Üç Aydır Alkol Almayan Bir Hastada Alkole Bağlı Asidoz Sanılan Metformine Bağlı Laktik Asidoz

Abstract

Metformine bağlı laktik asidoz, böbrekten değişmeden atılan bu ilacın akut bir hastalık sırasında birikmesiyle gelişen, nadir görülen ancak ölümcül seyredebilen bir komplikasyondur ve acil servise tıpkı alkolik ketoasidoz, etanol intoksikasyonu ve toksik alkol alımı gibi, bilinç değişikliğinin eşlik ettiği ayrımlaşmamış yüksek anyon açıklı metabolik asidoz tablosuyla gelir. Bu nedenle kayıtlı bir alkol kullanım öyküsü güçlü, ancak yanıltıcı olabilen bir tanısal ipucudur. Sabit doz vildagliptin ve metformin kombinasyonu kullanan, tip 2 diabetes mellitus tanılı 62 yaşındaki erkek hasta evde bilinci kapalı olarak bulundu. Yakınları uzun süreli yoğun alkol kullanımı dışında kullanılabilir bir öykü veremedi ve öncelikli tanılar olarak alkolik ketoasidoz ile metanol alımı araştırıldı. Arteriyel pH sevk eden merkezde cihazın ölçüm aralığının altında kaldı; altı saat sonra yoğun bakım ünitemize varışta 6,60 olarak ölçüldü ve bikarbonat 1,2 mmol/L, laktat 16,9 mmol/L, anyon açığı 42 mmol/L, kreatinin 7,21 mg/dL saptandı. Serum etanol düzeyi saptanabilir sınırın altındaydı, nörogörüntülemede metanol toksisitesini düşündüren lezyon izlenmedi ve hemoglobin A1c değeri %13,9 olmasına karşın hasta her iki hastanede de hipoglisemikti. Vazoaktif destek, sodyum bikarbonat, mekanik ventilasyon, aralıklı hemodiyaliz ve 40 saatlik sürekli renal replasman tedavisi uygulandı ve hasta dördüncü günde ekstübe edildi. Belirleyici bilgiler ancak o zaman, öykü doğrudan hastadan alınabildiğinde ortaya çıktı: on gün süren ve oral alımın ileri derecede azaldığı ishal tablosu boyunca metformin kullanımını sürdürmüş olması ve üç aydır alkolü tamamen bırakmış olması. Hasta nörolojik olarak sekelsiz ve renal replasman tedavisinden bağımsız şekilde taburcu edildi. Alkol kullanım öyküsü, son alımın üzerinden aylar geçmiş olsa bile değerlendirmeye egemen olabilir; metformin kullanan hastalarda bu öykü, özellikle güvenilir bir yakın öyküsü alınamadığında, ayırıcı tanıyı daraltmak yerine genişletmelidir.

Keywords

• metformin
• laktik asidoz
• tanı hataları
• akut böbrek hasarı
• renal replasman tedavisi
• hipoglisemi

Metformin-associated lactic acidosis mistaken for alcohol-related acidosis in a patient abstinent for three months

Abstract

Metformin-associated lactic acidosis is an uncommon but potentially fatal complication that develops when this renally eliminated drug accumulates during an acute illness, and it reaches the emergency department as an undifferentiated high anion gap metabolic acidosis with altered consciousness, exactly as alcoholic ketoacidosis, ethanol intoxication and toxic alcohol ingestion do. A documented history of alcohol use is therefore a powerful and potentially misleading diagnostic cue. We report a 62-year-old man with type 2 diabetes mellitus taking a fixed-dose vildagliptin and metformin combination who was found unconscious at home. His relatives could give no usable history beyond long-standing heavy drinking, and alcoholic ketoacidosis and methanol ingestion were pursued as the leading diagnoses. Arterial pH was below the measurable range of the analyser at the referring hospital and, six hours later on arrival at our intensive care unit, 6.60, with a bicarbonate of 1.2 mmol/L, a lactate of 16.9 mmol/L, an anion gap of 42 mmol/L and a creatinine of 7.21 mg/dL. Serum ethanol was undetectable, neuroimaging showed no lesion suggestive of methanol toxicity, and he was hypoglycaemic at both hospitals despite a glycated haemoglobin of 13.9%. He was treated with vasoactive support, sodium bicarbonate, mechanical ventilation, intermittent haemodialysis and 40 hours of continuous renal replacement therapy, and was extubated on the fourth day. Only then, when a history could be taken directly from him, did the decisive facts emerge: ten days of diarrhoea with minimal oral intake throughout which he had continued metformin, and three months of complete abstinence from alcohol. He was discharged neurologically intact and independent of renal replacement therapy. A drinking history can dominate the assessment months after the last drink; in metformin-treated patients it should widen the differential rather than close it, particularly when no reliable collateral history is available.

Keywords

• metformin
• acidosis, lactic
• diagnostic errors
• acute kidney injury
• renal replacement therapy
• hypoglycemia

Supporting Institution

This case report received no specific grant from any funding agency in the public, commercial or not-for-profit sectors.

Ethical Statement

Ethics committee approval is not required for single case reports at our institution. The report was prepared in accordance with the Declaration of Helsinki as revised in 2013, and written informed consent was obtained from the patient.

Thanks

The authors express their deepest and most heartfelt gratitude to Prof. Dr. Melda Dilek for her unconditional and unfailing support. Her generosity, guidance and encouragement have been invaluable throughout, and the authors remain sincerely indebted to her.

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