Derm - Nodules and discharging sinuses Flashcards
What is a discharging sinus?
An intense inflammatory response to infectious agents or foreign material
Leads to formation fo a tract between the epidermis surface and deeper tissues
eg. a cat bite abcess
How do you investigate nodules?
Cytology from fine needle aspirate
How do you investigate infectious nodules associated with discharging sinus tracts?
DIff quik gram stain exudate
How do you investigate superficial lesions extending into the dermis?
Punch biopsy
Histopathology
Culture
How do you investigate nodules extending into the hypodermis?
Partial excision biopsy using a scalpel
When should you use haematology and biochemistry to investigate skin conditions?
Extensive skin disease
Signs of systemic disease
Old
What are some bacterial causes of nodules?
Staphylococci
Mycobacteria
What are some fungal causes of nodules?
Dermatophytosis
Eumycotic mycetomas
Deep fungal infections
What can cause feline tuberculosis?
Commercial raw food diet
What are cutaneous signs of feline tuberculosis?
Nodular ulcerated lesions
Subcut tissue/joints/bone
Regional lymphadenopathy
What causes feline leprosy?
3 mycobacterial species
Caught from bites from wildlife eg. rodents
When is mycobacteria infection in cats notifiable?
In dead non bovine species or when culture is positive in a live cat
Contact APHA
What is sterile granuloma and pyogranuloma syndrome (SGPS)?
When an inflammatory infiltrate causes pyogranulomatous lesions in the absence of infection
Where does sterile granuloma and pyogranuloma syndrome (SGPS) affect?
Varied lesion affecting ocular tissues, nasal tissues and head
What are some differential diagnoses of sterile granuloma and pyogranuloma syndrome (SGPS)?
Neoplasia
Granulomatous reactions to foreign bodies etc.
Panniculitis
How can you manage sterile granuloma and pyogranuloma syndrome (SGPS)?
Reduce trigger factors - treat infections etc.
High dose corticosteroids - pred
Tetracycline and nicotinamide
What are some examples of epidermal tumours?
Basal cell carcinoma - cat
Papilloma - dog
Squamous cell carcinome - cat
What are some examples of hair follicle tumours?
Follicle cyst
Infundibular keratinising acanthoma
What are some examples of sebaceous gland tumours?
Nodular sebaceous hyperplasia
Perianal gland carcinoma
Sebaceous adenoma
What are some examples of nailbed tumours?
Squamous papilloma
Keratoacanthoma
Basal cell carcinoma
Metastatic pulmonary carcinoma
What tumour is accompanied by GI signs?
Mast cell tumours
What tumour is accompanied by polydipsia?
Lymphoma - hypercalcaemia
Where are cutaneous T cell lymphomas found?
In the epithelium or in the dermis - epitheliotropic or non-epitheliotropic
What are some examples of cutaneous T cell lymphomas?
Mycosis fungoides, Sezarys syndrome
How does cutaneous T cell lymphoma present?
Generalised erythema, scaling and pruritus
Plaques and nodules
Loss of pigment
How do you treat cutaneous T cell lymphoma?
Palliative
High dose prednisolone
Retinoids
Chemotherapy
