Memory Loss

Memory loss is a distressing and perilous symptom for both sufferers and caring relatives. It may be due to organic or non-organic causes. Memory is classified into immediate, short-term (or recent) and long-term (or remote) memory. The type of loss varies according to the cause. Memory loss is also a feature of any cause of acute confusion; this problem is covered in the 'Confusion, acute' section.

Published: 2nd August 2022 | Updated: 15th August 2022

Differential diagnosis

Common Diagnoses

  • Anxiety/Stress
  • Depressive Illness
  • Dementia (Multi-infarct, Alzheimer’s Disease and Dementia with Underlying Cause, Such as Tumour, Neurosyphilis, Hypothyroidism, Vitamin B12 and Folate Deficiency)
  • Trauma: Head Injury
  • CVA (Infarct in Posterior Cerebral Artery Territory)

Occasional Diagnoses

  • Chronic Excess Alcohol Intake (Thiamine Deficiency: Korsakoff’s Syndrome)
  • Subarachnoid Haemorrhage
  • Other Thiamine Deficiency: Malabsorption, Carcinoma Stomach, Hyperemesis Gravidarum
  • Transient Global Amnesia
  • Fugue States and Psychogenic Amnesia
  • Tumour of Third Ventricle or Hypothalamus

Rare Diagnoses

  • Personality Disorder
  • Malingering
  • Intractable Epilepsy
  • Carbon Monoxide Poisoning
  • Herpes Simplex Encephalitis

Ready reckoner

Key distinguishing features of the most common diagnoses

Aware of ProblemPossibleNoPossiblePossibleYes
Memory Loss Recent EventsYesYesPossibleYesYes
Memory Loss Remote EventsPossibleNoPossibleNoNo
Neurological SignsPossiblePossiblePossibleNoNo
Sudden OnsetYesNoYesNoNo

Possible investigations

Likely: (Unless obvious depression or anxiety) FBC, TFT, LFT, calcium.

Possible: B12 and folate levels, CT/MRI scan.

Small Print: Syphilis serology

  • FBC may show raised MCV, suggesting either alcohol abuse or B12/folate deficiency. Check B12 and folate levels if MCV raised.
  • TFT: Hypothyroidism is an important remediable cause of dementia.
  • LFT and γGT will give useful clues to alcohol intake (history likely to be unreliable).
  • Calcium level: May show hypo- or hypercalcaemia.
  • Syphilis serology: For possible neurosyphilis as underlying cause of dementia.
  • CT scan/MRI: Will detect space-occupying lesions, cerebrovascular disease, atrophy and subarachnoid haemorrhage.

Top Tips

  • Patients with dementia are often unaware of, or deny, their memory loss; the problem is more often brought to the GP’s attention by a concerned friend or relative.
  • Patients who present themselves to the GP complaining of memory loss are most likely to be suffering from anxiety or depression.
  • Even if a diagnosis of anxiety or depression seems obvious, patients are likely to be concerned about the possibility of dementia, which will exacerbate the situation; explaining that the problem is more to do with poor concentration than failing memory will help reassure them.
  • Establishing the onset gives valuable clues to the problem – a dementia pattern progressing slowly over a year or two is likely to be Alzheimer’s or multi-infarct dementia; with a shorter history, an underlying cause is possible; and sudden onset of memory loss is likely to be caused by a vascular event or trauma.
  • It can be very difficult to distinguish between depression and dementia – and the two may coexist. Consider a trial of antidepressants.

Red Flags

  • Rapid onset of apparent dementia over 3–6 months or less suggests a possible underlying cause.
  • True memory loss after a head injury suggests significant trauma.
  • Depression in the elderly may mimic dementia (pseudodementia) with behavioural changes like hoarding and bad temper. Do not miss this treatable condition.
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Website disclaimer

Pulse Reference is based on the best-selling book Symptom Sorter.

The experts behind Pulse Reference are Dr Keith Hopcroft who is the co-author of Symptom Sorter, a GP in Essex and Pulse’s editorial advisor and Dr Poppy Freeman, a GP in Camden and also a clinical advisor to Pulse.

This website is for clinical guidance only and cannot give definitive diagnostic information. Practitioners should work within the limits of their individual professional practice, seek guidance when necessary and refer appropriately.