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Visceral Leishmaniasis-KALA-AZAR

LEISHMANISES is caused by parasitic protozoa of the genus Leishmania. Humans are infected via the bite of phlebotomine sandflies, which breed in forest areas, caves, or the burrows of small rodents. There are four main types of the disease:In cutaneous forms, skin ulcers usually form on exposed areas, such as the face, arms and legs. These usually heal within a few months, leaving scars.Diffuse cutaneous leishmaniasis produces disseminated and chronic skin lesions resembling those of lepromatous leprosy. It is difficult to treat.In mucocutaneous forms, the lesions can partially or totally destroy the mucous membranes of the nose, mouth and throat cavities and surrounding tissues.Visceral leishmaniasis, also known as kala azar, is characterized by high fever, substantial weight loss, swelling of the spleen and liver, and anaemia. If left untreated, the disease can have a fatality rate as high as 100% within two years.

• The disease and its epidemiology The vector The leishmaniases are caused by 20 species pathogenic for humans belonging to the genusLeishmania, a protozoa transmitted by the bite of a tiny 2 to 3 millimetre-long insect vector, the phlebotomine sandfly. Of 500 known phlebotomine species, only some 30 of them have been positively identified as vectors of the disease. Only the female sandfly transmits the protozoa, infecting itself with theLeishmania parasites contained in the blood it sucks from its human or mammalian host in order to obtain the protein necessary to develop its eggs. During a period of 4 to 25 days, the parasite continues its development inside the sandfly where it undergoes a major transformation. When the now infectious female sandfly feeds on a fresh source of blood, its painful sting inoculates its new victim with the parasite, and the transmission cycle is completed. The insect vector of leishmaniasis, the phlebotomine sandfly, is found throughout the world's inter-tropical and temperate regions. The female sandfly lays its eggs in the burrows of certain rodents, in the bark of old trees, in ruined buildings, in cracks in house walls, in animal shelters and in household rubbish, as it is in such environments that the larvae will find the organic matter, heat and humidity which are necessary for their development. In its search for blood (usually in the evening and at night), the female sandfly covers a radius of a few to several hundred metres around its habitat. Various forms of leishmaniasis Leishmaniasis currently threatens 350 million men, women and children in 88 countries around the world. The leishmaniases are parasitic diseases with a wide range of clinical symptoms: cutaneous, mucocutaneous and visceral. Cutaneous forms Cutaneous forms of the disease normally produce skin ulcers on the exposed parts of the body such as the face, arms and legs. The disease can produce a large number of lesions - sometimes up to 200 - causing serious disability and invariably leaving the patient permanently scarred, a stigma which can cause serious social prejudice. Mucocutaneous forms In mucocutaneous forms of leishmaniasis, lesions can lead to partial or total destruction of the mucous membranes of the nose, mouth and throat cavities and surrounding tissues. These disabling and degrading forms of leishmaniasis can result in victims being humiliated and cast out from society. Visceral forms Visceral leishmaniasis - also known as kala azar - is characterized by irregular bouts of fever, substantial weight loss, swelling of the spleen and liver, and anaemia (occasionally serious). If left untreated, the fatality rate in developing countries can be as high as 100% within 2 years.

A wound leak

A wound leak

A housewife aged 68 years had a left hemicolectomy

performed for severe diverticular disease complicated by a

pericolic abscess. Her postoperative course was a stormy

one. She developed a severe pulmonary collapse (she had

been a heavy smoker), had a marked paralytic ileus, with

severe abdominal distension and ran a persistent pyrexia.

After a week, the abdominal scar was noted to be

considerably infl amed and 3 days later faecal fl uid and

fl atus began to discharge through its lower end.

What is this condition called?

Postoperative faecal fi stula, which has resulted from

an – at least partial – break down of the large bowel

anastomosis.

What is the definition of the term ‘fistula’?

A fi stula is a pathological communication between two

epithelial surfaces – in this case, colon and skin. We have

to add the word ‘pathological’ to this defi nition otherwise

some purist would be able to call the alimentary tract a

‘fi stula between the mouth and the anal verge’!

What is the sheet of material that has

been affi xed around the fi stula called

and what is its importance?

This is a sheet of Stomahesive. A central hole has

been cut out of it, which corresponds to the opening

of the fi stula. This material is invaluable. Unlike

other dressings, it adheres to the skin even when this

is wet and soggy. A collecting ileostomy pouch is

attached to the Stomahesive. This prevents the

enzyme-containing effl uent intestinal contents from

reaching, and digesting, the skin around the fi stulous

opening.

Before this material was available, gross excoriation of

the skin was a distressing complication of bowel fi stulae,

especially of the upper alimentary tract, where the trypsin

from escaping pancreatic juice is particularly harmful in

this respect.

How can the track of the fi stula be

visualized radiologically?

By the injection of radio-opaque contrast fl uid, for

example Gastrografi n, through a fi ne catheter into the

fi stula – a fi stulogram.Contrast is introduced

into a midline wound fi stula and rapidly fi lls a loop of

small bowel and then moves on into the colon. There is

contrast already in the rectum from a previous contrast

enema.

In general terms, what conditions

will prevent any fi stula from

healing spontaneously?

• If the two ends of the intestine are not in apposition

to each other

• If the mucocutaneous junction of the fi stula has

epithelialized . This is why a surgically established

colostomy or ileostomy will not close – the

surgeon sutures the mucosal edge of the bowelthe adjacent skin margin. The first step in closure

of a stoma is to detach the mucosa from the skin

edge.

• If there is distal obstruction; for example,

a suprapubic cystostomy will close within a few days of

removal of the cystostomy tube in the normal subject,but if there is distal obstruction, from an enlarged prostate

or a urethral stricture, for example, the fi stula goes

on draining urine.

• If there is disease in the fi stula track; for example, if the

bowel fi stula leads down to an area of Crohn’s disease

What are the principles in the treatment

of a bowel fi stula?

• Protect the skin around the fi stula from excoriation by

means of Stomahesive and a stoma pouch to collect the

effl uent.

• Replace the patient’s fl uid and electrolytes, ensure

adequate nourishment and restore the haemoglobin level

if necessary. (Note that in a high intestinal fi stula this will

require intravenous nutrition by means of an intravenous

central line.)

• Investigate the anatomy of the fi stula by means of a

fi stulogram and drain any pus collection. If any factors

are found to be present that will prevent spontaneous

healing of the fi stula (see question above), proceed to

appropriate surgery when the patient’s general condition

has been returned to as near normal as possible.