Mark Crislip, MD


September 25, 2012

Clinical Presentation: Man With Monoarticular Arthritis

The patient is a 56-year-old man who has been ill for 10 days with fevers, rigors, sweats, and migratory arthralgias that became a monoarticular arthritis of the knee.

History and Physical Examination

History. History revealed the following:

  • Medical history: schizophrenia, hypertension, type 2 diabetes

  • Medications: none currently; has taken antipsychotics in the past

  • Allergies: none

  • Habits: polysubstance use: heroin, methamphetamine, and cocaine; all intermittent, on the basis of finances and availability. Smokes tobacco and drinks alcohol.

  • Pets: owns several pet rats (wild rats he catches and cages). One rat bit him 2 weeks ago.

  • Diet: regular

  • Social: sexually active with both men and women

  • Immunizations: up to date

  • Sports/water exposure: none

  • Infectious disease exposure: none

Physical examination. The following were noted:

  • Vital signs: temperature, 102° F; pulse, 80 beats/min; respiratory rate, 14 breaths/min; blood pressure, 130/85 mm Hg

  • General: ill-appearing

  • HEENT: poor dentition

  • Lungs: wheezes

  • Heart: grade 3/6 murmur

  • Abdomen: possible mild splenomegaly

  • Extremities/skin: no emboli; erythematous, edematous knee, warm to touch

  • Skin: healed rat bite

  • Neuro: normal

Diagnostic Evaluation

Laboratory results. The following values were obtained:

  • WBC count: 15,000 cells/µL

  • Hemoglobin level: 12 g/dL

  • Differential: 12% bands

  • Knee arthrocentesis: 52,000 WBC; Gram stain, negative

  • Bilirubin level: normal

  • Aminotransferase levels: twice normal

  • Urinalysis: 10-20 RBCs


  • Chest x-ray: lungs hyperinflated

  • Echocardiogram: moderate mitral regurgitation; no vegetation (poor-quality study)