Compartment Syndrome and May-Thurner Syndrome: Diagnosis and Management
Overview
These are two completely distinct conditions that require different diagnostic and therapeutic approaches. Compartment syndrome is an acute surgical emergency involving elevated pressure within a closed muscle compartment, while May-Thurner syndrome is a chronic venous compression disorder causing iliofemoral deep venous thrombosis.
COMPARTMENT SYNDROME
Clinical Diagnosis
Pain out of proportion to injury is the earliest and most reliable warning sign of acute compartment syndrome and should trigger immediate action 1.
The classic clinical presentation follows a progression:
- Pain on passive stretch of the affected muscle compartment is the most sensitive early sign 1
- Increasing firmness/tension of the compartment as pressure rises 1
- Paresthesia (sensory changes) from nerve ischemia 1
- Paralysis (motor deficits) is a late sign indicating significant irreversible tissue damage 1
- Pulselessness, pallor, and decreased temperature are also late signs indicating severe tissue damage—waiting for these signs leads to permanent disability 1, 2
Critical Diagnostic Pitfalls
Clinical signs alone have poor sensitivity (approximately 25% with severe pain alone) but high specificity 1. The combination of severe pain plus pain on passive stretch increases diagnostic accuracy to 68%, and when paralysis is added, accuracy reaches 93%—but by then irreversible muscle ischemia has already occurred 1.
Palpation of the suspected compartment is unreliable in isolation (sensitivity 54%, specificity 76% in children) and should never be relied upon alone 1, 2.
High-Risk Populations Requiring Heightened Vigilance
- Young men under 35 years with tibial fractures are at highest risk 1
- Crush injuries or high-energy trauma patients 1
- Vascular injuries, burns, or patients on anticoagulation 1
- Importantly, compartment syndrome can occur with soft tissue injuries alone without fractures 2, 3
Immediate Emergency Management Algorithm
When compartment syndrome is suspected, follow this sequence without delay:
- Remove all constricting dressings, casts, splints, or bandages immediately 2, 3
- Position the limb at heart level—elevation decreases arterial inflow and worsens tissue ischemia 2, 3
- Arrange immediate surgical consultation for fasciotomy without waiting for confirmatory tests 2, 3
Compartment Pressure Measurement (When Diagnosis Uncertain)
Measure compartment pressures only if diagnosis remains in doubt, particularly in obtunded, sedated, or uncooperative patients who cannot reliably report pain 1, 2.
Measurement can be performed using:
- Traditional needle manometry
- Multiparameter monitors
- Dedicated transducer-tipped intracompartmental pressure monitors 1
Fasciotomy is indicated when:
- Compartment pressure ≥30 mmHg, OR
- Differential pressure (diastolic BP minus compartment pressure) ≤30 mmHg 1
The differential pressure threshold is the most recognized cut-off for intervention in current practice 1.
Definitive Surgical Treatment
Perform immediate fasciotomy of all involved compartments through long incisions of both skin and fascia 2, 3.
Post-fasciotomy management includes:
- Monitor for myoglobinuria and maintain urine output >2 mL/kg/h if myoglobinuria develops to prevent acute kidney injury from rhabdomyolysis 4, 2, 3
- Alkalinize urine with sodium bicarbonate to prevent myoglobin precipitation and acute kidney injury 4
- Consider negative pressure wound therapy to facilitate closure in patients not candidates for delayed primary closure 1, 3
- Monitor for compartment syndrome recurrence, particularly in severe cases 1, 3
Prophylactic Fasciotomy Indications
Consider prophylactic fasciotomy in acute limb ischemia with threatened but salvageable limb (Category IIa or IIb), particularly when time to revascularization exceeds 4 hours 1, 3.
Critical Pitfalls to Avoid in Compartment Syndrome
- Never wait for late signs (pulselessness, pallor, paralysis)—these indicate irreversible tissue damage 1, 2, 3
- Never rely solely on palpation for diagnosis 1, 2, 3
- Never delay diagnosis in obtunded or sedated patients—measure compartment pressures earlier in these populations 1, 2, 3
- Never elevate the limb excessively—this further decreases perfusion pressure and worsens ischemia 2, 3
- Never miss compartment syndrome in patients without fractures—it can occur with soft tissue injuries alone 2, 3
MAY-THURNER SYNDROME
Pathophysiology and Clinical Presentation
May-Thurner syndrome is an anatomical variant in which the right common iliac artery overlies and compresses the left common iliac vein against the lumbar spine, causing iliofemoral deep venous thrombosis 5.
This anatomical variant is present in over 20% of the population but is rarely symptomatic 5.
Clinical presentations include:
- Pain and swelling of the left lower extremity 6
- Venous stasis ulcers 6
- Skin discoloration 6
- Extensive ipsilateral deep vein thrombosis 6
- Postphlebitic syndrome with all its sequelae 6
- In severe cases, pulmonary embolism 7
Diagnostic Approach
Color Doppler and duplex Doppler ultrasound allow easy localization of deep vein thrombosis, measurement of its extension, and highlighting of vascular changes typical of May-Thurner syndrome: compression and consequent hypertension of the left common iliac vein 7.
MDCT findings demonstrate compression of the left common iliac vein between the lower lumbar spine and the right common iliac artery 8.
Management Strategy
Systemic anticoagulation alone is insufficient treatment, and a more aggressive approach is necessary to prevent recurrent DVT 5.
Treatment is based on clinical presentation and includes:
- Staged thrombolysis with or without prophylactic retrievable inferior vena cava filter placement 6
- Followed by angioplasty/stenting of the left iliac vein in patients with extensive DVT 6
- In cases of severe stenosis of the left common iliac vein, the first-choice treatment consists of positioning a vascular stent, which resolves compression and significantly reduces chronic thrombotic episodes 7
- Chronic anticoagulation with warfarin for 6 months following stent placement 5
The therapy depends on the degree of venous stasis and presence of venous thrombosis; generally, it consists of short- or long-term anticoagulant and thrombolytic drugs 7.
Key Diagnostic Consideration
May-Thurner syndrome is rarely considered in the differential diagnosis of DVT, particularly in patients with other risk factors, leading to underdiagnosis 5. A comprehensive diagnostic approach including imaging of the iliac veins is necessary when left lower extremity DVT is present, especially in younger patients without obvious risk factors 5, 8.