18. HIV + NUTRITION Flashcards
pathogenesis of HIV
virus with gp41 and gp120
gp120 binds to CD4
gp41 penetrates membrane
viral genome into host
3 phases of HIV infection
acute
chronic
crisis aids
Acute retroviral syndrome primary infection
Infection of CD4+ T cells
Viremia => body wide seeding of
lymphoid tissue, ↓CD4 count
40-90% develop flu like symptoms
Fevers, chills, night sweats & rashes, lymphadenopathy, diarrhea & vomiting 3-6wks after infection & resolve 2-4 wks later spontaneously
No symptoms may be present
Activation of CD8+ T cells
↓↓ viral load, ↑ CD4 count (800)
Seroconversion
Antibody production 3-7wks
Clinical latency
Asymptomatic period “clinical latency”, 2-15yrs or more
Continuous HIV replication and cell destruction in spleen and lymph nodes
Co-receptor switch to CXCR4
Gradual decreased in function and no. of CD4 T cells
Persistent generalized lymphadenopathy (PGL)
Minor opportunistic infections
Oral or vaginal candidiasis, herpes zoster and TB
persistent generalized lymphadenopathy (PGL)
Presence of lymph nodes >1 cm at 2 or more extrainguinal sites for > 3 months
AIDS (final crisis phase)
Breakdown of host defense
Dramatic ↑↑ in plasma viral load & life threatening disease
Fever (>1month), fatigue, wt. loss & diarrhea
AIDS indicator (defining) diseases emerge
Serious opportunistic infections
Secondary neoplasms e.g. Kaposi’s sarcoma, Non Hodgkin’s lymphoma, cervical cancer
Clinical neurological disease
opportunistic infection
protozoal
fungal
bacterial myco avium
viral
Pneumocystis pneumonia (PCP)
= Pneumocystis jirovecii pneumonia (PJP)
Caused by the yeast-like fungus Pneumocystis jirovecii.
Typically dry/non-productive cough because sputum becomes too viscous to be coughed up.
PaO2 is strikingly lower than would be expected from symptoms.
progressive multifocal leukoencephalopathy
by jc virus polioma
infect oligodendrocytes
shown by luxol fast blue stain
AIDS-Defining Neoplasms
kaposi sarcoma
primary lymphoma of brain
invasive cancer of uterus
kaposi sarcoma
by HHV 8
purple redish macules plaques and nodules
4 types of kaposi sarcoma
classic
endemic
immunosuppresed
epidemic/AIDS
Squamous cell carcinoma of uterus
by HPV
16 18 31 33
Pathogenesis of Central Nervous System Involvement
HIV predominantly infect microglia
Imported by infected T cells or monocytes
Mechanism of HIV-induced damage of the brain is idiopathic
Neurologic deficit (»neuropathologic changes ) is caused indirectly by viral products and by soluble factors produced by infected microglia(IL-1, TNF, and IL-6). gp41 induced nitric oxide and Direct damage of neurons by soluble HIV gp120
Protein energy malnutrition(PEM)
= severe malnutrition
Inadequate consumption of protein and/or energy resulting in a range of clinical syndromes
Marasmus
Caused primarily by severe reduction in caloric intake
Results in > 60% reduction in body weight adjusted for height and sex
Child suffers growth retardation and loss of muscle (catabolism)
Loss of somatic protein compartment»_space;> visceral protein compartment
Albumin levels either normal or only slightly reduced
Extremities are emaciated, head appears to be too large for the body
Anemia, multivitamin and T cell mediated immuno deficiency
Kwashiorkor
Protein deficiency with adequate calorie intake
Severe than marasmus
Severe loss of the visceral protein compartment with relative sparing of subcutaneous fat and muscle mass
Hypoalbuminemia generalized edema
Weight of affected children is 60 to 80% of normal (i.e true loss of weight is masked by the edema)
Hepatomegaly with fatty liver
predisposing factors for kwashiorker
Early weaning, exclusive carbohydrate diet are predisposing factors
Physiologic Function of Vit. A
Maintains normal vision
Potentiate differentiation of specialized cells
Enhance immunity against infection
Photoprotective and Antioxidant
Manifestations of vitamin A deficiency
Poor vision (night blindness)
earliest symptom of deficiency
Xerophthalmia
Dry conjunctivae, Bitot’s spot, corneal erosion and Keratomalasia
Lithiasis: eg. Urinary tracts and Kidney
Respiratory epithelium squamous metaplasia
Skin: Follicular hyerplasia and Hyperkeratosis follicular or papular dermatosis.
Immune deficiency: eg complicated measles and Diarheal diseases
metabolism of vitamin d
chole calciferol
25 hydroxycholecalciferol
1, 25 dihydroxycholecalciferol
Physiologic function of Vit. D
Maintains Ca and P level at supersaturate level
Helping mineralization of bone
Stimulates intestinal absorpition of calcium and phosphorus
Collaborates with PTH in the mobilization of Ca from bone
Stimulates the PTH dependant reabsorption of Ca in the distal renal tubule
Physiologic Function
vit c
Synthesis and stability of proteins (collagens-hydroxylation of proline and lysine)
Facilitates Iron absorption
Antioxidant
