Furunculosis
(Dermatophytes don’t like to be in dermis, usually die and act as foreign body)
15
Q
Dermatophytic psuedomycetoma
A
- Subcutaneous nodules
- Most common on trunk
- Frequent ulceration
- M. canis
- Persian cats
- Histopath - pyogranulomatous dermatitis w/ fungal hyphae, tissue grains
16
Q
Pythiosis (general info)
A
- “Swamp cancer” (not actual cancer)
- Fungus/algae-like oomycete
- Plant parasite
- Subtopical/tropical areas
- Infection by contact w/ contaminated water
17
Q
Pythiosis affects what species?
A
- Humans
- Dogs (esp. german shepherds, golden retrievers)
- Horses (not as aggressive as in dogs)
- Cattle
18
Q
Pythiosis clinical signs
A
- Rapidly developing nodules & draining tracts
- Intense pruritis
19
Q
Pythiosis diagnosis
A
- Cytology - eosinophils, rarely hyphae
- Biopsy
- Histopath
- Nodular to diffuse pyogranulomatous dermatitis
- “Ghost” hyphae (hard to see)
- Culture
- Immunohistochem
- Histopath
20
Q
Pythiosis treatment
A
- 100% mortality w/ out treatment
- Response dependent on age of lesions
- WIDE surgical excision
- Treat 2º bacterial infections
- Amphotericin B
- Itraconazole (synergistic w/ doxy)
- Terbinafine
- Hyperbaric chamber
- Vaccine changes immune response, not preventative
21
Q
Lagenidiosis
A
- Oomyces
- Infeciton occurs by contact w/ contaminated water
- Nodules & draining tracts
22
Q
Zygomycosis
A
- Caused by fast growing, sapropytic fungi
- Wound contamination
- Nodular lesions (pyogranulomatous dermatitis & panniculitis)
- Clinically indistinguishable from pythiosis
- Poor prognosis
23
Q
Deep pyoderma
A
- Furuncolosis
- Panniculitis
- Diagnos by clinical signs, cytology, biopsy
- Tx 2-3 mos of systemic abx
- ID & corrent underlying dz
24
Q
Acral lick dermatitis presentation
A
- Raised, ulcerated mass usually on extremities
- Caused by or worsened by licking
- Incr. incidence in large breeds
- Furunculosis
- Associated w/ 2º infections
25
Q
Possible underlying causes of acral lick dermatitis
A
- Demodex
- Dermatophytes
- Allergies (fleas)
- Hypothryroidism
- Pain
26
Q
Acral lick dermatitis diagnosis
A
- Skin scrape
- Fungal culture
- Biopsy - histopath, culture
- R/O pythium
27
Q
Acral lick dermatitis treatment
A
- Abx for 6+ wks
- Tx underlying cause
- Mechanical devices
- Topicals
- Hycodan (narcotic)
- Naltrexone (narcotic antagonist)
- Behavior modification
- Acupuncture
- Cryosurgery
- Guarded long term prognosis
28
Q
Opportunistic mycobacteria
A
- Non-healing wounds
- Chronic ulcers
- Draining tracts
- Lesions in cats often in ventral fat pads
29
Q
Diagnosis of mycobacteria
A
- Cytology (very few organisms)
- Biopsy - histopath, culture (may still be false negative)
30
Q
Mycobacteria treatment
A
- Specific sensitivity testing
- Fluoroquinolones
- Doxycycline
- Clarithromycin
31
Q
Nocardia
A
- Mimic mycobacteria, but animal is sick, anorexic
- Culture
- Tx w/
- penicillin and sulfa
- Na iodide
- Guarded prognosis
32
Q
Sterile nodular panniculitis
A
- Uncommon
- Nodules w/ discharge
- Systemic signs
- Combo of foreign body & hypersensitivity
- Associated w/ vax & injections
- Dachshunds, collies, GSD predisposed
- R/O infection
33
Q
Sterile pyogranulomas
A
- Rare
- Typically solitary lesions, frequently on head
- R/O infectious causes
- Immunomodulation successful in some cases
