This all started after a few weeks of having a nosebleed and going to the emergency room. A tech in the ER placed nasal packing in his nose very hard without soaking the item before using it. His doctors tell him that they cannot prove this leak was caused by the nasal packing.

What is the cause? No one else has ever heard of this problem. My son is a healthy 51-year-old male who is not on any meds. Please explain this to me.

— W.M.

Answer: CSF surrounds and supports the brain and spinal cord. The meninges normally form a fluid-proof barrier, but if the outer layer of the meninges (the dura mater) is damaged, CSF can leak out.

Trauma is the most common cause of a CSF leak. This can be in the form of a skull fracture, whether at the base of the skull, the sinuses, or other places. The trauma does not have to be a fracture. I absolutely found reports of CSF leaks after nasal packing for a nosebleed. Given that his symptoms started after the placement of the nasal packing material, it is nearly certain that this caused his CSF leak, although it’s remotely possible that there was another reason.

In the four cases I found in the literature, the leak stopped spontaneously in three of these cases, but surgery was required in the fourth after a fracture of one of the delicate sinus bones was found and repaired.

One treatment is a “blood patch,” which uses the patient’s own blood and gets injected into the CSF so that a clot can form around the hole in the dura mater until the body repairs the hole. I’ve seen this used in people with fluid drainage after a spinal tap or an epidural injection.

Dear Dr. Roach: Why don’t we eat eggshells? Aren’t they full of calcium?

— C.S.

Answer: We can eat eggshells, but I don’t recommend it unless you are willing to go through some preparation to make the eggshells safe. Eggshells are made out of calcium carbonate, which is a common calcium supplement that you can buy (and is much easier than the process I’m about to explain to you).

There are also trace amounts of protein and a few other minerals. Unfortunately, there are also bacteria in and on eggs, and you really can’t wash them off. The eggshells need to be boiled to kill the bacteria, which may include salmonella, campylobacter, and other pathogenic bacteria that you really don’t want to be eating.

Secondly, eggshells are sharp and not at all pleasant to have slicing up your mouth, pharynx, esophagus, and other places further down your intestinal tract. So, in addition to boiling the eggshells, you need to grind them into a fine powder — with a mortar and pestle, for example.

Dosing of calcium carbonate is important, since too much calcium can cause kidney stones. There remains debate about calcium supplements (whether they’re bought or made from eggshells) increasing the risk of coronary artery disease.

Half an eggshell is roughly a day’s worth of calcium for most people.

Contact Dr. Roach at ToYourGoodHealth@med.cornell.edu.