Fig. 17.11 Major features of a lateral CXR. Trachea Clavicle Aortic arch 2nd rib 1st rib Right upper lobe Scapula Left upper lobe Posterior rib Carina Right middle lobe Anterior rib Left ventricle Cardiophrenic angle Left lower lobe Gastric bubble Right lower lobe Right atrium Spine Costophrenic angle Fig. 17.12 Major features on an anteroposterior CXR. Central lines (b p534) check for pneum othorax and haemothorax; note the position of the end of the line, it should be at the leve l of the carina. Feeding NG tubes (b p549) the end of the tube should be seen below the dia phragm; if not advance the tube 5cm and repeat CXR. If tube in bronchus, remove completely and resite. Chest drains (b p540) the end should be within the ribcage, ideally angled down wards for eff usions and up for pneumothoraces; note the size of pneumothorax or eff usion and any surgical emphysema. _OHFP.indb 583 _OHFP.indb 583 30/05/2014 16:19 30/05/2014 16:19 584 CHAPTER 17 Interpreting results Arterial blood gasses (ABGs) \200\223 in a ABG analysis measures PaO2 and PaCO2, and calcu lates HCO3 heparinised specimen (can also be undertaken on venous or capillary blood or on fl uid aspirated from the chest or abdomen). Base excess and anion gap are also calculated. In addition, pH, O2 saturation, and concentrations of Na+, K+, Ca2+, Cl \200\223 and lacta te are measured. For advice on how to perform an ABG see b p522. See Table 17.17. Table 17.17 Normal ranges (patient breathing room air) Parameter Value Parameter HCO \200\223 Base excess (BE) O2 saturation Value pH PaO2 PaCO2 7.35 \200\2237.45 10.6 \200\22313.3kPa 4.7 \200\2236.0kPa 22 \200\22328mmol/l \210\2222 to +2 95 \200\223100% 3 NB Note that a low or normal PaO2 in a patient on a high concentration of inspired O2 is ve ry worrying and suggests signifi cantly impaired gas exchange. First look at the pH: \200 pH <7.35 = acidaemia \200 pH 7.35 to 7.45 = normal pH \200 pH >7.45 = alkalaemia. Next look at the PaCO2 and bicarbonate (HCO3 17.19): \200\223) (Tables 17.18 and Table 17.18 Types of acidaemia dHCO \200\223 3 Metabolic acidosis Mixed acidosis Mixed acidosis nHCO \200\223 3 iHCO \200\223 3 dPaCO2 X X nPaCO2 iPaCO2 X Acute respiratory acidosis X Chronic respiratory acidosis X \200\223 incompatible Table 17.19 Types of alkalaemia dHCO \200\223 3 nHCO \200\223 3 iHCO \200\223 3 dPaCO2 Chronic respiratory alkalosis X X Acute respiratory alkalosis X X Mixed alkalosis nPaCO2 iPaCO2 Mixed alkalosis Metabolic alkalosis X \200\223 incompatible OHFP.indb 584 OHFP.indb 584 30/05/2014 16:19 30/05/2014 16:19 585 ARTERIAL BLOOD gasses (ABGS) Base excess This is the amount of \200\230base \200\231 needed to restore pH to the normal range (Table 17.20): \200 Base excess >+2, patient has excess base present (ie alkalosis ) \200 Base excess < \210\2222, patient has insuffi cient base present (ie acidosis). Table 17.20 Causes of acid \200\223base disturbance Acidosis Alkalosis Shock DKA Renal/liver failure Drug overdose (eg TCA) Renal tubular acidosis Lactate (b p477 ) Refer to \200\230anion gap \200\231 box Vomiting Diarrhea Hypokalaemia Metabolic Respiratory Severe asthma/COPD Cranial lesions (eg stroke) Anxiety/hyperventilation Severe pneumonia Severe pulmonary oedema Myasthenia gravis Drugs (eg sedatives, opioids) Ch est trauma/scoliosis Obesity If all else fails calculate the anion gap or speak to a biochemist If the diff erentials fo r a metabolic acidosis are still unclear then calculate the anion gap which should answer a ny remaining problems (see box); alternatively ask a senior or speak directly to the clinic al biochemist in the laboratory. The anion gap This is calculated by ([Na+] + [K+]) \200\223 ([Cl \200\223 ] + [HCO3 Normal value is 6 \200\22316mmol/l. It helps to distinguish the diff erent causes of a metabolic acidosis: \200 Raised anion gap (>16mmol/l): \200\223 ]). lactic acidosis (b p477 shock, sepsis/infection) \200 urate (renal failure) \200 ketone s (DKA, alcohol, starvation) \200 drugs/toxins (salicylates, biguanides, ethylene glycol, methanol) Normal anion gap (6-16mmol/l): Addison \200\231s disease \200 pancreatic fi stula \200 ammonium chloride ingestion. renal tubular acidosis \200 diarrhea \200 drugs (acetazolamide) _OHFP.indb 585 _OHFP.indb 585 30/05/2014 16:19 30/05/2014 16:19 586 CHAPTER 17 Interpreting results Respiratory function tests Peak expiratory \202 ow rate (PEFR) Indications used for the diagnosis, monitoring (eg da ily diary/obs) and severity assessment of asthma (Table 17.21). Method reset the tab and fi t a clean mouthpiece. Ask the patient to stand up and hold it i n their hands (not covering the scale), breathe in deeply and blow as hard and fast as they can (with encouragement). Use the best reading of three attempts. Table 17.21 PEFR in asthma (exacerbation severity) PEFR1 Asthma severity >80% Normal Mild \200\223moderate 80 \200\22350% 55 \200\22333% Severe <33% Life-threatening 1 Compared with best or predicted (see Fig. 17.14). Spirometry Indication diagnosis and monitoring of respiratory disease. Before testing omit morning inhalers or nebulisers (unless severely ill) to allow reversibility assessment. Method can be performed by technicians in a respiratory function laboratory or by you at th e patient \200\231s bedside. The patient must inhale as deeply as they can then exhale as f ast and as long as they can manage. The following measurements are made (Table 17.22): \200 Forced expiratory volume in 1s (FEV1), the volume exhaled in the fi rst second after deep inspiration and forced expiration, similar to PEFR \200 Forced vital capacity (FVC), the total volume exhaled from maximal inspiration to maximal exhalation. Beyond spirometry respiratory function laboratories can also measure: Residual volume (RV), the volume of gas remaining in the lungs after a maximum expiration Total lung capacity (TLC) is the combination of FVC and RV. Table 17.22 Spirometry \201 ndings in lung disease Obstructive dd d Normal n n Restrictive d dd FEV1 FVC FEV1/FVC RV TLC <75% i i 75 \200\22380% n n >80% d d Obstructive asthma, COPD, emphysema. Restrictive interstitial lung disease, sarcoid, connec tive tissue disorders, neuromuscular disease (including myasthenia gravis and Guillain \200 \223Barr ). OHFP.indb 586 OHFP.indb 586 30/05/2014 16:19 30/05/2014 16:19 587 RESPIRATORY FUNCTION TESTS Other spirometry measurements Reversibility asthma (a reversible obstruction) is diagnosed if there is \211 250ml and \211 15% improvement in PEFR or FEV1 with bronchodilators. Ast hma can coexist with COPD (non-reversible obstruction). Gas transfer also called transfer factor; is measured using carbon monoxide. It is reduced in emphysema, acute asthma, anemia and interstitial lung disease and increased with chronic asthma, left heart failure, polycythaemia and exercise. Flow volume loops graphical representations of the results with volume on the x-axis and fl ow rate on the y-axis. Exhalation is above the line and inhalation below the line. There a re four main patterns (Fig. 17.13). Upper airway obstruction lesion occluding the bronchi, trachea or larynx associated with st ridor, see b p284. Normal Obstructive Restrictive Upper airway obstruction Fig. 17.13 Flow volume loops (fl ow on y-axis, volume on x-axis). 700 Age (yrs): 20 \200\22325 30 40 50 60 20 \200\22325 30 40 50 60 Men Women 11 650 ) n m / ( 10 600 ) s / ( i l l w o fl 550 9 w o fl y r o t a r i p x e k a e P 500 y r o t a r i p x e k a e P 8 450 7 400 6 350 4 11 \235 5 3 \235 5 7 \235 5 11 \235 300 5 1.6 m 1.7 m 1.8 m 1.9 m 1.4 m 1.5 m Height (m) = meters, = feet, \235 = inches Fig. 17.14 Normal peak expiratory fl ow values. _OHFP.indb 587 _OHFP.indb 587 30/05/2014 16:19 30/05/2014 16:19 588 CHAPTER 17 Interpreting results Abdomen X-ray (AXR) The main patterns of disease are: \200 Bowel perforation free gas seen on lateral decubit us AXR (ie patient lying on one side) abdominal fi lm or erect CXR underneath the diaphragm Dilated loops of small bowel >2.5cm or large bowel >6cm (see Table 17.23) Sigmoid volvulus grossly dilated loop of bowel ( \200\230coff ee bean \200\231-shaped) \200 Constipation fecal loading in the large bowel, often starting from the rectum. If feces seen, the colon is unlikely to be infl amed Gallstones/renal stones calcifi cations in the RUQ or along the urinary tract; 10% of galls tones and 60% of renal stones are visible on AXR \200 Chronic pancreatitis calcifi ed spe cks in the epigastric/pancreatic area \200 Chronic renal failure small kidneys \200 Abd ominal aortic aneurysm wide aorta on the left hand side of the spine; may see a calcifi ed outline of the aortic walls (b p474). Develop a routine so you spot all the abnormalities (Figs 17.5 and 17.16): Bowel pathology \200 Bowel wall oedema can be seen on plain AXR \200 Bowel gas (best se en in a supine fi lm) dilated loops of bowel due to mechanical obstruction or paralytic ileus \200 Fluid level obstruction, ileus, gastroente ritis \200 Stomach dilated in pyloric stenosis; look for linitis plastica ( \200\230leath er bottle stomach \200\231) in advanced stomach cancer Gas outside the lumen bowel perforation (look for air under the diaphragm on erect CXR or lateral decubitus AXR). Biliary tree look for: \200 Gallstones (NB only 10% are radio-opaque) \200 Is there a s tent in situ? Urinary tract and bladder look for: \200 Renal and ureteric stones (60% are visible) \200 Urinary catheters or ureteric stents \200 Size of the kidneys, obvious d ilatation of the pelvicalyces; the right kidney should be lower than the left one, as the l iver is above it. Pelvis \200 Uterus/ovaries foreign bodies (eg IUCD, ring pessary), fi broids, cysts \200 Prostate size, calcifi cation (diffi cult to see). Bones \200 Lytic lesions (dark) thin k bronchial/breast/renal carcinoma, myeloma \200 Sclerotic lesions think prostate/breast carcinoma, Paget \200\231s disease \200 Fusion of the vertebrae/sacroiliac joints, curvin g of the spine degenerative disease, scoliosis, ankylosing spondylosis. Other soft tissues \200 Psoas muscle if absent, think of ascites, haematoma or retroperit oneal mass. OHFP.indb 588 OHFP.indb 588 30/05/2014 16:19 30/05/2014 16:19 589 ABDOMEN X-RAY (AXR) Hints and tips \200 AXRs are daunting to interpret initially, so it \200\231s important t o keep in mind what you are trying to confi rm/exclude on them \200 Stand back and approach things in a systematic manner \200 Take the fi ndings on AXR together with the clinical picture and discuss what management is necessary with the rest of your team. Table 17.23 Large bowel vs. small bowel obstruction Small intestine Large intestine Number of loops Distribution of loops Diameter of loops Haustrae1 Valvulae conniventes2 Fec es present Lots Central >2.5cm No Yes No Few Peripheral >6cm Yes No Yes 1 Haustra: folds which do not completely cross the bowel lumen wall. 2 Valvulae conniventes : folds which completely cross the bowel lumen wall. Small bowel with valvulae conniventes Large bowel with haustrae Fig. 17.15 Radiological diff erences between small bowel and large bowel. Liver edge Stomach bubble Gas in transverse colon Kidney outline Psoas outline Gas in loop of small bowel Sigmoid colon SI joint Caecum Sacrum Head of femur Bladder dome Fig. 17.16 Features of the abdominal X-ray. _OHFP.indb 589 _OHFP.indb 589 30/05/2014 16:19 30/05/2014 16:19 590 CHAPTER 17 Interpreting results Urine tests Urine samples should be \200\230mid-stream \200\231 (MSU) to limit urethral co ntamination, alternatively they can be taken from a catheter (CSU). Dipstick UTIs can be asymptomatic and urinary symptoms (dysuria, frequency, urgency) can be present without a UTI. See box on b p484 for information regarding the sensitivity of urin e dipsticks for detecting UTIs. Nitrites are produced by Gram-negative bacteria (eg E. coli ) and suggest urinary tract infection (UTI). Leucocytes (white cells) arise from infl ammat ion of the kidneys and urinary tract, most commonly UTIs, but also stones, trauma, neoplasi a, infection of related structures (eg prostate, appendix) and renal disease. Blood dipstic ks detect hemoglobin and may distinguish this from blood cells. Send the urine for microsco py if either are seen. A positive dipstick with no red cells on microscopy suggests myoglob inuria or haemoglobinuria. See b p374 for the causes of haematuria. Protein dipsticks detec t albumin which should not be present in urine. If protein is persistently positive then se e b p375. Bence Jones protein (seen in myeloma) is not detected by dipsticks. Glucose shoul d not be present in urine but is common with increasing age; its presence may suggest, but cannot diagnose, DM (b p328). Ketones are raised in DKA (along with glucose). They can also be raised after fasting, low carbohydrate diets and acute illness. pH normal range 4.5 \200\2238; urine pH can be aff ected by systemic acidosis and alkalosis. Acid pH suggests s ystemic acidosis and vise versa. Speci \201 c gravity a very rough guide to urine concentr ation; it should not be relied upon (urine osmolality is a superior measure). b-hCG a separ ate urine dipstick can be used to test for pregnancy; it should be positive within 12d of c onception. It is important to test all women of reproductive age to exclude pregnancy as a cause of their symptoms and before harmful medications or investigations (eg X-ray). Microscopy A mid-stream urine MSU or CSU should be sent for microscopy if there are nitrite s, leucocytes, blood or protein on the dipstick or if there is clinical suspicion of a UTI. In children a clean catch, catheter urine or suprapubic aspirate is used. White cells >10/ mm3 is abnormal; same causes as leucocytes on dipstick. Bacteria may be seen on simple micr oscopy and this is highly suggestive of a UTI; Gram staining may help identify the pathogen . The sample needs to be cultured for complete identifi cation and for antibiotic sensitivi ties. Red cells >2/mm3 is abnormal; see b p374 for management of haematuria. Casts hyaline and fi ne granular casts are not signifi cant; dense granular, red-cell and epithelial cast s suggest renal disease; white-cell casts are found with pyelonephritis. OHFP.indb 590 OHFP.indb 590 30/05/2014 16:19 30/05/2014 16:19 591 URINE TESTS Culture and sensitivity Samples sent for microscopy are routinely cultured over 48h. The cu lture is said to be positive if >100,000 colony forming units/ml are present. The sample is recultured in diff erent mediums to determine the bacteria present and their sensitivity t o antibiotics. A mixed culture (more than one organism present) suggests a contaminated sam ple. Urine culture is not 100% sensitive or specifi c \200\223 it can be wrong and require repeating. CSU obtained from long-term catheters are frequently positive. Only treat if th e patient is symptomatic. Biochemistry Sodium concentration is a useful test in acute renal failure. A low urine sodi um (<20mmol/l) suggests hypoperfusion, eg hypovolaemia, while a raised concentration (>40mm ol/l) suggests acute tubular necrosis. It is also used in the assessment of hyponatraemia ( b p386). Urine osmolality is a measure of the concentration of the urine; the normal range is 500 \200\223800mOsmol/kg. It is used in the investigation of renal disease and diagnosis of dia betes insipidus. In acute renal failure it can help distinguish between prerenal failure (> 500mOsmol/kg) and acute tubular necrosis (<350mOsmol/kg). 24h urine protein total protein and microalbumin can be measured, total protein is the more common test; microalbumin is used to detect developing renal failure in diabetics and a va lue of >30mg/24h is abnormal. Urine creatinine should also be measured to determine GFR. Se e Table 17.24. Table 17.24 Proteinuria 24h protein Signi \201 cance <150mg 150mg \200\2233g >3g Normal Proteinuria, likely renal losses if >2g (b p375) Nephrotic syndrome (b p376) Creatinine clearance the excretion of creatinine per minute can be calculated from a 24h ur ine collection and this gives an estimation of the glomerular fi ltration rate (GFR), b p37 3. Catecholamines/VMA if a phaeochromocytoma is suspected a 24h urine sample is analyzed for t otal catecholamines, vanillylmandelic acid (VMA), metanephrines and creatinine. Toxicology urine can be screened for a wide range of recreational and medical drugs. Dipsti cks give results in <10min while lab-based tests can often take several days. _OHFP.indb 591 _OHFP.indb 591 30/05/2014 16:19 30/05/2014 16:19 592 CHAPTER 17 Interpreting results CSF Microscopy Red cells (normal 0 per mm3) these are raised from a bloody tap (more in the fi rst bottle than the third) or from a subarachnoid hemorrhage (same in fi rst and third bott les), however the two can only be distinguished reliably by measuring for xanthochromia (su barachnoid only). High levels of blood cells will disrupt the measurement of WBC and protei n. The following calculations may help: \200 True CSF WBC = CSF WBC \200\223 (bld WBC \227 CSF RBC bld RBC) \200 True CSF protein = CSF protein \200\223 (RBC 100). Whit e cells (normal <4 per mm3) raised levels in infection or post-sub- arachnoid, levels tend to be higher in bacterial meningitis (Table 17.25). The main type of white cell suggests th e infectious agent: \200 Neutrophils/polymorphs (normal 0 per mm3) bacterial infection \200 Lymphocytes/mononuclear (normal <4 per mm3) viral infection or TB. Bacteria a Gram st ain may show bacteria in the sample; this is always pathological. Talk to a microbiologist about treatment. Biochemistry Protein (normal <0.4g/l); levels >1.0g/l are usually only seen in bacterial or TB meningitis (Table 17.24). Less dramatic rises can occur in all types of meningitis and also multiple sclerosis or Guillain \200\223Barr . Glucose (>2.2mmol/l or >70% plasma) reduced in meningitis, especially bacterial meningitis (Table 17.25). Xanthochromia is a yellowing of the CSF caused by the breakdown of blood; it is present 4 \200\22312h following a subarachnoid hemorrhage. Table 17.25 CSF in diff erent forms of meningitis Normal Bacterial TB Viral Appearance Clear White cells <4 \227 106/l Type of cell Glucose Protein Cloudy 5 \200\2232000 \227 106/l 5 \200\223500 \227 106/l 5 \200\2231000 \227 106/l Clear Clear Lymphocytes Neutrophils >70% plasma Very low <0.4g/l Lymphocytes Lymphocytes <50% plasma >70% plasma >1g/l >1g/l 0.5 \200\2230.9g/l Culture and PCR Bacteria it can take several days for bacteria to grow but the majority are positive within 48h. It may take a further 24 \200\22348h to identify the type of bacteria and its sensitivity to antibiotics. Liaise with a microbiologist. TB culture can take weeks because it is a slow growing bacteria. It may be possible to dete ct TB sooner using PCR. Talk to the laboratory technicians and microbiologists. Viral PCR should be requested at the time of submitting a sample, if viral meningitis or en cephalitis is suspected OHFP.indb 592 OHFP.indb 592 30/05/2014 16:19 30/05/2014 16:19 593 AUTOANTIBODIES AND ASSOCIATED DISEASES Autoantibodies and associated diseases Table 17.26 Autoantibodies and associated diseases Autoantibody Disease (% frequency where known) Acetylcholine receptor Myasthenia gravis (80%) Antinuclear (ANA) SLE (95%), RA (32%), JIA (76%), chronic active hepatitis (75%), Sj gren \200\231s syndrome (70%), systemic sclerosis (64%), normal \200\230controls \200\231 (0 \200\2232%) Primary antiphospholipid syndrome Limited systemic sclerosis (70%) Sj gren \200\231s syndrome, sub acute cutaneous lupus, SLE (30%), systemic sclerosis (60%), interstitial pneumonitis Sj gr en \200\231s syndrome (65%), SLE (15%) Anticardiolipin Anticentromere Anti-Ro Anti-La c-ANCA/Anti-MPO Wegener \200\231s granulomatosis (90%), MPA (11%), Churg \200\223Strauss syndrome Churg \200\223Strauss syndrome (60%) SLE (60%) SLE (70%), au toimmune rheumatic disease, infl ammation Includes: Anti-Ro, Anti-La, Anti-Jo-1, RNP, Scl-7 0, Anti-Sm Autoimmune gastritis, pernicious anemia Multi-focal motor neuropathy, Guillain \200\223Barr syndrome, Miller \200\223Fisher syndrome Goodpasture \200\231s syndrome p-ANCA/Anti- PR3 dsDNA ssDNA ENA Gastric parietal cell Glycolipid Glomerular basement membrane IgA-endomysial Anti-Jo-1 Coeliac disease Myositis Mitochondrial (AMA) Rheumatoid factor Primary biliary cirrhosis (>95%) RA (50 \200\22390%), SLE (15 \200\22335%), systemic sclero sis (20 \200\22330%), juvenile RA (7 \200\22310%), polymyositis (5 \200\22310%), infection (0 \200\22350%) SLE and MCTD Diff use systemic sclerosis (30%) SLE (30 \200\22340%) RNP Anti-Scl-70 Anti-Sm Smooth muscle (SMA) Chronic active hepatitis (40 \200\22390%), prim ary biliary cirrhosis (30 \200\22370%), idiopathic cirrhosis (25 \200\22330%), viral infect ions (80%), \200\230controls \200\231 (3 \200\22312%), autoimmune sclerosing cholangitis H ashimoto \200\231s thyroiditis (>80%), Graves \200\231 disease (50%) Graves \200\231 diseas e (50 \200\22380%) Thyroid peroxidase Thyrotropin receptor _OHFP.indb 593 _OHFP.indb 593 30/05/2014 16:19 30/05/2014 16:19 594 CHAPTER 17 Interpreting results Cervical spine radiographs Cervical spine (C-spine) radiographs are mainly taken in trauma patients to exclude bony injury to this area that could result in high spinal cord damage a nd major disability. The patient normally has their neck immobilized with blocks, stiff -ne ck collar, and tape when the images are taken, which can make obtaining adequate views more diffi cult. If the patient \200\231s history suggests a fracture you must proceed with caution. Signifi cant neck injury can be present even when plain C-spine x-rays appear normal. If in any do ubt, discuss with your senior or a radiologist as CT imaging may be necessary. Spinal cord injury can still be present despite a normal CT (SCIWORA \200\223 spinal cord injury witho ut radiological abnor- mality). This is due to non-bony injury causing instability (eg inju ry to carti- lage, or ligaments). See b p441 for a selection of patients for imaging. The standard images taken in a C-spine series are: \200 Lateral view \200\223 an X-ray t aken from the side \200 Long AP view \200\223 an X-ray taken from the front \200 Peg v iew \200\223 an open mouth AP view, which shows C1/C2 articulation and the odontoid peg. Identi \201 cation Check the radiograph for the name of the patient and when the image was taken. Interpreting the lateral view \200\223 ABCDE approach Adequacy Is the X-ray penetration appropriate; can you see the vertebral bodies, spinous pr ocesses and soft tissues clearly? Can the whole of the C-spine be seen from C1 to the top o f the T1 vertebral body? Is any part of the view obscured by a radio-opaque item such as je welry? Bodies Check all vertebral bodies have smooth outlines and attached spinous processes. All bodies below the level of C2 should be of similar size and shape. Check for any fragments o f bone that have become detached (avulsed); this could suggest ligament injury. Curves (alignment) Follow the three curves in Fig. 17.17 and ensure they are smooth. Ligame nt injury or fractures can cause disruption of these arcs. Disc spaces Should be roughly equal between each vertebral body. Widening suggests serious injury. Everything else (soft tissues) Abnormal widening of the prevertebral soft tissue or a local ized bulge suggests a serious neck injury. Revisit the bodies, curves and disc spaces if th ere is widening. Maximum normal width of prevertebral soft tissues C1 \200\2234 C5 \200\2237 7mm 22mm (roughly equal to the width of the vertebral bodies) OHFP.indb 594 OHFP.indb 594 30/05/2014 16:19 30/05/2014 16:19 595 CERVICAL SPINE RADIOGRAPHS Long AP view Lateral view C1 C2 C3 C1 C2 C3 C4 Trachea C4 C5 C5 Prevertebral soft tissues C6 C6 C7 C7 T1 T1 T2 Lateral borders of vertebrae Spinous process line Lateral borders of vertebrae Anterior vertebral line Anterior spinal line Posterior spinal line Fig. 17.17 Lateral (left) and long AP (right) views of the cervical spine. Interpreting the anteroposterior (AP) view \200 Check the spinous processes are in a stra ight line and the distance between the spinous processes is equal Check each vertebral body for any obvious bony injury. Interpreting the peg view \200 Che ck that the lateral margins of C1 and C2 line up \200 Check the distance between the odon toid peg and the inner aspect of C1 is equal on both sides (Fig. 17.18). (This may not be t he case due to injury or if the neck is rotated. If lateral C1 and C2 margins line up, this is more likely to be due to rotation.) Check there are no obvious fractures of C1 or C2. Look closely to ensure the odontoid peg is not fractured at its base. Odontoid peg a a C1 C1 C2 \200\230a \200\231 should be equal on both sides Lateral border Lateral border Fig. 17.18 Peg view showing central location of the odontoid peg. _OHFP.indb 595 _OHFP.indb 595 30/05/2014 16:19 30/05/2014 16:19 596 CHAPTER 17 Interpreting results Skeletal radiographs Identi \201 cation Check the radiograph for the name of the patient a nd when the image was taken; check if the image is of the left or right side. Bones For eac h bone follow the edge of the cortex around the whole circumference, looking for steps, or cracks; does the bone look normal, or clearly very bowed or angulated around a fracture? Ch eck the consistency of the bone matrix itself; is it uniformly pale and very opaque (osteop enic) or dense and very mineralised (sclerotic); are there cysts (lytic lesions) or patches of more dense bone (sclerotic lesions or callus)? See Table 17.27. Joints Always check the joint above and below the bone in question, eg elbow and wrist when looking at the radius or ulna. Does the joint look normal, are the bones involved in the articulation in their no rmal position, is the distance between these bones increased or decreased? Re-check for bre aks in the cortex of the bones within the joint (intra-articular fractures). Soft tissue si gns Soft-tissue oedema is often subtly seen on some radio- graphs, suggesting there is over lying swelling; this is especially seen around peripheral bones/joints (wrists, hands, ankl es, feet, etc). Very occasionally gas can be seen on radiographs, and appears black; this c an arise from gas- forming bacteria (classically Clostridium species), but also from open w ounds. Bleeding and oedema adjacent to some joints gives rise to specifi c features; one of the best examples of these is the anterior fat pad sign of the elbow (Fig. 17.19). Small a mounts of intra-articular hemorrhage force a normally hidden fat pad to appear on the later al elbow radiograph, anterior to the distal humerus. The presence of this sign strongly sug gests there is a peri- articular fracture. The posterior fat pad is often seen even in the absence of trauma/injury. Humerus Anterior fat pad Posterior fat pad Ulna Fig. 17.19 The anterior and posterior fat pads on a lateral elbow X-ray. If all else fails Sometimes it is diffi cult to see a radiological cause of the patient \200\231s complaint. Always ask a senior to review the radiograph or show it to a senior ra diographer or the radiologist who is \200\230hot reporting \200\231. PACS Picture Archiving and Communication System is the electronic system on which hospitals store their radiology images. Viewing the images is undertaken on-screen and various manip ulations of the image can be performed by the user such as inverting, rotating, magnifying, and altering the contrast \200\223 this makes fi nding fractures much easier. OHFP.indb 596 OHFP.indb 596 30/05/2014 16:19 30/05/2014 16:19 597 SKELETAL RADIOGRAPHS Table 17.27 Describing fractures Right or left, dominant or not Clavicle, radius, tibia etc Proximal, midshaft, distal Simpl e (2 bits), comminuted ( \211 3 bits), oblique, spiral Displaced, angulated, impacted, rota ted Intra-articular fracture or not, dislocation Side Bone Location Type Shape Joint surface Complications Compound (open fracture, b p435), neurovascular involvement Fractures in children Children \200\231s bones are still growing and generally softer and m ore malleable than adult bones. The greenstick fracture is a frac- ture of the shaft of a l ong bone, but like a green twig, snapping it often only breaks just one cortex rather than both (the classical defi nition of a fracture is a break to both cortices). Greenstick frac tures are most common in the forearm. Fractures at the growing ends of bones usually take o n one of fi ve forms (see Salter \200\223Harris classifi cation \200\223 Fig. 17.20) and m ust be managed carefully to ensure the bone continues to develop/grow normally. Diaphysis (shaft of bone) Metaphysis Growth plate (epiphyseal plate) Epiphysis Normal Type I Type II Type III Type IV Type V Fig. 17.20 Long bone nomenclature (top) and the Salter \200\223Harris classifi cation of gr owth plate fractures (bottom). Pathological fractures are fractures at a site where the bone is weakened, usually where th ere is a cyst, metastatic lesion or inherited defect. For speci \201 c bones/joints covered elsewhere b p147 b p147 b p148 b p148 b p150 b p151 b p151 b p152 b p149 b p440 Hip Knee Ankle Foot Shoulder Elbow Wrist Hand Back C-spine _OHFP.indb 597 _OHFP.indb 597 30/05/2014 16:19 30/05/2014 16:19 This page intentionally left blank 599 Appendices Useful numbers and websites 600 Height conversion 602 Weight conversion 603 Body mass index (BMI) 604 Driving regulations 605 Interesting cases 606 Telephone numbers 1 608 Your fi rm \200\231s timetable 1 609 Telephone numbers 2 610 Your fi rm \200\231s timetable 2 611 Tel ephone numbers 3 612 Your fi rm \200\231s timetable 3 613 _OHFP.indb 599 _OHFP.indb 599 30/05/2014 16:19 30/05/2014 16:19 600 Appendices Useful numbers and websites Medical organizations General Medical Council (GMC) \200 0161 923 6602 (cid:27)www.gmc-uk.org British Medical Association (BMA) \200 020 7387 4499 (ci d:27)bma.org.uk Medical Defense Union (MDU) \200 0800 716 376 (cid:27)www.the-mdu.com \200 24h help 0800 716 646 Medical Protection Society (MPS) \200 08457 187 187 (cid:27)w ww.medicalprotection.org \200 24h help 0845 605 4000 Medical and Dental Defense Union of Scotland (MDDUS) \200 0845 270 2034 (cid:27)www.mddus.com \200 24h help 0845 270 2034 C ounseling lines BMA Counseling Service \200 08459 200 169 or 01455 254 189 Doctors \200 \231 Support Network (mental illness) \200 0844 395 3010 (cid:27)www.dsn.org.uk Sick Doct or \200\231s Trust (alcohol and drug addiction) \200 0370 444 5163 (cid:27)www.sick-docto rs-trust.co.uk Financial organizations BMA Services \200 0845 609 2008 (cid:27)www.bmas.c o.uk Other Gay and Lesbian Association of Doctors and Dentists (GLADD) \200 (cid:27)www.g ladd.co.uk National Confi dential Enquiry into Patient Outcome and Death (NCEPOD) \200 (c id:27)www.ncepod.org.uk Medical Research Council (MRC) \200 01793 416 200 (cid:27)www.mrc .ac.uk Medical Women \200\231s Federation \200 0207 387 7765 (cid:27)www.medicalwomensfed eration.org.uk M decins Sans Fronti res (MSF) \200 0207 404 6600 (cid:27)www.msf.org Vo luntary Services Overseas \200 0208 780 7500 (cid:27)www.vso.org.uk Wellcome Trust \200 0207 611 8888 (cid:27)www.wellcome.ac.uk OHFP.indb 600 OHFP.indb 600 30/05/2014 16:19 30/05/2014 16:19 601 USEFUL NUMBERS AND WEBSITES (Royal) College of Anesthetists 020 7092 1500 (cid:27)www.rcoa.ac.uk 020 7404 1999 (cid:27)www.collemergencymed.ac.uk 020 3 188 7400 (cid:27)www.rcgp.org.uk 020 7772 6200 (cid:27)www.rcog.org.uk 020 7935 0702 (cid:2 7)www.rcophth.ac.uk 020 7092 6000 (cid:27)www.rcpch.ac.uk 020 7451 6700 (cid:27)www.rcpath. org 020 7935 1174 (cid:27)www.rcplondon.ac.uk 0131 225 7324 (cid:27)www.rcpe.ac.uk 00353186 39700 (cid:27)www.rcpi.ie Emergency Medicine General Practitioners Obstetricians and Gynecologists Ophthalmologists Pediatrics and Child Health Pathologists Physicians of London Physicians of Edinburgh Physicians of Ireland Physicians and Surgeons of Glasgow 0141 221 6072 (cid:27)www.rcpsg.ac.uk Psychiatrists 020 7235 2351 (cid:27)www.rcpsych.ac.uk 020 7636 4432 (cid:27)www.rcr.ac.uk 0131 527 1600 ( cid:27)www.rcsed.ac.uk 020 7405 3474 (cid:27)www.rcseng.ac.uk 0035314022100 (cid:27)www.rcs i.ie Radiologists Surgeons of Edinburgh Surgeons of England Surgeons of Ireland Selected learned bodies Academy of Medical Royal Colleges Academy of Medical Sciences Anato mical Society of Great Britain Association for Palliative Medicine Association for Study of Medical Education Association of Anesthetists Association of British Neurologists British Association of Dermatologists British Association of Pediatric Surgeons British Cardiac Soc iety British Geriatrics Society British Society for Rheumatology British Society of Gastroe nterology British Thoracic Society Resuscitation Council Royal Society of Medicine (cid:27)www.aomrc.org.uk (cid:27)www.acmedsci.ac.uk (cid:27)www.anatsoc.org.uk (cid:27)www. palliative-medicine.org (cid:27)www.asme.org.uk (cid:27)www.aagbi.org (cid:27)www.theabn.or g (cid:27)www.bad.org.uk (cid:27)www.baps.org.uk (cid:27)www.cardiac.org.uk (cid:27)www.bgs .org.uk (cid:27)www.rheumatology.org.uk (cid:27)www.bsg.org.uk (cid:27)www.brit-thoracic.or g.uk (cid:27)www.resus.org.uk (cid:27)www.roysocmed.ac.uk Online reference sources British National Formulary Cochrane Library NHS Clinical Knowledge Summaries NICE Evidence Search NICE Clinical Knowledge Summaries NICE Pathways NICE Guidance (cid:27)www.bnf.org (cid:27)www.thecochranelibrary.com (cid:27)www.cks.nhs.uk (cid:27)www.e vidence.nhs.uk (cid:27)cks.nice.org.uk (cid:27)pathways.nice.org.uk (cid:27)guidance.nice.o rg.uk _OHFP.indb 601 _OHFP.indb 601 30/05/2014 16:19 30/05/2014 16:19 602 Appendices Height conversion Meters (m) to inches (inch), multiply by 39.37 (12 inches to the foot) I nches to meters, multiply by 0.0254. m inch feet inch m inch feet inch 1.36 1.37 1.38 1.40 1.41 1.42 1.43 1.45 1.46 1.47 1.48 1.50 1.51 1.52 1.54 1.55 1.56 1.57 1 .59 1.60 1.61 1.62 1.64 1.65 1.66 53.5 54 54.5 55 55.5 56 56.5 57 57.5 58 58.5 59 59.5 60 60.5 61 61.5 62 62.5 63 63.5 64 64. 5 65 65.5 4 4 4 4 4 4 4 4 4 4 4 4 4 5 5 5 5 5 5 5 5 5 5 5 5 5.5 6 6.5 7 7.5 8 8.5 9 9.5 10 10.5 11 11.5 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 1.67 1.69 1.70 1.71 1.73 1.74 1.75 1.76 1.78 1.79 1.80 1.81 1.83 1.84 1.85 1.87 1.88 1.89 1 .90 1.92 1.93 1.94 1.95 1.97 1.98 66 66.5 67 67.5 68 68.5 69 69.5 70 70.5 71 71.5 72 72.5 73 73.5 74 74.5 75 75.5 76 76.5 77 77.5 78 5 5 5 5 5 5 5 5 5 5 5 5 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6.5 7 7.5 8 8.5 9 9.5 10 10.5 11 11.5 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 Temperature Degrees Fahrenheit ( F) to degrees Celsius (centigrade C) C = ( F \200\223 32) \227 0.56 Degrees Celsius (centigrade C) to degrees Fahrenheit ( F) F = ( C \227 1.8) + 32 Pressure Millimeters of mercury (mmHg) to kilopascals (kPa) kPa = mmHg \227 0.113 Kilopascals (kPa) to millimeters of mercury (mmHg) mmHg = kPa \227 7.519 OHFP.indb 602 OHFP.indb 602 30/05/2014 16:19 30/05/2014 16:19 603 WEIGHT CONVERSION Weight conversion kg to pounds (lbs), multiply by 2.2046 (14lb to the stone; 16oz per lb) P ounds to kg, multiply by 0.4536. lbs 2lb 3oz 4lb 7oz 6lb 10oz 8lb 13oz 11 13 1 4 6 8 10 12 1 3 5 7 9 12 0 2 4 7 9 11 13 1 4 6 8 10 12 1 3 5 7 9 12 0 2 4 6 9 lbs 11 13 1 3 6 8 10 12 0 3 5 7 9 11 0 2 4 6 8 11 13 1 3 6 8 10 12 0 3 5 7 9 11 0 2 4 6 8 1 1 13 1 3 lbs 5 8 10 12 0 2 5 7 9 11 13 2 4 6 8 10 13 1 3 5 7 10 12 0 2 5 7 9 11 13 2 4 6 8 10 13 10 7 4 1 12 9 kg 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 3 3 34 35 36 37 38 39 40 41 42 St 0 0 0 0 0 0 1 1 1 1 1 1 2 2 2 2 2 2 3 3 3 3 3 3 3 4 4 4 4 4 4 5 5 5 5 5 5 6 6 6 6 6 kg 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 7 2 73 74 75 76 77 78 79 80 81 82 83 84 St 6 6 7 7 7 7 7 7 8 8 8 8 8 8 9 9 9 9 9 9 9 10 10 10 10 10 10 11 11 11 11 11 11 12 12 12 1 2 12 12 12 13 13 kg 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 125 130 135 140 145 150 St 13 13 13 13 14 14 14 14 14 14 14 15 15 15 15 15 15 16 16 16 16 16 16 17 17 17 17 17 17 1 7 18 18 18 18 18 18 19 20 21 22 22 23 _OHFP.indb 603 _OHFP.indb 603 30/05/2014 16:19 30/05/2014 16:19 604 Appendices Body mass index (BMI) BMI calculation BMI Weight status BMI = weight (kg)/height2 (m2) eg: 77kg, 1.83m 77/(1.83 x 1.83) = 23 (normal) <18.5 Underweight 18.5 \200\22324.9 Normal 25.0 \200\22329.9 Overweight \211 30 \211 40 Obese Morbidly obese Body mass index chart for adults Weight in kg 40 50 60 70 80 90 100 110 120 130 140 150 6 6 6 5 6 4 6 3 6 2 6 1 6 5 11 5 10 5 9 5 8 5 7 5 6 5 5 5 4 5 3 5 2 5 1 5 4 11 4 10 1.98 1.96 1.94 1.92 1.90 1.88 1.86 1.84 1.82 1.80 1.78 1.76 1.74 1.72 1.70 1.68 1.66 1.64 1 .62 1.60 1.58 1.56 1.54 1.52 1.50 1.48 Under - Under - weight weight Normal Normal Over - Over - weight weight Obese Obese Morbidly Morbidly obese obese s e h c n s e r t e m n i d n a t e e i t h g e H f n i i t h g e H i 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Weight in stones Fig. A1 Body mass index. Plotting weight against height estimates BMI. OHFP.indb 604 OHFP.indb 604 30/05/2014 16:19 30/05/2014 16:19 605 DRIVING REGULATIONS Driving regulations (August 2013) The DVLA issues strict regulations about which medical co nditions aff ect your ability to drive. A summary of this information for holders of standa rd Group 1 licenses is shown here; the full guidelines are available on the DVLA website (( cid:27)www.dvla.gov.uk). This list is not exhaustive and a patient should stop driving if t hey, or their doctor, believe they are incapacitated. Neurology Stroke Cardiovascular Angina If symptoms at rest, at wheel or with emotion, cease until stabilized Cease for 1wk if succ essful angioplasty, else cease for 4wk Cease for 1wk Cease for 1wk* Cease 6mth after insert ion/shock* Cease for 1mth Cease for 1mth; resume only if minimal residual defi cit Cease for 1mth Variable* MI/ACS TIA Chronic neuro disorder Meningitis First seizure (or suspected) Epilepsy Angioplasty Pacemaker ICD (if inserted for incapacitation) ICD (if inserted prophylatically ) Cease for 4wk* CABG Cease for 4wk after Incapacitating arrhythmia controlled* Stable arrh ythmia Drive if well AAA \211 6cm Drive if well Cease for 6mth* Cease until 1yr since last seizure (continue if seizures during sleep only for >3yr)* Cease for 6 \200\22312mth* Severe head injury/intra- cranial bleed Brain tumors and mets Neurosurgery Visual fi eld de fects and diplopia Visual acuity Variable* Annual review required if 6 \200\2236.5cm; if \211 6.5cm, cease until repaired* Cease if s ymptomatic* Variable* Cease driving (may be allowed if stable) Aortic stenosis Psychiatry and substance abuse Severe psychiatric illness Alcohol dependenc e Opioid, benzo + cocaine dependence Other recreational drugs Other COPD Sleep apnoea + nar colepsy Chronic renal failure HIV Better than 6/12 corrected with both eyes Cease 4wk if low risk or cause found; else cease for 6mth* Once attacks controlled* Cease until stable for 3mth* Cease until 1yr abstinence* Cease for 1yr after previous use* Unexplained syncope