Bma Illustrated Medical Dictionary

walking as before. Prolonged use of the

arms may also cause pain. Symptoms

then become worse until, eventually,

pain is present even when the person is

at rest and the affected limb is cold and

numb. In the final stage, there is gan-

grene. Sudden arterial blockage may

occur, causing sudden severe pain. Move-

ment and feeling in the limb are lost.

A diagnosis is often based on results

of doppler ultrasoundor angiography.

Exercise and giving up smoking are

important aspects of treatment. Arterial

reconstructive surgery, bypass surgery,

or balloon angioplastymay be needed.

Amputationis needed for gangrene.

peristalsisWave-like movement caused

by rhythmic contraction and relaxation

of the smooth muscles in the walls of

the digestive tract and the ureters. Peri-

stalsis is responsible for the movement

of food and waste products through the

digestive system and for transporting

urine from the kidneys to the bladder.

peritoneal dialysisSee dialysis.

peritoneumThe 2-layered membrane

that lines the abdominal cavity and cov-

ers and supports the abdominal organs.

The peritoneum produces a lubricating

fluid that allows the abdominal organs to

glide smoothly over each other, and pro-

tects the organsagainst infection. It also

absorbs fluid and acts as a natural fil-

tering system. The peritoneum may

become inflamed as a complication of

an abdominal disorder (see peritonitis).

peritonitisInflammation of the peri-

toneum. Peritonitis is a serious, usually

acute, condition. The most common

cause is perforationof the stomach or

intestine wall, which allows bacteria and

digestive juices to move into the abdom-

inalcavity. Perforation is usually the

result of a peptic ulcer, appendicitis, or

diverticulitis. Peritonitis may also be

associated with acute salpingitis, chole-

cystitis, or septicaemia.

There is usually severe abdominal

pain. After a few hours, the abdomen

feels hard, and peristalsisstops (see

ileus, paralytic). Other symptoms are

fever, bloating, nausea, and vomiting.

Diagnosis is made from a physical

examination. Surgery may be necessary

to deal with the cause. If the cause is

unknown, a laparoscopyor an explor-

atory laparotomymay be performed.

Antibiotic drugsand intravenous infu-

sions of fluid are often given. In most

cases, a full recovery is made. Intestinal

obstruction, caused by adhesions, may

occur at a later stage.

peritonsillar abscessA complication

of tonsillitis.

permanent teethThe 2nd teeth, which

usually start to replace the primary teeth

at about the age of 6. There are 32 per-

manent teeth: 16 in each jaw. Each set of

16 consists of 4 incisors, 2 canines, 4

premolars and 6 molars. (See also erup-

tion of teeth.)

permethrinA drug included in prepa-

rations used to treat liceand scabies.

pernicious anaemiaA type of anae-

mia caused by a failure to absorb vitamin

B 12. Deficiency leads to the production

of abnormal, large red blood cells.

pernioAn alternative term for chilblain.

peroneal muscular atrophyA rare,

inherited disorder characterized by

muscle wasting in the feet and calves

and then in the hands and forearms. The

condition, also known as Charcot–Marie–

Tooth disease, is caused by degeneration

of some peripheral nerves. It is more

common in boys, and usually appears

in late childhood or adolescence. Mus-

cle wasting stops halfway up the arms

and legs, making them look like invert-

ed bottles; sensation may be lost. There

is no treatment, but the sufferer rarely

PERISTALSIS PERONEAL MUSCULAR ATROPHY

P

PERITONEUM

Peritoneum

Small

intestine

Pancreas

Large

intestine

Stomach