Screening and diagnosis

Classification and risk stratification

Perioperative care

Quality improvement

Patient education

Nonpharmacologic interventions

Therapeutic procedures

Respiratory support

Follow-up and surveillance

Specific circumstances

Preventative measures

Medical management

Surgical interventions

Inpatient care

Diagnostic procedures

Diagnostic investigations

Insufficient evidence to make a recommendation.

Strongly favor this test or intervention.

The McMahon Score calculator estimates the risk of kidney failure or mortality in individuals with rhabdomyolysis, considering a combination of clinical and demographic factors. The calculator processes input across eight specific areas:

1. **Age (years)**
   - <= 50: 0 points
   - 51-70: 1.5 points
   - 71-80: 2.5 points
   - > 80: 3 points

2. **Sex**
   - Male: 0 points
   - Female: 1 point

3. **Initial creatinine (mg/dL)**
   - < 1.4: 0 points
   - 1.4-2.2: 1.5 points
   - > 2.2: 3 points

4. **Initial calcium (mg/dL)**
   - < 7.5: 2 points
   - >= 7.5: 0 points

5. **Initial creatine phosphokinase (U/L)**
   - > 40,000: 2 points
   - <= 40,000: 0 points

6. **Cause of rhabdomyolysis (secondary to seizures, syncope, exercise, statins, or myositis)**
   - Yes: 0 points
   - No: 3 points

7. **Initial phosphate (mg/dL)**
   - < 4.0: 0 points
   - 4.0-5.4: 1.5 points
   - > 5.4: 3 points

8. **Initial bicarbonate**
   - < 19 mEq/L: 2 points
   - > 19 mEq/L: 0 points

To calculate the total score, each selected option is transformed into a numerical value as per the above scale, then aggregated to produce a score ranging from 0 to 19. 

The interpretation of the total score is straightforward:

- A score less than 6 indicates a low risk of death or acute kidney injury requiring renal replacement therapy.
- A score of 6 or higher denotes a high risk of these adverse outcomes. 

This score helps guide clinical decisions, highlighting the urgency and level of intervention required based on risk.

The McMahon Score is a clinical calculator used to predict kidney failure or mortality in patients with rhabdomyolysis. Rhabdomyolysis is a serious syndrome due to a direct or indirect muscle injury, which can lead to severe kidney damage or death. The McMahon Score is particularly useful in the early stages of patient presentation, helping clinicians to stratify risk and guide treatment decisions.

The score is calculated based on five parameters: age, gender, serum creatinine level, serum phosphate level, and the cause of rhabdomyolysis. Each parameter is assigned a certain number of points, and the total score is used to predict the likelihood of kidney failure or mortality.

The McMahon Score is applicable to all patients suspected of having rhabdomyolysis. However, it may not be as accurate in patients with pre-existing kidney disease or other comorbidities that can affect kidney function or mortality. Therefore, it should be used in conjunction with clinical judgment and other diagnostic tools.

Rhabdomyolysis

Guidelines

Key sources