Caso clinico Patológico NEJM Paciente com parestesia, perda de peso, anemia e ictericia

CASE RECORDS OF THE MASSACHUSETTS GENERAL HOSPITAL

Richard C. Cabot, Founder, Nancy Lee Harris, M.D., Editor, Jo-Anne O. Shepard, M.D., Associate Editor, Eric S. Rosenberg, M.D., Associate Editor, Alice M. Cort, M.D., Associate Editor, Sally H. Ebeling, Assistant Editor, Christine C. Peters, Assistant Editor

Case 13-2012 — A 62-Year-Old Man with Paresthesias, Weight Loss, Jaundice, and Anemia

Alberto Puig, M.D., Ph.D., Mari Mino-Kenudson, M.D., and Anand S. Dighe, M.D., Ph.D.

N Engl J Med 2012; 366:1626-1633April 26, 2012

Article

References

PRESENTATION OF CASE

Dr. Norifumi Kamo (Medicine): A 62-year-old man was admitted to this hospital because of paresthesias, weight loss, jaundice, and anemia.

The patient had been well until approximately 2 months before admission, when numbness, tingling (“pins and needles”), and burning in his hands developed; the symptoms intermittently radiated proximally to the mid-forearm and gradually progressed to an estimated 40% of his normal sensation. Pain, stiffness, and weakness of the hands occurred; he noted decreased dexterity of his hands, without swelling, and he began to drop objects. He took ibuprofen, with minimal symptomatic improvement. His appetite decreased, and an unintentional weight loss of more than 6.5 kg occurred.

Approximately 6 weeks before admission, the patient's family noted that his eyes and skin (most noticeably his palms) gradually became pale and yellowed. Two weeks before admission, extreme fatigue, shortness of breath, and weakness with exertion developed, and episodes of abdominal pain occurred in the lower quadrants. Stiffness in his axillae developed, and it migrated to his shoulders and abdomen. One week before admission, his wife noted a change in his gait, and he appeared unsteady. He was unable to climb four stairs without resting and was unsteady on standing, with resolution after ambulating. Two nights before admission, dyspnea, weakness, and diaphoresis developed. During the day, pressure radiated up his arms; this was associated with diffuse abdominal pain that intermittently radiated to the axillae, and dark urine developed. On the day of admission, he rated the pain in his joints at 7 on a scale of 0 to 10, with 10 indicating the most severe pain. At that time, he came to the emergency department at this hospital.

The patient reported increased respiratory secretions, with a cough of 2 weeks' duration that was productive of white or yellow sputum, without hemoptysis, fever, headache, nausea, vomiting, hematochezia, melena, diarrhea, other changes in bowel function, or symptoms in his legs or feet. He had hypertension and benign prostatic hypertrophy.

The patient had been well on routine examination 4 months before admission. Medications included lisinopril (daily) and ibuprofen and acetaminophen as needed for discomfort; he had no known allergies. He lived with his wife and was retired, after working in the food industry and in manufacturing, and he was previously very physically active. He ate chicken, fish, and vegetables regularly and ate red meat rarely. He stopped smoking (after 40 pack-years) and drinking alcohol 26 years before admission, and he had not used illicit drugs. Four years before admission, he had visited his family in Greece. He also had gone fishing and deer hunting in New England. His father was well, and his mother was bedridden; both were in their 90s. A sister had died of breast cancer, and two brothers had died of lung cancer; his children were healthy.

On examination, the patient appeared pale. The temperature was 37.5°C, the blood pressure 136/63 mm Hg, the pulse 113 beats per minute, the respiratory rate 20 breaths per minute, and the oxygen saturation 99% while he was breathing ambient air. The tongue was swollen and smooth, the conjunctivae were pale and icteric, and the palate, subglossal mucosa, and skin were jaundiced. The abdomen was soft, with mild-to-moderate tenderness in the epigastrium, without rebound, guarding, organomegaly, or masses. On neurologic examination, there was pronator drift bilaterally. Sensation to light touch was decreased by approximately 80% in the hands and feet; sensation to vibration and temperature was decreased in both legs in a “stocking” pattern and was normal in both arms. A Romberg test was positive, with swaying and falling when the patient's eyes were closed; toe, heel, and heel-to-toe gaits were normal. Muscle strength, reflexes, and the remainder of the examination were normal. The blood level of potassium was 3.2 mmol per liter (reference range, 3.4 to 4.8) and globulin 2.1 g per deciliter (reference range, 2.3 to 4.1). Blood levels of the other electrolytes, glucose, calcium, phosphorus, magnesium, alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, amylase, lipase, total protein, and albumin were normal, as were tests of renal function; tests for creatine kinase isoenzymes and troponin I were negative, and other test results are shown in Table 1TABLE 1

Laboratory Data.

. An electrocardiogram was normal. A chest radiograph showed degenerative changes of the thoracic spine and was otherwise normal. A stool specimen was negative for occult blood. One liter of crystalloid solution was administered intravenously, with improvement in the tachycardia. Three hours after presentation, the patient was admitted to this hospital; 2 units of red cells were transfused.

Diagnostic test results were received.

DIFFERENTIAL DIAGNOSIS

Dr. Alberto Puig: As in most complex cases in medicine, this patient has multiple signs and symptoms on presentation, and we must decide whether to attempt to fit them all under one diagnosis or to assign each individual finding a different but equally important cause. I will focus on the most salient abnormalities in this case: paresthesias, ataxic gait, and anemia.

Paresthesias

Paresthesias involve a sensation of tingling, numbness, crawling, or deadness, and they are felt mainly in distal parts of the extremities. Although on rare occasions they can involve the thalamus, paresthesias are mostly considered to originate from a spinal cord disorder that probably results from ectopic discharge in damaged dorsal-column axons and may be present before any other abnormalities are detectable on neurologic examination.1,2 Although there are many possible causes of paresthesias (Table 2TABLE 2

Causes of Paresthesias.

), most are not considerations in this case.

Ataxic Gait

A second salient neurologic feature in this case is the unsteady, ataxic gait that developed insidiously over the course of this patient's illness. Our patient felt unsteady on standing, had difficulty climbing stairs, and seemed to improve with ambulation. The differential diagnosis of ataxic gait is more concrete and includes cerebellar, vestibular, and sensory causes.3 In this case, there is no evidence of cerebellar dysfunction such as truncal ataxia, wide gait, word scanning, apraxia, lack of coordination, or dysmetria. There is also no evidence of vestibular dysfunction such as dizziness, vertigo, nausea, or falls to one side.

Sensory ataxia, which is characterized by decreased proprioception, is often caused by a pathologic process affecting the dorsal columns or a large-fiber polyneuropathy that may result in ataxic gait. In this patient, sensory ataxia affecting the dorsal columns was manifested by a Romberg sign, decreased proprioception, and pronator drift on examination. The patient feels unsteady because the brain is deprived of information about the position of the feet and must rely on visual input and light to see ground. This is why patients often have difficulty climbing stairs or walking in the dark. Vision is able to compensate for the loss of position sense to a great degree and thus minimizes sensory ataxia. If the lesion affects the cervical cord, there is also upper-extremity ataxia.

The list of possible causes of sensory ataxia is limited (Table 3TABLE 3

Common Causes of Sensory Ataxia.

). On the basis of what we know from this patient's clinical presentation and history, we can safely rule out hereditary ataxias, sensory polyneuropathies, and multisystem atrophy. If we combine the two features that we have selected — paresthesias and sensory ataxic gait — the differential diagnosis would further narrow to those disorders caused by dysfunction of the dorsal columns, including syphilis, tickborne illnesses, human immunodeficiency virus (HIV) infection, vitamin deficiencies (e.g., deficiencies of vitamin B₁₂, folate, and vitamin E), and systemic inflammatory conditions (e.g., neoplasia, paraneoplastic syndromes, and autoimmune diseases). Although they are less likely, multiple sclerosis and amyloidosis should also be considered. 2,3

Anemia

This patient presented with a hematocrit of 18.7%, which probably explains his fatigue, shortness of breath, and pallor. His wife commented that he appeared pale and yellow, and these findings were corroborated by the admitting physician's examination, which confirmed that he was pale and jaundiced. Hemolysis is the likely mechanism to explain his anemia and jaundice. If we consider causes of paresthesias, ataxia, and anemia, our differential diagnosis narrows considerably to include infections (tickborne disease and HIV), vitamin deficiencies (of vitamin B₁₂ or folate), and autoimmune, neoplastic, and paraneoplastic causes.4,5

We are not given a history of a recent tick exposure, making a tickborne illness unlikely. Although we cannot rule out autoimmune or paraneoplastic phenomena with the information we are given, one feature that perhaps makes our clinical approach more discerning is the description of glossitis (swollen and smooth appearance of the tongue) on physical examination.6 In addition to the other clinical features cited above, the presence of glossitis makes it likely that this patient has a profound deficiency of vitamin B₁₂ that is responsible for the subacute degeneration of the dorsal columns of the spinal cord and hemolysis. Indeed, we could easily make the diagnosis of vitamin B₁₂ deficiency on the basis of clinical information alone, since this patient presented with weakness and fatigue, glossitis, and paresthesias — the classic triad of clinical findings associated with vitamin B₁₂ deficiency. In addition, other clinical findings were also present, including anemia, clumsiness and unsteady gait, nonspecific gastrointestinal symptoms, and weight loss, making the likelihood of this diagnosis more certain.

Although the clinical findings in this case strongly suggest a profound vitamin B₁₂ deficiency, the diagnosis needs to be confirmed with an appropriate laboratory evaluation. The hemogram reveals profound anemia with a hemoglobin level of 6.3 g per deciliter and a markedly elevated mean corpuscular volume of 124 fl. In addition, we found that the patient also had elevated levels of total bilirubin, most of which was unconjugated, almost nonexistent serum haptoglobin levels, and a markedly elevated serum level of lactate dehydrogenase; all these findings strongly suggest the presence of a hemolytic process as the probable cause of the severe anemia.

When evaluating a patient with anemia, a quick look at three basic hematologic studies — the red-cell indexes (mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, and red-cell distribution width), the reticulocyte count, and the peripheral smear — is likely to yield a manageable list of potential causes. Although we are not shown the peripheral-blood smear, it was certainly done in this case and should be considered a “biopsy” of the blood. It allows us to visually analyze the hemogram in its entirety for count, shape, and size of cells. Although far from perfect, when analyzed together, the combination of these three studies has a rather high initial diagnostic accuracy for anemia.7

Red-Cell Indexes

Perhaps the most salient and discernible abnormality in this patient's red-cell indexes is the markedly elevated mean corpuscular volume of 124 fl (normal range, 80 to 100) in contrast to the reticulocyte count (0.8%), which is low for the degree of anemia. The mean corpuscular volume gives the approximate size (volume) of a population of red cells in a patient's blood. We can quickly ascertain by the mean corpuscular volume of 124 fl that our patient has macrocytic anemia. On the basis of the pathogenesis, the different causes of macrocytic anemia can be classified as arising from immature or stress cells (e.g., reticulocytosis, aplasias, and Fanconi's anemia), abnormal DNA metabolism (e.g., vitamin B₁₂ and folate deficiency and drugs or toxins), abnormal lipid metabolism (e.g., liver disease and hypothyroidism), a bone marrow disorder (e.g., myelodysplastic syndromes, leukemia, and congenital abnormalities), and an unknown mechanism (e.g., alcoholism and plasma-cell dyscrasias).8,9

Although relatively short, this list is still too long to be of much help. Examination of the mean corpuscular hemoglobin, the mean corpuscular hemoglobin concentration, and the red-cell distribution width can help us further characterize our patient's anemia. The mean corpuscular hemoglobin describes the amount of hemoglobin per red cell in a population of cells. This patient's mean corpuscular hemoglobin is 41.7 pg (reference range, 26.0 to 34.0) and tells us that the patient, although anemic, has red cells that contain more hemoglobin than expected; this argues against a hemoglobinopathy as the cause of anemia. However, the mean corpuscular hemoglobin concentration is normal at 33.7 g per deciliter (reference range, 31.0 to 37.0), indicating that the patient's erythrocytes, although large and plentiful in hemoglobin content, are indeed normochromic. Furthermore, red cells can be described according to the relative frequency with which varied shapes occur in a population of cells. The relative red-cell distribution width, which in this patient is elevated at 21.8% (reference range, 11.5 to 14.5), suggests that a large proportion of the cells are of widely varied shapes and sizes. On the basis of the red-cell indexes, we can conclude that this patient's anemia is macrocytic and normochromic, with an elevated hemoglobin content per red cell and a wide variety of shapes and sizes in the overall red-cell population. How may these findings help us to further distinguish our patient's anemia among the causes of macrocytosis?

Returning to our list for mechanisms of macrocytosis, we can exclude the presence of immature cells as a likely culprit, given that the reticulocyte count in this patient's serum was normal. We can also discard disorders of the bone marrow, heavy alcohol use, and plasma-cell dyscrasias as likely causes, given that other cell lines, white cells, and platelets are intact. We are left with abnormal DNA metabolism causing megaloblastic anemia or abnormal lipid metabolism of the cell wall due to liver disease or hypothyroidism as the possible etiologic mechanisms for macrocytosis in this patient. The markedly elevated lactate dehydrogenase level, low haptoglobin level, and unconjugated hyperbilirubinemia all point to a hemolytic process as a contributing cause of anemia. Condensing all these variables into a unifying explanation for this patient's anemia, we are left with megaloblastic anemia caused by vitamin B₁₂ or folate deficiency as the likely diagnosis.

A hallmark of megaloblastic anemia is ineffective erythropoiesis due to defective DNA and nuclear maturation and the consequent intramedullary destruction or hemolysis of fragile and abnormal megaloblastic erythroid precursors. Such ineffective erythropoiesis, if persistent and severe, may deplete iron stores, leading to the coexistence of iron-deficiency anemia. This explains the absence of high peripheral reticulocytosis in patients with profound vitamin B₁₂ deficiency despite avid red-cell destruction.4,7,9 In addition, overwhelming, ineffective erythropoiesis with severe hemolysis may also result in depleted levels of serum potassium, which is probably the case in this patient. The elevated red-cell distribution width is further evidence of mixed anemic cell populations and may be explained by the coexistence of vitamin B₁₂ deficiency and iron-deficiency anemia.

Vitamin B₁₂ Deficiency

In this case, the clinical signs and laboratory evaluation lead us to the diagnosis of profound vitamin B₁₂ deficiency. Given this patient's age at the onset of illness, clinical presentation, laboratory evaluation, and history of maintaining a normal diet, the most likely cause of his vitamin B₁₂ deficiency is pernicious anemia. In the classic sense, pernicious anemia is caused by inadequate production of intrinsic factor by parietal cells, thus impeding the proper absorption of vitamin B₁₂ in the ileum. It is believed to be an autoimmune disease, with a high proportion of patients having antibodies against parietal cells as well antibodies against intrinsic factor as compared with healthy persons.4,8,9

To make a firm diagnosis of pernicious anemia in this patient, I would carefully examine the peripheral-blood smear and obtain vitamin B₁₂ and red-cell folate levels. To differentiate between vitamin B₁₂ deficiency and folate deficiency, I would obtain methylmalonic acid and homocysteine levels. The homocysteine level is elevated in both anemia due to vitamin B₁₂ deficiency and anemia due to folate deficiency. In contrast, the methylmalonic acid level is elevated only in vitamin B₁₂ deficiency and is normal in folate deficiency. Although it has fallen out of favor, the Schilling test would reveal the cause of vitamin B₁₂ deficiency, and serologic testing for antibodies to intrinsic factor would point to pernicious anemia as a cause. To complete the workup, it would be prudent to obtain serum iron studies, given the high suspicion of concomitant iron deficiency.

Dr. Eric S. Rosenberg (Pathology): Dr. Van Allen, would you tell us your clinical impression?

Dr. Eliezer M. Van Allen (Hematology/Oncology): When we initially saw this patient, we were impressed by the gradual onset of symptoms, neurologic findings, weight loss, and extent of the macrocytosis, with a mean corpuscular volume of 124 fl. The associated hemolysis and iron-deficiency anemia make vitamin B₁₂ deficiency from autoantibody production leading to pernicious anemia the most likely diagnosis.

We also considered infections associated with vitamin B₁₂ deficiency, including Helicobacter pyloriand the fish tapeworm Diphyllobothrium latum. However, this patient had no obvious risk factors for these infections. We also considered myelodysplastic syndromes, given the elevated mean corpuscular volume, but he did not have trilineage dysplasia, neutropenia, leukopenia, or thrombocytopenia to invoke myelodysplastic syndromes. Finally, severe alcoholism can lead to a macrocytic anemia. However, with alcoholism, one generally observes a mean corpuscular volume between 100 and 110 fl. It would be extremely rare for alcoholism alone to cause a mean corpuscular volume of 124 fl independent of any other symptoms.

CLINICAL DIAGNOSIS

Vitamin B₁₂ deficiency (pernicious anemia).

DR. ALBERTO PUIG'S DIAGNOSIS

Vitamin B₁₂ deficiency (pernicious anemia).

PATHOLOGICAL DISCUSSION

Dr. Anand S. Dighe: A peripheral-blood smear showed anisocytosis with oval macrocytes and abundant neutrophil hypersegmentation; no schistocytes or spherocytes were present (Figure 1FIGURE 1

Peripheral-Blood Smear.

). Anemia studies were obtained. The level of vitamin B₁₂ was very low at 61 pg per milliliter (45 pmol per liter) (reference range, >250 pg per milliliter [>185 pmol per liter]) and the level of folate was normal at 17.2 ng per milliliter (38.9 nmol per liter) (reference range, 3.1 to 17.5 ng per milliliter [70.5 to 39.7 nmol per liter]). Iron studies revealed a low serum iron level of 19 μg per deciliter (3 μmol per liter) (reference range, 45 to 160 μg per deciliter [8 to 29 μmol per liter]), a slightly low total iron-binding capacity of 221 μg per deciliter (40 μmol per liter) (reference range, 230 to 404 μg per deciliter [41 to 72 μmol per liter]), and an elevated ferritin level of 340 ng per milliliter (reference range for men, 30 to 300). The calculated transferrin saturation (calculated as the level of iron divided by the total iron-binding capacity) was 8.6%, suggestive of iron deficiency. It is well described that iron deficiency and elevated ferritin levels may develop in patients with pernicious anemia.10,11

Since the initial laboratory evaluation was suggestive of pernicious anemia, additional laboratory evidence for the diagnosis was sought. The presence of cellular vitamin B₁₂ deficiency was assessed by measurement of methylmalonic acid, the metabolism of which requires vitamin B₁₂ as a cofactor. The level of serum methylmalonic acid was highly elevated at 19.78 nmol per liter (reference range, <0.40), confirming the presence of cellular vitamin B₁₂ deficiency. Classic findings associated with pernicious anemia include atrophic gastritis of the body of the stomach (atrophic body gastritis) and intrinsic factor deficiency. A highly elevated fasting gastrin level (504 pg per milliliter; reference range, <100) and a reduced level of pepsinogen I (<24.6 ng per milliliter; reference range, 28 to 100) were consistent with atrophic body gastritis. Since the Schilling test is now unavailable at most centers, the detection of antibodies to intrinsic factor may be used to support the diagnosis of pernicious anemia. In approximately 40 to 60% of patients with pernicious anemia, positivity for anti–intrinsic factor antibodies is present and provides evidence to support the diagnosis of pernicious anemia, with a specificity approaching 100%. 12 Anti–intrinsic factor blocking antibodies were measured, and the patient was found to be positive.

Dr. Mari Mino-Kenudson: Patients with pernicious anemia have an increased risk of gastric carcinoma and carcinoid tumors.13 The patient underwent endoscopy to evaluate the upper and lower gastrointestinal tract to assess for a neoplastic condition and to rule out gastrointestinal bleeding as a possible contributor to the patient's iron deficiency. The mucosal surfaces of the gastric fundus and body appeared atrophic, and histologic sampling confirmed mucosal atrophy with pseudopyloric and intestinal metaplasia, consistent with autoimmune gastritis. No evidence of gastric carcinoma or carcinoid was present (Figure 2A and 2BFIGURE 2

Endoscopic Evaluation and Biopsy Specimen.

). The remainder of the endoscopic evaluation was unremarkable. The role of H. pylori in the pathogenesis of pernicious anemia is an area of active investigation.14 The patient was assessed for the presence of H. pylori; bothH. pylori IgG serologic tests and stool antigen tests were negative.

Dr. Kamo: In the emergency department, the patient received 2 units of packed red cells. We consulted with the hematology service, and an intramuscular vitamin B₁₂ regimen as well as the administration of intravenous iron were initiated. He had improvement in his peripheral neuropathy, and the hematocrit on discharge was 23%. Since discharge, he has received monthly vitamin B₁₂ injections. One year after discharge, the hematocrit is 44%, the vitamin B₁₂ level 581 pg per milliliter, and the iron level normal. He continues to have numbness and tingling in his hands bilaterally, as well as some numbness in the distal part of his toes.

ANATOMICAL DIAGNOSIS

Vitamin B₁₂ deficiency due to pernicious anemia.

Presented at the Medical Case Conference.

Disclosure forms provided by the authors are available with the full text of this article at NEJM.org.

No potential conflict of interest relevant to this article was reported.

This article (10.1056/NEJMcpc1111575) was updated on April 26, 2012, at NEJM.org.

SOURCE INFORMATION

From the Departments of Medicine (A.P.) and Pathology (M.M.-K., A.S.D.), Massachusetts General Hospital; and the Departments of Medicine (A.P.) and Pathology (M.M.-K., A.S.D.), Harvard Medical School — both in Boston.