Basal and ACTH-stimulated plasma aldosterone concentrations are normal or increased in dogs with trichuriasis-associated pseudohypoadrenocorticism

Clinical and Diagnostic Findings in Dogs Infected with Trichuris vulpis: A Retrospective Study

Trichuris vulpis is a parasite of the large intestine of canids and has a global distribution. Despite its well-established epidemiology, the question of its pathogenicity in dogs remains debated. It has been suggested that younger age and concurrent infection with Ancylostoma caninum may be responsible for more severe clinical presentations. This retrospective study aimed to describe the clinical and diagnostic features of T. vulpis-infected dogs and to compare these findings with dogs infected with both T. vulpis and other intestinal parasites (poly-infected dogs). Forty-five dogs were included, with twenty-five being solely infected by T. vulpis and twenty poly-infected dogs. Only weight loss was more frequent (p = 0.006) in poly-infected dogs compared to T. vulpis mono-infected dogs. No significant differences were observed in laboratory abnormalities between mono-infected and poly-infected dogs. Only diarrhea was more frequent (p = 0.007) in younger dogs compared to adults. The egg shedding pattern was significantly higher (p = 0.04) among adult dogs compared to young ones, and there was a significant positive correlation between egg shedding and age (r = 0.41; p = 0.005). These findings suggest that T. vulpis might be responsible for both clinical signs and laboratory abnormalities in dogs, irrespective of the host's age and the presence of other intestinal parasites.

Urinary cortisol-creatinine ratio in dogs with hypoadrenocorticism

Background

Basal serum cortisol (BSC) ≥2 μg/dL (>55 nmol/L) has high sensitivity but low specificity for hypoadrenocorticism (HA).

Objective

To determine whether the urinary corticoid:creatinine ratio (UCCR) can be used to differentiate dogs with HA from healthy dogs and those with diseases mimicking HA (DMHA).

Animals

Nineteen healthy dogs, 18 dogs with DMHA, and 10 dogs with HA.

Methods

Retrospective study. The UCCR was determined on urine samples from healthy dogs, dogs with DMHA, and dogs with HA. The diagnostic performance of the UCCR was assessed based on receiver operating characteristics (ROC) curves, calculating the area under the ROC curve.

Results

The UCCR was significantly lower in dogs with HA (0.65 × 10⁻⁶; range, 0.33‐1.22 × 10⁻⁶) as compared to healthy dogs (3.38 × 10⁻⁶; range, 1.11‐17.32 × 10⁻⁶) and those with DMHA (10.28 × 10⁻⁶; range, 2.46‐78.65 × 10⁻⁶) (P < .0001). There was no overlap between dogs with HA and dogs with DMHA. In contrast, 1 healthy dog had a UCCR value in the range of dogs with HA. The area under the ROC curve was 0.99. A UCCR cut‐off value of <1.4 yielded 100% sensitivity and 97.3% specificity in diagnosing HA.

Conclusions and Clinical Importance

The UCCR seems to be a valuable and reliable screening test for HA in dogs. The greatest advantage of this test is the need for only a single urine sample.

Prevalence and characterization of hypoadrenocorticism in dogs with signs of chronic gastrointestinal disease: A multicenter study

Background

Dogs with hypoadrenocorticism (HA) frequently show signs of gastrointestinal disease (SGD). The prevalence of dogs presented for chronic SGD with HA is unknown.

Objectives

The aims of this study were to determine the prevalence of HA in dogs with chronic SGD and to identify clinical and laboratory variables for HA in this population.

Animals

One hundred fifty‐one dogs with chronic SGD.

Methods

In this multicentered prevalence study a standardized workup was performed in prospectively enrolled dogs with SGD > 3 weeks duration. Basal serum cortisol concentration was measured in every dog with ACTH stimulation test (ACTHST) if basal serum cortisol concentration was <3 μg/dL.

Results

Basal serum cortisol concentration was <3 μg/dL in 80/151 (53%) dogs, <2 μg/dL in 42/151 (28%) dogs, and < 1 μg/dL in 9/151 (6%) dogs. In 6/151 dogs HA was diagnosed based on ACTHST (stimulated serum cortisol concentration < 2 μg/dL), a prevalence of 4%. There was no difference in history, physical examination, and laboratory variables between dogs with HA and those with other causes of chronic SGD. In 4/6 dogs with HA, there was melena or hematochezia indicating gastrointestinal blood loss. Hyperkalemia, hyponatremia, or both was not observed in any dog.

Conclusion and Clinical Importance

The prevalence of HA among dogs with chronic SGD is higher than in the general population. Based on these results, testing adrenal function should be performed as a standard screening test in dogs with chronic SGD to differentiate between HA and chronic enteropathies.

Pseudohypoadrenocorticism in a Siberian Husky with Trichuris vulpis Infection

An entire male Siberian Husky presented for diarrhoea, weakness, inappetence, and collapse following a six-day period of illness. On clinical examination the dog displayed vasoconstrictive circulatory shock, dehydration, and melena. Laboratory tests revealed a marked hyponatraemia, hyperkalaemia, and a decreased sodium/potassium ratio of ≤ 12.4. The baseline and poststimulation serum cortisol concentrations were markedly elevated following adrenocorticotropin hormone (ACTH) stimulation test, yielding 712 nmol/L and 706 nmol/L, respectively. The elevated cortisol concentration excluded hypoadrenocorticism. A concurrent Trichuris vulpis (whipworm) infection was also identified. The dog was treated with supportive care including fenbendazole and recovered uneventfully. The final diagnosis was Trichuris vulpis infection with secondary pseudohypoadrenocorticism. This case report further supports a previous observation that the Siberian Husky breed may have an increased sensitivity to infection with Trichuris vulpis and development of pseudohypoadrenocorticism.

Mineralocorticoid before glucocorticoid deficiency in a dog with primary hypoadrenocorticism and hypothyroidism

A dog with an unexpected presentation of primary hypoadrenocorticism was evaluated for clinical signs and electrolyte abnormalities characteristic of Addison's disease. Although the initial adrenocorticotropic hormone (ACTH) stimulation test documented serum cortisol concentrations within the reference range, subsequent assessments confirmed hypoaldosteronism. Mineralocorticoid replacement promptly normalized electrolytes and transiently improved clinical illness. Six weeks after initial ACTH stimulation testing, the dog became glucocorticoid deficient. Concurrent primary hypothyroidism was also documented. Hypoaldosteronism preceding hypocortisolemia is a unique presentation of canine Addison's disease.

Presumptive pseudohypoaldosteronism secondary to chronic urinary tract obstruction from sloughed urinary bladder mucosa and urinary tract infection in a cat

OBJECTIVE

To describe a case of presumptive secondary pseudohypoaldosteronism (PHA) in a cat with urinary tract infection and chronic urethral obstruction. The obstruction was believed to have resulted from sloughed urinary bladder mucosa secondary to pressure necrosis.

CASE SUMMARY

A 5-year-old, 4 kg, castrated male Siamese cat presented for vomiting and stranguria. Medical history included a perineal urethrostomy for urethral obstruction. Physical examination revealed a large, painful, nonexpressible urinary bladder. Point-of-care testing demonstrated electrolyte derangements consistent with a postrenal azotemia and metabolic acidosis. Results of urine culture was positive for bacterial growth. Diagnostic imaging revealed presence of retroperitoneal fluid, marked urinary bladder wall thickening, bilateral hydroureter, mild bilateral pyelectasia, and small nephroliths. The patient was treated for a urinary tract obstruction and infection. In the 3 weeks following initial discharge, the patient was evaluated on multiple occasions for lethargy, intermittent vomiting, inappropriate urination, and progressive polyuria and polydipsia. Although the urinary bladder was easily expressed during repeat examinations, it was persistently distended and subjectively thickened upon palpation. Repeat ultrasound of the urinary tract showed evidence of sloughed tissue in the bladder lumen, likely secondary to chronic urethral obstruction and pressure necrosis. A cystotomy was performed to remove the necrotic tissue, and a revised perineal urethrostomy was done due to a partial urethral stricture. Bladder biopsies were obtained at this time. Postoperatively, the cat was reported by the owners to be urinating normally but continued to be polyuric and polydipsic in the week following discharge. One week after surgery, the cat presented in hypovolemic shock with laboratory findings consistent with a presumptive diagnosis of secondary PHA.

NEW OR UNIQUE INFORMATION PROVIDED

PHA has not been reported previously in a cat. This case report suggests that aldosterone resistance should be considered in cats with consistent laboratory findings and a history of documented obstructive uropathy and urinary tract infection.

A Dog with Pseudo-Addison Disease Associated with Trichuris vulpis Infection

A female Rottweiler dog was presented with a history of intermittent vomiting and diarrhoea, dysorexia, weakness, and weight loss. Haemocytometry and biochemistry values were within normal ranges except for electrolyte analyses, that demonstrated hyponatremia and hyperkalemia with a decreased sodium/potassium ratio. A diagnosis of hypoadrenocorticism was suspected. Basal and post-ACTH stimulation cortisolemia were within the normal values. Electrocardiography was normal, and thoracic radiography showed no significant modifications. On abdominal ultrasonography, adrenal glands appeared normal, while the bowel was distended, and several thin linear hyperechoic objects floating in the lumen were observed. Two adult female whipworms (Trichuris vulpis) were collected following bowel irrigation. Anthelmintic treatment against the parasite was curative.

Hyponatremia and hyperkalemia associated with peritoneal effusion in four cats

Four cats with considerable peritoneal effusion and corresponding hyponatremia and hyperkalemia were evaluated. The Na:K ratio in all cats was < 25, which is suggestive of adrenal insufficiency. An ACTH stimulation test was performed on 3 cats for evaluation of adrenal gland function. Serum cortisol and aldosterone concentrations did not support a diagnosis of adrenal gland insufficiency. In 1 cat, histologic evaluation of the adrenal glands at necropsy also failed to support a diagnosis of hypoadrenocorticism. On the basis of these findings, and because hyponatremia and hyperkalemia could not be readily explained by another cause, the electrolyte abnormalities were presumed to be secondary to peritoneal effusion.

Combined hyponatremia and hyperkalemia mimicking acute hypoadrenocorticism in three pregnant dogs

Differential diagnoses for hyponatremia with concurrent hyperkalemia should include hypoadrenocorticism. Renal failure, chylothorax, and gastrointestinal tract disorders may also cause abnormally low serum sodium:potassium ratios. The ACTH stimulation test is the gold standard for diagnosis of hypoadrenocorticism.