Differential Diagnosis

• Single most likely diagnosis
  • Tetanus: The patient's symptoms, such as difficulty opening his mouth (lockjaw), tension in the masticatory muscles, and neck muscles, along with the sharp tension of the muscles of the trunk, arching, and clenching of teeth, are classic signs of tetanus. The history of a recent untreated wound also supports this diagnosis, as tetanus bacteria can enter the body through wounds.
• Other Likely diagnoses
  • Botulism: Although botulism can cause muscle weakness and difficulty swallowing, it typically presents with descending flaccid paralysis, which is not consistent with the patient's symptoms of muscle tension and spasms.
  • Rabies: Rabies can cause hydrophobia, agitation, and increased salivation, but the primary symptoms described do not align closely with rabies, which typically includes signs of neurological dysfunction such as agitation, confusion, and fear of water.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Meningococcal meningitis: This condition is a medical emergency that can present with fever, neck stiffness, and altered mental status. Although the patient's symptoms do not strongly suggest meningitis, the fever and neck muscle tension warrant consideration of this diagnosis to ensure prompt treatment if present.
  • Epidemic typhus: While less likely given the symptoms, epidemic typhus can cause severe illness with fever, headache, and muscle pain. The absence of a rash or exposure history makes this less likely, but it should not be entirely dismissed without further investigation.
• Rare diagnoses
  • Other rare conditions that could potentially cause some of these symptoms, such as strychnine poisoning (which can cause muscle spasms and rigidity), are not listed among the options but would be considered in a broader differential diagnosis. However, based on the provided options, the focus remains on the listed conditions.