the tonsils and adenoids form part of the first-line defenses against inhaled or ingested pathogens
they tend to enlarge substantially in early childhood especially after age 5yrs and can be prone to recurrent streptococcal bacterial infections, viral infections such as EBV / glandular fever / infectious mononucleosis and may cause obstructive sleep apnoea
their removal was thought to have no significant long term consequences although this may not be the case
tonsils have recently been noted to be the reservoir of T cells besides thymus
a large 2024 Swedish study over over 1 million people suggests those who have had tonsillectomy have a 34% higher risk of stress-related disorders and a 41% higher risk of PTSD disorders compared to siblings who did not have the surgery 1)
possible increased risk of:
irritable bowel syndrome
1.8 fold higher risk but small numbers with IBS studied 2)
2 to 3 fold increase in diseases of the upper respiratory tract 4)
allergic disease
infectious diseases
pre-existing antigen-specific IgA antibodies in the nasopharynx declined sharply after adenotonsillectomy in children, suggesting the tonsils are important for generating mucosal immunity 5)
adjusted hazard ratio of 1.44 if removed before age 20yrs 7)
some cancer types
an excess risk was consistently observed for cancer of the breast, prostate, thyroid, and for lymphoma in both population and sibling comparisons with overall hazard ratio of 1.15 for sibling comparisons 8)