Lini S. Bhatia, M.D., PGY2, Department of Internal Medicine, James H. Quillen College of Medicine, ETSU, Johnson City, TN

The objective is to teach proper management of stingray bites and their potential complications. This case also illustrates an important side effect of the nearly ubiquitous fluoroquinolone antibiotics: Achilles tendonitis. A 44-year-old man was walking barefoot on a beach in South Carolina. He suddenly felt a sharp jab in his left foot and realized he had stepped on a stingray and was stung. He noticed a puncture wound with active bleeding. He developed ascending cellulitis and tissue necrosis. Cultures grew Staphylococcus aureus sensitive to levofloxacin. Due to concern for early osteomyelitis and to cover seaborne bacteria, levofloxacin 750mg/day was started and continued for 6 weeks. The wound ultimately healed in 3 months after 2 surgical debridements. The patient developed bilateral Achilles tendonitis within 14 days of starting levofloxacin. The tendonitis gradually improved after stopping the antibiotic. Atlantic Stingrays are the most common venomous fish found in the shallow waters of US beaches and are responsible for over 1,500 injuries per year. Stingrays attack people with its tail spine only as a form of defense if stepped on or threatened. Stingray bites may produce severe penetrating injuries and subsequent infections including tetanus. The venom has serotonin, 5’-nucleotidase, and phosphodiesterase, which cause both local and systemic effects. Treatment of stingray bites includes immersion of wound in hot water to inactivate heat-labile venom, thorough debridement and irrigation, pain control, prophylactic antibiotics, and to tetanus immunization. Achilles tendonitis is a well recognized but rare adverse effect of levofloxacin and other fluoroquinolones. The incidence of achilles tendonitis is between 0.01–0.1% and of tendon rupture is less than 0.01%. Pefloxacin and ofloxacin have the highest incidence of this side effect. Tendon disorders usually occur during the first month of treatment, but have been described to occur 2 to 42 days after starting the fluoroquinolone. Risk factors for tendinopathy is old age, chronic lung disease, steroid treatment and impaired renal function, and exceeding the therapeutic range of fluoroquinolone levels. The exact pathological mechanism of tendinitis due to fluoroquinolones is unknown. Animal studies suggest chelation of magnesium and free radical formation result in oxidative stress leading to a direct toxic effect on collagen. Arthropathy is seen in immature animals of various species when fluoroquinolones are administered at doses close to the therapeutic dose in humans, therefore is best avoided in children, adolescents, and pregnant or lactating women. The medication should be discontinued immediately at first sign of tendinopathy. Patients may need to be hospitalized and have surgical repairs. They may become disabled for prolonged periods. Stingray bites require special attention and treatment to prevent serious complications. Treatment requires debridement, irrigation, pain control (including immersion of wound in hot water (45o) for 30-90 minutes which can inactivate heat-labile venom), and prophylactic antibiotics. Antibiotics should cover Staphylococcus, Streptococcus, Vibrio, and Aeromonas species. Update the patient’s tetanus immunization. Cryotherapy is contraindicated. Wounds should be allowed to heal by secondary intention or delayed closure. While fluoroquinolones may be used for such infections, Achilles tendonitis and tendon rupture are potential side effects.