Background Current guidelines for the investigation of sudden unexpected death in infancy (SUDI) include full neuropathological examination with recommendations for brain fixation for 1–2 weeks. Little evidence is available regarding the yield of such examination in determining cause of death in clinical practice. This study examines the frequency of neuropathological findings determining cause of death at postmortem examination in SUDI in relation to clinical and macroscopic features.

Methods All postmortem examinations performed for the indication of SUDI at a single specialist centre over a 14-year period were reviewed, including clinical history, macroscopic and neuropathological findings.

Results 6% of postmortem examinations performed for cases of SUDI demonstrated a neuropathological cause of death; in almost all (>90%) the clinical history and/or macroscopic examination suggested the cause of death. In 2% of all cases the cause of death was determined by histological neuropathological examination, but there were no cases in which histological neuropathological examination of a macroscopically normal brain revealed the cause of death in the absence of a ‘neurological history’. Macroscopic brain abnormalities and the presence of a ‘neurological history’ were significantly more likely to yield histological brain abnormalities (11-fold and fourfold, respectively).

Conclusions Histological neuropathological examination rarely determines the cause of death in SUDI in the absence of macroscopic abnormalities or neurological clinical history. A macroscopically abnormal brain and the presence of a clinical history of possible neurological disease or of inflicted injury are significantly more likely to be associated with significant histological brain abnormalities.