Bma Illustrated Medical Dictionary

associated withnumbnessand, some-

times, a burning feeling. The medical

term is paraesthesia. Transient pins-and-

needles is due to a temporary disturbance

in the conduction of nerve signals from

the skin. Persistent pins-and-needles may

be caused by neuropathy.

pintaA skin infection, caused by TRE-

PONEMA CARATEUM,occurring in remote

villages in tropical America. A large spot

surrounded by smaller ones appears on

the face, neck, buttocks, hands, or feet.

After 1–12 months it is followed by red

skin patches that turn blue, then brown,

and finally white. A penicillin drugor

tetracyclineclears up the infection, but

the skin may be permanently disfigured.

pinworm infestationAn alternative

name for threadworm infestation.

pioglitazoneAn oral hypoglycaemic drug

that is used in combination with other

oral hypoglycaemics (either metformin

or a sulphonylurea) in the treatment of

type 2 diabetes mellitus. Pioglitazone acts

by reducing peripheral insulin resistance.

Side effects may include gastrointestinal

disturbances, weight gain, and anaemia.

piperazineAn anthelmintic drugused

to treat infestationby roundwormsand

threadworms. Possible adverse effects

include abdominal pain, nausea, vomit-

ing, and diarrhoea.

piroxicamA type of nonsteroidal anti-

inflammatory drug(NSAID) that is used

to relieve the symptoms of types of

arthritis, and to relieve pain in bursitis,

tendinitis, and after minor surgery. Pos-

sible adverse effects include nausea,

indigestion, abdominal pain, swollen

ankles, peptic ulcer, and liver problems.

pituitary glandSometimes referred to

as the master gland, the pituitary is the

most important endocrine gland. It regu-

lates and controls the activities of other

endocrine glands and many body pro-

cesses. The pituitary gland is a pea-sized

structure attached by a stalk of nerve

fibres to the hypothalamus. The anterior

lobe produces growth hormone; pro-

lactin; ACTH; TSH (thyroid-stimulating

hormone), which stimulates hormone

production by the thyroid gland; the

gonadotrophinsFSH (follicle stimulating

hormone) and LH (luteinizing hormone);

and melanocyte-stimulating hormone

(MSH), which controls darkening of the

skin. The posterior pituitary secretes

ADHand oxytocin.

pituitary tumoursGrowths in the pitu-

itary gland. Pituitary tumours are rare,

and mostly noncancerous, but tumour

enlargement can put pressure on the

optic nerves, causing visual defects.

The causes of pituitary tumours are

unknown. They may lead to inadequate

hormone production, causing problems

such as cessation of menstrual periods

or reduced sperm production. They may

also cause the gland to produce excess

hormone. Overproduction of growth hor-

mone causesgigantism or acromegaly;

too much thyroid-stimulating hormone

(TSH) can lead to hyperthyroidism.

Investigations include blood tests,

X-rays, MRIof the pituitary, and usually

also vision tests. Treatment may be by

surgical removal of the tumour, radio-

therapy, hormone replacement, or a

combination of these techniques. The

drug bromocriptinemay be used; it can

reduce production of certain hormones

and shrink some tumours.

pityriasis albaA common skin condi-

tion of childhood and adolescence.

Irregular, fine, scaly, pale patches appear

on the face. Caused by mild eczema, it

usually clears up with emollients.

pityriasis roseaA common, mild skin

disorder in which a rash of flat, scaly-

PINTA PITYRIASIS ROSEA

P

PITUITARY GLAND

Blood vessels

Anterior lobe

of pituitary

gland

Posterior lobe

of pituitary

gland

Skull bone

Pituitary gland

LOCATION

Nerve

Brain fibre

Hypothalamus