Page 229 - The Netter Collection of Medical Illustrations - Integumentary System_ Volume 4 ( PDFDrive )

Plate 8-6 Nutritional and Metabolic Diseases

PELLAGRA (Continued) MUCOSAL AND CENTRAL NERVOUS SYSTEM MANIFESTATIONS OF PELLAGRA

tract, as can cystic dilation of the mucous glands. The
colon may show small submucosal abscesses.
Subtle neurological findings precede full-blown
encephalopathy in pellagra. These clinical findings
include poor concentration, headaches, and apathy.
Dementia eventually sets in as the disease causes a
diffuse encephalopathy. The encephalopathy may
mimic psychiatric disease, especially depression with
suicidal tendency. Other well-defined symptoms include
confusion, hallucination, delirium, insomnia, tremor,
seizures, and extrapyramidal rigidity. The entire central
nervous system is involved in severe pellagra. Cortical
nerve cells show degeneration. The Betz cells show
chromatolytic changes with displacement of the nucleus
toward the cell wall. There is an increased amount
of adipose in the nerve cells as well as an increase in
the lipofuscin pigment within the cytoplasm of these Genital lesions in pellagra
cortical cells. The posterior columns may undergo Pellagra tongue
demyelination, leading to tremor, gait disturbance, and
movement difficulties. Chromatolysis has been shown
to occur in the pontine nuclei, spinal cord nuclei, and
multiple cranial nerve nuclei. As the encephalopathy
progresses, disorientation and delirium take over, and
the patient eventually slips into a coma. Death may
shortly ensue unless the disease is diagnosed and treated
appropriately. These unique clinical findings seen in
pellagra can be simplified in the oft-quoted mnemonic,
“4 D’s”: dermatitis, diarrhea, dementia, and death.
The diagnosis is typically made on clinical grounds,
and laboratory analysis is used for confirmation. One
should always consider other vitamin deficiencies when
evaluating a patient with pellagra. The 24-hour urine
secretion of N-methyl nicotinamide is normally in the
range of 5 to 15 mg/day; in patients with pellagra, it is Degeneration of cells of cerebral cortex Degeneration in spinal cord
less than 1.5 mg/day. Measurement of this metabolite
serves as an easy, noninvasive test to confirm the defi-
ciency of niacin. Serum niacin levels can be measured
directly, although they are not as accurate as the urinary
excretion levels.
Histology: The skin biopsy findings are nonspecific
and show epidermal pallor with a mixed inflammatory
infiltrate that is predominantly composed of lympho-
cytes in a perivascular location. Occasional areas of
inflammatory vesiculation within the epidermis may
be seen.
Pathogenesis: Niacin is an essential vitamin that is
found in many food sources, including whole grain
breads and meats. Patients whose diet is deficient in
niacin are seen in regions of the world where corn is
the main food source. Various levels of niacin deficiency
occur. This disease can also be seen in alcoholics who
do not maintain a balanced diet and receive almost all
their caloric intake from alcoholic products. Patients
who develop pellagra also have a diet deficient in tryp-
tophan. Major sources of tryptophan include eggs and Glossitis and angular cheilitis
milk. Tryptophan is a precursor of niacin and can be Aqueous stool in diarrhea of pellagra are commonly seen in pellagra.
converted to niacin. Niacin is required for the proper
production of nicotinamide adenine dinucleotide
(NAD) and nicotinamide adenine dinucleotide phos-
phate (NADP), important coenzymes for many bio-
chemical reactions. Both molecules are capable of Tryptophan is the precursor for serotonin as well as a coexisting vitamin deficiency should be sought. If
acquiring two electrons and acting as reducing agents niacin, and in this syndrome all tryptophan is shunted possible, a nutritionist should be consulted to advise the
in various reduction-oxidation (redox) reactions. When to make serotonin at the expense of tryptophan. This patient on proper dietary intake. Alcoholics, who can
a deficiency of niacin occurs, many biochemical reac- results in decreased production of niacin and, poten- be deficient in many B vitamins, are often treated with
tions throughout the human body cannot be properly tially, the clinical symptoms of pellagra. multiple B vitamins. Patients with carcinoid syndrome
performed, and the clinical manifestations occur. Treatment: Pellagra rapidly responds to supplemen- need to take supplemental niacin to avoid pellagra
Carcinoid syndrome is a rare cause of pellagra. Car- tation with niacin. Niacin is given orally every 6 hours symptoms, but the goal of therapy is to treat the under-
cinoid is a syndrome of excessive secretion of serotonin. until the patient responds. If a patient does not respond, lying tumor.

THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS 215