What to Know About Shih Tzus

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Shih Tzus are prone to several serious health issues, particularly related to their eyes and neurological system. Regular veterinary check-ups, early diagnosis, and appropriate management strategies are essential to ensure the well-being of these dogs. Breeders should also be aware of the genetic components of these conditions and seek genetic counseling to reduce their prevalence in future generations.

Shih Tzus are a popular breed known for their distinctive appearance and affectionate nature. However, they are also prone to several health issues, particularly related to their eyes and neurological system. This article provides an overview of the common health problems in Shih Tzus, focusing on ocular and neurological conditions, and offers insights into their diagnosis and management.

Ocular Health Issues

Ophthalmic Examination Findings

Shih Tzus are susceptible to various ocular surface diseases. A comprehensive ophthalmic examination of Shih Tzus revealed a high prevalence of ocular pathologies, including adnexal abnormalities and corneal opacification. Common findings included caruncular trichiasis, medial lower lid entropion, and corneal pigmentation1. These conditions often lead to ocular irritation and reduced globe protection, necessitating prophylactic measures such as medial canthoplasty and topical lubrication to improve ocular health.

Dry-Eye Syndrome

Keratoconjunctivitis sicca (KCS), or dry-eye syndrome, is prevalent in Shih Tzus. This condition is characterized by a deficiency in tear production, leading to ocular surface inflammation and damage. Clinical and histomorphological evaluations have shown that KCS can progress from mild to severe stages, with significant impacts on the tear film and conjunctival health5. Early identification and routine evaluation are crucial for managing KCS and maintaining the quality of life in affected dogs.

Retinal Detachment and Glaucoma

Shih Tzus are also at risk for retinal detachment (RD) and glaucoma, particularly following surgical procedures like phacoemulsification. Studies have reported a cumulative incidence of RD and glaucoma in Shih Tzus, with glaucoma being more prevalent than in other breeds4. Regular ophthalmic examinations and early intervention are essential to prevent and manage these conditions.

Meibomian Gland Dysfunction

Meibomian gland dysfunction is another common issue in Shih Tzus, particularly those with KCS. Noncontact infrared meibography has revealed significant morphological abnormalities in the meibomian glands of affected dogs, including gland shortening and dropout7. These abnormalities exacerbate tear film deficiencies, highlighting the need for comprehensive ocular surface evaluations in Shih Tzus.

Neurological Conditions

Lissencephaly

Lissencephaly, a rare brain malformation characterized by a smooth and thickened cerebral surface, has been documented in Shih Tzus. This condition often presents with early-onset forebrain abnormalities, including cluster seizures and behavioral changes. Magnetic resonance imaging (MRI) is essential for diagnosing lissencephaly and associated brain malformations2. While antiepileptic drugs can control seizures, other neurological symptoms may persist.

Genetic Disorders

Progressive Retinal Atrophy

Progressive retinal atrophy (PRA) is an autosomal recessive disorder leading to photoreceptor degeneration and blindness in Shih Tzus. Whole genome sequencing has identified a homozygous nonsense mutation in the JPH2 gene as a potential cause of PRA in this breed8. Genetic testing and counseling are recommended for breeders to manage and reduce the incidence of PRA.

Hepatocutaneous Syndrome

Hepatocutaneous syndrome (HCS) is another condition with a potential heritable component in Shih Tzus. This syndrome is characterized by progressive superficial necrolytic dermatitis and degenerative vacuolar hepatopathy. Clinical signs include lethargy, inappetence, weight loss, and lameness. Histologic examination of skin and liver specimens is crucial for diagnosis, and pedigree analysis suggests a common ancestry in affected dogs3.