What's The "Take Home"? Severe Elbow Pain in an Elderly Man

A 71-year-old man complains of left elbow pain that increases with movement and has worsened over the past 12 hours. He has also had a cough with sputum production for the past several days.

HISTORY
The patient has hypertension, treated with a diuretic, and degenerative joint disease. He has not received an influenza or pneumococcal vaccine. He denies recent trauma or insect bite. For the past 50 years, he has smoked 1 pack of cigarettes a day and has drunk 1 pint of beer daily. He has no history of injection drug use and is not currently sexually active.

PHYSICAL EXAMINATION
Temperature is 38.7°C (101.7°F); heart rate, 12 beats per minute; respiration rate, 28 breaths per minute; and blood pressure, 157/88 mm Hg. The patient is oriented to person, place, and time. Skin is normal, with no erythema (except over the tender elbow) or jaundice. Auscultation of the lungs reveals egobronchophony, crackles, and decreased breath sounds at the right base. Heart and abdomen are normal.

His left elbow is warm, swollen, and tender, with decreased range of motion. An effusion is present, but there are no indurations, excoriations, or track marks.

LABORATORY AND IMAGING RESULTS
Hemoglobin level is 12.0 g/dL; hematocrit, 35.1%; platelet count, 257,000/µL; white blood cell (WBC) count, 10,900/µL, with 61% segmented neutrophils and 16% band neutrophils. Electrolyte levels and results of liver function tests are normal.

Joint fluid analysis reveals bloody, turbid fluid with poor viscosity, no crystals, and a synovial WBC count of 113,000/µL, with 91% segmented neutrophils and 8% lymphocytes. Gram stain is positive for Gram-positive cocci.

Sputum culture reveals normal respiratory flora; blood cultures are negative. Joint fluid grows Streptococcus pneumoniae.

Chest radiograph shows consolidation in the right middle lobe. A radiograph of the left elbow shows moderate to severe degenerative changes about the elbow and a large elbow effusion. An MRI scan of the left elbow reveals a large effusion in the distal humerus and proximal radius and ulna, which suggests septic arthritis and associated relative hyperemia.

Which of the following is true about this patient's condition?A. Arthritis such as this is usually associated with other pneumococcal disease.
B. Diagnosis can be made based on the history and physical examination alone.
C. Antibiotic treatment should be withheld until the diagnosis is confirmed and the causative organism identified.
D. Pneumococcal arthritis has relatively low morbidity and mortality.
 

CORRECT ANSWER: A

The incidence of septic arthritis in the United States is increasing. The estimated annual incidence is 2 to 10 per 100,000 in the general population and is much higher in patients with rheumatoid arthritis. Most affected patients have a preexisting joint disease (rheumatoid arthritis is by far the most common). Other risk factors include osteoarthritis, prosthetic joints, chronic alcoholism, skin infections, and injection drug use. The most common route of spread is hematogenous; others include trauma or inoculation during corticosteroid injections.

Most septic arthritis infections are monomicrobial, but polymicrobial infections may be seen occasionally, especially after direct inoculation. The bacteria most often found in a native joint are Gram-positive cocci, with Staphylococcus aureus the most common (accounting for 50% of cases of septic arthritis). S pneumoniae is more common than is generally thought (3% to 6% of cases) and should be suspected if a patient presents with pulmonary or meningeal symptoms, as occurred in this man. Thus, choice A is true. Alcoholism is a significant predisposing factor and is present in as many as 70% of patients with pneumococcal arthritis.¹ Neisseria gonorrhoeae infection, once the leading cause of septic arthritis in young adults, has become less common since 1980, most likely because of the more widespread practice of safer sex during the AIDS era.

Presentation and comorbidities. The classic presentation of septic arthritis consists of fever and a single warm, swollen joint that is exquisitely painful on active or passive movement. Large joints are more likely to be affected than smaller joints; the knee is the most common site of infection (56% of cases), followed by the hip, shoulder, elbow, wrist, and ankle. Polyarticular arthritis occurs in 10% of patients; it is more common in patients with prior joint damage or when S pneumoniae is the causative organism.¹ Surprisingly, high fever is present in only 58% of patients with septic arthritis, and leukocytosis is present in only 50% to 60%.

Diagnosis. The differential diagnosis of acute arthritis includes infections, crystal-induced arthritis, osteoarthritis, trauma, and systemic disease (eg, rheumatoid arthritis). All of these can present with fever, joint swelling, pain, and stiffness.² Joint fluid studies, smears, and cultures are therefore mandatory, and choice B is not true.

Most patients with septic arthritis have a synovial leukocyte count of greater than 50,000/µL with more than 75% polymorphonuclear leukocytes. WBC counts in the range of 100,000/µL, as seen in this patient, are not unusual.

The diagnosis of septic arthritis must be confirmed with a positive synovial fluid Gram stain or culture. Smears of joint fluid stained for bacteria are positive in about a third of patients. Blood cultures are positive in up to 60% of adults, and joint cultures are positive in 90% of cases.

Radiographs are usually normal early in the disease process, and MRI changes are often not specific.³

Treatment. Prescribe empiric antimicrobial therapy to cover most pathogens after blood and synovial fluid for culture have been obtained. Waiting until culture confirmation (choice C) increases morbidity.

Because an increasing number of infections in the United States and elsewhere are caused by methicillin-resistant S aureus, vancomycin, 1 g q12 h, is an excellent first choice. Ceftriaxone should be given to sexually active adults in whom gonococcal arthritis is suspected. Adjust therapy once the culture results and sensitivities are available.¹ Give 1 to 2 weeks of intravenous antibiotics, followed by oral antibiotics for a total of 3 to 4 weeks of therapy.⁴

Surgery is indicated if aspiration has failed, if the joint effusion is loculated, or if the hip is involved.

Prognosis. It is extremely important to diagnose the cause quickly because nongonococcal septic arthritis has high morbidity: cartilage destruction occurs within days of symptom onset. The mortality of septic arthritis correlates with age, regardless of the organism. It is 5% in patients younger than 65 years and 35% in those older than 65 years.⁵ The mortality of pneumococcal septic arthritis is similar to that of other nongonococcal bacterial joint infections.⁵ Thus, choice D is not true.

References:

REFERENCES:

1.

Ross JJ, Saltzman CL, Carling P, Shapiro DS. Pneumococcal septic arthritis: review of 190 cases. Clin Infect Dis. 2003;36:319-327. Epub 2003; Jan 13.

2.

Margaretten ME, Kohlwes J, Moore D, Bent S. Does this adult patient have septic arthritis? JAMA. 2007;297:1478-1488.

3.

Graif M, Schweitzer ME, Deely D, Matteucci T. The septic versus nonseptic inflamed joint: MRI characteristics. Skeletal Radiol. 1999;28:616-620.

4.

Pioro MH, Mandell BF. Septic arthritis. Rheum Dis Clin North Am. 1997;23:239-258.

5.

Weston VC, Jones AC, Bradbury N, et al. Clinical features and outcome of septic arthritis in a single UK Health District 1982-1991. Ann Rheum Dis. 1999;58:214-219.