Bma Illustrated Medical Dictionary

(vomiting of blood) and melaena, and is

a medical emergency. Chronic bleeding

may cause iron-deficiency anaemia. Rare-

ly, an ulcer may perforate the wall of the

digestive tract and lead to peritonitis.

An ulcer is usually diagnosed by an

endoscopyof the stomach and duode-

num; less commonly, a barium meal (see

barium X-ray examination) is performed.

Tests will be carried out to see whether

the individual is infected with the HELI-

COBACTERbacterium. If this is the case,

a combination of antibioticsand an ulcer-

healing drugwill be given. A further test

may be done to check that treatment

has been successful. If HELICOBACTERis

not detected – for example, in ulcers

caused by nonsteroidal anti-inflammatory

drugs(NSAIDs) – treatment is with pro-

ton pump inhibitorsor H 2 -blockers, and

the NSAIDs will be stopped. Surgery is

now rarely needed for peptic ulcers,

except to treat complications such as

bleeding or perforation.

peptideA protein fragment consisting

of 2 or more amino acids. Peptides that

consist of many linked amino acids are

known as polypeptides; chains of poly-

peptides are called proteins. In the

body, peptides occur in forms such as

hormonesand endorphins.

perceptionThe interpretation of a sen-

sation. Information is received through

the 5 senses (taste, smell, hearing, vis-

ion, and touch) and organized into a

pattern by the brain. Factors such as

attitude, mood, and expectations affect

the final interpretation. Hallucinations

are false perceptions that occur in the

absence of sensory stimuli.

percussionA diagnostic technique in-

volving tapping the chest or abdomen

with the fingers and listening to the

sound produced to deduce the condi-

tion of the internal organs. (See also

examination, physical.)

percutaneousA medical term meaning

through the skin.

perforationA hole made in an organ

or tissue by disease or injury.

peri-A prefix meaning around.

perianal haematomaA haematoma

under the skin around the anus.

pericarditisInflammation of the peri-

cardium, which often leads to chest pain

and fever. There may also be an increased

amount of fluid (effusion) in the pericar-

dial space, which may restrict the heart.

Long-term inflammation can cause con-

strictive pericarditis, a condition in which

the pericardium becomes scarred, thick-

ens, and contracts, interfering with the

heart’s action.

Causes of pericarditis include infection;

myocardial infarction; cancer spreading

from another site; and injury to the

pericardium. The disorder may accom-

pany rheumatoid arthritis, systemiclupus

erythematosus, and kidney failure.

Pericarditis causes pain behind the

breastbone, and sometimes in the neck

and shoulders. There may also be fever.

Constrictive pericarditis causes oedema

of the legs and abdomen.

Diagnosis is made from a physical ex-

aminationand an ECGand chest X-rays

or echocardiography. If possible, treat-

ment is aimed at the cause. Analgesic

drugsor anti-inflammatory drugsmay

be given. If an effusion is present, fluid

may be drawn off through a needle. In

constrictive pericarditis, part of the peri-

cardium may be removed.

pericardiumThe membranous bag that

surrounds the heartand the roots of the

major blood vessels that emerge from

it. The pericardium has 2 layers separat-

ed by a space called the pericardial

space, which contains a small amount

of fluid that lubricates the heart.

PEPTIDE PERICARDIUM

P

PERICARDIUM

Myocardium

(heart muscle)

Outer layer of

pericardium

DETAIL

Inner layer of pericardium

Pericardial fluid

STRUCTURE OF HEART