Abstract
BackgroundPrevalence of cobalamin deficiency is high especially in older patients and an immediate therapy start is necessary to prevent irreversible neurological damages. Unfortunately, the diagnosis of cobalamin deficiency is difficult and at present, there is no consensus for diagnosis of this deficiency. Therefore, we aim to elucidate a meaningful diagnostic pathway by a case report with an initially misleading medical history.Case presentationA 57 year-old Caucasian man suffering from dramatic myelosis of the cervical posterior columns. Apart from associated neurological symptoms (tactile hypaesthesia, reduced vibration sensation, loss of stereognosis and of two-point-discrimination) there were no further complaints; especially no gastrointestinal, haematological or psychiatric disorders were provable. Cobalamin (vitamin B12) serum level was normal. The diagnosis of subacute combined degeneration of spinal cord was confirmed by an elevated methylmalonic acid, and hyperhomocysteinemia. Cobalamin deficiency was caused by asymptomatic chronic atrophic inflammation of the stomach with a lack of intrinsic factor producing gland cells. This was revealed by increased gastrin and parietal cell antibodies and finally confirmed by gastroscopy. Parenteral substitution of cobalamin rapidly initiated regeneration.ConclusionsThis case demonstrates that normal cobalamin serum levels do not rule out a cobalamin deficiency. In contrast, path-breaking results can be achieved by determining homocysteine, holotranscobalamin, and methylmalonic acid.
Highlights
Prevalence of cobalamin deficiency is high especially in older patients and an immediate therapy start is necessary to prevent irreversible neurological damages
This case demonstrates that normal cobalamin serum levels do not rule out a cobalamin deficiency
Path-breaking results can be achieved by determining homocysteine, holotranscobalamin, and methylmalonic acid
Summary
The report of an accident three months before the onset of symptoms combined with a cervical myelon lesion suggested a traumatic injury. Increased MMA values are highly sensitive and highly specific for cobalamin deficiency [28, 30]. Lowered serum holoTC concentration is the earliest marker of cobalamin deficiency and is reduced even before any clinical symptoms are apparent [2, 32]. In our case increased values for MMA and homocysteine were determined After cobalamin substitution both values returned to normal. In this patient SACD was caused by a disruption of cobalamin processing in the stomach due to parietal cell antibodies inducing an increased pH-value and a decreased production of intrinsic-factor. It is important to determine more sensitive parameters: HoloTC is the earliest and MMA the most specific marker of a cobalamin deficiency.
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