Rosen & Barkin's 5-Minute Emergency Medicine Consult (513 page)

• Patients with superior, medial, or intra-articular dislocation or in whom a lateral dislocation cannot be reduced require orthopedic consultation in the ED and possible admission
  
• Patellar dislocation associated with a fracture (osteochondral or lateral femoral condyle) requires orthopedic consultation in the ED
  
• Indications for operative intervention:
  
  • Fragments displaced >4 mm
    
  • Unable to raise extended leg off bed
    
  • Articular step-off >3 mm
    
• All open fractures require débridement and irrigation; such patients should be admitted.
  
• For patellar tendon rupture, discuss case with orthopedics.
  

• Dislocation: Patients with successful reduction of lateral patellar dislocation and normal postreduction radiographs may be discharged with knee immobilization, crutches, and orthopedic follow-up.
  
• Fracture: If displaced <3 mm and patient has full active knee extension:
  
  • Knee immobilizer, or bulky long-leg splint, partial to full weight bearing as tolerated with crutches and orthopedic follow-up within a few days
    

• Lateral patella dislocations often reduce spontaneously prior to arrival in ED; do not dismiss patient’s history of dislocation.
  
• In patella tendon ruptures, tendon defect may not be palpable if sufficient time has elapsed and swelling has occurred
  

• Ahmad CS, McCarthy M, Gomez JA, et al. The moving patellar apprehension test for lateral patellar instability.
  Am J Sports Med
  . 2009;37(4):791–796.
  
• Fithian DC, Paxton EW, Stone ML, et al. Epidemiology and natural history of acute patellar dislocation.
  Am J Sports Med
  . 2004;32(5):1114–1121.
  
• Hing CB, Smith TO, Donell S, et al. Surgical versus non-surgical interventions for treating patellar dislocation.
  Cochrane Database Syst Rev
  . 2011;(11):CD008106.
  
• Melvin JS, Mehta S. Patellar fractures in adults.
  J Am Acad Orthop Surg
  . 2011;19(4):198–207.
  
• Rees JD, Maffulli N, Cook J. Management of tendinopathy.
  Am J Sports Med
  . 2009;37(9):1855–1867.
  
• Scolaro J, Bernstein J, Ahn J. Patellar fractures.
  Clin Orthop Relat Res
  . 2011;469(4):1213–1215.
  
• Stefancin JJ, Parker RD. First-time traumatic patellar dislocation: A systematic review.
  Clin Orthop Relat Res
  . 2007;455:93–101.
  

CODES

• 726.64 Patellar tendinitis
  
• 836.3 Dislocation of patella, closed
  
• 836.59 Other dislocation of knee, closed
  

BASICS

• Patent vessel in the fetal heart connects the pulmonary trunk to the descending aorta.
  
• Shortly after birth, changes normally provoke contraction, closure, and fibrosis:
  
  • Sudden increase in the partial pressure of oxygen
    
  • Changes in the synthesis and metabolism of vasoactive eicosanoids
    
• In the preterm infant, persistent patency of the ductus may be a normal life-saving response.
  
• The patent ductus usually has a normal structural anatomy.
  
• Patency results from hypoxia and immaturity.
  
• In the full-term newborn, patency of the ductus is a congenital malformation.
  
• Deficiency of both the mucoid endothelial layer and the muscular media of the ductus
  
• As pulmonary vascular resistance falls, aortic blood is shunted into the pulmonary artery.
  
• Extent of the shunt reflects the size of the ductus and the ratio of the pulmonary to systemic vascular resistances.
  
• Up to 70% of the left ventricular output may be shunted through the ductus to the pulmonary circulation.
  
• Risk factors:
  
  • Premature birth
    
  • Coexisting cardiac anomalies
    
  • Conditions resulting in hypoxia
    
  • High altitude
    
  • Maternal rubella infection
    
  • Female-to-male ratio, 3:1
    

• Prematurity
  
• Congenital anomaly
  
• Hypoxia
  
• Prostaglandins
  

DIAGNOSIS

• Isolated patent ductus arteriosus (PDA), an unanticipated event
  
• PDA, as part of a larger congenital cardiac anomaly, may be diagnosed by US during pregnancy.
  

• Asymptomatic when the PDA is small, but otherwise may present with a range of findings.
  
• Congestive heart failure (CHF), often in 1st day of life
  
• Wide pulse pressure
  
• Prominent apical impulse
  
• Thrill
  
• Systolic and continuous murmur.
  
• Sounds like a humming top or rolling thunder
  
• Begins soon after onset of the 1st sound, reaches maximal intensity at the end of systole, and wanes in late diastole
  
• Localized to the 2nd left intercostal space or radiates down the left sternal border toward the apex or to the left clavicle
  
• Recurrent pulmonary infections
  
• Retardation of physical growth
  

• Establish the diagnosis with imaging studies.
  
• Rule out complications such as heart failure and endocarditis.
  

Unhelpful in making the diagnosis

• CXR:
  
  • Usually normal in infants
    
  • In children and adults:
    
    • Increased intrapulmonary markings
      
    • Calcifications
      
    • Left ventricle and left atrial enlargement
      
    • Dilated ascending aorta
      
    • Dilated pulmonary arteries
      
• EKG:
  
  • Abnormal if the ductus is large:
    
    • Left ventricular hypertrophy
      
    • Right ventricular hypertrophy is a sign of greater severity.
      
• Echocardiography:
  
  • Normal if the ductus is small
    
  • Left atrial enlargement
    
  • Size of the ductus can be determined by scanning from the suprasternal notch.
    
  • Doppler studies will determine aortic to pulmonary artery flow during diastole.
    
• Cardiac catheterization:
  
  • Normal or increased right-sided pressure
    
  • Oxygenated blood in the pulmonary artery confirms left-to-right shunting.
    
  • Injection of contrast into the ascending aorta shows opacification of the pulmonary arteries.
    

• Venous hum:
  
  • Common insignificant bruit
    
  • Heard in the neck or anterior portion of the chest
    
  • Soft humming sound in systole and diastole
    
  • Decreased by light compression of the jugular venous system
    
• Total anomalous pulmonary venous connection to the innominate vein:
  
  • Continuous murmur like venous hum
    
• Aorticopulmonary septal defect:
  
  • Murmur is often only systolic.
    
  • Heard at the right sternal border
    
• Ruptured sinus of Valsalva
  
• Coronary arteriovenous fistulas
  
• Anomalous origin of left coronary artery from the pulmonary artery
  
• Absence or atresia of pulmonary valve
  
• Aortic insufficiency with ventricular septal defect
  
• Peripheral pulmonary stenosis
  
• Truncus arteriosus
  

TREATMENT

Monitoring and oxygen

• Small, asymptomatic shunts may not need closure.
  
• Pulmonary support
  
• Supplemental oxygen
  

• Sodium and fluid restriction
  
• Correction of anemia to hematocrit >45%
  
• Antibiotic prophylaxis for endocarditis
  
• Preterm infants:
  
  • Usually closes spontaneously
    
  • Varies with the magnitude of shunting and severity of respiratory distress syndrome
    
  • Pharmacologic inhibition of prostaglandin synthesis with indomethacin during the 1st 2–7 days of life
    
• Full-term infants and children:
  
  • Surgical closure is required, even in asymptomatic patients, as spontaneous closure is rare.
    
  • Ligation and division
    
  • Transfemoral catheter technique to occlude PDA with foam plastic plug or double umbrella
    

Indomethacin: 0.2–0.25 mg/kg per dose; repeat q12–24h for 3 doses