Fascial compartments

Fascial compartments US Medical PG Question 1: A 20-year-old woman is brought to the emergency department because of severe muscle soreness, nausea, and darkened urine for 2 days. The patient is on the college track team and has been training intensively for an upcoming event. One month ago, she had a urinary tract infection and was treated with nitrofurantoin. She appears healthy. Her temperature is 37°C (98.6°F), pulse is 64/min, and blood pressure is 110/70 mm Hg. Cardiopulmonary examination shows no abnormalities. The abdomen is soft and non-tender. There is diffuse muscle tenderness over the arms, legs, and back. Laboratory studies show: Hemoglobin 12.8 g/dL Leukocyte count 7,000/mm3 Platelet count 265,000/mm3 Serum Creatine kinase 22,000 U/L Lactate dehydrogenase 380 U/L Urine Blood 3+ Protein 1+ RBC negative WBC 1–2/hpf This patient is at increased risk for which of the following complications?

• A. Myocarditis
• B. Metabolic alkalosis
• C. Compartment syndrome
• D. Acute kidney injury (Correct Answer)
• E. Hemolytic anemia

Fascial compartments Explanation: ***Acute kidney injury*** - The patient's elevated **creatine kinase (CK)** of 22,000 U/L, muscle soreness, and dark urine (positive for blood but negative for red blood cells) are all indicative of **rhabdomyolysis**. - **Rhabdomyolysis** releases large amounts of myoglobin, which is nephrotoxic and can precipitate in the renal tubules, leading to **acute tubular necrosis** and subsequent acute kidney injury. *Myocarditis* - While CK elevations can be seen in myocarditis, this patient's presentation is dominated by **skeletal muscle symptoms** and a history of intense exercise. - There are no specific cardiac symptoms or signs (e.g., chest pain, arrhythmias) to suggest myocardial involvement. *Metabolic alkalosis* - Rhabdomyolysis typically causes **metabolic acidosis** due to the release of cellular contents, including phosphate and sulfate. - There is no clinical or lab evidence (e.g., vomiting, diuretic use) to suggest metabolic alkalosis. *Compartment syndrome* - **Compartment syndrome** involves increased pressure within a muscle compartment, leading to pain, pallor, paresthesia, pulselessness, and paralysis. - While rhabdomyolysis can occasionally lead to severe swelling that causes compartment syndrome, the diffuse muscle tenderness and absence of focal limb findings make it less likely as the primary direct complication. *Hemolytic anemia* - Though the urine is positive for blood and negative for RBCs, this is characteristic of **myoglobinuria**, not hemoglobinuria, which would indicate hemolytic anemia. - The patient's **hemoglobin** is normal (12.8 g/dL), and there are no other signs of hemolysis (e.g., jaundice, reticulocytosis).

Fascial compartments US Medical PG Question 2: An epidemiologist is evaluating the efficacy of Noxbinle in preventing HCC deaths at the population level. A clinical trial shows that over 5 years, the mortality rate from HCC was 25% in the control group and 15% in patients treated with Noxbinle 100 mg daily. Based on this data, how many patients need to be treated with Noxbinle 100 mg to prevent, on average, one death from HCC?

• A. 20
• B. 73
• C. 10 (Correct Answer)
• D. 50
• E. 100

Fascial compartments Explanation: ***10*** - The **number needed to treat (NNT)** is calculated by first finding the **absolute risk reduction (ARR)**. - **ARR** = Risk in control group - Risk in treatment group = 25% - 15% = **10%** (or 0.10). - **NNT = 1 / ARR** = 1 / 0.10 = **10 patients**. - This means that **10 patients must be treated with Noxbinle to prevent one death from HCC** over 5 years. *20* - This would result from an ARR of 5% (1/0.05 = 20), which is not supported by the data. - May arise from miscalculating the risk difference or incorrectly halving the actual ARR. *73* - This value does not correspond to any standard calculation of NNT from the given mortality rates. - May result from confusion with other epidemiological measures or calculation error. *50* - This would correspond to an ARR of 2% (1/0.02 = 50), which significantly underestimates the actual risk reduction. - Could result from incorrectly calculating the difference as a proportion rather than absolute percentage points. *100* - This would correspond to an ARR of 1% (1/0.01 = 100), grossly underestimating the treatment benefit. - May result from confusing ARR with relative risk reduction or other calculation errors.

Fascial compartments US Medical PG Question 3: Three days after undergoing laparoscopic colectomy, a 67-year-old man reports swelling and pain in his right leg. He was diagnosed with colon cancer 1 month ago. His temperature is 38.5°C (101.3°F). Physical examination shows swelling of the right leg from the ankle to the thigh. There is no erythema or rash. Which of the following is likely to be most helpful in establishing the diagnosis?

• A. D-dimer level
• B. Compression ultrasonography (Correct Answer)
• C. CT pulmonary angiography
• D. Transthoracic echocardiography
• E. Blood cultures

Fascial compartments Explanation: ***Compression ultrasonography*** - This patient's presentation with **unilateral leg swelling and pain** after surgery, especially given his recent **colon cancer diagnosis** (a hypercoagulable state), is highly suspicious for a **deep vein thrombosis (DVT)**. - **Compression ultrasonography** is the gold standard, non-invasive imaging modality for diagnosing DVT, allowing direct visualization of thrombi and assessing venous compressibility. *D-dimer level* - While a **positive D-dimer** indicates recent or ongoing clot formation, it is **non-specific** and can be elevated in many conditions, including surgery, cancer, and infection. - A normal D-dimer can rule out DVT in low-probability patients, but a high D-dimer in a high-probability patient (like this case) requires further imaging for confirmation, making it less definitive than ultrasound. *CT pulmonary angiography* - This imaging is used to diagnose a **pulmonary embolism (PE)**, which is a complication of DVT, but the primary symptoms here are localized to the leg. - While PE is a concern, diagnosing the source (DVT) in the leg is the immediate priority for treatment and prevention of future complications. *Transthoracic echocardiography* - **Echocardiography** evaluates cardiac structure and function and can sometimes detect large clots in the right heart leading to PE, but it is not the primary diagnostic tool for DVT in the leg. - It would be done if signs of cardiac strain or shunting associated with acute PE were prominent, which is not the case here. *Blood cultures* - **Blood cultures** are used to diagnose **bacteremia or sepsis**, which might explain a fever, but the prominent, unilateral leg swelling and pain are not typical for a primary infectious cause in the leg without local signs of cellulitis or abscess. - While a low-grade fever is present, the absence of erythema or rash makes a primary infectious etiology less likely than DVT given the risk factors.

Fascial compartments US Medical PG Question 4: A 35-year-old man is referred to a physical therapist due to limitation of movement in the wrist and fingers of his left hand. He cannot hold objects or perform daily activities with his left hand. He broke his left arm at the humerus one month ago. The break was simple and treatment involved a cast for one month. Then he lost his health insurance and could not return for follow up. Only after removing the cast did he notice the movement issues in his left hand and wrist. His past medical history is otherwise insignificant, and vital signs are within normal limits. On examination, the patient’s left hand is pale and flexed in a claw-like position. It is firm and tender to palpation. Right radial pulse is 2+ and left radial pulse is 1+. The patient is unable to actively extend his fingers and wrist, and passive extension is difficult and painful. Which of the following is a proper treatment for the presented patient?

• A. Surgical release (Correct Answer)
• B. Botulinum toxin injections
• C. Collagenase injections
• D. Needle fasciotomy
• E. Corticosteroid injections

Fascial compartments Explanation: ***Surgical release*** - The patient presents with classic signs of **established Volkmann's ischemic contracture** (claw-like hand, firm fibrotic tissue, limited movement, decreased radial pulse), which is the end-stage result of untreated compartment syndrome that occurred during fracture healing. - Since this is **chronic contracture (one month post-injury)**, the appropriate surgical treatment involves **reconstructive procedures** such as muscle slide operations, tendon lengthening, tendon transfers, neurolysis, or in severe cases, free functional muscle transfer to restore hand function. - Emergency fasciotomy would have been appropriate for **acute compartment syndrome** (within 6-8 hours of onset), but at this stage, the treatment focuses on releasing fibrotic tissue and restoring function through reconstructive surgery. *Botulinum toxin injections* - **Botulinum toxin** is used to relax spastic muscles in neurological conditions (e.g., cerebral palsy, stroke), but it does not address the underlying **ischemic fibrosis and muscle necrosis** of Volkmann's contracture. - It would not improve the structural contracture or restore blood flow in this patient. *Collagenase injections* - **Collagenase injections** are used for localized fascial contractures like Dupuytren's contracture, where enzymatic breakdown of collagen cords can restore finger extension. - They are ineffective for **Volkmann's contracture**, which involves widespread ischemic muscle necrosis, fibrosis, and nerve damage requiring surgical reconstruction. *Needle fasciotomy* - **Needle fasciotomy** is a minimally invasive technique for Dupuytren's contracture, involving percutaneous disruption of fascial cords. - It is not suitable for **Volkmann's contracture**, which requires extensive surgical release of fibrotic muscle compartments, possible tendon transfers, and neurolysis—procedures that cannot be accomplished with needle techniques. *Corticosteroid injections* - **Corticosteroids** reduce inflammation in conditions like tenosynovitis or trigger finger. - They would not address the **ischemic muscle necrosis and fibrotic contracture** in Volkmann's contracture and could potentially delay appropriate surgical treatment.

Fascial compartments US Medical PG Question 5: A 31-year-old man presents to the Emergency Department with severe left leg pain and paresthesias 4 hours after his leg got trapped by the closing door of a bus. Initially, he had a mild pain which gradually increased to unbearable levels. Past medical history is noncontributory. In the Emergency Department, his blood pressure is 130/80 mm Hg, heart rate is 87/min, respiratory rate is 14/min, and temperature is 36.8℃ (98.2℉). On physical exam, his left calf is firm and severely tender on palpation. The patient cannot actively dorsiflex his left foot, and passive dorsiflexion is limited. Posterior tibial and dorsalis pedis pulses are 2+ in the right leg and 1+ in the left leg. Axial load does not increase the pain. Which of the following is the best next step in the management of this patient?

• A. Lower limb CT scan
• B. Lower limb ultrasound
• C. Splinting and limb rest
• D. Fasciotomy (Correct Answer)
• E. Lower limb X-ray in two projections

Fascial compartments Explanation: ***Fasciotomy*** - The patient presents with classic signs and symptoms of **acute compartment syndrome**, including unrelieved pain by analgesics, paresthesias, pain with passive stretching, and a tense compartment due to the bus door trauma. - **Fasciotomy** is the definitive and urgent treatment to relieve pressure within the muscle compartments, prevent muscle ischemia, and avoid permanent nerve damage or limb loss. *Lower limb CT scan* - A **CT scan** is primarily used to evaluate bony structures and soft tissue injuries but is not the most immediate or definitive diagnostic tool for acute compartment syndrome. - Delaying **fasciotomy** for imaging in a clear case of compartment syndrome can lead to irreversible damage. *Lower limb ultrasound* - **Ultrasound** can assess vascular flow and some soft tissue aspects but is not accurate or rapid enough for diagnosing compartment syndrome. - It would not provide the necessary information to guide urgent surgical intervention. *Splinting and limb rest* - This approach is appropriate for fractures or soft tissue injuries without compartment syndrome; however, in acute compartment syndrome, **splinting or limb rest** will worsen the condition. - **Immobilization** and elevation are contraindicated as they can further decrease blood flow and increase compartment pressure. *Lower limb X-ray in two projections* - An **X-ray** is useful for ruling out fractures but will not provide information about compartment pressure or muscle viability. - While a fracture can sometimes cause compartment syndrome, the immediate concern here is the compartment syndrome itself, for which **X-rays** are not diagnostic.

Fascial compartments Flashcard 1 of 5

Question: In an anterior urethral injury, blood accumulates in the _____, and can spread into the perineal space

Answer: scrotum

Fascial compartments Flashcard 2 of 5

Question: Structures of the _____ system include the hippocampus, amygdala, fornix, mammillary bodies, and cingulate gyrus

Answer: limbic

Fascial compartments Flashcard 3 of 5

Question: The _____ artery is commonly injured due a knee dislocation

Answer: popliteal

Fascial compartments Flashcard 4 of 5

Question: Volkmanns ischemic contracture is a result of scarring / stiffening / shortening of the _____ muscles

Answer: forearm

Fascial compartments Flashcard 5 of 5

Question: In Iliotibial Band Syndrome, pain develops secondary to friction of the iliotibial band against the _____

Answer: lateral femoral epicondyle