Other cases - ix Flashcards
Cataracts ix
- Clouding of lens
- Slit lamp examination of the anterior chamber – cataract visible (lens appears brown or white)
- Reduced red reflex
- Glare vision test - reduced visual acuity under the conditions of glare stress
- Normal eye examination apart from opacity in the crystalline lens
- Dilated fundus examination – fundus + optic nerve are normal
- Measurement of intra-ocular pressure – normal
Glaucoma ix
- Gonioscopy – measurement of the angle between the cornea and the iris to determine whether glaucoma is open-angle or close-angle
- Corneal thickness measurement/Pachymetry – influence IOP reading
• Tonometry
o Normal range: 10-21 mmHg
o Glaucoma if intra-ocular pressure >21mmHg
• Fundoscopy
o Optic disc cupping (normal cup:disc ratio is 0.3-0.7) – rim gets thinner and thinner as the disease progresses until there is no rim left (i.e. cup:disc ratio increases)
o Flame haemorrhages in late disease
• Slit-lamp biomicroscopy
o Most frequent method used
o Assessment of cornea, anterior chamber, drainage angle
o Measurement of intra-ocular pressure
• Ocular coherence tomography
o Produces visual records + provides quantification of exact cup:disc ratio + areas of neuroretinal thinning
• Visual field testing
o Scotomas indicating loss of the nerve fibre layer
Closed angle oedema also shows
• Shallow anterior chamber
Uveitis ix
• Clinical diagnosis
• Slit lamp findings in anterior uveitis
o White cells in anterior chamber
o Hypopyon
o Keratic precipitates
Conjuctivitis ix
- Clinical diagnosis
- Rapid adenovirus immunoassays
- Cell culture
- Gram stain
- PCR
Closed angle glaucoma diagnostic criteria
• Based on at least two of these symptoms
o Ocular pain
o N/V
o Hx of intermittent blurring of vision
• And at least 3 of the following signs o IOP >21mmHg o Corneal epithelial oedema o Mid-dilated non-reactive pupil o Shallow chamber in the presence of occlusion o Conjunctival hyperaemia
rheumatic fever ix/dx
Hx of streptococcal infection (increased anti-streptolysin O titre, anti-DNAse, anti-hyaluronidase etc or throat culture showing growth of GABHS)
+ 2 major criteria or 1 major + 2 minor
J<3NES PEACE
Joints (polyarthirits, hot/swollen joints, restricted movement)
Heart (carditis (can be pericarditis, myocardtis or endocarditis), valve damage)
Nodules
Erythema marginatum
Sythenham chorea
Previous rhuematic fever (increased anti-streptolysin O titre, anti-DNAse, anti-hyaluronidase etc or throat culture showing growth of GABHS)*
ECG with PR prolongation** (does not count if carditis present)
Arthralgia (does not count arthritis present)
CRP + ESR elevated
Elevated temperature
- Positive serology is the most important means of demonstrating antecedent infection
- ECG might also show features of pericarditis (saddle shaped ST elevation + PR segment depression)
• Echo
o Morphological changes to the mitral valves
o Severity of regurgitation (mitral>aortic>tricuspid)
o Pericardial effusion if pericarditis if present
o Myocardial thickening or dysfunction
o Valvular dysfunction
• Throat culture
o Growth of β-haemolytic group A streptococci (GAS)
o However, group A streptococci have usually been eradicated before onset of the disease
• Rapid antigen test for group A strep – positive
• *Anti-streptococcal serology – above normal range (demonstrates previous infection)
o Anti-streptolyisin O titre
o Anti-DNAse B titre
o Anti-hyaluronidase titre
o Positive serology is the most important means of demonstrating antecedent infection
GABHS = group A β-haemolytic streptococcus
HSV ix
- Viral culture
- HSV PCR
- Glycoprotein G-based type-specific serology (gG1, gG2) – positive antibody to HSV-1 or HSV-2
VZV ix
• Clinical dx – based on the way skin lesions appear
- PCR – viral DNA
- Viral culture – positive varicella zoster virus in culture
- Direct fluorescent antibody testing (DFA) – positive for varicella-zoster virus antigen
- Tzanck test - multinucleated giant cells in the fluid of the vesicles
• Latex agglutination
• ELISA
o These two tests are not used in acute disease, but can be useful in determining seroconversion after vaccination or documenting immune status
o Result – positive for IgG for varicella
EBV infectious mononucleosis glandular fever ix
• FBC
o Lymphocytosis (highest in week 2-3)
o Atypical lymphocytosis
• Heterophile antibodies - Monospot test, Paul Bunnell test
o Non-specific for EBV infection
o IgM antibodies produced form infected B cells agglutinate RBC from other species (sheep, horse, goat, bovine)
o May be negative in the early course of EBV IM
• Adults – repeat
• In children <4 (B cells do not produce heterophile antibodies) – EBV ab
o Patients who remain heterophile-negative after 6 weeks with a mononucleosis illness are considered to be heterophile-negative IM + should be tested for EBV-specific antibodies
• EBV-specific antibodies
o Indicated if pt has infectious mononucleosis symptoms but negative heterophile antibodies
- Early primary infection - VCA IgM
- Acute primary infection - VCA-IgM, VCA-IgG
- Past infection - VCA-IgG, IgG EBV EBNA
- Real-time PCR – EBV DNA detection
- If splenic rupture is suspected (but pt is haemodynamically stable) – CT abdo
HIV ix
• False negatives during the window period
o Serum HIV ELISA
o Serum HIV rapid test
o Serum Western blot – used as a confirmatory test following a positive ELISA or rapid test
• Testing during the window period/ acute infection
o Serum p24 antigen – present during high viral replication [detectable in the blood during acute infection + again during late stages of infection]
o HIV DNA PCR in peripheral blood mononuclear cells – infants
• CD4 count
o Indicates immune status + assists in the staging process
o CD4 count <200 cells/microlitre – defines AIDS and places the patient at high risk of most opportunistic infections
• Serum viral load (HIV RNA)
o Establishing a baseline viral load before therapy
o Monitoring response to antiretroviral therapy
o quantitative viral RNA in plasma – used to confirm acute HIV
• FBC – may be normal or show anaemia, thrombocytopenia, lymphocytopenia, reduced CD4 cell count
Tonsilitis ix
• Throat culture
o Standard test for the definitive dx of bacterial tonsillitis
- Suspected rheumatic fever = group A β-haemolytic streptococci throat infection – serological testing for streptococci – rapid streptococcal antigen test
- Suspected infectious mononucleosis – heterophile antibodies
- Not recommended – throat swabs, rapid antigen tests
Alcohol withdrawal ix
Questionnaires
• Screen the patient for alcohol-use disorder using a formal assessment tool (AUDIT-C, FAST, PAT)
o Number of alcohol units = % ABV x Volume (L)
• Identify patients who have tested positive for alcohol misuse + are at risk of alcohol withdrawal by assessing their level of alcohol dependence
o CAGE questionnaire – considered positive if score >2
• Severity of withdrawal
o CIWA-Ar scale (clinical institute withdrawal assessment from alcohol revised scale)
- O/E – signs of alcohol abuse (e.g. chronic liver disease)
- Obs – tachycardia, temperature
• VBG
o Respiratory alkalosis – pt with delirium tremens, hyperventilation
o Hypochloraemic metabolic acidosis – vomiting
o Metabolic acidosis with a high anion gap – alcohol ketoacidosis
• Blood glucose
o Hypoglycaemia is common – secondary to poor nutrition or heavy alcohol use
• FBC
o Macrocytic anaemia
o Thrombocytopenia – splenomegaly, folate deficiency, toxic effect of alcohol on platelets
• U+E
o Low Mg2+, K+, PO43-
• ECG – always performed on pt with electrolyte deficiencies – they can cause life-threatening cardiac arrhythmias
• LFT – elevated
o AST>ALT
o raised GGT
• Bone profile
o Hypocalcaemia 2y to hypomagnesaemia suppressing PTH
o Low Vitamin D – poor intake, lack of exposure to sunlight, toxic effects of alcohol, malabsorption
- Coagulation studies – prolonged INR + PT in chronic liver disease
- CT head – in patients with a) alcohol related seizure, b) altered cognition – more likely to bleed heavily due to deranged clotting + thrombocytopenia, subdural haemorrhage
- Ammonia – consider in all patients with an altered level of consciousness + signs of liver disease – may indicate liver failure
Anaphylaxis ix
• Clinical dx
• Mast cell tryptase
o Normally undetectable in serum
o Elevated in anaphylaxis
• Histamine levels
Aspirin overdose ix
• ABG
o Initially – respiratory alkalosis
o Later – high anion gap metabolic acidosis
• Serum salicylate level
o Salicylate intoxication - >350 mg/L (2.5 mmol/L)
• Ketones – positive particularly in children
• Glucose – hyper or hypoglycaemia
• U+E - Low K, Ca, Mg
• LFTs
o Direct hepatotoxicity can occur
o Most patients develop asymptomatic elevation of transaminases
• PT, APTT, INR
o Coagulopathy may be present
o Platelet dysfunction, low F 7, hypoprothrombinaemia
• CXR – non-cardiogenic pulmonary oedema may be present
• ECG
o Commonly sinus tachycardia
o Prolonged QT or ventricular dysrhythmias may occur - life threatening
Paracetamol ix
• Serum paracetamol level 4h after overdose - to determine which patients would benefit from N-acetylcysteine
• Serum AST + ALT
o May be normal
o May rise to ALT >1000 IU/L – hepatotoxicity
- FBC
- Glucose
- Coagulation screen - Serum PT + INR – used to monitor the severity of hepatotoxicity
- Arterial pH + lactate level – acidosis, raised lactate
- U+Es or renal function tests
