Australasian Anaesthesia 2011 - Australian and New Zealand ...

Sickle Cell Disease in Australia – a phantom menace? 151150 Australasian Anaesthesia 2011interpretation. A diagnostic flow chart is outlined below. 23MusculoskeletalIn infants with SCD, a common presentation is with hand-foot syndrome; a painful dactylitis with radiologicalevidence of cortical destruction of the metacarpal and metatarsal bones 3-5 weeks after the swelling begins.Repeated infarction of joints, bones and growth plates results in aseptic necrosis, particularly of the femoraland humeral heads. Areas of infarcted bone can develop Salmonella osteomyelitis. 20GastrointestinalGallstone disease is common in SCD secondary to chronic haemolysis, with cholecystectomy being the mostcommon surgical procedure carried out in these patients.Figure 5. A protocol for pre-anaesthetic sickle cell disease testing. FBC, full blood count; HPLC,high performance liquid chromatography. Reproduced with modification with permission fromBlackwell PublishingAssess if surgeryand anaesthesiaare urgent ornon-urgentRenalRenal disease is not uncommon in SCD 21 ; defective urine concentrating ability causes enuresis and can precipitatedehydration in an already unwell patient. Renal papillary necrosis results in haematuria and renal or ureteric colic.Nephropathy tends to be more common in Hb SC disease.DIAGNOSISTesting for SCD occurs in several clinical scenarios; pre-natal testing to facilitate genetic counselling, newbornSurgery isSurgery isscreening and opportunistic testing after, for example, detection of anaemia or abnormalities on a blood film, or inurgentindividuals presenting to healthcare services from at risk groups with an unknown sickle status.Basic laboratory tests include a full blood count to detect anaemia and peripheral blood film examination tosearch for sickled erythrocytes.Elective testing can employ several different tests depending on local expertise and availability. Three commonlyused tests detect the β globin gene product, haemoglobin. They are performed on blood samples, which caninclude umbilical cord blood and dried blood spots from neonatal heel prick tests. These methods are listed belowAssess patient,alongside their sensitivity and specificity for detecting sickle cell disease. 1 Detailed description of each method isperform FBC,beyond the scope of this article.Clinical featuresblood film, sicklesuggestive ofsolubility test, HbTable 3 Haemoglobin variant detection methodselectrophoresis orMethod Sensitivity (%) Specificity (%)Cellulose acetate / citrate agar electrophoresis 93.1 99.9Isoelectric focusing 100 100Proceed toHigh performance liquid chromatography 100 100ClinicalClinicalsurgery whenfeaturesfeaturesinvestigationsIn an emergency setting, for example prior to anaesthesia and surgery, sickle results need to be obtained rapidlyto inform peri-operative management.The peri-operative period is a well-recognised, predictable time of disease exacerbations. SCD complicationsrange from 0-19% depending on the surgical procedure being carried out, with a peri-operative mortality of 1.1%. 22Identification of SCD and trait patients prior to anaesthesia is important to enable planning of peri-operativecare. This would include decisions regarding transfusion requirements, adequate hydration, analgesic options,FBC and sickleFBC, sicklesuitability of cell salvage techniques and tourniquet use, prevention of post-operative sickle complications and thesolubility test –solubility testappropriate level of post-operative care i.e. high dependency unit.if pt is anaemic,Pre-anaesthetic testing for SCD in the emergency setting requires a rapid, easily accessible and accurate meansand examineexamine bloodof determining whether a patient with an unknown sickle status is likely to be a carrier or homozygote for Hb S.This can be readily achieved using a combination of a full blood count, sickle solubility testing +/- blood filmNo clinicalfeatures,-ve sicklesolubility andNo clinical features,normal or abnormalHb, blood film notindicative of SCDbut +vesickleClinical features+/- blood filmsuggest SCD+/- positive sickleClinical features+/- blood filmsuggest SCD+/- positivesickle solubilityTreat pt asTreat pt assickle celltrait. AvoidTreat patient asSCD. Consulthaematologist, avoidhypoxia, hypotension,hypothermia andTreat patient asSCD. Consulthaematologist, avoidhypoxia, hypotension,hypothermia and