Causative subtypes of dementia may be based on a known disorder, such as Parkinsons disease, for Parkinsons disease dementia; Huntingtons disease, for Huntingtons disease dementia; vascular disease, for vascular dementia – as vascular brain injury, including stroke, often results in vascular dementia; or many other medical conditions, including HIV infection, causing HIV dementia; and prion diseases. Subtypes may be based on various symptoms, possibly due to a neurodegenerative disorder: frontotemporal lobar degeneration for frontotemporal dementia, or Lewy body disease for dementia with Lewy bodies. More than one type of dementia, known as mixed dementia, may exist together. Diagnosis is usually based on history of the illness and cognitive testing with imaging. Blood tests may be taken to rule out other possible causes that may be reversible, such as an underactive thyroid, and to determine the subtype. One commonly used cognitive test is the Mini–Mental State Examination. The greatest risk factor for developing dementia is aging, however dementia is not a normal part of aging. Several risk factors for dementia, such as smoking and obesity, are preventable by lifestyle changes. Screening the general older population for the disorder is not seen to affect the outcome.Dementia is currently the seventh leading cause of death worldwide, with 10 million cases reported every year. That is about one new case every 7 seconds a day. There is no known cure for dementia. Acetylcholinesterase inhibitors such as donepezil are often used and may be beneficial in mild to moderate disorder. The overall benefit, however, may be minor.
Sigmoid colon volvulus, also known as sigmoid volvulus, is volvulus affecting the sigmoid colon. It is a common cause of bowel obstruction and constipation. It is common in Asia, India (7% of intestinal obstruction) and especially South India because of the high fibre diet. It is a very common cause of large bowel obstruction in Peru and Bolivia due to high altitude. Signs and symptoms
Pain in abdomen – initially left-sided, eventually all over
Absolute constipation
Enormous distension of abdomen
Late vomiting and eventually dehydration
Features of peritonitis
Hiccup and retching may occur
Tyre-like feel of the abdomen is diagnostic

Cause
The condition is more common in males and with old age. It is also common in people with chronic constipation and laxative abuse. It is common in:
Ogilvie syndrome
Individuals with learning difficulties
Chagas disease
Hypothyroidism
Anticholinergic drugs
Multiple sclerosis
Scleroderma
Parkinsons diseaseIn sigmoid, volvulus rotation is always anticlockwise. It requires one and a half rotation to cause vascular obstruction and gangrene which eventually leads to perforation either at the root or at the summit of the sigmoid loop. Diagnosis
Plain X-ray (diagnostic in 70–80%): coffee bean sign is seen
Contrast enema: bird beak sign
CT scan: shows characteristic whirl pattern
Blood: haematocrit, renal functions, serum electrolytes

Treatment
RT aspiration
IV fluids
Catheterisation
Antibiotics
By flatus tube or sigmoidoscope, derotation is done
If derotation does not occur, then laparotomy through midline incision should be done. It is derotated manually. If viable, it can be fixed to lateral wall of abdomen or pelvis
If sigmoid colon is gangrenous, then Hartmanns operation or Paul Mikulicz operation is done

References


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