Differential Diagnosis

• Single most likely diagnosis
  • Meningococcal meningitis: The patient's symptoms, such as sudden onset of high fever, severe headache, vomiting, general hyperesthesia, and pronounced rigidity of the occipital muscles, along with a positive Kernig sign, are highly suggestive of meningitis. The cloudy cerebrospinal fluid (CSF) that flows out under pressure further supports this diagnosis, as it indicates increased intracranial pressure and possible infection. The elevated leukocyte count and ESR also point towards a bacterial infection.
• Other Likely diagnoses
  • Meningococcal meningoencephalitis: This condition involves both meningitis (inflammation of the meninges) and encephalitis (inflammation of the brain tissue). Given the patient's severe symptoms, including general hyperesthesia and dilated pupils with preserved light reaction, meningoencephalitis is a possible diagnosis, although the primary presentation suggests meningitis.
  • Meningococcal infection, meningococcemia: Meningococcemia refers to the presence of Neisseria meningitidis in the blood and can lead to meningitis or septicemia. The patient's high fever, tachycardia, and hypotension could be indicative of meningococcemia, but the specific symptoms of meningitis (e.g., neck stiffness, positive Kernig sign) make meningococcal meningitis more likely.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Pneumonia: Although pneumonia might not be the first consideration given the neurological symptoms, bacterial pneumonia can lead to severe complications, including sepsis and meningitis, especially if caused by Streptococcus pneumoniae. The patient's symptoms of high fever and vomiting could initially suggest pneumonia, but the neurological signs point more directly to meningitis.
  • Meningococcal nasopharyngitis: This is an infection of the nasopharynx by Neisseria meningitidis. While it's less severe than meningitis or meningococcemia, it can be a precursor to more serious infections. However, the patient's severe systemic and neurological symptoms make this a less likely primary diagnosis.
• Rare diagnoses
  • These would include other causes of meningitis (viral, fungal, tuberculous) or encephalitis, which could present with similar symptoms but are less likely given the acute onset and specific combination of symptoms described. Other rare bacterial causes of meningitis, such as Haemophilus influenzae type b (Hib), could also be considered, especially if vaccination status against common pathogens is unknown or incomplete.