Heparin-induced thrombocytopenia: An update for the COVID-19 era.

The increased use of heparin during the current COVID-19 pandemic has highlighted the risk of a rare but potentially serious complication of heparin therapy, viz. heparin-induced thrombocytopenia (HIT). This is a short review on the pharmacology of heparin and its derivatives, and the pathophysiology of HIT. Guidance on laboratory testing for and clinical management of HIT is presented in accordance with international guidelines. There are important similarities and differences between HIT and the new entity of vaccine-induced immune thrombotic thrombocytopenia, also known as thrombosis with thrombocytopenia syndrome, which clinicians need to be aware of.

Establishing local reference intervals for full blood count and white blood cell differential counts in Cape Town, South Africa.

BACKGROUND: Accurate laboratory reference intervals (RIs) are essential to differentiate between health and disease. There are variations in haematological indices within populations relating to gender, age, ethnicity and environment. Iron deficiency is common, has a wide range of clinical morbidities and affects red cell indices. Locally derived RIs for full blood count (FBC) parameters are needed for the Western Cape region of South Africa, after the exclusion of iron deficiency. In addition, information regarding the prevalence of iron deficiency in first-time blood donors would inform blood transfusion services regarding policies to screen for and treat iron deficiency. OBJECTIVES: To establish locally derived RIs for FBC and white blood cell (WBC) differential count parameters in healthy adults in the Cape Town area, by including first-time blood donors and excluding those with iron deficiency and thalassaemic indices. These new locally established RIs could update those in use by the local National Health Laboratory Service. A secondary objective was to establish the prevalence of iron deficiency in first-time blood donors. This would inform blood donation policies regarding screening and appropriate iron supplementation in high-risk groups prior to blood donation. METHODS: This was a prospective, descriptive study with direct convenience sampling. Participants were prospective voluntary blood donors aged between 18 and 60 years, presenting for first-time blood donation. Ethnicity was self-identified. Participants who tested positive for HIV or hepatitis B and/or C viruses were excluded. Prospective participants with iron deficiency, defined by serum ferritin levels below the RI, and those with red cell indices suggestive of an underlying thalassaemia trait were excluded. FBC samples were analysed using a Sysmex XN-1000 cell counter. Statistical non-parametric methods were used to calculate the RIs, according to international guidelines. RESULTS: Of the 774 participants screened, 82 (11%) had iron deficiency and were excluded. Six hundred and sixty-two patients were included for analysis, 409 (62%) female and 253 (38%) male. The majority of the participants, 348 (53%), were between 20 and 29 years of age, with a mean age of 29 years for females and 28 years for males. Participants comprised a mix of the various ethnic groups residing in Western Cape Province. The mean haemoglobin concentration for females was lower than that for males (p<0.0001). There were significant gender differences for total WBC count, absolute neutrophil count and platelet count, with females having higher counts than males. CONCLUSIONS: Locally established, population-specific RIs are essential for the accurate interpretation of haematological indices. This study established locally derived gender-specific RIs for the Cape Town region, after exclusion of iron deficiency. These new RIs have implications for the accurate diagnoses of cytopenias, cytoses and other blood count abnormalities. Iron deficiency is common in first-time blood donors, and screening for iron deficiency using point-of-care testing should be considered.

The utility of bone marrow sampling in the diagnosis and staging of lymphoma in South Africa.

INTRODUCTION: The bone marrow biopsy (BMB) is a diagnostic and staging tool in lymphoma that remains practically useful and relevant in resource-constrained settings, despite restricted applications in international staging guidelines, which favour less invasive nuclear medicine techniques. METHODS: Retrospective laboratory data review of BMBs in adult lymphoma patients from 2005 to 2010 to determine subtypes, rates of bone marrow involvement (BMI), human immunodeficiency virus (HIV) seroprevalence and CD4 counts, trephine length and additional findings. RESULTS: A total of 1215 BMBs reported in lymphoma included 759 newly diagnosed patients, with BMI in 43.6% of non-Hodgkin lymphoma (NHL) overall, 28.9% of high-grade B subtypes and 35.7% of Hodgkin lymphoma (HL). HIV seroprevalence was 38.8%, 53.0% and 33.9% in the 3 respective groups. There was a statistical association between BMI and HIV seropositivity in Burkitt lymphoma and HL, and BMI and CD4 count in HIV-related HL. Over 10% (n = 79) of new lymphoma cases were diagnosed by BMB with ancillary tests. Occasional histological discordance and transformation were reported in NHL. Focal/unilateral BMI was uncommon. Bilateral BMB and biopsy length exceeding 26 mm did not improve BMI detection. CONCLUSION: In the South African public sector, high HIV prevalence leads to a different lymphoma pathology profile from the developed world. High BMI rates are encountered. Here, and in similar resource-constrained settings, international lymphoma staging guidelines can be logistically challenging and unaffordable. BMB remains useful in the staging and diagnosis of lymphoma. Unilateral sampling with a processed trephine length of at least 26 mm is recommended.

Anaemia in patients with HIV-associated TB: relative contributions of anaemia of chronic disease and iron deficiency.

BACKGROUND: Anaemia commonly complicates both human immunodeficiency virus (HIV) infection and tuberculosis (TB), contributing substantially to morbidity and mortality. The mechanisms underlying anaemia and corresponding treatments in co-infected patients are poorly defined. OBJECTIVE: To determine the relative contributions of anaemia of chronic disease (ACD) and iron deficiency to anaemia in patients with HIV-associated TB. DESIGN: Consecutively recruited hospitalised (n = 102) and matched ambulatory patients (n = 51) with microbiologically confirmed HIV-associated TB in Cape Town, South Africa, were included. Haemoglobin levels, iron status markers, hepcidin and pro-inflammatory cytokines in blood were measured. We determined the prevalence of ACD and iron-deficiency anaemia (IDA) using seven different published definitions of IDA. RESULTS: More than 80% of enrolled HIV-associated TB patients were anaemic, and anaemia was more severe among in-patients. Over 95% of anaemic HIV-associated TB patients had ACD, whereas the proportion with IDA using a range of seven different definitions was low overall (median <3%, range 0-32.6) in both patient groups. The proportion with IDA and hepcidin concentration â©¿ 20.0 ng/ml (predictive of responsiveness to oral iron supplementation) was also very low (median <3%, range 0-15.1). CONCLUSIONS: ACD was the predominant cause underlying anaemia in HIV-associated TB patients, and IDA was very uncommon in this setting. The majority of anaemic HIV-associated TB patients were unlikely to benefit from oral iron supplementation.

"Stone heart" in a neonate.

A neonate presented at this institution in September, 1978, with interrupted aortic arch complex, including ventricular septal defect, atrial septal defect, and patent ductus arteriosus. Additional anomalies included bilateral cleft lip and palate, low set ears, and bilateral colobomas. One-stage total correction of the interrupted aortic arch complex was undertaken with standard hypothermic techniques. The repair was completed within a 65 minute period of circulatory arrest at 18 degrees C, perfusion was re-established, and the patient was returned to normothermia. Tetanic contracture of the myocardium, stone heart, was evident at 27 degrees C. Cardiac action did not resume despite several therapeutic maneuvers, and the infant died on the operating table. Extensive calcium flooding was a notable feature on histological sections of the heart, associated with myofibrillar degeneration (contraction bands). This complication has never been reported before in a neonate with congenital heart disease. Deep hypothermia did not prevent ischemic contracture of the myocardium, and this complication must now be added to an already lengthy list of complications of neonatal heart surgery.

Successful palliation by pulmonary artery banding in absent pulmonary valve syndrome with aneurysmal pulmonary arteries.

Three infants with absent pulmonary valve syndrome were treated between 1977 and 1980. All infants were in critical cardiorespiratory failure refractory to medical therapy. Pulmonary artery banding was performed to reduce the volume occupied by the large pulsating pulmonary artery in a limited mediastinal space. The band reduced tracheobronchial compression and increased effective cardiac output. All three infants survived the procedure and, at follow-up, significant improvement in cardiorespiratory function has been noted, with satisfactory growth. This experience suggests that pulmonary artery banding has a place in the initial management of absent pulmonary valve syndrome, allowing survival so that total correction can be undertaken more safely at a later stage.

Hemorrhage control after removal of surgically implanted intraaortic balloon pump.

Surgically implanted intraaortic balloon catheters have a substantial potential to cause hemorrhage on percutaneous removal. Because of the unacceptably high incidence of uncontrollable hemorrhage in patients in a life-threatening situation, a new percutaneous surgical modification allowing removal of these balloons with low blood loss has been devised and has proved highly successful in hemorrhage control.

Pericardial substitutes: delayed reexploration and findings.

Four patients' experience with two varieties of pericardial substitutes has been evaluated. Two patients received glutaraldehyde-preserved, formalin-fixed bovine bioprosthetic pericardial substitutes. These were associated with dense prosthesis-to-epicardium adhesions and the formation of a thick gelatinous peel. Two other patients received glutaraldehyde-preserved, ethanol-fixed bovine bioprosthetic pericardial substitutes. One patient had minimal prosthesis-to-epicardium adhesions, and the remaining patient demonstrated moderate prosthesis-to-epicardium adhesions with giant-cell and lymphocyte fibrosis. In all patients prosthesis-to-sternum adhesions were minimal. These observations suggest that careful washing is essential in all bioprosthetic implants to eliminate residual preservatives and fixatives. In addition, preservation in ethanol is associated with less prosthesis-epicardium reaction than is formalin preservation. Both products are successful in easing reentry, and no episode of infection has been associated with either prosthesis.

Warm blood cardioplegia.

Between 1990 and 1992, 346 consecutive patients underwent coronary artery bypass procedures. Ninety-eight patients (group A) from 1990 served as historical controls, and 248 patients (group B) from 1991 to 1992 served as a prospective, consecutive cohort for statistical comparison. The two groups varied in the type of myocardial protection used: intermittent cold crystalloid cardioplegia was used in group A and continuous warm blood cardioplegia in group B. (Two patients in group A received intermittent cold blood cardioplegia, and these 2 patients are grouped with the crystalloid group for the sake of convenience. The presence or absence of these 2 patients did not alter the group A statistics in any noticeable manner). Class IV high-risk groups demonstrated a 63% reduction in mortality (p = 0.07), and overall group B experienced a 28% reduction in mortality (4.4% versus 6.1%; p = not significant), an 86% reduction in perioperative myocardial infarction rate (1.6% versus 12.2%; p < 0.05), a 20% reduction in postoperative bleeding (275 versus 345 mL.day-1.m-2), and a marked reduction in reentry rates (p = 0.05). Also noted was a 32% reduction in postoperative ventilation requirements (25 versus 37 hours; p = 0.05). Less inotrope was required and intraoperative stroke was not seen in the patients with warm blood cardioplegia. Group B patients were less likely to have development of complex postoperative arrhythmias. Ventricular fibrillation at unclamping was noticeably rare (2.0% in group B versus 84% in group A; p < 0.05). The average group B heart resumed sinus rhythm 72 seconds after declamping.(ABSTRACT TRUNCATED AT 250 WORDS)

Endobronchial closure of a postpneumonectomy bronchopleural fistula.

Successful permanent endobronchial closure of a serious postpneumonectomy bronchopleural fistula is reported in a patient with a delayed diagnosis of Mycobacterium fortuitum-cheloni infection. Increasing experience, improved plugging agents, and a review of the literature suggest that in selected patients, this procedure can avoid complex repeat operations and reverse life-threatening situations. Although atypical mycobacterial infections occur with infrequency, they are difficult to treat and may lead, as in this patient, to a misdiagnosis. Operations on granulomatous tissues are prone to heal poorly, thus inviting tissue breakdown and chronic fistulas.

Experience with polytetrafluoroethylene grafts in children with cyanotic congenital heart disease.

Survival and event-free rates of 47 polytetrafluoroethylene (PTFE) (Gore-Tex) shunts for severe cyanotic congenital heart defects were studied in 42 children from April, 1981, to March, 1983. Retrospective actuarial analysis was conducted over the 27 months of the study in 3-month intervals of the follow-up. The estimated actuarial patient survival at two years was 86% with an estimated actuarial event-free rate of 57.2%. The grafts were found to be patent in 89% (42/47) of the grafts. Complications associated with PTFE grafts were thrombosis, infections, heart failure, shunt stenosis, and deformity of the pulmonary arteries. Polytetrafluoroethylene grafts for systemic-pulmonary shunts offer good palliation, but the frequency of complications indicates that close follow-up is mandatory to avoid or treat serious sequelae of the complications.

Recurrence of aortic coarctation following repair by re-implantation of the subclavian artery.

Four patients mean age six months, range 11 days to 2 years, underwent repair of aortic coarctation by the technique of reimplantation of the subclavian artery (Mendonca repair). All developed re-coarctation within six months of an initially successful repair.

Fundoplication and pediatric esophageal manometry: actuarial analysis over 7 years.

Sixty-one children and infants who had significant gastroesophageal reflux and associated complications underwent 73 surgical procedures to control the reflux. In order to evaluate the procedure, several esophageal manograms were obtained from each patient, before, during, and after the operation. Delayed follow-up reports were also obtained from follow-up visits, letter and telephone contact, in order to assess how the patient had progressed. The results were evaluated by actuarial analytic methods. Ninety-four percent of the patients remained alive over the 7-year follow-up period. At the completion of the seventh year, 62% of these patients (actuarially calculated) remained event free. All events occurred within 18 months of surgery. One patient could not be traced at long-term follow-up, which was therefore 92% complete. The 7-year actuarial probability of failure of the fundoplication at this institution is 24% when performed using this technique in these patients. These findings support that manometric calibration of the antireflux procedure tends to give uniform results in pediatric patients, but, compared with other published series has not proved to be superior to procedures that employ only a rubber bougie in the esophagus as an obdurator to prevent a repair that will be too tight.

The effects of hearing loss and noise masking on the masking release for speech in temporally complex backgrounds.

Speech recognition was measured in three groups of listeners: those with sensorineural hearing loss of (presumably) cochlear origin (HL), those with normal hearing (NH), and those with normal hearing who listened in the presence of a spectrally shaped noise that elevated their pure-tone thresholds to match those of individual listeners in the HL group (NM). Performance was measured in four backgrounds that differed only in their temporal envelope: steady-state (SS) speech-shaped noise, speech-shaped noise modulated by the envelope of multi-talker babble (MT), speech-shaped noise modulated by the envelope of single-talker speech (ST), and speech-shaped noise modulated by a 10-Hz square wave (SQ). Threshold signal-to-noise ratios (SNRs) were typically best in the ST and especially the SQ conditions, indicating a masking release in those modulated backgrounds. SNRs in the SS and MT conditions were essentially identical to one another. The masking release was largest in the listeners in the NH group, and it tended to decrease as hearing loss increased. In 5 of the 11 listeners in the HL group, the masking release was nearly identical to that obtained in the NM group matched to those listeners; in the other 6 listeners, the release was smaller than that in the NM group. The reduced masking release was simulated best in those HL listeners for whom the masking release was relatively large. These results suggest that reduced masking release for speech in listeners with sensorineural hearing loss can only sometimes be accounted for entirely by reduced audibility.

The effect of long-term deafness on speech recognition in postlingually deafened adult CLARION cochlear implant users.

Research suggests that duration of deafness prior to cochlear implantation affects postoperative speech recognition in adults. Duration of deafness usually is defined as the number of years between the onset of profound deafness and implantation. The purpose of this study was to examine the effects of duration of deafness--expressed as percentage of life with deafness--independent of age at implantation on postoperative speech recognition in adult postlingually deafened CLARION Multi-Strategy Cochlear Implant users. Speech recognition tests (CID sentences and NU6 words) were administered to 202 consecutively implanted adults preoperatively and at 3 and 6 months after initial device fitting. Patients implanted at a younger age and those with smaller percentages of their lives with deafness achieved the highest levels of short-term postoperative speech recognition. Patients who had been deaf for > or =60% of their lives demonstrated a slower rate of speech recognition improvement than those with shorter durations of deafness, but still continued to improve with increased implant experience.

Acute pancreatitis ten years experience in the Waikato district.

Seventy patients admitted to Waikato Hospital between 1964-74 with acute pancreatitis have been reviewed. Biliary tract disease and alcohol are the most common aetiological agents. The disease is most common in middle age. Europeans and Polynesians have similar incidence rates. The diagnosis is frequently not made at admission and most admissions are in the afternoon or early evening. Radiology is helpful in the diagnosis although nonspecific. Abnormal biochemistry is discussed and related to mortality. Additional tests, serum catalase/methaemalbumin are promoted to assist in the diagnosis and indicating the severity of the disease. Glucagon and Trasylol are discussed as being beneficial in this disease and combination therapy is suggested. The role of surgery is discussed.

The diagnostic utility of bone marrow biopsies performed for the investigation of fever and/or cytopenias in HIV-infected adults at Groote Schuur Hospital, Western Cape, South Africa.

INTRODUCTION: A bone marrow biopsy is frequently requested in the work-up of patients with human immunodeficiency virus (HIV) infection who present with fever and/or cytopenias in the search for opportunistic infections and malignancies. METHODS: This is a retrospective review of the results of consecutive bone marrow biopsies performed at our institution over a three-year period on HIV-positive patients for the investigation of fever and/or cytopenias. Clinical data, haematological parameters, morphological features, Ziehl-Neelsen staining and microbiological culture results were analysed. The aim of the study was to determine the diagnostic yield of this investigation. RESULTS: Sixty-three males and 84 female patients were included for analysis. The bone marrow biopsy gave a high diagnostic yield of 47% (70 patients) and a unique diagnosis in 33% (49 patients). Immune thrombocytopenic purpura and disseminated mycobacterial infections were the most common unique diagnoses made (14%, respectively), followed by malignancies (4%). In this cohort, four cases of primary bone marrow involvement by Hodgkin lymphoma and one case of involvement by non-Hodgkin lymphoma were diagnosed. CONCLUSION: In our study group, a bone marrow biopsy was a useful investigation with a high diagnostic yield.

The vibrant soundbridge for conductive and mixed hearing losses: European multicenter study results.

BACKGROUND/AIMS: The Vibrant Soundbridge (VSB) is an active middle ear implant, 'direct-drive' hearing system for the treatment of hearing loss. Recently, the VSB has been applied to conductive and mixed hearing losses. The aim of this study is to evaluate aided benefit, speech recognition in quiet and noise, subjective benefits, changes in residual hearing, and medical and surgical complications in adults with conductive or mixed hearing losses implanted with the VSB using Round Window (RW) Vibroplasty. METHODS: Twelve German-speaking adults participated in a single-subject, repeated measures study design comparing their performance using the VSB with their own unaided preoperative performance. Hearing performance and changes in residual hearing were assessed using routine audiometric measures, sound field thresholds, and word and sentence recognition in quiet and in noise. Subjective benefits, including subjective hearing performance, device satisfaction, and quality of life were evaluated using the Abbreviated Profile of Hearing Aid Benefit, the Hearing Device Satisfaction Scale, and the Glasgow Benefit Inventory, respectively. RESULTS: Aided hearing thresholds, word recognition at conversational levels, and sentence recognition in quiet and noise were significantly improved without significant changes in residual cochlear hearing and without major medical and surgical complications. One subject required repositioning surgery to improve transducer coupling with the RW membrane. Subjective benefit and device satisfaction were good, as were overall and general quality of life. CONCLUSION: The VSB, implanted using RW vibroplasty, is a safe and effective treatment for adults with conductive and mixed hearing losses who may have few, if any, other options.