Question

15. What leads to anorexia and cachexia of body wasting in a patient with end-stage cancer or severe illness? 16. What are the therapeutic (mechanism of action) and adverse effects of chemotherapy and radiation? 17. What occurs in each stage of the cell cycle? What mechanisms prevent cancer from occurring most of the time? 18. What are the laboratory consequence of cancer treatments and medications? What interventions are given to treat them?

Answer 1

15.# Anorexia - pathogenesis and presentation in advanced illness.

may be related to underlying and /or concurrent disease, the effect of various treatments, and/or psychological and emotional response to adv. illness

Other potential etiologies include:

Systemic Infections

Infections of mouth, pharynx, and/or esophagus

Metabolic abnormalities

GI Disorders ( delayed gastric emptying, diarrhea, constipation, chronic N/V)

Medications and anti-neoplastic therapies

Limited chewing or swallowing conditions ie xerostomia, trismus, poor dentition)

Psychological symptoms ie anxiety, depression, spiritual or existential distress)

#. Cachexia - pathogenesis and presentation in advanced illness.

Not fully understood mechanism - current focus is on variable combinations of reduced food intake and abnormal metabolism.

* chronic inflammation thought to be related to cytokine production induced by underlying disease

* Other complex metabolic and neuro-hormonal imbalances and differences that may vary depending on underlying disease, causing unique manifestations of cachexia in each condition.

Decreased intake and abnormal metabolism lead to a negative protein and energy balance - catabolic rather than anabolic state.

16. Mechanism of action of chemotherapy :

Alkylating Agents Form highly reactive carbonium ion Transfer alkyl groups to nucleophilic sites on DNA bases Results in Cross linkage Abnormal base pairing DNA strand breakage Alkylation also damages RNA and proteins I cell proliferation

Mechanism of action of radiation therapy :

Radiatior. < a Direct action Indirect action Free radicals DNA damage DNA damage DNA damage xos.cox xocok Double strand breaks Single strand break

#. Adverse effects of chemotherapy and radiation therapy :-

- bone marrow suppression

- neutropenia

- fever

- anemia

- thrombocytopenia

- nausea and vomiting

- mucositis

- anorexia

- alopecia

- skin pigmentation

17. Stages of cell cycle :-

Interphase :

The cell grows to its mature size, makes a copy of its DNA, and prepares to divide into two cells. Centrioles are also copied.

Prophase :

Chromatin in the nucleus condenses to form chromosomes. Spindle Fibers form a bridge between the ends of the cell.

Metaphase :

The chromosomes line up across the center of the cell. Each chromosome attaches to a spindle fiber at its centromere.

Anaphase :

The centromeres split. The two chromatids separate. One chromatid is drawn by its spindle fiber to one end of the cell. The other chromatid moves to the opposite end. The cell stretches out as the opposite ends are pushed apart.

Telophase :

The chromosomes begin to stretch out and lose their rodlike appearance. A new nuclear envelope forms around each region of chromosomes.

Cytokinesis :

The cell membrane pinches in around the middle of the cell. The cell splits in two. Each daughter cell ends up with an identical set of chromosomes and about half the organelles.

#. DNA repair mechanism and mechanisms that cause cell death preventa cancer from occurring most of the time.

18. Laboratory consequences of chemotherapy are :-

- low Hb

- low platelets

- high bilirubin

- low WBC

- low ANC

- increased urea and creatinine

- increased or decreased potassium

Interventions :-

Blood and platelets transfusion

Medications for decreasing bilirubin

Potassium by intravenous route for low and potassium binders for high

Administration of GSCF for low counts