Repeated Medical PG Question- 67

#MEDICINE (NEETPG Pattern)

A 25 year old  man  presents  to  the  emergency department  complaining  of  a  severe headache,  stiff  neck,  and  fever.  While  waiting  for treatment,  the  patient  has  a  seizure.  A neurologist  suspects  meningitis,  and  performs  this  procedure  as  shown  in  image patient.  Immediately  after the  needle  passes through  the  interlaminar space  between  the 4th  and  5th  lumbar vertebrae,  which  space  does  it  enter?

A. Epidural 

B. Intramuscular 

C. Subarachnoid 

D. Subcutaneous 

Answer: C. Subarachnoid space

Expaination:

▪️During LP a needle is inserted between two vertebrae in the lower back through two layers of the meninges and into the subarachnoid space. Within the subarachnoid space lies CSF, which then slowly flows outward through the needle and into a waiting test tube.

▪️Since the meninges and CSF are in direct contact, one affects the other. As a result, analyzing collected CSF can help diagnose the various forms of meningitis.

▪️For instance, white blood cells—the cells responsible for fighting infection—are not normally found in the CSF. Conversely, their presence suggests infection, as do abnormal CSF protein and sugar levels. In addition, entirely normal CSF findings essentially eliminate the possibility of serious forms of meningitis.

Image showing Lumbar puncture