CARDIOVASCULAR JOURNAL OF AFRICA • Volume 34, No 1, January–April 2023 AFRICA 43 These patients usually have non-specific symptoms such as fatigue, loss of appetite, vomiting, abdominal pain and dyspnoea. Although features of cardiac failure typically form part of the clinical presentation, there have been cases reported with the absence of cardiac failure.2 Neither of our patients displayed overt signs of cardiac failure. In the first patient this was likely due to volume depletion from vomiting and the associated ileus. Given the non-specific characteristics of clinical presentation of this condition, it is often confused with other acute medical problems such as massive pulmonary embolism, myocardial infarction or sepsis with multi-organ failure.1-3 Of importance, several clinical and radiological factors led the clinician away from suspecting thiamine deficiency in both cases. In the first patient, the gastrointestinal symptoms and abdominal distension together with the X-ray appearance of the bowel suggested a sigmoid volvulus, all of which resolved completely after thiamine admission. In retrospect, these manifestations were most likely precipitated by vomiting, which led to hypokalaemia and paralytic ileus, resulting in gaseous abdominal distension. The CT abdomen showing thickened bowel loops was likely due to bowel wall oedema. Furthermore, accompanying co-morbidities may direct attention away from a metabolic aetiology for the tachypnoea. In the second patient, the HIV status and the presence of lung crackles suggested infection and directed the clinician’s attention away from a diagnosis of type B lactic acidosis due to thiamine deficiency. Furthermore, the raised troponin levels and ST-segment elevation on the electrocardiogram in the first patient led the clinician to also suspect a diagnosis of myocardial infarction. The electrocardiographic changes that have been described in Shoshin beriberi are non-specific and have varied from ST-segment elevation or depression to T-wave inversion.1-4,6,7 A notable feature that has been described is T-wave inversion in the precordial leads that occurs after thiamine replacement, as was the case in both of our patients. This transient repolarisation abnormality following reversal of acidosis is thought to be due to marked shifts in myocardial cell polarity.1-4,6 The actual mechanism of myocardial dysfunction in Shoshin beriberi has not been fully studied. In the first patient, the admission echocardiogram showed preserved left ventricular function and there was no obvious evidence of a wall-motion abnormality, suggesting myocardial infarction due to underlying atherosclerotic disease. It is well established that elevated troponins may be caused by several factors other than myocardial infarction.8 The transient ST-segment elevation that resolved with thiamine replacement therapy was most likely due to acute myocardial ischaemia secondary to the effect of severe acidosis and accompanying hypotension on the myocardial cell. Previous studies also suggest that the true myocardial contractility in beriberi is concealed by the systemic vasodilatation and may become apparent on recovery when the systemic resistance elevates back towards normal levels.9 Patients who abuse alcohol may have an underlying alcoholic cardiomyopathy that may become unmasked during recovery when the systemic resistance returns to normal.10 Laboratory tests that are considered diagnostic (red cell transketolase activity and blood thiamine concentration) are not readily available or have prolonged turn-around times and are not practical for use in the acute-care setting of medical emergencies that require immediate empiric management before laboratory results become available.2,3 Administration of intravenous thiamine is the only definitive treatment for Shoshin beriberi and the response to thiamine is generally dramatic, with improvement in haemodynamic parameters and resolution of lactic acidosis within minutes to hours if the diagnosis is not delayed. Rapid response to thiamine confirms the diagnosis in the acute setting,2 as was the case in the second patient who received empirical thiamine at admission and recovered almost immediately (Table 1). Conclusion Shoshin beriberi is an easily treatable condition that may masquerade as other life-threatening medical conditions. Treatment with intravenous thiamine must be empirical to avoid delay in diagnosis and potential fatalities. It should be administered to any patient who presents with circulatory shock and unexplained severe metabolic acidosis. References 1. Naidoo DP. Beriberi heart disease in Durban. A retrospective study. S Afr Med J 1987; 72: 241–244. 2. Dabar G, Harmouche C, Habr B, Riachi M, Jaber B. Shoshin beriberi in critically-ill patients: case series. Nutr J 2015; 14(1): 51. 3. Saya, R, Baikunje, S, Prakash P, Subramanyam K, Patil V. Clinical correlates and outcome of Shoshin beriberi. Nth Am J Med Sci 2012; 4: 503–506. 4. Naidoo DP, Singh B, Haffejee A, Aitcheson J, Barker EM. Acute pernicious beriberi in a patient receiving parenteral nutrition. A case report. S Afr Med J 1989; 75(11): 546–548. 5. Candau M, Massengo J. Evidence of a thiamine deficiency in sheep fed maize silage. Ann Rech Vet 1982; 13(4): 329–334. 6. Naidoo DP, Rawat R, Dyer RB, Sadhabiriss A, Makgoba MW. Cardiac beriberi. A report of 4 cases. S Afr Med J 1987; 72(4): 283–285. 7. Kim J, Park S, Kim JH, Kim SW, Kang WC, Kim SJ. A case of Shoshin beriberi presenting as cardiogenic shock with diffuse ST-segment elevation, which dramatically improved after a single dose of thiamine. Cardiovasc J Afr 2014; 25(6): e1–e5. 8. Tanindi A, Cemri M. Troponin elevation in conditions other than acute coronary syndromes. Vasc Health Risk Manag 2011; 7: 597–603. 9. Attas M, Hanley HG, Stultz D, Jones MR, McAllister RG. Fulminant beriberi heart disease with lactic acidosis: presentation of a case with evaluation of left ventricular function and review of pathophysiologic mechanisms. Circulation 1978; 58(3 Pt 1): 566–572. 10. Seedat YK, Cassim B, Dyer R. Acute pernicious or fulminating beriberi with severe lactic acidosis. A case report. S Afr Med J 1985; 68(11): 817–818. Key points • Shoshin beriberi presents as severe metabolic acidosis with/ without shock. • Metabolic acidosis should be suspected in any patient with severe tachypnoea and relatively clear lung fields. • The lactic acidosis in Shoshin beriberi is refractory to resuscitative measures and responds only to thiamine. • Shoshin beriberi can mimic severe medical problems such as massive pulmonary embolism, extensive myocardial infarction or sepsis. • Intravenous thiamine should be administered immediately to patients presenting with severe metabolic acidosis, while they are being resuscitated.
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