Meningitis First Hour: Cultures, Steroid, Antibiotic, Then the Tap
Bacterial meningitis is treatable with a drug already on your unit, and the outcome is measured in minutes to first antibiotic dose. The inflammatory response — not the organism — does most of the damage, which is why the steroid goes in before the antibiotic lyses the bacteria. Run the hour in order, then take the fluid apart against the real reference values.
2130 — Mr Hale, 71, room 618Admitted two days ago for cellulitis, on prednisone for polymyalgia rheumatica. New fever of 39.4 with a severe headache and now confused. GCS 13, neck stiff, photophobic, blood pressure 96/54, heart rate 118. Put the hour in order, earliest first — five options in this list are wrong at any point.
Tap what you do next
The tap has come back — now interpret itNormal cerebrospinal fluid is crystal clear, opening pressure 6–20 cm H2O, 0–5 white cells/mm3 (lymphocytes), protein 15–45 mg/dL, glucose 45–80 mg/dL at roughly two-thirds of a simultaneous serum glucose. Move the sliders, or load a preset, and the bench names the pattern and tells you what to do about it.
Load a result
Why the order is the order
The mechanism behind the sequenceOnce bacteria are in the subarachnoid space they replicate where there is almost no immune surveillance, and it is the inflammatory response that does most of the damage: cytokines open the blood–brain barrier and produce vasogenic oedema, purulent exudate obstructs cerebrospinal fluid outflow and produces hydrocephalus and rising intracranial pressure, and inflamed vessels thrombose and produce infarcts and cranial nerve palsies. Antibiotics lyse bacteria and release a burst of inflammatory material — so dexamethasone only works if it precedes that burst. It reduces hearing loss and mortality in pneumococcal disease. And it is why a patient can deteriorate during the first hours of apparently correct treatment.