Differential Diagnosis for Low Lumbar Puncture Opening Pressure with Radiological Suspicion of Benign Intracranial Hypertension

• Single Most Likely Diagnosis:
  • Idiopathic Intracranial Hypertension (IIH) with variable cerebrospinal fluid (CSF) pressure: The diagnosis of IIH can be challenging, and a single lumbar puncture (LP) opening pressure measurement may not definitively exclude the condition. Factors such as body position, time of day, and respiratory status can influence CSF pressure. Thus, a pressure of 11 mmHg does not necessarily rule out IIH, especially if other clinical and radiological signs are present.
• Other Likely Diagnoses:
  • Secondary intracranial hypertension due to other causes (e.g., cerebral venous sinus thrombosis, space-occupying lesions): These conditions can present with similar symptoms and radiological findings to IIH but may have a normal or low CSF opening pressure at the time of measurement.
  • Intracranial hypotension: This condition can sometimes mimic the symptoms of intracranial hypertension and may have a low CSF opening pressure. However, the clinical context and additional diagnostic findings would help differentiate it.
• Do Not Miss Diagnoses:
  • Cerebral venous sinus thrombosis: This is a potentially life-threatening condition that can present with signs of increased intracranial pressure. A low CSF opening pressure does not exclude this diagnosis, and imaging findings are crucial for its detection.
  • Space-occupying lesions (e.g., tumors, abscesses): These can cause increased intracranial pressure and may have variable effects on CSF pressure measurements. Early detection is critical for appropriate management.
• Rare Diagnoses:
  • Pseudotumor cerebri syndrome associated with other medical conditions (e.g., tetracycline use, vitamin A toxicity): These rare causes of intracranial hypertension might not be immediately suspected but could be considered in the differential diagnosis if common causes are ruled out.
  • Cranial vault abnormalities or other structural issues affecting CSF dynamics: Rare anatomical variations or abnormalities could potentially affect CSF pressure measurements and the interpretation of radiological findings.