EXTRACT FROM

CARTER’S ENCYCLOPAEDIA

OF HEALTH AND MEDICINE

 

 

G

G

The single capital letter G is an abbreviation used in medicine in a number of ways -

- Giardia - Giardia lamblia is a single celled parasite of the intestine

- gravida - a term indicating the number of pregnancies a woman has had. G3P2 would indicate gravida 3 and para 2 (third pregnancy and two previous births).

In lower case, as g, the abbreviation usually means gram, a measure of weight (or more precisely, mass).

See also GIARDIASIS; GRAM; GRAVIDA; MASS; PARA

G6PD

See GLUCOSE-6-PHOSPHATE DEHYDROGENASE

GA

GA is an abbreviation used in medicine for a general anaesthetic.

See also GENERAL ANAESTHETIC

GABAPENTIN

Gabapentin (with the common trade name of Neurontin) is an anticonvulsant medication used to treat epilepsy (particularly epilepsy that affects only part of the body) and nerve pain.

It should be used with caution in pregnancy, breastfeeding, children under 12 years and kidney disease. Do not stop this medication suddenly, but reduce the dose slowly.

Common side effects may include tiredness, drowsiness, incoordination, nausea and dizziness, while unusual ones may be vomiting, blurred vision, tremor and weight gain. It interacts with antacids, cimetidine, evening primrose (linoleic acid), Gingko biloba and borage.

An overdose is unlikely to be lethal but may cause double vision, slurred speech, drowsiness and diarrhoea.

Gabapentin is one of the newer medications for poorly controlled epilepsy that was introduced in the late 1990s, and is also very effective in treating intractable nerve pain.

See also ANTICONVULSANTS; BARBITURATES; BENZODIAZEPINES; EPILEPSY

GAD

See GLUTAMIC ACID DECARBOXYLASE ANTIBODIES; GENERALISED ANXIETY DISORDER

GABITRIL

See TIAGABINE

GAENSLEN’S SIGN

Gaenslen's sign is a test performed by doctors for diseases involving the sacroiliac joint between the sacrum and pelvis in the lower back.

The patient lies on their side on firm couch. The bottom leg is bent up onto the abdomen, and the upper leg is extended. The test is positive if sacroiliac joint pain occurs, and indicates the presence of diseases such as ankylosing spondylitis or a ligamentous tear.

See also ANKYLOSING SPONDYLITIS; SACROILIAC JOINT

GAG

In medicine and dentistry, a gag is a surgical device for holding the mouth open during operations, or it may be a term used to describe an unsuccessful attempt to vomit.

GAG REFLEX

The gag or pharyngeal reflex is demonstrated by lightly touching a spatula (flat stick) against the back of the pharynx (throat). This causes an uncontrollable contraction of the pharyngeal muscles and gagging. The reflex may be absent with damage to the glossopharyngeal (9th cranial) nerve (eg. injury, tumour), hysteria or anaesthesia.

See also CRANIAL NERVES; PHARYNX; REFLEX

GAISBÖCK SYNDROME

Also known as stress erythrocytosis, Gaisböck syndrome is possibly a familial (inherited) condition in which there are an excessive number of erythrocytes (red blood cells) present in the blood. The patient has a reddish complexion, and it is a condition that is more common in middle aged, overweight, white males who abuse alcohol. No treatment is usually necessary.

See also RED BLOOD CELL

GAIT

Gait is al term that describes the way in which a person walks, particularly the rhythm of the walk.

See also WALK ABNORMAL

GAIT ABNORMAL

See WALK ABNORMAL

GALACT-

The prefix galact- is used in medicine for terms related to milk. It is derived from the Greek word “gala” that means milk.

GALACTOKINASE

A deficiency of galactokinase in red blood cells is an inherited condition that predisposes to the onset of cataracts (clouded or milky lens in eye) in teenagers, and galactosaemia (inherited blood sugar disorder). The normal level in red blood cells is 8 to 40 mU/g Hb (micro units per gram of haemoglobin).

See also GALACTOSAEMIA; GALACTOSE; KINASE

GALACTORRHOEA

Galactorrhoea is a term used in medicine for an abnormal or excessive discharge of milk from the breast.

See also NIPPLE DISCHARGE; -RRHOEA

GALACTOSAEMIA

Galactosaemia is a congenital lack of the liver enzyme galactokinase that is responsible for the metabolism (break down) of galactose, which is one of the sugars in milk. These infants vomit, fail to thrive, and develop liver disease, intellectual disability, frequent infections and eye cataracts. A specific diagnostic test can be performed on red blood cells. A strict dietary avoidance of all milk products will prevent all the symptoms except intellectual disability.

See also INTELLECTUAL DISABILITY

GALACTOSE

Galactose is a form of sugar that is formed by the break down of lactose, the main sugar in milk.

The normal level on a blood test is less than 1.0 mmol/L. A high level may be an indication of galactosaemia (an inherited disturbance of the breakdown of the sugar galactose in milk to cause vomiting, failure to thrive, liver disease and eye cataracts), or galactose-1-phospahte deficiency  (inherited lack of a liver enzyme).

See also GALACTOSAEMIA; GALACTOSE-1-PHOSPHATE; LACTOSE; SUGAR

GALACTOSE-1-PHOSPHATE

The amount of galactose-1-phosphate in red blood cells can be measured in a blood test. The normal level is less than 170 nmol/g Hb (nanomols per gram of haemoglobin).

Very high levels (greater than 500 nmol/g Hb) are found in galactosaemia (an inherited disturbance of the breakdown of the sugar galactose in milk to cause vomiting, failure to thrive, liver disease and eye cataracts). Even on a galactose free diet, high levels may still be found in galactosaemia on galactose free diet. The test is used to both diagnose and monitor the severity of galactosaemia.

See also GALACTOSAEMIA; GALACTOSE

GALANTAMINE

Galantamine is a medication used for the management of Alzheimer disease.

It is not designed for use in pregnancy, breastfeeding and children, and should be used with caution with heart rhythm irregularities, peptic ulcer, recent surgery, epilepsy, severe asthma, emphysema, poor urinary flow and liver disease. Do not take it if suffering severe liver or kidney disease. Patients should take adequate fluids with medication.

Common side effects may be nausea, diarrhoea, weight loss, tiredness and a poor appetite. Unusual side effects can include low blood pressure, low blood potassium levels, urinary infection, watery nasal discharge. Severe but rare reactions include irregular heart beat, abnormal bleeding.

Galantamine interacts with anticholinergics, digoxin, beta-blockers, paroxetine, ketoconazole, erythromycin, quinidine, fluoxetine and fluvoxamine.

Introduced in 2001, it assists memory and reasoning power in only some patients with Alzheimer disease. Regular mental tests are necessary to assess its effectiveness.

See also ALZHEIMER DISEASE; DONEPEZIL; RIVASTIGMINE; TACRINE

GALEAZZI FRACTURE

A Galeazzi fracture is a break of the radius in the forearm two-thirds the way down its length combined with a dislocation of the joint between the radius and ulna bones (radioulnar joint) just above the wrist. The patient feels pain in the forearm and wrist, and the fracture and dislocation can be confirmed by an x-ray.

The best treatment in adults is surgery to place the broken bone ends in the correct position for healing, but in children a simple plaster for three weeks is all that is necessary.

See also COLLES’ FRACTURE; FRACTURE; RADIUS; SMITH FRACTURE

GALEAZZI SIGN

The Galeazzi sign is a test for a congenital (present since birth) dislocation of a hip in a child between 6 and 18 months of age.

With the child lying on their back, the hips are bent to 90 degrees and the feet are placed flat on the examination couch. Positive for a dislocated hip if one knee appears lower than the other. The lower knee is on the side of the dislocated hip as the leg is slightly shortened by the dislocated hip. It is also difficult to tilt the knee out from the midline on the side of the dislocated hip.

See also HIP DISLOCATION

GALEN

Claudius Galen was born in Pergamon (Pergamum), in present day Turkey, in about 130 and died about 200 AD. He was a Greek physician in Rome, and chief physician to the gladiators, and a well-respected physician. He was an anatomist who dissected apes and extrapolated their anatomy to that of humans. His mistaken ideas about the circulation of blood and numerous anatomical structures (eg. he thought there was an opening between the left and right sides of the heart) persisted unchallenged until the 15th. Century. He was a believer in the humoral theory of disease, in that imbalances between the four humours of the body (phlegm, blood, yellow bile, black bile) were responsible for all illness.

See also HIPPOCRATES; VESALIUS

GALL BLADDER

The liver, which sits behind the lower ribs on the right side of the body, produces bile at a more or less constant rate. This bile moves through a series of collecting ducts, which join up to form the common bile duct. This duct leads to the small intestine. There is a side duct to the common bile duct that leads to the gall bladder.

Bile is required to help in the digestion of food, but as we do not eat constantly, it is not needed in the gut all the time. There is a valve at the lower end of the common bile duct where it opens into the intestine. This valve opens when food passes to allow bile to be added to the food in the gut. When the valve is closed, the bile must be stored, and this is where the gall bladder fits in to the picture.

The gall bladder is a storage area for bile that is not immediately required, and the bile from the liver is directed into it when the valve is closed. When extra bile is required in the gut to digest food, the gall bladder contracts to squeeze the bile out through the open valve onto the food.

If the gall bladder is removed, the bile trickles into the gut constantly, and although not an ideal situation, the bile and food will eventually mix together, and digestion will occur, with minimal consequences to you or your gut.

See also CHOLANGIOCARCINOMA; CHOLANGIOGRAM; CHOLANGITIS; CHOLECYSTECTOMY; CHOLECYSTITIS; DUODENUM; GALLSTONES; LIVER; PANCREAS

GALL BLADDER REMOVAL

See CHOLECYSTECTOMY

GALLOP RHYTHM

The term gallop (or triple) rhythm refers to a doctor hearing a third heart sound (normally there are only two), and sometimes even a fourth sound, when listening to the heart through a stethoscope.

There are many varied causes that can be diagnosed by the timing of the extra heart sounds, and by more sophisticated tests on the heart (eg. echocardiography, electrocardiogram - ECG). The possible causes may include a distended heart, mitral valve leakage (incompetence) or narrowing (stenosis), left ventricular heart failure, alveolitis (a lung disease), constrictive pericarditis, aortic stenosis, enlargement of the upper chambers of the heart (atrial hypertrophy), abnormal electrical conduction within the heart or it may be a normal variation in a particular person.

The extra sound is caused by various flow and valve movement abnormalities.

See also ARRHYTHMIA; ECHOCARDIOGRAPHY; ELECTROCARDIOGRAM; HEART; HEART, EXTRA BEATS; PALPITATIONS and separate entries for conditions mentioned above.

GALLOWAY-MOWAT SYNDROME

The Galloway-Mowat syndrome is a very rare inherited condition. Both parents must be carriers of an abnormal gene for a child to be affected (autosomal recessive inheritance). Affected children have a small head (microcephaly), hiatus hernia (stomach slips through diaphragm up into chest) and kidney failure (nephrotic syndrome).

See also AUTOSOMAL INHERITANCE; HEAD SMALL; HIATUS HERNIA; NEPHROTIC SYNDROME

GALLSTONES

The development of one or more stones in the gall bladder is called cholelethiasis.

The liver produces bile, which is stored in the gall bladder. Bile is required to help in the digestion of food, and when this is required in the gut, the gall bladder contracts to squeeze out the bile. If the bile becomes too concentrated it may precipitate out as a stone. Up to 10% of men over 60 years of age, and 20% of women over 60 have some gallstones.

Larger stones may block the bile duct, and when the gall bladder contracts with eating, the movement of the stone in the duct causes severe intermittent pain (biliary colic) in the upper right side of the abdomen. The pain can also be felt in the back at the lower end of the shoulder blade. Indigestion, burping and passing wind rectally (farting), are common. If the stone becomes stuck, constant severe pain results, and an emergency operation is required to clear it. Infection of the gall bladder (cholecystitis) may occur when its drainage is blocked by a stone. The patient is feverish, nauseated and in constant pain. In extreme cases, an infected gall bladder will rupture and cause peritonitis.

The presence of gallstones may be confirmed by an ultrasound scan, or special X-rays (cholecystograms) taken after a dye, which concentrates in the bile, has been swallowed or injected. In difficult cases, x-rays of the gall bladder can be performed by passing a gastroscope into the small intestine and then injecting dye through the opening into the bile duct (endoscopic retrograde cholecystopancreatography - ERCP). Blood tests to check liver function are usually normal unless a gallstone is blocking the bile duct and preventing waste products leaving the liver.

A low fat diet will reduce demands on the gall bladder for bile and reduce painful spasms. The most effective treatment is surgery to remove the gall bladder (cholecystectomy) The operation can be performed by open exposure of the gall bladder or by laparoscopic surgery. If the stones are very low in the common bile duct, they may be removed by an instrument that is passed through the mouth and stomach and into the intestine (an endoscope). Patients who are too ill for an operation may use drugs (eg. ursodeoxycholic acid) that slowly dissolve some gallstones over many months. Lithotripsy is a treatment in which the stones are shattered by a high-frequency sound wave, but it is only suitable for a small number of cases.

See also CHOLANGITIS; CHOLECYSTECTOMY; CHOLECYSTITIS; CHOLELETHIASIS; CHOLELITHOTOMY; CYSTIC DUCT SYNDROME; ENDOSCOPE; ENDOSCOPIC RETROGRADE CHOLECYSTOPANCREATOGRAPHY; GALL BLADDER; LIVER; MIRRIZZI SYNDROME; MURPHY’S LAW; MURPHY’S SIGN; ROKITANSKI-ASCHOFF SINUS

GAMBLING

Gambling becomes a medical problem (pathological) when the person has a preoccupation with gambling for its own sake, that becomes more intense when under stress. Pathological gambling is a psychiatric illness, a form of obsessive compulsive neurosis, which normally starts in the teenage years, but intensifies in early adult life, and may be triggered by stress. The children of pathological gamblers are more likely to develop the problem.

Most victims are men who gamble alone, try to conceal their gambling and losses, gamble more when they lose, are unable to confine losses to a budget, borrow money to gamble, and may steal money to gamble. They experience an intolerable build up of tension when there is an opportunity to gamble that can only be relieved by partaking in the bet. Serious family, social and financial loss may occur.

Group therapy run by psychiatrists, psychologists and groups such as Gamblers Anonymous are the most successful treatments. Only rarely are drugs prescribed to quieten a particularly manic phase. Often, not until a crisis such as bankruptcy, gaol or separation from a wife results will the sufferer seek, or be forced to undertake, any form of treatment.

See also OBSESSIVE COMPULSIVE NEUROSIS