The condition usually results from lesions in the posterior hypothalamus and nearby midline structures, but occasionally results from bilateral hippocampal lesions.
It is often described as Korsakov’s syndrome, after the Russian neurologist who first described the clinical features, or as the Wernicke–Korsakov syndrome.
The prominent causal factor in most cases appears to be thiamine deficiency. 
Sign & Symptoms:
- Recent memory severely impaired: The impairment of memory is characterised by a severe impairment of recent memory or short-term memory (inability to learn new material). This is associated with impaired remote memory or long-term memory (inability to recall previously learned material). There is however no impairment of immediate memory (i.e. immediate retention and recall). Recent memory impairment also leads to disorientation in time and place. 
- Remote memory spared
- Disorientation in time: One consequence of the profound disorder of memory is an associated disorientation in time. 
- Confabulation: Gaps in memory are often filled by confabulation.  With the progression of the disease, confabulation often disappears. 
- Other cognitive functions preserved: It including remote memory, are relatively well preserved. 
Unlike the patient with dementia, the patient with an amnesic syndrome seems alert and able to reason or hold an ordinary conversation, so that the interviewer may at first be unaware of the extent of the memory disorder. 
1. Thiamine deﬁciency:
Alcohol abuse is the most frequent cause, and seems to act by causing a deficiency of thiamine.
2. Any other lesion involving bilaterally the inner core of limbic system:
That is mammillary bodies, fornix, hippocampus and para-hippocampal structures of medial temporal lobe, posterior hypothalamus and dorsomedial thalamic nuclei.
- Head trauma,
- Surgical procedure (e.g. bilateral temporal lobectomy),
- Posterior cerebral artery stroke (bilateral),
- Herpes simplex encephalitis, and
- Space occupying lesions in the region of III ventricle (e.g. neoplasms) 
- Carbon monoxide poisoning,
- Vascular lesions,
- Tumours of the third ventricle. 
According to ICD-10, the following features are require for the diagnosis:
- Recent memory impairment (anterograde and retrograde amnesia)
- No impairment of immediate retention and recall
- Attention, consciousness
- Global intellectual functioning
- Historical or objective evidence of brain disease or injury (occurs particularly with bilateral involvement of diencephalic and medial temporal structures). 
The patient may give a vivid and detailed account of recent activities that, on checking, turn out to be inaccurate. It is as though he cannot distinguish between true memories and the products of his imagination or recollection of events from times other than those he is trying to recall. Such a patient is often suggestible; in response to a few cues from the interviewer, he may give an elaborate account of taking part in events that never happened. 
- For cases that may be due to thiamine deficiency, this vitamin should prescribe in the hope of limiting further damage. Oral thiamine is sufficient in non-urgent situations, but patients admitted to hospital should give parenteral B vitamins (Pabrinex®). 
- Supportive care for general condition and treatment of the associated medical illness. 
Homeopathic Medicine for Organic Amnesic syndrome:
Homeopathy is one of the most popular holistic systems of medicine. The selection of remedy is based upon the theory of individualization and symptoms similarity by using holistic approach.
There are some specific homeopathic remedies which are quite helpful in amnesia treatment.
Belladonna, Anacardium, Hyoscyamus, Digitalis, Arnica Montana, Plumbum Met, Mercurius, Kali Phos, Natrum Mur, Natrum Carb, Zincum Met, Hypericum, Veratrum Album and many other medicines.