Presentation on theme: "Diagnostic tests Reasons for medical tests"— Presentation transcript:
1Diagnostic tests Reasons for medical tests To confirm or exclude a proposed diagnosisTo screen for diseaseTo screen for the presence of risk factorsTo monitor the course of al illnessTo monitor the effect of treatment
2Categories 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).
3pathologyIs the collection of specimens such as blood, tissue, body fluids and using laboratory tests to find the abnormal values/ structure etc.Histology of tissueSystem / organ functionsImmunity , infection, autoimmunityGenetics- chromosomal DNADrug monitoringCancer markers
4Diagnostic imagingX –Ray- with or without contrast, videoScans.
12scopesMany of the scopes today are fiber optics which allows the catheter to be flexibleThese 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
13Respiratory system diagnostic tests BronchoscopyA fiber optic endoscope is inserted into the bronchusThe patient is fasted and sedated
15bronchoscopy Tumors or bronchial cancer Airway obstructions and or stricturesInflammation and infections such as tuberculosis, pneumonia, or fungal or parasitic lung infections.Interstitial pulmonary diseasePersistent cough or haemoptysisBiopsy of tissue or collection of other specimens, such as sputumVocal cord analysis
17Bronchoscopy -therapeutic Removal of secretions, blood, mucus plugs, or polyps (growths) to clear airways.Control bleeding in the bronchiRemoval of foreign objects or other obstructionsLaser therapy or brachytherapy (radiation treatment) for bronchial tumors.Stent placement ( a device used to keep the airway open)Draining of an abscess
18Bronchoscopy complications BleedingInfectionBronchial perforationBronchospasm or laryngospasmPneumothorax
19Lung biopsies Types Needle biopsy- under CT or fluoroscopy guidance Transbronchial biopsy- via bronchoscopeThoracoscopic 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.
21Lung perfusion and / or ventilation scans A dye is eitherInjected into a vein and the blood flow to the lungs and the alveoli is observed (perfusion)This test shows pulmonary embolism orInhaled into the lungs to assess the ventilation capabilities of the lungs.
24Thoracentesis Is the removal of effusion from the pleural space for Diagnosis purposes- infection, malignancyTherapeutic purposes – remove excess fluid, to re-expand the lungPerformed under local anestheticPost Procedure checkVital signs especially respiratory rate and coughWatch for signs of distress , shock and bleedingdressing
27bloodsFBEU&E’sTropinin levelsGroup and cross match
28FBE Haemoglobin (Hb) Red Cells Number Shape – eg sickle cell, spherocytes, pencil cells, ovalocytesSize – normo- micro- macro-cyticColour –normo- hypo- chromicWhite cell count and differentiationPlatelet count
29Urea and electrolytesUrea 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 areDiet high in proteinLoss of salt and water eg vomiting , diarrhoeaDecreased blood flow to the kidneys eg CCFLow levels can be due toSevere liver damagePoisoning
30electrolytes Acid –base balance Normal 7.4 Acidic 7.36 Alkaline 7.44 Water sodium balanceElectrolytesSodium potassiumChloride BicarbonateCalcium Magnesium
31Tropinin 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 –AMIThere may be mild elevation in severe unstable angina
32Bone marrow biopsy Reasons for doing Diagnose certain conditions Assess the stage or progression of certain conditionsmonitor treatment of certain conditionsProcedureIntravenous (IV) sedationLocal aesthesiaComplicationsBleedingInfection
33Cardiac catheterA 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.ComplicationsBleedingAnginaAMI
34Electrocardiograph - ECG Views the conduction of the heartThe tracing shows PQRST formationP wave = depolarization of the atriaQRS = depolarization of the ventricleT wave = depolarization of the ventricle
35EchocardiographUses 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.
36Electrocardiograph - ECG One small square is 0.04 seconds.One large square ( 5 small squares) is 0.2Damage or malfunction of the heart can be observed in an ECG.Also the heart can be calculated.
37DopplerA 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)
38Angiograms 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)
40Lumbar puncture (spinal tap) Reasons for performingMeningitis and encephalitisMetastatic tumors and central nervous system tumors.SyphilisBleeding (hemorrhaging) in the brain and spinal cord.Multiple sclerosis.Guillain-Barre, a demyleinating disease involving peripheral sensory and motor nerves
42Lumbar puncture Post procedure Lay flat for 4-6 hours Neurological observations andCheck 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.ComplicationsInfectionBleeding or CSF discharge from site of entryNumbness to legs and lower back pain
43myelogramDuring a lumbar puncture a dye is injected into the subarachnoid spaceReasons for procedureHerniated discsSpinal cord or brain tumorsAnkylosing spondylisisBone spursArthritic discsCysts – benign capsules that may be filled with fluid or solid matter tearing away or injury of spinal nerve rootsAracnoiditis – inflammation of arachnoid mater.
44Electroencephalograph (EEG) Observes the electrical activity of the brain.Reasons for procedureDiagnosis of epilepsy or brain injuryTo assess conditions and diseases that affect the brain.
46Urinary system diagnostic procedures Glomerular filtration rate measures the volume of blood filtered by the Glomerular membrane to form the Glomerular filtrate .Blood flowBlood pressureThe number of functioning glomeruliPermeability of the glomerular membraneBack pressure in the tubules.Still most used to determine kidney function.Declines as we get older
47Glomerular 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.
49Serum urateUric acid is the breakdown of purine components (guanidine and adenine) of the nucleic acids1/3 derived from the diet (meat and meat products)2/3 derived from turnover of body cellsCan also be measured from 24 hour urinary specimen.
50urea Urea is the end product of protein metabolism. Urea levels rise withHigh protein dietsExcessive tissue breakdownGI bleeding
51creatinine Creatinine is the product of creatine metabolism in muscle Blood levels depend closely on GFRCreatinine levels are proportionate to muscle massIf the blood value doubles then renal function has probably fallen to half normal stateCan also be measured by doing a 24 hour urine creatinine clearance test.
52Cystoscopy Internal view of the bladder. The patient is sedated. Often a biopsy is taken
53Retrograde pyelogram Performed during a Cystoscopy. A dye is inserted into the ureters via a small catheterX-ray is taken to view the kidneys , ureters and bladder
57BariumBarium is a radio-opaque substance that is used to highlight the gastrointestinal tractIt can be given as a swallow, meal or enemaTo 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
59Endoscope - gastroscopy Are used to perform diagnostic procedures and also therapeutic procedures.GastroscopyThe patient is to fastLight anesthetic givenReasons for procedureAnemia – bleeding from unknown sourceEpigastric pain or indigestionSwallowing difficultiesBiliary tree disease
61Colonoscopy reason for procedure Diagnosis of disease process eg, ulcerative colitis, diverticulitisChecking condition of polyps – biopsyAssessing possible cause of anaemia (GI bleeding)Investigate cause of frequent diarrhoea, bleeding , change in bowel habits - biopsy
62Preparation 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 procedureBowel cleansing day before procedure –cathartic (eg. Fleet, politely) may be required.
63Colonoscopy 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.
67Endoscopic 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
68Abdominal 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.