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Diagnostic tests Reasons for medical tests

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Presentation on theme: "Diagnostic tests Reasons for medical tests"— Presentation transcript:

1 Diagnostic tests Reasons for medical tests
To confirm or exclude a proposed diagnosis To screen for disease To screen for the presence of risk factors To monitor the course of al illness To monitor the effect of treatment

2 Categories of patients
Those with signs and symptoms of a specific illness or condition and the test will either confirm or exclude a diagnosis. Broad screening tests for patients who have non specific symptoms or present with vague signs of illness eg FBE. Screening tests for patients with no signs or symptoms . The test aims to detect the presence of disease before it has manifested (eg PSA) or identify risk factors (eg elevated cholesterol).

3 pathology Is the collection of specimens such as blood, tissue, body fluids and using laboratory tests to find the abnormal values/ structure etc. Histology of tissue System / organ functions Immunity , infection, autoimmunity Genetics- chromosomal DNA Drug monitoring Cancer markers

4 Diagnostic imaging X –Ray- with or without contrast, video Scans .



7 MRI- combination of large magnets, radiofrequencies and a computer

8 Ultrasound – high frequency sound waves and a computer are used to create an image.

9 Scans-Nuclear – small amounts of radioactive substances are used.

10 ECG – study the hearts electrical activity

11 EEG-study of the brain’s electrical activity

12 scopes Many of the scopes today are fiber optics which allows the catheter to be flexible These instruments can be inserted into organs and cavities. The structure/s are either observed directly or viewed on a screen. Dyes and X-Rays can also be used

13 Respiratory system diagnostic tests
Bronchoscopy A fiber optic endoscope is inserted into the bronchus The patient is fasted and sedated


15 bronchoscopy Tumors or bronchial cancer
Airway obstructions and or strictures Inflammation and infections such as tuberculosis, pneumonia, or fungal or parasitic lung infections. Interstitial pulmonary disease Persistent cough or haemoptysis Biopsy of tissue or collection of other specimens, such as sputum Vocal cord analysis


17 Bronchoscopy -therapeutic
Removal of secretions, blood, mucus plugs, or polyps (growths) to clear airways. Control bleeding in the bronchi Removal of foreign objects or other obstructions Laser therapy or brachytherapy (radiation treatment) for bronchial tumors. Stent placement ( a device used to keep the airway open) Draining of an abscess

18 Bronchoscopy complications
Bleeding Infection Bronchial perforation Bronchospasm or laryngospasm Pneumothorax

19 Lung biopsies Types Needle biopsy- under CT or fluoroscopy guidance
Transbronchial biopsy- via bronchoscope Thoracoscopic biopsy or video – assisted thoracic surgery (VATS) biopsy- after a general anesthetic is given, an endoscope is inserted through the chest wall into the chest cavity. In addition therapeutic procedures such as the removal of a nodule or other tissue lesion my be performed. Open biopsy- after a general anesthetic is given, the physician makes an incision in the skin on the chest and surgically removes a piece of lung tissue.


21 Lung perfusion and / or ventilation scans
A dye is either Injected into a vein and the blood flow to the lungs and the alveoli is observed (perfusion) This test shows pulmonary embolism or Inhaled into the lungs to assess the ventilation capabilities of the lungs.



24 Thoracentesis Is the removal of effusion from the pleural space for
Diagnosis purposes- infection, malignancy Therapeutic purposes – remove excess fluid, to re-expand the lung Performed under local anesthetic Post Procedure check Vital signs especially respiratory rate and cough Watch for signs of distress , shock and bleeding dressing

25 Thoracentesis photo

26 Cardiovascular diagnostic procedures

27 bloods FBE U&E’s Tropinin levels Group and cross match

28 FBE Haemoglobin (Hb) Red Cells Number
Shape – eg sickle cell, spherocytes, pencil cells, ovalocytes Size – normo- micro- macro-cytic Colour –normo- hypo- chromic White cell count and differentiation Platelet count

29 Urea and electrolytes Urea is formed in the liver from the by products of protein metabolism. The levels will be raised if the kidney filtration rate is less than 50 % of normal. Other causes of raised urea are Diet high in protein Loss of salt and water eg vomiting , diarrhoea Decreased blood flow to the kidneys eg CCF Low levels can be due to Severe liver damage Poisoning

30 electrolytes Acid –base balance Normal 7.4 Acidic 7.36 Alkaline 7.44
Water sodium balance Electrolytes Sodium potassium Chloride Bicarbonate Calcium Magnesium

31 Tropinin Tropinin is a part of muscle
There are two types that are found only in cardiac muscle. If the level of these is raised then there has been some damage to the myocardium –AMI There may be mild elevation in severe unstable angina

32 Bone marrow biopsy Reasons for doing Diagnose certain conditions
Assess the stage or progression of certain conditions monitor treatment of certain conditions Procedure Intravenous (IV) sedation Local aesthesia Complications Bleeding Infection

33 Cardiac catheter A cardiac catheter is performed to view the obstructed coronary blood vessels. The patient is awake but sedated. A dye is injected to show the blood vessels. Complications Bleeding Angina AMI

34 Electrocardiograph - ECG
Views the conduction of the heart The tracing shows PQRST formation P wave = depolarization of the atria QRS = depolarization of the ventricle T wave = depolarization of the ventricle

35 Echocardiograph Uses ultrasound and computer technology to crate an image of blood flow through the heart. It can be done through the chest wall or via the oesophagus ( posterior view of the heart). If done via the oesophagus the patient is to be fasted and sedated.

36 Electrocardiograph - ECG
One small square is 0.04 seconds. One large square ( 5 small squares) is 0.2 Damage or malfunction of the heart can be observed in an ECG. Also the heart can be calculated.

37 Doppler A Doppler uses sound waves to study the flow and rate of blood through vessels . It can depict alterations to the flow of blood through vessels (blockages)

38 Angiograms and venograms
Dyes are injected into arteries or veins to highlight the flow of blood through the vessels. The vessels can be anywhere in the body. (great site to view the dye in arteries of heart)

39 Nervous system diagnostic procedures

40 Lumbar puncture (spinal tap)
Reasons for performing Meningitis and encephalitis Metastatic tumors and central nervous system tumors. Syphilis Bleeding (hemorrhaging) in the brain and spinal cord. Multiple sclerosis. Guillain-Barre, a demyleinating disease involving peripheral sensory and motor nerves


42 Lumbar puncture Post procedure Lay flat for 4-6 hours
Neurological observations and Check wound site (dressing) Lumbar puncture headaches typically begin within two days after the procedure and persist form a few days to several weeks or months. Complications Infection Bleeding or CSF discharge from site of entry Numbness to legs and lower back pain

43 myelogram During a lumbar puncture a dye is injected into the subarachnoid space Reasons for procedure Herniated discs Spinal cord or brain tumors Ankylosing spondylisis Bone spurs Arthritic discs Cysts – benign capsules that may be filled with fluid or solid matter tearing away or injury of spinal nerve roots Aracnoiditis – inflammation of arachnoid mater.

44 Electroencephalograph (EEG)
Observes the electrical activity of the brain. Reasons for procedure Diagnosis of epilepsy or brain injury To assess conditions and diseases that affect the brain.


46 Urinary system diagnostic procedures
Glomerular filtration rate measures the volume of blood filtered by the Glomerular membrane to form the Glomerular filtrate . Blood flow Blood pressure The number of functioning glomeruli Permeability of the glomerular membrane Back pressure in the tubules. Still most used to determine kidney function. Declines as we get older

47 Glomerular filtration rate (GFR)
is the amount of filtrate formed by both kidneys per minute; in a normal adult, it is about 125 ml/minute. This amounts to 180 liters per day.

48 Glomerular filtration rate (GFR)

49 Serum urate Uric acid is the breakdown of purine components (guanidine and adenine) of the nucleic acids 1/3 derived from the diet (meat and meat products) 2/3 derived from turnover of body cells Can also be measured from 24 hour urinary specimen.

50 urea Urea is the end product of protein metabolism.
Urea levels rise with High protein diets Excessive tissue breakdown GI bleeding

51 creatinine Creatinine is the product of creatine metabolism in muscle
Blood levels depend closely on GFR Creatinine levels are proportionate to muscle mass If the blood value doubles then renal function has probably fallen to half normal state Can also be measured by doing a 24 hour urine creatinine clearance test.

52 Cystoscopy Internal view of the bladder. The patient is sedated.
Often a biopsy is taken

53 Retrograde pyelogram Performed during a Cystoscopy.
A dye is inserted into the ureters via a small catheter X-ray is taken to view the kidneys , ureters and bladder

54 Retrograde pyleogram

55 Intravenous pyelogram (IVP)
A dye is inserted into a vein. As the dye passes through the urinary system X- Rays are taken. To ensure clarity of the X-ray images the bowel needs to be empty.

56 Gastrointestinal diagnostic procedures

57 Barium Barium is a radio-opaque substance that is used to highlight the gastrointestinal tract It can be given as a swallow, meal or enema To enhance the X- Rays the patient usually needs to have an empty gastrointestinal system. The introduction of air into the area with the barium also improves the X-Ray image

58 Barium enema

59 Endoscope - gastroscopy
Are used to perform diagnostic procedures and also therapeutic procedures. Gastroscopy The patient is to fast Light anesthetic given Reasons for procedure Anemia – bleeding from unknown source Epigastric pain or indigestion Swallowing difficulties Biliary tree disease

60 Endoscope

61 Colonoscopy reason for procedure
Diagnosis of disease process eg, ulcerative colitis, diverticulitis Checking condition of polyps – biopsy Assessing possible cause of anaemia (GI bleeding) Investigate cause of frequent diarrhoea, bleeding , change in bowel habits - biopsy

62 Preparation for procedure
No consuming of solid food for hours prior to procedure . Can have clear fluids such as broth, jellies, Fast 8-10 hours prior to procedure Bowel cleansing day before procedure –cathartic (eg. Fleet, politely) may be required.

63 Colonoscopy Complications Perforation of intestinal wall
Heavy bleeding due to the removal of the polyp or from the biopsy site (rare) Infections (extremely rare) Patients with artificial or abnormal heart valves are usually given antibiotics before and after the procedure to prevent an infection.

64 colonoscopy

65 Endoscopy Find photos of Reflux oesophagitis Angio – dysplasia
Pseudo- polyposis Colon cancer

66 Endoscopic retrograde cholangiopancratography ERCP

67 Endoscopic retrograde cholangiopancreatography ERCP
Is used for diagnosing and treating disease of the pancreas, gallbladder, liver, and bile ducts. An endoscope is inserted to the duodenum and a dye injected into the pancreatic duct and common bile duct. Then an X-ray is taken

68 Abdominal paracentesis
Is the removal of accumulated fluid form the peritoneal cavity. A needle is inserted into the abdominal cavity and it may be connected to a collecting bag. Done under local anesthetic. A sedative may be needed. The drainage of fluid may take time. It should not be removed too quickly as it may cause shock and collapse.


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