A 23 year old gentleman presented to hospital with complaints of acute onset left sided chest pain and heaviness for 6 hours. This was associated with profuse sweating and shortness of breath. He did not have a family history of premature coronary artery disease. Clinical examination revealed normal blood pressure and normal heart sounds with no murmurs. ECG showed sinus rhythm with ST elevation in leads V2–V5,1 and avL suggestive of extensive anterior wall myocardial infarction . Reciprocal ST depression was noted in inferior leads. Echocardiography revealed mild left ventricular dysfunction with ejection fraction 47%, regional wall motion abnormalities were noted in anterior segments with severe hypokinesia of apical segment. The patient was thrombolysed with streptokinase . Post thrombolysis, his chest pain subsided. ECG taken at 90 min post lysis showed <50% resolution in ST segment height as compared to baseline. Initial troponin T and N-Terminal pro B-natriuretic peptide levels were 4.3 ng/ml and 5370 pg/ml respectively. Hemogram, liver and renal function tests were normal. Considering a pro-thrombotic state, thrombotic panel was done which turned out to be negative. Patient was subsequently referred to our hospital where he underwent coronary angiogram. CAG showed normal left main coronary artery bifurcating into LAD and LCX. LAD was a type III vessel with 60% hazy lesion in the mid LAD and no other lesions and had TIMI III flow distally. LCX and RCA were normal . In view of borderline stenosis in the setting of acute coronary syndrome, intravascular imaging was performed to determine the culprit lesion morphology. Optical coherence tomography run showed presence of red thrombus at the site of lesion which obscures the underlying vessel wall due to its characteristic high attenuation . No thin cap fibroatheroma/macrophages/micro-channels were noted. Plaque burden was insignificant. Minimum lesional area measured was 6mm2 . In view of satisfactory minimum lumen area and TIMI III flow distally, intervention was deferred. Patient was started on anticoagulation . Follow up CAG after 2 weeks showed normal coronaries without any lesions . OCT was repeated which showed complete resolution of red thrombus . Mild lipidic plaque was noted at the site of previous lesion with a thick intact fibrous cap which points to plaque erosion as the cause of acute coronary syndrome. On further enquiry, the patient admitted to recreational use of marijuana 12 hours prior to the onset of chest pain. He had been a regular marijuana user for the last 5 years and used to smoker once or twice every week. He was discharged on dual antiplatelets and warfarin.
Patient is on regular follow up and is otherwise asymptomatic. He was counselled regarding the adverse effects of Marijuana smoking at discharge. Substance abuse is an uncommon cause associated with acute myocardial infarction. The World Health Organization estimates that about 2.5% of the total world population uses cannabis, ten times more than cocaine or opiates.1 The cardiovascular effects of marijuana are well documented. It stimulates the sympathetic nervous system causing elevation in heart rate as well as systolic and diastolic blood pressure.It reduces the exercise time to angina due to increased cardiac workload and relative reduction in oxygen delivery to tissues due to carboxyhaemoglobin formation. Marijuana is postulated to act via CB1 and CB2 receptors. CB1 receptor has a pro-atherogenic action as it increases reactive oxygen species and promotes endothelial injury. On the other hand, CB2 has an anti-atherogenic action. CB1 expression is abundant on vascular smooth muscle cell where upregulation is induced by oxidised LDL which leads to activation of pro-atherogenic pathways.3 Marijuana intake is also a known trigger for acute coronary syndrome. Mittleman et al. showed that 3.2% of patients were marijuana users in a cohort of 3882 acute myocardial infarction patients. These patients were predominantly males who were current smokers. The risk of AMI was substantially increased in the 1st hour after marijuana smoking, with gradual reduction in risk with time.Our patient had history of marijuana smoking within 24 hours of myocardial infarction. Heightened sympathetic stimulation after marijuana intake can lead to atherosclerotic plaque rupture.It has also been proposed that marijuana can lead to prothrombotic states by increasing Factor VII activity leading to thrombus formation.Our patient demonstrated significant thrombus burden on OCT without any underlying plaque which indicates de-novo coronary thrombosis. Patients with thrombus who have an intact fibrous plaque cap as well as those without any underlying plaque may not require a stent as they have reasonable luminal area. EROSION study has shown that these lesions can be managed conservatively, with use of dual antiplatelet agents,vertical grow system leading to near complete resolution of thrombus on follow up. Majority of these patients are free of adverse cardiovascular events on follow up.6 Thus, dual antiplatelet therapy is an attractive option in such circumstances. Our patient had good luminal area inspite of significant thrombus burden with minimal underlying plaque burden. Thus, he was managed with dual antiplatelets and anti-coagulants, without stenting. This patient was investigated for conventional pro-thrombotic markers and all turned out to be negative. This highlights the prothrombotic milieu associated with marijuana use and its adverse cardiovascular effects. Road traffic injuries are among the leading causes of emergency care in many low- and middle-income countries. Currently, Africa has the world’s highest road traffic fatality rates, with motorcyclists being disproportionately over represented . Also, RTIs among motorcyclists often go unreported and consequently, the official statistics tend to be an underestimation of the true magnitude of the problem. Tanzania is one of the countries in Africa with a high burden of motorcycle-related RTIs.
A study conducted at six public hospitals in Tanzania showed more than half of all injury-related admissions were due to motorcycle RTIs . A large proportion of injured motorcyclists were commercial motorcycle riders . The high rate of road traffic crashes in this group was documented elsewhere in Tanzania where, half of the riders reported to be involved in crashes and more than 80% experienced near-crash events within the past month before the interview . Commercial motorcycle riders in Tanzania are mostly men with limited formal motorcycle training . A report by Bishop et al. showed that only 23% of commercial motorcycle riders had received formal motorcycle training . Furthermore, there is no standardised curriculum in Tanzania for training motorcycle riders, and when available, it is mostly theory-based as opposed to practical skills training . Studies have shown that risky driving behaviours are common among commercial motorcycle riders . Even though it is illegal to drive without a license in Tanzania , however, many commercial motorcycle riders tend to disobey the law . For example, a study found that only 29% of commercial motorcycle riders reported having a driving license . . Additionally, profitability among riders depends on the number of trips they can complete during the working day, which incentivises commercial motorcycle riders to work for long hours and ride at higher speeds to maximise the number of trips . Regarding the use of protective safety measures, motorcycle helmet usage has been reported to be about 75% to 80%; however, the quality of helmets differs, and they are often not fastened correctly . Evidence suggests that helmet use is associated with reduction of mortality and the risk of head injuries among motorcycle riders . Studies have also indicated that alcohol consumption and psychoactive drug use are common among commercial motorcycle riders . The consumption of alcohol, even in small doses is associated with an increased risk of being involved in a crashes and RTIs . Alcohol intake affects judgment, slows down visual information processing and the ability to discriminate traffic signs, impairs psychomotor skills, and prolongs reaction time . Moreover, the influence of alcohol has been shown to be a stronger risk factor for crashes among motorcycle riders than for other motorists . Epidemiological studies have reported lower mean Blood Alcohol Concentration among motorcycle riders who were involved in road crashes relative to car drivers, evincing the need for greater physical coordination and balance when driving a motorcycle . Simulation experiments of alcohol’s effect on driving show increased reaction time and errors for motorcycle riders compared to car drivers . Other documented effects of alcohol include excessive or inappropriate speed, inattention, failure to navigate curves, and increased probability of running off the road . The risk of RTIs related to alcohol consumption is linked to both the amount and drinking pattern. Two studies conducted in sub-Saharan Africa found that alcohol consumption was associated with an increased risk of RTIs among commercial motorcycle riders .
Studies have shown that motorcycle riders with a hazardous pattern of alcohol consumption are more likely to drink and drive . High-risk drinking has also been shown to be associated with other unsafe driving behaviours including the use of mobile phone while driving, speeding, not wearing a helmet and other protective gear . Risky drinkers have also been shown to be less compliant to traffic rules and road signs as well as driving without a driving license . Recently,mobile grow systems there has been increasing recognition of the effect of psychoactive drugs on RTIs . The potential psychoactive drugs reported to be associated with the risk of RTIs are including marijuana/cannabis, amphetamines, cocaine, heroin and opiates . These substances impair driving performance by altering the perception of external stimuli, and consequently, their response to them . A cohort study conducted among trauma patients in Tanzania indicated that more than third of patients were tested positive for psychoactive drugs, and the most of the patients were motorcycle drivers.Moreover, the combination of psychoactive drugs and alcohol has been shown to compound the impairment and further increase the risk of RTIs . Motorcycle riders who operate commercially are a distinct population in the traffic environment. They are exposed to a greater risk of road crashes and injuries as they spend more hours on the road and have different incentives for taking risks than other road users. There is limited evidence on the role of alcohol consumption and marijuana on RTIs among this group of riders in sub-Saharan Africa. Therefore, this study aimed to determine the association between alcohol consumption, marijuana use and RTIs among commercial motorcycle riders in the city of Dar es Salaam, taking into consideration sociodemographic, driver’s and work-related factors.Cases were identified and recruited from two tertiary hospitals of Muhimbili National Hospital and Muhimbili Orthopedic Institute , and three main regional referral hospitals of Mwanayamala, Temeke, and Amana located in Dar es Salaam. These hospitals were purposefully selected because they are major public hospitals that provide care to RTI victims in Dar es Salaam. The three regional hospitals represent the second-highest level of hospital care next to the tertiary hospitals, and the majority of RTIs victims with moderate and severe injuries would eventually end up at these hospitals. This approach ensured the capture of the majority of injured commercial motorcycle riders who sought hospital-level of care. At the tertiary hospitals, cases were identified retrospectively from patient admission records at the Emergency Department by a research assistant on a weekly basis. The information such as hospital registration number, name, phone number, date of the crash, and mechanism of injury that were recorded in the hospital patient registration system was extracted to assist tracing of commercial motorcycle riders who admitted due to RTIs at MNH and MOI wards. Once the cases were identified at the wards, they were informed about the study and, after informed consent, interviewed by our trained research assistant. At the regional hospitals, cases were identified by a triage nurse at the outpatient/surgery department daily. The triage nurse then alerted our research assistant to interview without hindering or delaying the care or diagnostic services. Cases visiting during the weekend or nighttime were recorded in a logbook and invited for an interview the next day at the hospital. Cases that were discharged before the interview could take place were tracked by phone number and then invited for an interview at the hospital when they came in for clinical check-up, at homes or at the parking stages.