[Diagnosis of vitamin B12 deficiency: only apparently child's play]

We performed a systematic literature search for diagnostic criteria in establishing cobalamin deficiency. The diagnostic procedure is particularly uncertain in elderly patients with neurological symptoms and in cases with borderline cobalamin values. In any patient with suspected cobalamin deficiency we recommend analysing a full blood count and determining cobalamin concentration in a serum sample. Particularly in elderly patients and cases with neurological symptoms presenting borderline cobalamin values and no abnormalities in the blood count, we recommend further investigation with methylmalonic acid, homocystein and Schilling test. These additional tests should make it possible to decide whether to recommend lifelong substitution with cobalamin. Various cobalamin assays, Schilling test, food cobalamin test, gastroscopic evaluation and the problems surrounding these assays in the elderly are discussed. Our own experience with methylmalonic acid, homocystein determination and food cobalamin test did not reveal a simple diagnostic procedure in such cases. We conclude that there is still no "gold standard" for diagnostic procedure in the special cases mentioned.

[Obstetric problems followed by stroke]

Obstetrical problems sometimes portend manifestations of atherosclerosis, as illustrated by two case reports. The first patient had the combination of hyperhomocysteinaemia due to chronic vitamin deficiencies in the diet, and smoking. The second was also a smoker and had a genetically determined mild hyperhomocysteinaemia, aggravated by chronic vitamin deficiencies resulting from poor dietary habits; she also had an increased folic acid requirement because of use of anti-epileptic drugs in combination with a familial predisposition for premature atherosclerotic manifestations. The first patient had four pregnancies, two of which ended in intrauterine foetal death due to placental infarction, and one in the birth of a dysmature boy. The second patient's four pregnancies ended twice in abortion and twice in the birth of a dysmature child; in one of the latter cases placental infarction was observed. Both women subsequently suffered cerebrovascular accidents while in addition, older cerebral infarctions were found to be present. Women with recurrent abortion, pre-eclampsia, placental infarction, placental detachment and foetal growth retardation should be examined, even if other risk factors are also present, for (mild) hyperhomocysteinaemia, and treated for it with vitamin suppletion (folic acid, vitamins B6 and B12), even although admittedly more research is necessary to make certain that such treatment has a preventive effect on the manifestations of this disorder.

Modern clinical testing strategies in cobalamin and folate deficiency

Folate or cobalamin deficiencies are usually detected by hematologic abnormalities, such as a macrocytic megaloblastic anemia, or often milder signs, such as hypersegmented neutrophils. In fact, these vitamin deficiencies may be associated with clinical conditions in which anemia and/or macrocytosis are absent, such as neuropsychiatric disorders and inborn errors of folate or cobalamin metabolism. A battery of sensitive tests, including blood vitamin levels, serum methylmaIonic acid and homocysteine assays, and the deoxyuridine suppression test in the bone marrow, allows for early detection of vitamin deficiency. Additional tests may be included to identify the causes of deficiency, such as the Schilling test using crystalline cyanocobalamin, or a modified Schilling test for showing food cobalamin malabsorption. Strategies for diagnosing a vitamin deficiency differ according to the hematologic and clinical presentations. The deleterious effects (aside from anemia) that arise from cobalamin or folate deficiency and include neurological complications, increased risk of vascular disease due to hyperhomocysteinemia, and increased risk of some types of cancer related to folate deficiency, underscore the importance of making an early diagnosis and instituting treatment with the appropriate vitamin in preventing permanent damage.

Folate deficiency beyond megaloblastic anemia: hyperhomocysteinemia and other manifestations of dysfunctional folate status

Folate plays a key role in nucleic acid synthesis. As a consequence, the most conspicuous complication of folate deficiency or of derangements of folate metabolism is megaloblastic macrocytic anemia caused by interdiction of normal proliferation of rapidly dividing bone marrow cells. Other rapidly dividing cells, including those in the gastrointestinal tract, may also be affected by the megaloblastic process. This may result in malabsorption. However, there is mounting evidence to indicate that there are other earlier manifestations of folate deficiency or of longstanding suboptimal folate nutrition. Chief among these manifestations of folate deficiency are an increased predisposition to occlusive vascular disease and thrombosis, which have been linked to increased levels of homocysteine found in folate deficiency and abnormal states of folate metabolism. In addition, folate deficiency, previously considered free of neurological consequences, is now known to be associated with disturbances of mood, and even spinal cord syndromes similar to those seen in vitamin B12 deficiency. Finally, there is both experimental and clinical evidence to suggest that folate deficiency may interfere with immunologic status and may be associated with an increased predisposition to neoplasia. Nutritional as well as genetic factors may contribute to these various nonhematological manifestations of folate insufficiency.

[Hemolysis and schizocytosis, malabsorption and the "folate trap": unusual semiological peculiarities associated with vitamin B12 deficiency]

INTRODUCTION

Hemolysis and red cell fragmentation accompanying vitamin B12 deficiency may misdirect the diagnosis. Signs of malabsorption and abnormalities related to folic acid metabolism characterized by discrepancies between folic acid normal serum levels and erythrocytic folic acid levels may also exist.

EXEGESIS

We report the occurrence of hemolysis and red cell fragmentation mimicking microangiopathic hemolytic anemia, malabsorption and folic acid deficiency in the course of vitamin B12 deficiency. Appropriate replacement therapy corrected all abnormalities.

CONCLUSION

An association between hemolysis, malabsorption and folic acid deficiency should lead physicians to search for signs of vitamin B12 deficiency.

Anaemia--more than meets the eye

Anaemia is a commonly encountered medical condition, although associated ophthalmic manifestations are not often sought or recognised. The authors present a case report of a patient with severe vitamin B12 deficiency anaemia with florid retinal changes classical of anaemic retinopathy. A review of the ocular involvement in anaemia is also presented.

An audit of the investigation and treatment of folic acid deficiency

On the suspicion that folate deficiency was not being thoroughly investigated we conducted a retrospective study of management in a teaching hospital. Notes from 84 consecutive patients with low red cell folates (mean age 69.5 years, range 21-95, M:F 33:51) were reviewed for haemoglobin, mean cell volume, dietary history, alcohol consumption, drug history, relevant medical history, relevant investigations, treatment, repeat measurement of red cell folate and diagnosis of deficiency. In 52 (61.9%, mean age 72.9 years, range 33-95, M:F 21:51) no diagnosis was reached. In only 32 (38.1%, mean age 63.9 years, range 21-89, M:F 12:20) was a definitive diagnosis established: 5 had coeliac disease, 1 had Crohn's disease, 9 had drug-associated deficiency (4 methotrexate, 3 phenytoin, 1 trimethoprim and 1 valproate), 1 had combined variable immunodeficiency and 16 had dietary deficiency. In most cases of folic acid deficiency no attempt was made to establish aetiology. We recommend that younger patients without an obvious cause are investigated initially by dietary assessment and measurement of anti-endomysial antibody and by duodenal biopsy with small-bowel follow-through if clinically indicated.

Reduced red-cell folate in mania

Forty-five hospitalised patients with DSM-III-R diagnosis of mania, were found to have a mean red-cell folate level of 193 nmol/l, as compared to 896 nmol/l in the control group (P < 0.00001). Assessment of serum folate in both groups showed no significant differences in the levels. Furthermore the manic patients and the controls were matched by the socio-economic status. This indicated that the reduced red-cell folate in mania is associated with the illness and not due to reduced absorption or dietary deficiency of folate. Considering previous studies that showed reduced red-cell folate in depression, our findings suggest that reduced red-cell folate occurred in both phases of bipolar disorders.

Severe folate deficiency masquerading as the syndrome of hemolysis, elevated liver enzymes, and low platelets

BACKGROUND

Although folate deficiency is common in pregnancy, progression to megaloblastosis is not. Hemolytic anemia, thrombocytopenia, and coagulopathy due to folate deficiency may mimic the syndrome of hemolysis, elevated liver enzymes, and low platelets (HELLP).

CASES

Two women presented in the second trimester with abdominal pain and severe thrombocytopenia. These symptoms were misinterpreted in the first woman as the HELLP syndrome, leading to an emergency cesarean delivery. Subsequent investigation revealed folate deficiency; treatment resulted in rapid normalization of all abnormalities. In the second woman, folate deficiency was diagnosed antenatally. Treatment allowed continuation of the pregnancy to term.

CONCLUSION

The serious complications of folate deficiency make a strong case for supplementation in pregnancy. Careful scrutiny of clinical and laboratory findings may help discriminate the HELLP syndrome from its mimics, avoiding preterm delivery.

[Megaloblastic anemia: rapid and economical study]

The diagnosis of megaloblastic anaemias caused by cobalamine or folate deficiency are still difficult. The dosage of these two substances help to differenciate between both carencies, but it is not determinant of any of them and is an expensive method. Homocisteinuria (HC), methylmalonuria (MMA) and formiminoglutamic acid (FIGLU) are cheap tests which could help in the differential diagnosis, if they are used properly. We report 62 patients to whom we made these test simultaneously. All of the patients received 10 micrograms of vit B12 and after 72 hours, 1 mg/day of folic acid (for 3 days). In both cases waiting for the increase of reticulocytyes up to 150 x 10(9)/L as a form of therapeutic test of diagnosis. By this simple way we have detected 97.9% of specificity for cobalamin deficiency of the MMA test, and only 4.2% for HC. This last test had increased its specificity up to 91.6% in association with the negative FIGLU test. We have also found a high specificity (92.3%) for FIGLU due to the detection of folate deficiency, in opposition with other authors who had described it as low as 50%. We have also compared the costs of the 3 tests with the dosage of cobalamine and folate, and we have found that the formers are 11 times less expensive than the last ones.

Unpredictable intra-individual variations in serum homocysteine levels on folic acid supplementation

OBJECTIVE

To determine if changes in serum homocysteine values during folic acid supplementation can identify objectively healthy subjects with subclinical folate deficiency.

DESIGN

Blood drawn and processed in a regimented fashion from fasting subjects. Serum homocysteine values determined by gas chromatography-mass spectrometry twice before and on days 5 and 8 of daily folic acid supplementation.

SETTING

Outpatient University Hospital Clinical Research Center, Denver, Colorado.

SUBJECTS

Subjectively healthy adults with normal hematologic and biochemical screening tests.

INTERVENTION

Folic acid 1 mg daily for eight consecutive days.

RESULTS

Homocysteine values of the group fell significantly during folic acid supplementation. Values pre supplementation were 7.8 +/- 1.8 and 7.4 +/- 2.4 mumol/L while values on days 5 and 8 of supplementation were 6.5 +/- 2.2 and 6.3 +/- 2.2 mumol/L. However, the homocysteine values of any given individual varied up to 60% (rises up to 7 mumol/L and falls of 5 mumol/L) during folic acid supplementation despite the controlled circumstances of blood handling, and an assay coefficient of variation of 8%.

CONCLUSIONS

Although group values of serum homocysteine fall during folic acid supplementation, intraindividual variation is so great that subjects with subclinical folate deficiency can not be identified using this study design. Furthermore, these data suggest than an individuals homocysteine values vary enough that single values must be interpreted with caution.

Folate and homocysteine status and haemolysis in patients treated with sulphasalazine for arthritis

In an attempt to estimate the frequency of folate deficiency and haemolysis in a group of 25 outpatients with arthritis treated with sulphasalazine (SASP), haematological measurements, including plasma total homocysteine (tHcy) which is a sensitive marker of folate deficiency, serum folate (S-folate), erythrocyte (RBC) folate, S-cobalamin and routine indices of haemolysis were performed. No patient had been taking folate-containing vitamins for at least 8 weeks prior to the study. Compared to a group of 72 healthy hospital staff, the median plasma tHcy was significantly higher in the patient group (8.8 mumol 1(-1) vs. 6.8 mumol 1(-1); p = 0.003). Five patients (20%) had plasma tHcy levels that exceeded the upper normal limit of plasma tHcy (median+2 SD of the reference group). Median S-folate was significantly lower in the patient group (6.0 nmol 1(-1) vs. 8.5 nmol 1(-1); p < 0.001), and 11 (44%) patients had depressed S-folate. Only three (12%) patients had RBC folate values below the reference interval. There was no difference in the levels of RBC folate between the two groups. A comparison of S-cobalamin levels in the two groups disclosed a significantly lower level in the patient group. However, no patient had cobalamin deficiency as assessed by S-cobalamin and S-methylmalonate measurements. Thus, it is unlikely that any patient had increased plasma tHcy due to cobalamin deficiency. Of 24 patients having a HbA1c measurement performed, 12 (50%) had decreased levels indicating chronic haemolysis. Only seven (28%) patients had reticulocytosis. HbA1c was positively correlated to haptoglobin levels (r = 0.77; p < 0.001) and negatively correlated to the percentage of reticulocytes (r = -0.50; p = 0.02). The percentage of reticulocytes was negatively correlated to haptoglobin levels (r = -0.42; p = 0.04). The chronic haemolysis of the patients' blood due to SASP might explain the similar RBC folate values in the two groups because of a relatively higher folate content of young erythrocytes. In conclusion, our results support previous findings of folate deficiency and haemolysis occurring in a considerable fraction of patients receiving treatment with SASP. Measurements of plasma tHcy suggest that a substantial number of patients may have folate deficiency at the tissue level.

Vitamin supplementation and other variables affecting serum homocysteine and methylmalonic acid concentrations in elderly men and women

OBJECTIVE

An elevated serum concentration of the metabolite, homocysteine (Hcys): 1) can indicate folate or vitamin B12 deficiency, 2) is an independent risk factor for vascular disease. The metabolite, methylmalonic acid (MMA), is elevated in deficiency of vitamin B12, but not folate. The purpose of this study was to determine the effect of self-selected vitamin supplementation and other variables on serum Hcys and MMA concentrations in elderly men and women.

METHODS

Serum concentrations of Hcys, MMA, folate and vitamin B12 were measured for elderly volunteers, age 68-96 years, and compared for those consuming (26 men, 25 women) and not consuming (24 men, 25 women) self-selected vitamin supplements.

RESULTS

Compared with the nonsupplemented group, the supplemented group had lower mean serum MMA (208 +/- 162 vs. 241 +/- 98 nmol/L [+/- SD]) and Hcys (9.5 +/- 2.6 vs. 11.2 +/- 2.7 mumol/L); and higher serum vitamin B12 (391 +/- 174 vs 292 +/- 107 pmol/L), and serum folate (46 +/- 15 vs. 24 +/- 10 nmol/L) p < 0.05. Among all 100 subjects, the prevalence of serum vitamin B12 < 221 pmol/L (300 pg/mL) was 18; MMA > 271 nmol/L, 16; Hcys > 16.2 mumol/L, 3; folate < 5.0 nmol/L, none. Based on serum vitamin B12 < 221 nmol/L with elevated serum MMA, vitamin B12 deficiency was probable in seven subjects, of whom two were supplemented. All three subjects with elevated serum Hcys had elevated serum MMA as well, suggesting vitamin B12 deficiency or renal insufficiency. A stepwise linear regression model for serum Hcys explained 61.7% of the variance, and included (in order) serum creatinine, folate, vitamin B12, albumin, age and body mass index (BMI). A model with serum MMA replacing serum vitamin B12 explained 64.1% of the variance in serum Hcys. Folate did not enter the model for supplemented subjects, supporting a "threshold effect": serum Hcys was inversely related to serum folate at lower serum folate (nonsupplemented subjects), but at higher serum folate (supplemented subjects), the relationship was flat. In supplemented subjects, serum Hcys was still related to vitamin B12 status, confirming that tissue deficiency of the vitamin was present.

CONCLUSIONS

Results showed potential usefulness of serum MMA and Hcys in identifying subclinical or tissue deficiency of vitamin B12. Clinicians should be aware of the risk of vitamin B12 deficiency in older people and of current screening algorithms using serum metabolites. These elderly volunteers had generally good folate status; nevertheless, some subjects seemed likely to benefit from an improvement in folate status that would reduce their serum Hcys within the normal range. The role of serum creatinine in the normal range in predicting serum Hcys, a vascular disease risk factor, remains unexplained.