High-rise syndrome

What it is

High-rise syndrome describes the characteristic pattern of injuries in cats that fall from a height of at least two storeys. During the fall the cat uses its righting reflex to rotate its body and point its feet toward the ground. On impact the extended limbs absorb part of the energy and the rest is transmitted to the thorax and head, which strike the ground. Hence the typical combination of injuries:

• Thoracic trauma: the most common; pneumothorax and pulmonary contusion, sometimes rib fractures or diaphragmatic hernia.
• Facial trauma: epistaxis, midline fracture of the hard palate, mandibular symphyseal separation, dental fractures (especially of the canines) and chin lacerations.
• Limb injuries: fractures of the thoracic and pelvic limbs, luxations and injuries of the tarsus and digits.

A classic study observed that limb injuries did not increase above a certain height, which was attributed to the cat relaxing its body and spreading its limbs like a parachute once it reaches its maximum speed; this interpretation is debated, because cats that die after falling from very high rarely reach the clinic.

Who it affects

Young cats in urban settings with access to unprotected windows, balconies or terraces, with more cases in warm months when windows are open. Falls usually happen while the cat chases insects or birds, or slips from a railing.

Anatomy involved

• Lungs and pleural space: pulmonary contusion and pneumothorax.
• Skull and mandible: the hard palate splits along the median suture, and the mandibular symphysis, a fibrous joint in the cat, separates in the midline; fractures of the mandibular ramus and of the teeth also occur.
• Thoracic limbs: fractures of the radius and ulna and of the humerus, and injuries of the digits and claws.
• Pelvic limbs: fractures of the tibia and femur and tarsal injuries (fractures and luxations), plus pad injuries.

Clinical signs

Dyspnoea and tachypnoea, shock, epistaxis, blood in the mouth, malocclusion or inability to close the mouth, lameness or limb deformity, injured pads and broken claws. Some cats have few visible injuries and a significant pneumothorax.

Diagnosis

• Stabilisation and primary survey: airway, breathing, circulation; point-of-care thoracic ultrasound for pneumothorax.
• Thoracic radiographs once the cat tolerates them: pneumothorax, contusion, rib fractures, diaphragmatic hernia.
• Oral examination (often under sedation) and CT of the head for palatal and mandibular fractures.
• Limb radiographs and abdominal ultrasound to rule out bladder and other organ injuries.

Treatment

Stabilisation first: oxygen, thoracocentesis for pneumothorax, analgesia and treatment of shock. Fractures are repaired once the cat is stable:

• Mandibular symphyseal separation: cerclage wire around the rostral mandible.
• Hard palate fracture: many are narrow and heal on their own; wide ones need suturing or flaps to prevent an oronasal fistula.
• Limb fractures: internal or external fixation depending on the bone and fracture configuration.

Most cats that reach the clinic alive survive with treatment. Prevention is simple: sturdy nets or screens on windows and balconies.

Key studies

• Whitney and Mehlhaff (1987), 132 cats seen in New York over 5 months. 90% had some thoracic trauma; among them, 68% had pulmonary contusion and 63% pneumothorax. Facial trauma was present in 57%, limb fractures in 39% and hard palate fracture in 17%. 37% needed emergency treatment, and 90% of the treated cats survived.
• Vnuk et al. (2004), 119 cats in Zagreb. 59.6% were under one year old, the average fall was four storeys and 96.5% survived. 46.2% had limb fractures, more often of the pelvic limbs (61.5%), and the tibia was the bone most often fractured; thoracic trauma was found in 33.6%. Falls from the seventh storey or higher were associated with more severe injuries.
• Bonner et al. (2012), 84 cats in Philadelphia, with a mean fall of 2.65 storeys. 66% had some orofacial injury: epistaxis, hard palate fracture, mandibular fracture or symphyseal separation, and dental and tongue injuries. Survival was 94%; one untreated palatal fracture ended in an oronasal fistula.
• Candela Andrade et al. (2025), the largest series, published in two parts: 1125 cats treated in Berlin between 2004 and 2013. Mean age was 2.3 years; 77% of falls happened in summer, 62.1% at night and 74.2% onto hard surfaces. Thoracic trauma was found in 58.3%, orofacial injuries in 51.1%, limb fractures in 47.2% and shock in 48.6%, and 87% survived. Injury severity correlated with age, landing surface and fall height. It is retrospective and from a single centre.