Dear Naapong,
Many thanks for your question which highlights a particular challenge around identification and management of acute malnutrition in young infants. There are currently no official MUAC cut-offs for infants under 6 months (though considerable work is underway on this). Weight for length z score is not possible to calculate where length is <45cm. Even when anthropometric indicators are available, they do not distinguish between a prem/LBW infant that is doing well versus one that is not. Identifying nutritional vulnerability of any infant under 6 months requires not only anthropmetry (ideally with serial measures so that you can see growth trajectory), but also clinical, feeding and maternal assessment to determine if there is a problem, and the nature of it to inform how to intervene.

These considerations are reflected in the C-MAMI tool that was developed as first step to help programmers manage these infants, applying relevant materials that exist and modelled/building on the IMCI approach.

Please have a look and see if this tool is helpful in addressing the question you asked - let us know if it is and also if it isn't. Your feedback is very helpful.

Best regards, Marie

Dear Naapong,

This is a difficult one and I'd be curious to find out what other people do.

MUAC is unreliable in this age group and I've always heard that height shouldn't be used for this in a child until they are standing, as the length of a child is not consistent when they are lying down.

Instead, I'd plot the weight according to age (corrected for prematurity) to identify and then monitor malnutrition. I usually use these WHO charts:

- http://www.rcpch.ac.uk/system/files/protected/page/GIRLS%20NICM%20(4th%20Jan%202013).pdf
- http://www.rcpch.ac.uk/system/files/protected/page/BOYS%20NICM%20(4th%20Jan%202013).pdf

Identification
If I thought a child was malnourished but I didn't have their birth weight, I would plot them on the WHO centile charts. Then you would get idea of how they compare to a similar cohort. i.e. if they are <0.4th centile. However these charts are notoriously based on a small and non-ethically diverse sample, therefore difficult to know how useful.

Monitoring
For LBW / premature following birth, they should be gaining 10-20g/kg/d (this varies in the literature), so if they are measured as not gaining this weight then I would classify them as FTT (failure to thrive) or poor weight gain, whatever the reason. I would follow this until they reach their birth weight (this unfortunately only works if you know their birth weight).

If you are monitoring them over a period of time, I normally use the centile charts to monitor their weight. They should follow a centile line (doesn't really matter which one as long as they're following it). Normally I follow the rule that they should be following their centile and if they fall across at least 2 centiles then there is a problem and they are again FTT / malnutrition.

I hope this helps, but would be useful to find out what others do.

Dear Dr. Garry:

Thank you for your input on Dr. Naapong's question; however, I think there are some potentially confusing statements in your answer which I would like to attempt to clarify. First, you say "height shouldn't be used for this in a child until they are standing, as the length of a child is not consistent when they are lying down". Measuring the length of children less than 24 months of age has been recommended by WHO, UNICEF, CDC, and many other organizations for several decades. It is the standard of practice and is routinely done in nutrition assessment surveys. We do not have to wait to measure length or height until a child can stand on his/her own.

Second, you say "the WHO centile charts...are notoriously based on a small and non-ethically (sic) diverse sample". The reference population which is currently recommended and almost universally used, the WHO Child Growth Standard, is based on about 8,500 children from six countries on five continents. It is neither based on small numbers nor an ethnically non-diverse sample.

Third, you say "Then you would get idea of how they compare to a similar cohort. i.e. if they are <0.4th centile". Low weight-for-height/length is usually defined by using z-scores as the anthropometric index; however, the definition of any wasting (<-2.0 z-scores) generally corresponds to the 2.3d centile. Waiting until a children falls below the 0.4th centile would delay necessary therapy.

I hope this clarifies these issues.

Many thanks for your message and apologies for the typo. Reflecting on your feedback, it is important that I clarify that I was sharing some personal experiences of treating this age-group.

- I have found practically speaking that there was a huge amount of variability in measuring length in nutrition programmes. Therefore we have chosen in some programmes not to use it in the <6 months. However this was a field decision and shouldn't detract from WHO recommendation of using length when assessing.

- a discussion we have had in the field is regarding the applicability of tools when designed based using other ethnic groups. The WHO tools (background information here: http://www.who.int/childgrowth/publications/technical_report_velocity/en/) are commonly used / adapted and have been widely discussed. Places I have worked have been ethnically very diverse and so we have discussed that there may be some difference from tools designed from data in other countries / with other backgrounds.

- the <0.4th centile was an example used due to difficulties faced of not knowing the birth weight. I have worked in European settings where centiles are used and so drew on what was familiar to me as an example; I appreciate your point about this being a ‘late’ cut-off. This was not intended as an absolute, but as an open discussion regarding how to approach this problem. When reviewing a child < 6 months for malnutrition I found that it was rare to know the exact gestational age at birth, or even correct birth date in many of the contexts I have worked in.

Many thanks for your comments and apologies for lack of clarity.

Excellent Woody. As always. I was getting very concerned.

Good all, Thanks for all the effective responses and sharing.
the tool @Dr.Marie is cuul with.