Disseminated histoplasmosis in cats: 12 cases (1981-1986)

Anemia, weight loss, lethargy, fever, anorexia, and interstitial lung disease were the predominant clinical findings in 12 cats with disseminated histoplasmosis. Some cats were examined because of dysfunction or lesions of bone, eyes, or skin. In most cases, the clinical signs were observed by the owner for 4 weeks or less before seeking veterinary care. Young cats were most commonly affected, with 7 of the 12 cats less than or equal to 1 year old. Identification of Histoplasma organisms in bone marrow aspirates was used to confirm the diagnosis of histoplasmosis in 11 of the 12 cats. Histoplasma infection of multiple organs was found at necropsy. In this study, disseminated histoplasmosis had a higher prevalence in cats than in dogs at the same veterinary medical teaching hospital. Feline disseminated histoplasmosis was not associated with FeLV infection. Treatment was attempted in 7 of the 12 cats.     

Histoplasmosis in dogs and cats

Histoplasma capsulatum is endemic throughout most of the United States with a high prevalence of infections in the Midwest and South. Histoplasmosis is the second most common systemic fungal disease in cats that may be more susceptible than dogs. Infection occurs by inhalation of conidia from the mycelial phase, which subsequently convert to the yeast form. Histoplasma capsulatum is phagocytized and harbored by cells of the mononuclear phagocyte system. Infection may be subclinical or cause clinical pulmonary granulomatous disease or dissemination. Disseminated disease predominantly affects the liver, spleen, gastrointestinal tract, bone and bone marrow, integument, and eyes. Primary gastrointestinal histoplasmosis also occurs. Clinical signs of histoplasmosis often are nonspecific, including chronic wasting, fever, anorexia, respiratory signs, and lameness. Gastrointestinal signs (eg, diarrhea with hematochezia or melena) are common in dogs. The definitive diagnosis is made by identification of the yeast in tissue samples. Itraconazole is the treatment of choice.     

Histoplasma capsulatum Osteomyelitis in the Cat

Seven cats with osseous lesions as the primary manifestation of disseminated Histoplasma capsulatum infection were evaluated. The major clinical signs in these cats were related to the bony lesions and included lameness, bone pain, and soft tissue swelling of limbs and joints. Other clinical and pathologic findings were similar to previously reported forms of disseminated histoplasmosis in the cat. The radiographic appearance of the lesions was predominantly osteolytic; periosteal and endosteal new bone production was present in some cases. Infection occurred primarily in bones of the appendicular skeleton with a predilection for sites below the elbow and stifle joints.     

Disseminated histoplasmosis in a Bengal tiger (Panthera tigris)

Disseminated infection with Histoplasma capsulatum was diagnosed in a 7-yr-old female Bengal tiger (Panthera tigris). Clinical signs were nonspecific with the exception of brief periods of tachypnea for 5 days prior to death. H. capsulatum organisms were found in the lungs, tracheobronchial lymph nodes, and liver. Diagnosis was confirmed by tracheal wash, urine H. capsulatum enzyme immunoassay, and necropsy results. This report represents the first published account of disseminated histoplasmosis in a tiger.     

Diagnosis of histoplasmosis in a dog by cytologic examination of CSF

A mixed inflammatory cell pleocytosis was identified in a cytocentrifuged sample of cerebrospinal fluid (CSF) and diagnosis of histoplasmosis was made on the basis of finding Histoplasma capsulatum organisms within macrophages. This dog had disseminated histoplasmosis with multiple organ involvement including the central nervous system (CNS) and eye.     

Itraconazole for the Treatment of Histoplasmosis in Cats

Eight cats with histoplasmosis were treated with itraconazole at 5 mg/kg per dose PO bid. There were multiple sites of infection, and 2 of the cats had hypercalcemia that was attributed to the histoplasmosis. All 8 cats were eventually cured, but 2 cats experienced recurrences of disease after completion of therapy, requiring 2 to 3 additional months of itraconazole. There were no clinically relevant adverse effects during treatment. Although a limited number of cats were treated, the study suggests that itraconazole is a well-tolerated and effective drug for the treatment of histoplasmosis in the cat.     

Diagnosis of histoplasmosis by detection of the internal transcribed spacer region of fungal rRNA gene from a paraffin-embedded skin sample from a dog in Japan

The lesions of histoplasmosis in dogs in Japan differ from those in dogs in North America. Affected dogs in Japan have had multiple granulomatous or ulcerated foci in skin or gingiva and have not had pulmonary or gastrointestinal lesions. The present report introduces a polymerase chain reaction (PCR) diagnosis of canine histoplasmosis and the characteristic of disease in Japan. The surgically removed skin ulcerate samples from a 5-years-old female Shiba-inu native to Japan without traveling out of the country were evaluated. Tissue samples had many yeast-like organisms in the macrophages. DNA was extracted from paraffin-embedded tissue samples. A nested PCR technique was applied. The detected sequence of the internal transcribed spacer of ribosomal RNA gene had 99.7% in homology with Ajellomyces capsulatus (the teleomorph of Histoplasma capsulatum). Clinical manifestations, historical background of equine epizootic lymphangitis in Japan, and a human autochthonous case of histoplasmosis farciminosi indicated that this dog might have been infected with H. capsulatum var. farciminosum as a heteroecism.     

Histoplasmosis in a dog from New Brunswick

A young dog was presented with a history of chronic diarrhea, anorexia, and weight loss. Histoplasma capsulatum was suspected, based on cytologic examination of lymph node aspirates and peritoneal fluid, and confirmed by fungal culture. To our knowledge, this is the first case of histoplasmosis diagnosed in a dog in Atlantic Canada.     

Disseminated histoplasmosis in dogs: 12 cases (1981-1986)

Diarrhea, intestinal blood loss, anemia, and lethargy were predominant clinical findings in 12 dogs with disseminated histoplasmosis. Young dogs were affected most commonly, with 6 dogs being 1 to 3 years old. A diagnosis of disseminated histoplasmosis was established on the basis of histologic or cytologic detection of Histoplasma organisms in intestinal or rectal mucosa in 7 dogs, in circulating leukocytes in 5 dogs, in bone marrow in 3 dogs, and in multiple tissues at necropsy in 1 dog (4 dogs had Histoplasma organisms detected in greater than 1 site). Anemia was detected in 10 dogs (PCV less than 20% in 3 dogs), and the anemia was inadequately regenerative or nonregenerative in 7. Hypoalbuminemia was detected in 9 dogs, and serum albumin concentrations were low (less than 1.0 g/dl) in 4 of the 9 dogs. Of 5 dogs treated with ketoconazole, 2 were in remission for greater than or equal to 1 year. Corticosteroid therapy may have exacerbated the disease in 4 dogs. Histoplasma infection of multiple organs was detected in 5 necropsied dogs.     

Atypical Histoplasma capsulatum infection in a dog

Disseminated histoplasmosis was diagnosed in a 10-year-old dog suspected of having hepatic carcinoma. Clinical abnormalities included diffuse hepatomegaly, gastrointestinal bleeding, thoracic and abdominal effusion, anemia, leukocytosis, and thrombocytopenia. Histoplasmosis characteristically is a disease of the mononuclear phagocyte system, but in this case was diagnosed by finding Histoplasma capsulatum organisms in neutrophils on the blood smear.     

Identification of Histoplasma organisms in circulating eosinophils of a dog

Disseminated histoplasmosis was diagnosed in a 10-year-old dog that had chronic diarrhea, weight loss, fever, and anemia. The diagnosis was based on detection of Histoplasma organisms in circulating neutrophils, monocytes, and eosinophils. The dog had severe histoplasmal fungemia, which may have been caused by treatment with prednisolone.     

Interdigital involvement in a case of primary cutaneous canine histoplasmosis in Japan

A 5-year-old male Siberian husky bred outdoor in Tokyo had a swollen paw with interdigital granulomatous lesions in the left hindlimb. The dog had no apparent pulmonary or gastrointestinal involvement. Histopathological analysis of the skin lesions demonstrated yeast-like organisms predominantly within macrophages. Sequence analysis of fungal ribosome RNA gene isolated from a paraffin sample revealed a 100% homology with the teleomorph of Histoplasma capsulatum. The present case may support the concept of primary cutaneous canine histoplasmosis as an endemic phenotype recognized in Japan.     

ULTRASONOGRAPHIC APPEARANCE OF HISTOPLASMOSIS IDENTIFIED IN THE SPLEEN IN 15 CATS

Histoplasmosis is the second most common fungal infection reported in the cat. The disseminated form involving lung, liver, lymph nodes, spleen, and bone marrow is a frequent manifestation of the disease. Limited information is available in the literature regarding the ultrasonographic appearance of the spleen in cats with disseminated or splenic histoplasmosis. A retrospective review of splenic ultrasound images from 15 cats confirmed to have histoplasmosis by splenic aspirates was performed. Size, echotexture, echogenicity, margin appearance, presence of nodules, and the overall shape of the spleen were reported in each case. Splenomegaly was documented in all cases (15/15) and a hypoechoic appearance of the spleen was documented in 14/15 of cases. The spleen was diffusely and uniformly affected in 14/15 (six homogenous and eight with a subtle mottled appearance) and had discrete nodules in 1/15 cats. Histoplasmosis should be included in the differential list for an enlarged and hypoechoic spleen in cats with consistent clinical findings. Additionally, ultrasound guided splenic aspirate may be a useful method to obtain a cytology sample for diagnosis.     

THE RADIOGRAPHIC APPEARANCE OF PULMONARY HISTOPLASMOSIS IN THE CAT

A retrospective study of 18 cats with pulmonary histoplasmosis was conducted to evaluate radiographic patterns of disease and to determine age, breed, and sex distributions. All cats had active disease confirmed by biopsy/aspiration cytology (lung, bone marrow, peripheral lymph nodes, pleural fluid) or necropsy examination. Cats 3 years of age or less had the highest incidence of disease; females outnumbered males 2 to 1. Radiographically, most cats had an interstitial pattern which appeared as a fine, diffuse or linear pattern, or as a more distinct nodular pattern. An alveolar pattern was an uncommon radiographic finding. Tracheobronchial lymphadenopathy and calcified lymph nodes or pulmonary parenchymal lesions were not identified in these cats.     

DIC and granulomatous vasculitis in a dog with disseminated histoplasmosis

Disseminated histoplasmosis and disseminated intravascular coagulopathy were diagnosed in a 7 mo old, female spayed mixed-breed dog. The dog improved transiently with supportive care, but deteriorated shortly after initiation of antifungal therapy. The dog was subsequently euthanized. At necropsy, marked granulomatous vasculitis was identified in all affected organs. The tunicae and laminae of the arteries and arterioles were obscured by epithelioid macrophages and multinucleated giant cells admixed with necrotic material. Intracytoplasmic yeast were present within some of these macrophages. To the authors' knowledge, this is the first reported case of granulomatous vasculitis associated with Histoplasma capsulatum in a dog.     

Cytologic diagnosis of disseminated histoplasmosis in the wall of the urinary bladder of a cat

A 10 yr old domestic longhair presented with a 2.5 mo history of recurrent hematuria. Abdominal ultrasound examination demonstrated a thickened urinary bladder, abdominal lymphadenopathy, and a thickened and rounded spleen. Cytologic examination of fine-needle aspirate samples revealed Histoplasma capsulatum organisms in the urinary bladder wall and spleen. The cat was treated with itraconazole (10 mg/kg per os q 24 hr for 2.5 wk). The cat was euthanized after 19 days of treatment because of lack of improvement. To the authors' knowledge, this is the first documented case of feline disseminated histoplasmosis diagnosed in the urinary bladder wall.     

Use of corticosteroids for treating dogs with airway obstruction secondary to hilar lymphadenopathy caused by chronic histoplasmosis: 16 cases (1979-1997).

OBJECTIVE: To examine use of corticosteroids in treating dogs with airway obstruction secondary to hilar lymphadenopathy caused by chronic histoplasmosis. DESIGN: Retrospective study. ANIMALS: 16 dogs. PROCEDURE: Records for dogs with airway obstruction examined from January 1979 through December 1997 were reviewed. Dogs were included in the study if they had hilar lymphadenopathy documented radiographically and bronchoscopically, had serum antibodies against Histoplasma capsulatum, and did not have organisms in any cytologic or histologic samples. Dogs were assigned to groups on the basis of treatment given (5 dogs, corticosteroids only; 5 dogs, corticosteroids and antifungal medication; 6 dogs, antifungal medication only). RESULTS: Clinical signs resolved in < 1 week in dogs treated only with corticosteroids. In dogs treated with corticosteroids and an antifungal medication, improvement was evident in a mean of 2.6 weeks. In 5 of 6 dogs treated with only an antifungal medication, clinical signs resolved in a mean of 8.8 weeks. Dogs receiving corticosteroids did not develop active or disseminated histoplasmosis. CLINICAL IMPLICATIONS: Corticosteroids can be used successfully in the treatment of dogs with hilar lymphadenopathy secondary to histoplasmosis. Affected dogs must be carefully evaluated for active infection. Specimens obtained by means of bronchoalveolar lavage, tracheal washing, or other methods should be examined to exclude the possibility of an active infection, which could result in corticosteroid-induced dissemination of disease.     

Causes of urine marking in cats and effects of environmental management on frequency of marking.

OBJECTIVE: To evaluate effects of environmental management alone on marking frequency in cats with urine marking and to obtain demographic data on cats with urine marking and data on owner-perceived factors that contributed to urine marking behavior. DESIGN: Single-intervention study. ANIMALS: 40 neutered male and 7 spayed female cats. PROCEDURE: During a 2-week baseline phase, owners maintained a daily record of the number of urine marks. This phase was followed by a 2-week environmental management phase during which owners cleaned recently deposited urine marks daily, scooped waste from the litter box daily, and changed the litter and cleaned the litter box weekly while continuing to record urine marks. RESULTS: Male cats and cats from multicat households were significantly overrepresented, compared with the general pet cat population in California. The most commonly mentioned causative factors for urine marking were agonistic interactions with other cats outside or inside the home. Environmental management procedures resulted in an overall reduction in urine marking frequency. Among cats that marked > or = 6 times during the baseline phase, females were significantly more likely to respond to treatment (> or = 50% reduction in marking frequency) than were males. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that male cats and cats from multicat households are more likely to exhibit urine marking behavior than females and cats from single-cat households. Results also suggest that attention to environmental and litter box hygiene can reduce marking frequency in cats, regardless of sex or household status of the cats, and may come close to resolving the marking problem in some cats.     

Evaluation of urine specific gravity and urine sediment as risk factors for urinary tract infections in cats

Background: It has been suggested that diseases that promote isosthenuria predispose to urinary tract infections because of a lack of the common bacteriostatic properties present in concentrated urine. Objectives: The purpose of this study was to assess the clinicopathologic risk factors for positive urine culture outcome in cats with chronic kidney disease (CKD), diabetes mellitus (DM), uncontrolled hyperthyroidism (HT), or lower urinary tract disease (LUTD). Methods: For this retrospective study, medical records of all cats in which a urinalysis and aerobic bacterial urine culture were performed between January 1995 and December 2002 were reviewed. Signalment, body weight, and clinicopathologic data were recorded. Based on the medical records, cats were diagnosed with CKD, DM, HT, or LUTD. Prevalence odds ratios and 95% confidence intervals were calculated using logistic regression. Multivariate models were created for each variable of interest while controlling for the confounding effect of disease group. Results: Six hundred fourteen cats met the criteria for inclusion in the study. Overall, positive urine cultures were identified in 16.9% of cats with CKD, 13.2% of cats with DM, 21.7% of cats with HT, and 4.9% of cats with clinical signs of LUTD. Decreasing urine specific gravity was not associated with positive urine culture when controlled for disease but pyuria, bacteriuria, and hematuria were all associated with positive urine culture outcome. Persians, females, increasing age, and decreasing body weight were all associated with positive urine culture outcome. Conclusions: Performing a urine culture sample based solely on the presence of isosthenuria does not seem warranted. Further studies are warranted to help identify host predisposing factors for urinary bacterial colonization in cats with these diseases.     

Influence of prednisolone on urinary calcium oxalate and struvite relative supersaturation in healthy young adult female domestic shorthaired cats

Prednisolone (10 mg PO q24h) or placebo was administered to healthy cats for 2 weeks in a masked, placebo-controlled, crossover-design study, and 24-hour urine samples were collected. When cats received prednisolone, 24-hour urine pH was lower and 24-hour urine excretion of creatinine, magnesium, phosphate, and potassium was higher than when cats received placebo. No significant difference was found in urinary relative supersaturation for calcium oxalate (CaOx) or struvite between treatment groups. Prednisolone administration did not induce diuresis, nor was it associated with increased calcium excretion or urinary saturation for CaOx in these healthy cats. Results of this study, however, should not be extrapolated to cats that form CaOx uroliths associated with idiopathic hypercalcemia.