Meningitis

[SaturdayDwarf]

I'm a little confused about the causes of bacterial meningitis in adults. For the most part, different books seem to agree on newborns, children and the elderly. But here is what different sources say on adults.:

First Aid (6-60 yrs):
1. N. meningitidis
2. S. pneumonia

MedEssentials (adolescence / young adults):
N. meningitidis

UWorld (adults):
1. S. pneumonia
2. N. meningitidis

I'm not including CMMRS because they do not differentiate between children and adults. But it doesn't even mentioned S. pneumonia as a major cause of bacterial meningitis.

What's the correct answer?

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[Green Chimneys]

I don't think any of these are wrong, it's just in the way they present the time tables. In older children, teens and young adults (college kids living in dorms seems to be popular), it's Meningococcal. In older adults it's Pneumococcal. FA is listing the whole set together and saying Neisseria is overall more common where UW is separating out young adults and older adults, in which the primary etiologies are different. Of course, your inevitable USMLE question on meningitis will probably involve an AIDS patient, so whatever...

 

[agranulocytosis]

I don't think any of these are wrong, it's just in the way they present the time tables. In older children, teens and young adults (college kids living in dorms seems to be popular), it's Meningococcal. In older adults it's Pneumococcal. FA is listing the whole set together and saying Neisseria is overall more common where UW is separating out young adults and older adults, in which the primary etiologies are different. Of course, your inevitable USMLE question on meningitis will probably involve an AIDS patient, so whatever...

Yea I'm gonna agree with you here, in the elderly it's s. pneumo, young adult n. meningitidis. BTW, isn't it cryptococcal menigitis in AIDS?

 

[SaturdayDwarf]

I don't think any of these are wrong, it's just in the way they present the time tables. In older children, teens and young adults (college kids living in dorms seems to be popular), it's Meningococcal. In older adults it's Pneumococcal. FA is listing the whole set together and saying Neisseria is overall more common where UW is separating out young adults and older adults, in which the primary etiologies are different. Of course, your inevitable USMLE question on meningitis will probably involve an AIDS patient, so whatever...

They actually use the same time tables. The part in the explanation section that confused me on UWorld said that "N. meningitidis is the second most common cause of meningitis in adults under 60 years old, after S. pneumoniae". FA separates older and younger adults at 60 also (Neisseria being the number one cause in adults under 60, and Strep being the number one cause in adults over 60). I'm just concerned because it's come up twice already in UWorld, so I'm concerned that I need to know it for my test.

 

[2cr8tive]

BTW, isn't it cryptococcal menigitis in AIDS?[/quote]
true

 

[TerpMD]

RR path (pg 579) says that N men is most common btw 1 mo and 18 years of age. S pneumo in those over 18 years of age. GBS in neonates.

I would go with s pneumo in any adult that does not have some other reason (exposure, military, colllege) to have N men but that is just me

 

[LUBDUBB]

I'm a little confused about the causes of bacterial meningitis in adults. For the most part, different books seem to agree on newborns, children and the elderly. But here is what different sources say on adults.:

First Aid (6-60 yrs):
1. N. meningitidis
2. S. pneumonia

MedEssentials (adolescence / young adults):
N. meningitidis

UWorld (adults):
1. S. pneumonia
2. N. meningitidis

I'm not including CMMRS because they do not differentiate between children and adults. But it doesn't even mentioned S. pneumonia as a major cause of bacterial meningitis.

What's the correct answer?

Don't forget the fungal meningitides and my favorites, Leukemic Meningitis and Lymphomatous meningitis

 

[kkc620]

Has anyone found a clear-cut answer to this question. Generally speaking, what are the most common causes of meningitis in the different age brackets? I can't seem to find a definite answer.

 

[osli]

No clear cut answer, but the following is probably a reasonable outline:

0-1 month:
- GBS
- Listeria

1 month -18 years:
- N. meningiditis
- S. pneumo

18+ years:
- S. pneumo

 

[opb]

I agree with the above poster. There are probably multiple lists from multiple sources. Here is what was given in my micro class:

Neonates < 1 month:
- Group B strep
- E. coli
- Listeria

1 month to 18 years:
- N. meningitidis
- S. pneumo
- H. influenza type B

Over 18 years:
- S. pneumo
- N. meningitidis
- Gram-negative bacilli
- Listeria

You'll most likely get information in the question stem that can help differentiate between the different bugs. For me, this list worked fine for the micro questions on my exam.