Cushing's syndrome

This disease is endocrine pathology characterized by an excessive presence of glucocorticoids in circulation.

The condition is very frequent in dogs and rare in cats.  

Racial predispositions ,Dogs that are More Sensitive 

For the pituitary form (Poodle, Dachshund, Boxer, Beagle), German shepherd and

Miniature poodles appear to be frequently affected by adrenal tumors.

Middle-aged or older dogs are also more affected. The pituitary-dependent form can

also affect 1 year old subjects. 

It seems that females are more predisposed than males to develop a neoplastic form of the adrenal gland.

It appears that small breeds <20 kg tend to have the pituitary form; while >20 kg 

adrenal.

More than 80% of dogs show PU/PD

- Decreased central release of ADH

- Interferences with the action of ADH at the level of the renal tubules and loss of tonicity

medulla due to increased renal blood flow

- Accompanying subclinical or manifest diabetes mellitus.

Possible Complication of  this Disorder

Pulmonary thromboembolism caused by a hyperadrenergic state, the clinical signs of this complication are acute dyspnea and orthopnea (dyspneic animal forced to stand) . 

How To Recognize the Cushing Syndrome condition 

Under examination radiographically, plauritic effusion and an increase in the caliber of the pulmonary vessels are observed, above all

the arteries.

We can have:

- Iatrogenic Cushing's;

- Spontaneous Cushing:

Pituitary (80/85%)

Adrenal (15/20%):

▪ Adenomas (40%)

▪ Carcinomas (60%)

From ACTH (ectopic)

Symptoms of the Cushing’s Syndrome 

With direct clinical examination we can detect 

- PU/PD

- Polyphagia (excessive hunger )

- Barrel abdomen

- Muscle atrophy and laziness

- Shallow and frequent breathing/dyspnea

- Gonadal atrophy and anestrus

- Hepatomegaly ( liver enlargement)

- Ectopic calcifications

- Cutaneous signs: bilateral and symmetrical alopecia( area without hair) thinning of the skin,

hyperpigmentation, skin calcinosis, comedones, dry seborrhea, febelectasias, ecchymosis.

The barrel abdomen is caused by the decrease in muscle component and redistribution of body fats (thin skin due to increased catabolism).

The physiological reproductive cycle is altered 

Neurological Symptoms

From a skin point of view, the vascular pattern becomes more visible, the alopecia is mainly localized trunk and neck. If you notice anything like said above ,maybe you should call your veterinarian.

Diagnosis

Often the diagnosis is made only thanks to clinical findings; diagnostic tests

they are often used to evaluate the functionality of the Hypothalamus – Pituitary – Adrenal axis, to confirm

the suspicion and start appropriate therapy.

Other diagnostic tests are ultrasound and laboratory tests and sometimes x-rays.

Collateral investigations

1. RX: Radiological findings : increase in abdominal contrast due to accumulation of fat in the abdomen, hepatomegaly (due to accumulation of steroids), enlargement of the

bladder due to polyuria, dystrophic calcifications of the trachea, bronchi and skin.

A very rare finding  is the presence of a mass of soft tissue or calcification in the adrenal area (neoplasm). Metastases may be present lung carcinomas.

2. Hematological profile Urinalysis

Leukocytosis Hyposthenuria

Neutropenia Possible glycosuria (due to diabetes mellitus)

Lymphopenia Leukocyturia

Eosinopenia

3. Biochemical findings 

> alkaline phosphatase ALP

> cholesterol and triglycerides (lipolysis)

> liver enzymes (ALT, GGT)

> Na + H2o ➔ Hypertension

< K, Ca, P

< urea nitrogen (BUN)

> Blood sugar (due to insulin resistance)

4. Urinalysis: hyposthenuria, glycosuria (due to diabetes mellitus), leukocyturia.

5. Ultrasound:

Pituitary Cushing ➔ Bilateral hyperplasia of both adrenal glands, which appear

increase in volume.

Adrenal Cushing's ➔ Increase in volume of the adrenal gland which is the site of the neoplasm,while the contralateral is often not visible because it is atrophied.

6. Tests

1. ACTH stimulation test
2. Low-dose dexamethasone suppression test
3. Suppression test with high dose dexamethasone 

Therapy to keep your Pet Healthy 

Chronic Cushing's has a deleterious effect, and if left untreated the your pet can die because of changes of immune and cardiovascular system 

1) Trilostane (Modrenal cps 60 mg)

Side effects: Vomiting, rarely diarrhea.

Contraindications: In case of pregnancy or severe hepato-renal dysfunction.

2) Mitotane ( human chemotherapy drug but can be used to treat Cushing in dogs ) 

It’s very similar to Trilostane and has similar side effects 

Other therapeutic options include surgical removal of an adrenal or adrenal tumor

both glands, the latter when we have pituitary cushing; radiotherapy for i pituitary macroadenomas.If you decide to have surgery, you will need to take post-operative care into account pharmacologically to the missing hormones, generally using prednisolone.

Prognosis 

The prognosis depends on the age of your pet, young subjects can survive for up to 6-7 years,

while older about 2 years after diagnosis.

Written by Imrana Sljivo DVM🐾