Table 1.
Commonly recognized sickle-related complications in adults
| Complication | Definition | Major risk factors and prevalence |
|---|---|---|
| Pain | Acute pain, most commonly in the long bones, chest, back | Episodes of acute pain commence from around 6 mo of age and continues throughout life |
| Adults with SCD experience pain on >54% of days but only access health care on 3.5% of days.36 | ||
| Chronic pain is pain lasting for >3 mo | Estimated to occur in >50% adults with SCD; 40% of adults with SCD take daily opioids.99 | |
| Anemia | Acute anemia: a decline in hemoglobin of 2 g/dL or more from steady-state values | Variety of causes including infection (transient red cell aplasia most commonly caused by acute parvo virus B19); acute hemolysis accompanying severe VOC, delayed transfusion reaction |
| Chronic hemolytic anemia: severity increases with age and major contributor to insidious organ dysfunction | Chronic hemolysis predisposes to gallstones and gallbladder disease | |
| ACS | Acute onset of respiratory symptoms with features similar to pneumonia | 24.5/100 PYO in young children; 8.8/100 PYO in older adults101; outcome more severe in adults |
| Pulmonary hypertension | Mean pulmonary artery pressure of >25 mm Hg at rest, measured by right heart catheterization | 6.0%-10.4% prevalence during adulthood.41-43,46,47 |
| Cardiac dysfunction | Left ventricular failure is most common abnormality | Universal to some degree in adults over age 30.44 Diffuse myocardial fibrosis is a common pathology, and associated with diastolic dysfunction, anemia, and high NT-proBNP. Fibrosis-mediated diasystolic dysfunction may contribute to elevated TRV in older adults via pulmonary venous hypertension.45 |
| Chronic sickle lung disease | Progressive restrictive lung function deficit with fibrotic changes on high resolution CT scan | Restrictive lung defects seen in >70% adults.38 |
| Asthma | Asthma is seen more commonly in children than in adults | |
| Sleep-disordered breathing | Sleep disordered breathing is seen in 40%-60% of adults.19 | |
| Stroke | Acute cerebrovascular accident | Effective screening and prevention have dramatically reduced infarctive stroke in children. Hemorrhagic stroke affects both children and adults, threefold more in adults.102 Risk factors for ischemic stroke include hypertension, diabetes mellitus, hyperlipidemia, atrial fibrillation, and renal disease in adults.103 |
| Silent cerebral infarcts | Clinically silent lesions of 3 mm or more on magnetic resonance imaging scanning | Important contributing factor to neurocognitive deficits; 53% in adults.20 |
| Acute renal injury | Acute deterioration in renal function | 2% during pain crisis and up to 14% during ACS |
| Renal failure | Deteriorating renal function, reduced concentrating ability, proteinuria, and progressive renal failure | Advanced disease (stage III-IV) in 4%-18% of adults.21 |
| Priapism | Unwanted painful and sustained erection of the penis for >4 h, often recurrent or persistent | 20%-89% lifetime prevalence in boys and men.104 |
| Avascular necrosis of bones | Avascular necrosis of any bone, most commonly the femoral head and shoulder joint | >20% lifetime prevalence of symptomatic disease. Increased prevalence of asymptomatic disease.105 |
| Leg ulceration | Most commonly around the malleolar regions | >14% lifetime prevalence.106,107 |
| Cholelithiasis | Gallstones and gallbladder disease | Important genetic modifier is polymorphic (AT) repeats in promoter of UGT1A1 gene.100 Gallbladder disease in 28% at median age of 28 y.11 |
| Retinopathy | Grade 2-4 retinopathy | >30% of patients.108 Increased in HbSC.109 |
ACS, acute chest syndrome; AT, adenine-thymidine; proBNP, N-terminal pro b-type natriuretic peptide; PYO, person-years of observation, VOC, vaso-occlusive crisis.