QuestionSBA
QuestionChoice
This patient has been given excessive volumes of normal saline in a short period of time which has led to high levels of chloride and a hyperchloraemic metabolic acidosis. In this stem, the patient has been managed in A&E rather than a dedicated burns unit, which may have resulted in this error. Parkland's formula is used to calculate resuscitation fluid required over the first 24 hours according to the estimated % of burn and the patient's weight. This patient should have received 6.5L of fluid over the first 8 hours and 6.5L over the next 16 hours. Aggressive fluid resuscitation can cause electrolyte imbalances. He would also be at risk of hypernatraemia in this case, and subsequent cerebral oedema. Some patients experience no symptoms with high levels of chloride whilst others may have muscle weakness, excessive thirst, and confusion.
53187
a
Hyperchloraemia
QuestionChoice
This patient has had high volumes of normal saline and is therefore likely to be hypernatremic as opposed to hyponatraemic, and abnormalities in the sodium alone are unlikely to explain any acid-base disturbance.
53191
e
Hyponatraemia
QuestionChoice
Hypercalcaemia typically presents with 'stones, bones, abdominal groans, thrones and psychiatric overtones'. This refers to kidney stones bone pain, constipation, excessive thirst and mood changes. Hypercalcaemia can be caused by multiple myeloma, paraneoplastic conditions, medication, sarcoidosis and over-active parathyroid glands. Patients with burns are at risk of tissue breakdown and rhabdomyolysis, which may actually result in initial hypocalcaemia. Hypercalcaemia is not associated with a metabolic acidosis but has been associated with a metabolic alkalosis.
53190
d
Hypercalcaemia
QuestionChoice
This patient is unlikely to be hypokalaemic, since in fact burns lead to tissue breakdown and potential rhabdomyolysis, which may cause hyperkalaemia. Hyperkalaemia can also cause a metabolic acidosis due to displacement of intracellular hydrogen ions and competition for excretion in the distal tubule. Hypokalaemia would actually be associated with a metabolic alkalosis.
53189
c
Hypokalaemia
QuestionChoice
This is incorrect because this patient has received a large volume of normal saline, which would lead to hyperchloraemia. Hypochloraemia is usually associated with diarrhoea and vomiting. This is not associated with a metabolic acidosis.
53188
b
Hypochloraemia
Concept
Chapter
# Summary

Burns patients necessitate prompt evaluation and intervention, including the measurement of burn size and depth. The primary treatment priorities include securing the airway, managing pain, and ensuring adequate fluid resuscitation. Utilization of the Parkland formula can guide fluid resuscitation, while application of the 'Rule of 9s' assists in estimating the body surface area (BSA) affected by the burn. Referral to a burns unit is critical in cases of full thickness burns covering >5% BSA, partial thickness burns covering >10% BSA, or if the patient is of extreme age (either very young or elderly).

# Definition

A burn is a type of injury to skin, or other tissues, caused by heat, cold, electricity, chemicals, friction, or radiation. Burns that affect only the superficial skin layers are known as superficial or first-degree burns. When the damage extends to deeper layers, they are classified as partial-thickness (second-degree) or full-thickness (third-degree) burns.

# Epidemiology

Burns can occur to anyone at any age but are particularly common in the very young or elderly. They can result from a variety of sources including domestic accidents, industrial mishaps, and natural disasters.

# Aetiology

Burns can be caused by multiple factors including:

-   Thermal (flames, scalds, contact with hot objects)
-   Chemical (acids, alkalis, organic compounds)
-   Electrical (low and high voltage)
-   Radiation (sunlight, tanning booths, radiotherapy)
-   Friction (road rash, rope burns)

# Signs and Symptoms

The signs and symptoms of burns may include:

-   Pain (can be absent in severe burns due to nerve damage)
-   Redness and swelling
-   Blisters
-   Peeling skin
-   White or charred skin (in severe burns)


# Differential Diagnosis

In addition to burns, several other conditions can present with similar features and should therefore be considered in the differential diagnosis. These include:

-   **Frostbite**: Characterized by skin that appears waxy and cold, changes in skin color from white or yellow to purple, numbness, and possible blister formation.
    
-   **Dermatitis**: Includes signs such as a skin rash, itching, redness, swelling, and possible blistering. Types of dermatitis include atopic dermatitis (eczema), contact dermatitis, and seborrheic dermatitis.
    
-   **Cellulitis**: Presents with skin redness, warmth, swelling, and tenderness. Fever and chills may also be present.
    
-   **Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis**: These severe reactions to medication or infection can cause skin pain, facial swelling, hives, and shedding of the skin.
    
-   **Necrotizing fasciitis**: This rapidly progressing bacterial infection of the fascia and subcutaneous tissue can lead to symptoms similar to severe burns, such as severe pain, fever, and erythema that progresses to necrosis.
    
-   **Deep Vein Thrombosis**: Pain, swelling, redness, and warmth over the affected area may mimic some of the signs of a burn, particularly in the extremities.
    
-   **Vasculitis**: Inflammation of the blood vessels can result in lesions that could be confused with burns. Symptoms can include a rash, fever, pain, and general discomfort.
    
-   **Pyoderma Gangrenosum**: This rare, ulcerative skin condition can be confused with burns due to its necrotic appearance. It is often associated with systemic diseases like inflammatory bowel disease or rheumatoid arthritis.
    

Each of these conditions has a different course of management and treatment, so accurate diagnosis is critical.

# Investigations

Investigations for burns can include:

-   Examination of burn depth and extent
-   Basic blood tests (Complete Blood Count, Urea, Electrolytes)
-   Arterial blood gas (in cases of smoke inhalation)
-   Chest X-ray (if smoke inhalation suspected)
-   Urinalysis (to check for myoglobin if rhabdomyolysis suspected)

# Management

Management strategies for burns include:

-   Ensuring airway patency, breathing, and circulation (ABCs)
-   Pain management, usually with opioids
-   Intravenous fluids will be required for children with burns greater than 10% of total body surface area, and adults with burns greater than 15% of total body surface area
-   Fluid resuscitation using the **Parkland formula.** The Parkland formula calculates the total fluid volume needed for the first 24 hours after a burn injury. It is calculated as follows:
	- Total body surface area of the burn % x weight (Kg) x 4
	- Half of the fluid is administered in the first 8 hours and the remaining half is administered over the next 16 hours.
-   Wound care (debridement, topical antibiotics, dressings)
-   Tetanus prophylaxis
-   Referral to a burns unit in severe cases or as defined by local protocol (often burns involving the face/hand/perineum and burns >10% in adults and >5% in children)

# Rule of 9's for Estimating Burns

The 'Rule of 9s' is a useful method to approximate the BSA affected by a burn:

-   Head = 9%
-   Torso (front) = 18%
-   Torso (back) = 18%
-   Whole arm = 9%
-   Hand = 1%
-   Whole leg = 18%

# Complications

- **Curling Ulcer:** Patients with severe burns are at risk of developing Curling ulcers, which are stress-induced gastric ulcers. These can result from the physiological stress response to burn injuries.

- **Airway Compromise:** In cases of burn injuries involving smoke inhalation, there is a risk of airway compromise due to the inhalation of hot gases and toxic substances. This can lead to respiratory distress and necessitates immediate attention.

# References

[Click here to see a diagram explaining the Rule of 9s](https://en.wikipedia.org/wiki/Wallace_rule_of_nines#/media/File:513_Degree_of_burns.jpg)
139
815
Burns
Topic
7
General Surgery
10698
A 35-year-old male presents to A&E with extensive burns from a house fire. His burns are widely disseminated over his back, left leg, and left arm. He is rapidly resuscitated with 13L of 0.9% normal saline over the next 8 hours as he awaits transfer within the department to the local burns unit. He weighs 72kg. On the following day, he appears confused and complains of a headache and fatigue. An ABG shows metabolic acidosis.

Which of the following electrolyte imbalances is the most likely cause of his acid-base disturbance?
a