(515) 280-3100
A Case of Fungal Pneumonia
Written by: Yaquelin Mijangos • 2022 Scholar
History:
Sam, an 8-year-old spayed female German Shepherd, presented to the ER after a week of having a persistent cough with hacking episodes that developed into respiratory distress. Prior to coming in, Sam’s owner also noted a slight decrease in both appetite and energy with lethargy reported in the last 2-3 days.
Physical Exam:
Initial vitals were: heart rate of 140 beats per minute, panting respiration, pink mucus membranes with a capillary refill time of less than 2 seconds –all of which are within normal limits. The only exception was that of an elevated temperature of 103.2 F (normal 99.9-102.5).
On auscultation decreased lung sounds on the left lung field and increased lung sounds on the right lung field were noted. A visibly increased respiratory rate and effort were also noted. However, no cardiac murmurs or arrhythmias were detected. The remainder of the physical exam showed no significant findings besides mild dental calculus and a body condition score of 4/9. Given the patient's history and presenting assessment, 3-view chest x-rays and baseline blood work were recommended.
Diagnostics:
Radiographs displayed a diffuse mixed bronchial or peribronchial and unstructured interstitial pulmonary pattern with consolidation in the left lung fields which raised the suspicion of a possible fungal pneumonia or a diffuse neoplasia such as with lymphoma or peribronchial metastasis. However, on the ventrodorsal image, the opacity of the entirety of the left lung was significantly increased but this change was more severe in the caudal lung lobes. Nevertheless, the cardiac silhouette was unremarkable on the lateral views and the cranial pulmonary lobar arteries and veins were normal. Other structures like the trachea, mainstem bronchi, and esophagus appeared normal in size. Lastly the x-rays showed no evidence of esophageal dilation or intrathoracic lymphadenopathy (enlarged/swollen lymph nodes). As for the blood work, both the chemistry panel and CBC were within normal limits with the hematocrit of 55.
Differentials:
Given the patient assessment and the diffuse lung changes noted in the radiographs, there was concern for pneumonia (primarily fungal vs. bacterial) or neoplasia such as lymphoma or peribronchial metastasis.
Unfortunately for this particular case, no further diagnostics were permitted. Nevertheless, additional diagnostics to confirm or rule out fungal pneumonia would have been the next step in treatment.
What is fungal pneumonia?
Fungal pneumonia is classified as a fungal infection resulting in an acute or chronic inflammatory response or granulomatous to pyogranulomatous
Treatment:
Once fungal pneumonia is diagnosed, depending on the severity of the patient’s symptoms, hospitalization with oxygen therapy can be warranted along with a long-course of antifungals and possibly anti-inflammatory medications. Currently the antifungal medications available to treat this infection include: itraconazole, fluconazole, amphotericin B, and voriconazole or terbinafine. However, these medications can be costly and require long-term treatment to be effective. Baseline blood work and continuous monitoring throughout treatment should also be considered since some of these medications can alter patient appetite, liver enzymes, and kidney values. For example, amphotericin B can be nephrotoxic. Therefore, it is imperative to talk to clients that this will require a long-term and strict course of treatment. Depending on the severity of disease and the organ systems involved (Respiratory vs. CNS), prognosis with adequate treatment can be promising but late detection can have a more guarded prognosis.
lymph nodes. pneumonia. Naturally the respiratory system is affected but this infection can also affect the skin, skeletal integrity, central nervous system and Infection can occur once an animal has inhaled the fungal spores, with two of the most common being Blastomyces dermatitidis or Blastomyces gilchristii. These spores tend to thrive in moist soils, particularly those long lakes or waterways. Once inhaled, the respiratory tract provides the ideal warm environment for the spores to thrive and transform into their active form (yeast) and cause the systemic infection that we see.
Once infection has set in, the classic respiratory clinical signs include: coughing, often productive with a thick nasal discharge, lethargy, emaciation, and dyspnea. As the disease progresses, respiratory effort increases and crackles can be expected upon auscultation. Other none symptoms include: fever, poor appetite, weight loss, skin sores or lesions that don’t heal.
Image of Blastomyces budding yeast (active spore) and a clinical patient with Blastomycosis.
Thoracic radiographs present a diffuse interstitial pneumonia and opacities that often resemble neoplasia–focal masses or lung lobe changes, much like our patient Sam. This lateral radiograph is of another clinical patient but note the diffused changes in opacity that are indicative of pneumonia.
To diagnose fungal pneumonia, visualizing the organism would be ideal but when fine-needle aspirates are not possible urine antigen is perhaps the most sensitive for detecting Histoplasma and Blastomyces. Serologic or PCR testing can also be used or CSF tap.
Treatment:
Once fungal pneumonia is diagnosed, depending on the severity of the patient’s symptoms, hospitalization with oxygen therapy can be warranted along with a long-course of antifungals and possibly anti-inflammatory medications. Currently the antifungal medications available to treat this infection include: itraconazole, fluconazole, amphotericin B, and voriconazole or terbinafine. However, these medications can be costly and require long-term treatment to be effective. Baseline blood work and continuous monitoring throughout treatment should also be considered since some of these medications can alter patient appetite, liver enzymes, and kidney values. For example, amphotericin B can be nephrotoxic. Therefore, it is imperative to talk to clients that this will require a long-term and strict course of treatment. Depending on the severity of disease and the organ systems involved (Respiratory vs. CNS), prognosis with adequate treatment can be promising but late detection can have a more guarded prognosis.
References:
McMichael, Maureen. “Fungal Pneumonia in Animals - Respiratory System.” Merck Veterinary Manual, Merck Veterinary Manual, 4 June 2022, https://www.merckvetmanual.com/respiratory- system/fungal-pneumonia/fungal-pneumonia-in-animals.
Hospitals, BluePearl Pet. “Blastomycosis: A Fungus among US - Bluepearl Pet Hospital.” BluePearl, 22 July 2020, https://bluepearlvet.com/medical-library-for-dvms/blastomycosis-a- fungus-among-us/.
“Fungal Pneumonia in Dogs: Causes, Symptoms & Treatment.” Fungal Pneumonia in Dogs: Causes, Symptoms & Treatment | Flat Rock Emergency Vet | Western Carolina Regional Animal Hospital & Veterinary Emergency Hospital, https://www.wcrah.com/site/blog-flat-rock- vet/2021/01/07/fungal-pneumonia-dogs-causes-symptoms- treatment#:~:text=Oxygen%20therapy%20and%20a%20prolonged,may%20need%20to%20be %20hospitalized.
