Page 200 - Cote clinical veterinary advisor dogs and cats 4th

82 Aspergillosis

organism, typically after routine exposure infection only, and when Aspergillus is
Clinical Presentation by inhalation. present, it may only be a contaminant.
DISEASE FORMS/SUBTYPES
VetBooks.ir • Systemic ment of the mycosis and identification Advanced or Confirmatory Testing
○ Systemic aspergillosis requires manage-
Systemic:
• Sinonasal
and management of any underlying
immunodeficiency.
• Sino-orbital (cats)
• With sinonasal aspergillosis, the role of • Fine-needle aspirates of enlarged lymph
nodes, affected intervertebral discs, or bone
HISTORY, CHIEF COMPLAINT immunocompromise is unclear. lesions may show hyphae.
Systemic: ○ Affected dogs generally do not have • Serologic testing variable, and many tests
• Nonspecific signs predominate (e.g., lethargy, any evidence of systemic illness or are unreliable. Serum and urine galactoman-
inappetence, decreased activity). immunocompromise. nan assays are most sensitive, but false-
• Signs may have been present and slowly ○ Impaired lymphocyte blastogenesis may positives and false-negatives are possible.
progressive for weeks to months. be a cause or a result of infection. • Histologic evaluation of biopsied tissue is
• Acute signs related to discospondylitis (e.g., ○ A dominant helper T-cell type 1 (T H 1)– diagnostic (fungal granulomas). If a clinical
acute paresis/paralysis) occur in some cases. regulated, cell-mediated immune response suspicion of aspergillosis exists at the time
Sinonasal: has been identified. of biopsy, a portion of the specimen should
• Chronic nasal discharge, sneezing, epistaxis, • Mutual exclusion: sinonasal aspergillosis also be submitted for fungal culture. Labora-
depigmentation of nares is not suspected to lead to disseminated tory culture is needed to differentiate
Sino-orbital (cats): aspergillosis, and disseminated aspergillosis Aspergillus spp from Penicillium spp and from
• Facial/ocular deformity along with nasal essentially never causes signs of nasal disease. other saprophytic infections such as Mucorales
signs or Alternaria spp.
DIAGNOSIS Sinonasal:
PHYSICAL EXAM FINDINGS • Diagnosis is confirmed when fungal hyphae
Systemic: Diagnostic Overview can be demonstrated histologically within
• Signs of ill thrift (lethargy, weight loss, poor • For systemic aspergillosis, the diagnosis is nasal tissue and/or when at least two of the
haircoat, dehydration) suspected in a German shepherd (other following criteria are fulfilled: positive serum
• Spinal pain during deep palpation breeds sometimes affected) with chronic titer for A. fumigatus, positive Aspergillus
• Firm/hard limb swelling with adjacent weight loss, neurologic deficits, and radio- fungal culture, visible fungal plaques on
cutaneous draining tracts may be present. graphic evidence of bony lesions or disco- rhinoscopy, and supportive imaging
• Signs of uveitis (e.g., conjunctival redness, spondylitis. Although serologic testing can (radiographic/CT) findings.
photophobia) are possible and may occur be helpful, confirmation ideally based on • Imaging: CT is the modality of choice
before other signs. cytology or histopathologic evaluation of (greater resolution than radiographs, good
Sino-nasal: affected organs. bone detail, unlike MRI). Typical findings
• Nasal discharge is common, generally • For sinonasal aspergillosis, the diagnosis are nasal turbinate loss, intranasal fluid
mucopurulent ± blood is suspected in a dolichocephalic or opacity (exudates), and possibly fluid opacity
• Evidence of nasal pain mesaticephalic breed with nasal discharge, in the frontal sinuses.
• Depigmentation/ulceration of the ventral epistaxis, and/or depigmentation of the nares. • Nasal radiographs show regional or diffuse,
nares (the path of nasal discharge) is Although serologic testing can be helpful, asymmetrical turbinate loss and increase (due
common. confirmation requires demonstration of to intranasal exudate) or decrease (if scant
• Epistaxis (unilateral or bilateral) fungal hyphae on samples of nasal tissue exudate and loss of turbinate and overlying
• Nasal airflow often sounds congested/ with supportive diagnostic imaging findings. mucosa) of soft-tissue/fluid opacity. A
obstructed due to nasal discharge but may drawback is the difficulty in determining
be clearer sounding than normal if no dis- Differential Diagnosis whether soft-tissue/fluid opacity in the nasal
charge is present and extensive turbinate • Systemic: other opportunistic mycoses, passages is due to discharge (fluid) or mass
destruction has occurred. bacterial discospondylitis, vertebral or other (e.g., neoplasm).
Sino-orbital: bone neoplasm • Rhinoscopy (p. 1159) is the preferred method
• In cats, an invasive sino-orbital form accounts • Sinonasal: nasal neoplasia, other fungal or for direct observation and sampling. An
for 65% of upper respiratory aspergillosis bacterial rhinitis, foreign body, bleeding abnormally vast, cavernous nasal cavity is
• Massive facial and ocular deformity are disorder (if epistaxis) (p. 1255) common (turbinate loss). Fungal plaques
typical, with inability to retropulse involved or granulomas may be observed directly.
eye Initial Database Microscopic identification of Aspergillus from
• CBC, serum biochemistry panel: mature a macroscopically visible intranasal or intra-
Etiology and Pathophysiology neutrophilia/stress leukogram common for sinus colony is considered pathognomonic.
• Systemic: Aspergillus terreus most common systemic disease but nonspecific. Rule out Both left and right nasal cavities are examined
• Sinonasal: Aspergillus fumigatus most thrombocytopenia as cause of epistaxis. because findings often are asymmetrical.
common • Systemic • Rhinotomy is highly invasive, and surgical
• Aspergillus fungi are normal environmental ○ Urinalysis may show fungal hyphae. exploration offers little or no advantage
organisms that often are found inciden- ○ Radiographs of the spine may reveal over rhinoscopy in patients with nasal
tally on the skin and mucosa of dogs. evidence of discospondylitis (vertebral aspergillosis.
Their presence alone does not indicate endplate lysis). • Aspergillus serologic results (agar gel immu-
infection. ○ Radiographs of bony swellings can reveal nodiffusion [AGID], ELISA) vary, and titers
• Aspergillus fungi are routinely inhaled, lytic-proliferative lesions. cannot be used as a sole diagnostic test for
ingested, and inoculated during normal ○ Abdominal ultrasound is indicated to nasal aspergillosis. Galactomannan antigen
activities and are eradicated by the host, espe- identify visceral fungal granulomas, ELISA useful for systemic disease is insensi-
cially by cell-mediated immune mechanisms. lymphadenomegaly. tive for sinonasal or sino-orbital disease.
• With systemic aspergillosis, multiplication • Sinonasal • Fungal culture results that demonstrate
and proliferation of Aspergillus spp occurs ○ Swabs of nasal exudates are not useful; Aspergillus from samples not involving a
when the patient fails to eradicate the generally identify secondary bacterial macroscopic fungal colony are equivocal and

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