A 42-year-old man comes to the emergency department due to worsening jaw pain and stiffness. His symptoms began 2 days ago and have limited his ability to eat. Today the patient also developed painful stiffness in his neck. He has had no fever, chills, headache, focal weakness, or numbness. The patient is a farmer in rural Pennsylvania and sustained a wooden splinter injury to his forearm while working in a barn a week ago. He has no chronic medical conditions but has not had medical care for many years. On examination, the patient is not able to open his mouth. The muscles of the neck are tense, and neck range of motion is impaired. Which of the following is the best approach to establishing diagnosis in this patient?

Question

A 42-year-old man comes to the emergency department due to worsening jaw pain and stiffness.  His symptoms began 2 days ago and have limited his ability to eat.  Today the patient also developed painful stiffness in his neck.  He has had no fever, chills, headache, focal weakness, or numbness.  The patient is a farmer in rural Pennsylvania and sustained a wooden splinter injury to his forearm while working in a barn a week ago.  He has no chronic medical conditions but has not had medical care for many years.  On examination, the patient is not able to open his mouth.  The muscles of the neck are tense, and neck range of motion is impaired.  Which of the following is the best approach to establishing diagnosis in this patient?

Quizplus · Accepted Answer

11ec160b_3b13_3b34_9249_e943d8f4342f_MD0001_00 Tetanus is rare in the developed world due to widespread vaccination with tetanus toxoid. However, cases can occur in individuals who were incompletely vaccinated as a child or those who have not received booster vaccination every 10 years (as is likely in this patient who has not been under medical care). The majority of patients who develop tetanus have a history of a puncture wound (eg, splinter) approximately a week prior to symptoms, which led to inoculation with Clostridium tetani spores. The spores germinate in anaerobic conditions into vegetative, rod-shaped bacteria and produce tetanus toxin (tetanospasmin). Tetanus toxin travels through lower motor neurons to the central nervous system where it inactivates inhibitory interneurons. Common manifestations include masseter muscle spasm (lockjaw [trismus]), muscle pain and stiffness, and difficulty swallowing. Tetanus is a clinical diagnosis that should be suspected in patients who have characteristic symptoms, particularly if they are unlikely to be adequately vaccinated or have a history of recent cutaneous trauma. Blood cultures are not helpful because C tetani only grows at the inoculation site (the clinical syndrome stems from toxin elaboration not bacterial invasion) (Choice A). Wound cultures can provide supportive evidence but often take several days to return, so they are not usually performed. (Choice B) The neurologic manifestations of tetanus are caused by toxin-mediated blockade of inhibitory interneurons at the level of the anterior horn cells. Cerebrospinal fluid testing is usually normal and is not typically part of diagnostic testing. (Choice D) Serum tetanus toxin assay is not widely available and is not routinely used to diagnose tetanus. Tetanus is largely a clinical diagnosis. (Choice E) Positive antitoxoid serology indicates that an individual is likely to be adequately vaccinated and reduces the chances that a patient has tetanus. Educational objective: Tetanus is a clinical diagnosis that should be suspected in patients who have characteristic symptoms (eg, lockjaw, muscle pain/spasms, difficulty swallowing), particularly if they are unlikely to be adequately vaccinated or have an antecedent cutaneous injury.

A 42-Year-Old Man Comes to the Emergency Department Due to Worsening