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Myelodysplasia 671

• Cytologic evaluation or biopsy of skin lesions • Surgical excision of leproid granulomas is PEARLS & CONSIDERATIONS
reveals an acid-fast bacillus; cytology using the treatment of choice. Comments
VetBooks.ir • Thoracic and abdominal radiographs reveal Chronic Treatment • Significant commitment of owner time and Diseases and Disorders
routine stains can reveal apparent “holes”
due to organisms that fail to take up stain.
resources is required for positive outcome.
• Consultation with an internist specializing
in infectious diseases is advised for drug
granulomas in systemic forms.
antimicrobial therapy recommendations are
recommendations; antibiotic resistance is • Accurate species identification and current
Advanced or Confirmatory Testing prevalent, and protocols are evolving rapidly. essential.
• Culture, including antibiotic susceptibility • Treatment of opportunistic forms, guided by • Diagnosis of M. tuberculosis infection should
testing and speciation, is essential; identifica- species identification (and sensitivity testing result in a recommendation for in-contact
tion of opportunistic forms by culture and when possible), requires a minimum of 3 people to be tested for TB. Infected in-
takes ≈6 weeks. months and typically longer. contact people are likely the source of the
• A specialized lab is required (e.g., National ○ Combination therapy with a fluoroquino- infection for the pet.
Jewish Center for Immunology and lone plus clarithromycin, gentamicin, or • Euthanasia may be recommended over
Respiratory Medicine in Denver, Colorado doxycycline may be acceptable empirical treatment of tuberculous forms (zoonotic
[www.nationaljewish.org/professionals/ therapy while definitive identification is risk).
clinical-services/diagnostics/adx/about-us/ pending.
lab-expertise/mycobacteriology]). • Treatment for tuberculous forms may not be Prevention
• Polymerase chain reaction (PCR) is increas- recommended; if treatment is undertaken, • Opportunistic forms are ubiquitous.
ingly available but technically challenging, combination antibiotic therapy must be • Limiting rodent exposure reduces risk of
prone to false-negatives; PCR has not administered for a minimum of 6-12 months. leproid forms.
replaced culture as the gold standard. • Medical therapy for leproid infections is • Vaccination with human or large-animal
• Intradermal tuberculosis (skin) testing is not indicated if complete surgical excision is products is not recommended.
helpful in dogs and cats. not possible.
Technician Tips
TREATMENT Possible Complications • Any chronic draining lesion in a dog or cat
• Surgical sites prone to dehiscence and recur- may contain mycobacteria or other agents
Treatment Overview rence of infection transmissible to people.
• Opportunistic forms can be curable with • Risks of drug resistance, toxicosis, or intoler- • Always wear gloves and wash hands
long-term treatment. ance with long-term antibiotic use thoroughly.
○ Treatment of opportunistic forms depends
on aggressive resection and guided combi- Recommended Monitoring SUGGESTED READING
nation antibiotic therapy for a minimum • Re-exam every 2-3 weeks for continued Greene CE, et al: Mycobacterial infections. In Greene
of 3 months. effectiveness of therapy CE, editor: Infectious diseases of the dog and cat,
• Tuberculous forms pose a significant • Periodic lab tests for evidence of drug ed 4, St. Louis, 2012, Saunders, pp 495-521.
human health threat; treatment may not toxicosis AUTHOR: Kate E. Creevy, DVM, MS, DACVIM
be recommended. EDITOR: Joseph Taboada, DVM, DACVIM
• Leproid forms are usually curable with PROGNOSIS & OUTCOME
aggressive surgical excision.
• Acute general treatment with wide surgical • Recurrence or incomplete clearance is likely.
debulking of large opportunistic lesions is • With appropriate intensive management,
the first step in long-term management. outcome of opportunistic infections can
○ Submit surgical biopsies for species be good.
identification. • Leproid forms have the best prognosis.

Myelodysplasia Client Education
Sheet

BASIC INFORMATION Synonyms RISK FACTORS
Ineffective hematopoiesis, refractory cytopenias, • FeLV and FIV infections
Definition preleukemia, smoldering acute leukemia • Some drugs: chloramphenicol, cephalospo-
• Myelodysplastic syndrome (MDS) describes Epidemiology rins, melphalan, cyclophosphamide, estrogen,
a group of bone marrow disorders character- and vincristine
ized by peripheral blood cytopenias and a SPECIES, AGE, SEX • Vitamin B 12/folate deficiency
hypercellular to hypocellular bone marrow Dogs and cats; the prevalence of MDS • Lead toxicosis
containing < 20% blast cells. It is considered in cats is decreasing as the prevalence of • Exposure to radiation
a precursor to acute leukemia, where the bone feline leukemia virus (FeLV) infection also • Immune-mediated diseases targeting the bone
marrow blast population exceeds ≈25%. decreases. MDS is occasionally associated marrow
• Morphologic signs of abnormal maturation with feline immunodeficiency virus (FIV) • Chronic exposure to alkylating chemotherapy
(dysplasia) may be seen in the erythroid, infections. drugs
myeloid, and/or megakaryocytic cells.

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