Ascariasis- Clinical Features

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CLINICAL FEATURES:

Majority of the infections are symptomless (about 85%). The severity of the

symptoms depends both on the number of eggs ingested and on the previous

infection history.

Symptoms can be produced by

1. Migrating larvae

2. Adult worm

3. Toxins released from the worms

SYMPTOMS PRODUCED BY MIGRATING LARVAE:

Pathogenitic effect of larval migration are due to allergic reactions and not

the presence of larvae as such. Therefore the initial exposure to larvae is usually

asymptomatic except when the larval load is very high. But when reinfection

occurs, subsequently there may be intense cellular reaction to the migrating larvae

in the lungs. This may cause symptoms like pneumonia.

Loeffler’s Syndrome:

In heavy infection typical symptoms such as

Þ Fever

Þ Cough

Þ Dyspnoea

Þ Cyanosis

Þ Urticaria

Þ Pain over the chest

Þ Mucoid and bloody sputum

The sputum may contain charcot-leydon crystals. The larvae may

occasionally be found in sputum, but are seen more often in gastric washings. The

clinical features generally clear in one or two weeks. Though it may sometimes be

severe, it is rarely fatal. Loffler’s syndrome can also be caused by hypersensitivity

to other agents, both living and non living.

In General Circulation:

Larvae pass beyond the pulmonary capillaries and reach the general

circulation and they may reach other organs of the body such as liver, spinal cord

and kidneys. Very rarely the larvae may occlude a small vessel in the heart and

brain.

Symptoms Due to Adult Worms:

Clinical manifestations due to adult worms vary from asymptomatic

infection to severe and even fatal consequences. It is not unusual to find children

apparently unaffected inspite of heavy infestation with the worms. The pathological

effects present are caused by,

1. Spoliative action

2. Toxic action

3. Mechanical effects

SPOLIATIVE ACTION:

It is otherwise called as nutritional effects, are usually seen when the worm

burden is heavy. The worms may be present in enormous numbers, sometimes

exceeding 500, occupying a large part of the intestinal tract. This interferes with

proper digestion and absorption of food. Ascariasis may contribute to protein

energy malnutrition and vitamin A deficiency.

TOXIC ACTION:

These are due to the hypersensitivity to the worm antigens and may

manifested as

v Fever

v Urticaria

v Angioneurotic oedema

v Conjunctivitis

v Wheezing

These are more often seen in persons who come into contact with the worm

occupationally, as in laboratory technicians and abbatoir workers.

MECHANICAL EFFECTS:

These are the most important manifestations of Ascaris lumbricoides. Due to

mechanical irritation there may be abdominal pain, nausea, vomiting, loose motion,

abdominal distension etc. The worms may be clumped together into a mass, filling

the lumen of intestine leading to Intussusception, i.e intestinal obstruction. The

male worm is more responsive to illness of the host, than the female. Typhoid ulcer

may be penetrated giving rise to perforation of gut, sometimes the worms may be

coughed up, vomitted or passed through the nose. It may going up it enter the

opening of the biliary or pancreatic duct causing acute biliary obstruction or

pancreatitis.

It may enter the liver parenchyma where it may lead to abscesses. It may

crawl into the trachea and the lung causing respiratory obstruction or lung

abscesses.

SYMPTOMS DUE TO SENSITATION:

The metabolises of Ascaris, both during the period of biological incubation

and after the worm mature in small bowels may produce sensitation phenomen on

of allergic manifestation.

Such as,

Skin – Urticaria

Nose – Rhinitis

Lungs – Bronchial asthma

Intestinal Tract – Diarrhoea

Eye – Conjunctivitis and photophobia

Excretory system – Haematuria

The irritation caused by Ascaris lumbricoides is due to the liberation of

“Ascarin” by the adult worm.

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