QuestionSBA
QuestionChoice
This is a sensible differential in a trauma patient with haemodynamic instability, although it would not explain the petechial rash and is unlikely to cause such significant respiratory compromise and neurological disturbance
31974
b
Internal haemorrhage
QuestionChoice
This would not explain his respiratory compromise or petechial rash. Although a subarachnoid haemorrhage is the most common type of brain haemorrhage secondary to trauma in the acute phase
31976
d
Subarachnoid haemorrhage
QuestionChoice
Although this may explain his respiratory compromise, it would not explain the petechial rash. It is unlikely to cause acute confusion and drowsiness in someone so young, and the normal temperature is also going against this diagnosis. Pneumonia would also typically cause unilateral crackles on auscultation
31975
c
Hospital-acquired pneumonia
QuestionChoice
Fat embolism classically presents with the triad of respiratory compromise, neurological disturbance and a petechial rash. It typically occurs 24-72 hours after a long bone injury or surgical procedure
31973
a
Fat embolism
QuestionChoice
This may explain his acute respiratory distress but would not explain the petechial rash and is unlikely to cause such acute neurological disturbance
31977
e
Acute respiratory distress syndrome (ARDS)
QuestionComment
Can someone explain the crackles?
61957
User
subscriber
rockinrobyn9
QuestionComment
would it give you hypotension though
62152
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subscriber
Vaccine Complement
Concept
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# Summary

Fat embolism refers to a medical condition characterized by the entry of fat fragments into the systemic circulation, subsequently lodging in the small vessels of the lungs or other tissues. This typically occurs due to fractures, especially long bone fractures. Clinical manifestations vary depending on the site of embolism, with breathlessness being a common symptom in pulmonary fat embolism. Investigations may include radiographic imaging and serum markers. The mainstay of management is supportive care, focused on oxygenation and symptomatic relief.

# Definition

Fat embolism is a clinical syndrome resulting from the dissemination and subsequent lodgment of fat droplets or fat globules in the small vessels of the systemic and/or pulmonary circulation. This event typically follows trauma, particularly fractures of long bones or pelvic bones, but it can also occur after non-traumatic events such as orthopedic surgery or severe burns.

# Epidemiology

The incidence of fat embolism varies and is largely dependent on the context. It is estimated to occur in 1-3% of all long bone fractures, but the incidence can be as high as 10-30% in patients with polytrauma or after major orthopedic surgeries. Fat embolism syndrome, a severe manifestation of fat embolism characterized by multisystem involvement, is estimated to occur in approximately 10% of all cases of fat embolism.

# Aetiology

The aetiology of fat embolism generally involves:

-   Trauma, particularly long bone and pelvic fractures
-   Non-traumatic events such as orthopedic surgeries (hip or knee arthroplasty)
-   Severe burns
-   Liposuction
-   Prolonged corticosteroid therapy

# Signs and Symptoms

The signs and symptoms of fat embolism are largely determined by the site of embolization:

-   Pulmonary: Breathlessness, hypoxia, tachycardia, tachypnea, and fever
-   Neurologic: Altered mental status, seizures, focal deficits, or coma
-   Dermatologic: Petechial rash predominantly on the upper body

# Differential Diagnosis

Differential diagnosis for fat embolism includes conditions that present similarly such as:

-   Pulmonary embolism: Presents with sudden onset shortness of breath, chest pain, and hemoptysis.
-   Acute respiratory distress syndrome (ARDS): Presents with severe shortness of breath, rapid breathing, and bluish skin coloration (cyanosis).
-   Pneumonia: Presents with cough (often productive), fever, shortness of breath, and chest discomfort.
-   Sepsis: Presents with fever, increased heart rate, increased respiratory rate, and confusion.

# Investigations

The diagnosis of fat embolism is typically clinical, supported by relevant investigations:

-   Imaging studies: Chest X-ray may reveal diffuse bilateral infiltrates; CT of the chest may show fat within the vessels.
-   Laboratory tests: Serum markers such as fat macroglobulinemia, increased serum lipase, and increased serum LDH.
-   Bronchoalveolar lavage: To identify fat droplets in macrophages.

# Management

Management of fat embolism is primarily supportive and includes:

-   Oxygen therapy: To relieve hypoxia and dyspnea.
-   Fluid resuscitation: To maintain hydration and support circulatory function.
-   Pharmacological therapy: Prophylactic low-molecular-weight heparin may be considered to prevent thromboembolic events.
-   Fracture stabilization: Early immobilization of fractures can reduce the incidence of fat embolism.

# References

-   [Ortho Bullets: Fat Embolism Syndrome](https://www.orthobullets.com/basic-science/9055/fat-embolism-syndrome)
1066
1127
Fat embolism
Topic
37
Orthopaedics
6395
Fat embolism syndrome typically presents 24-72 hours post-injury with respiratory distress, neurological symptoms, and a petechial rash.
A 40 year old man is admitted to hospital following a road traffic accident. He has a pelvic x-ray which shows a stable pelvic fracture which is managed conservatively.

Approximately 48 hours later, he becomes acutely confused, drowsy and breathless.

His observations are as follows:

- Respiratory rate: 25 breaths per minute
- Saturations: 90% on room air
- Heart rate: 90 beats per minute
- Blood pressure: 95/65mmHg
- Temperature: 36.5 degrees Celsius

On examination, auscultation of his chest reveals bibasal coarse crackles. There is also a petechial rash on the anterior aspect of his chest.

What is the most likely diagnosis?
a