Patient: Hedgehog 4 years old, weight 400g, unneutered female.
Ultrasonography: probed with the microconvex probe L13-3NS of the Mindray Animal Medical Vetus E7: the fluid-filled uterus was clearly demonstrated.
Analysis:
1. Common uterine diseases in hedgehogs: uterine pus accumulation, blood accumulation
2. Uterine pus accumulation in hedgehogs may be accompanied by other symptoms such as loss of appetite, abdominal distension, and discharge. Uterine pus accumulation is an emergency in unspayed females and requires immediate treatment, which usually includes surgical removal of the uterus and ovaries.

I. Ultrasonographic features and pathological inferences

Key differential points:

Pyometra: often associated with fever, purulent vaginal discharge, and ultrasound visualisation of intracavitary hyperechoic granules (pus);
Hemometra: mostly due to bleeding from the reproductive tract (e.g. hormonal disorders, trauma), more homogeneous fluid, no signs of infection.

II. Special considerations for hedgehog uterine disease
High prevalence factors:

Risk of uterine disease in unspayed female hedgehogs >60% (especially in individuals >2 years old);
Hedgehogs have irregular ovarian cycles and are susceptible to hormone-dependent lesions.
Secondary risks:

Uterine rupture (high fluid pressure);
Septicaemia (if infectious pyometra).

III. Emergency treatment

Steps to confirm the diagnosis:

Fine needle aspiration (FNA): aseptic collection of uterine fluid for cytology (pus cells/red blood cells) and bacterial culture;
Routine blood count: white blood cell count >20×10⁹/L suggests infection (supports pyometra).

Surgical treatment:
Ovariohysterectomy (OVH):