pediagenosis: Health
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Showing posts with label Health. Show all posts
Showing posts with label Health. Show all posts

Tuesday, June 8, 2021

Resuscitation

Resuscitation

Resuscitation

Figure 1-1 Pediatric and adult airway anatomy.
Figure 1-1 Pediatric and adult airway anatomy.


Cardiopulmonary gency interventi or in respiratory extre PR)  is the series of emergency interventions provided to a person who appears dead or in respiratory extremis, with the goal of restoring vital functions through optimization of cardiac output and tissue oxygen delivery. The two main components are external cardiac massage (chest compressions) and assisted respirations.

Saturday, May 29, 2021

Sideroblastic Anaemia

Sideroblastic Anaemia


Sideroblastic Anaemia
This is a refractory anaemia defined by the presence of many pathological ring sideroblasts in the bone marrow (Fig. 3.14). These are abnormal erythroblasts containing numerous iron granules arranged in a ring or collar around the nucleus instead of the few randomly distributed iron granules seen when normal erythroblasts are stained for iron. There is also usually erythroid hyperplasia with ineffective erythropoiesis. Sideroblastic anaemia is diagnosed when 15% or more of marrow erythroblasts are ring sideroblasts. They can be found at lower numbers in a variety of haematological conditions.

Figure 3.14 Ring sideroblasts with a perinuclear ring of iron granules in sideroblastic anaemia.

Sideroblastic anaemia is classified into different types (Table 3.8) and the common link is a defect in haem synthesis. In the hereditary forms the anaemia is usually characterized by a markedly hypochromic and microcytic blood picture. The most common mutations are in the ALA‐S gene which is on the X chromosome. Pyridoxal‐6‐phosphate is a coenzyme for ALA‐S. Other rare types include an X‐linked disease with spinocerebellar degeneration and ataxia, mitochondrial defects (e.g. Pearson’s syndrome when there is also pancreatic insufficiency), thiamine‐responsive and other autosomal defects. The much more common form is refractory anaemia with ring sideroblasts, which is a subtype of myelodysplasia (see Chapter 16). Acquired reversible forms may be due to alcohol, lead and drugs, e.g. isoniazid.
Lead Poisoning

Lead Poisoning


Lead Poisoning
Haemoglobin synthesis in the developing red cell
Figure 2.7  Haemoglobin synthesis in the developing red cell. The mitochondria are the main sites of protoporphyrin synthesis, iron (Fe) is supplied from circulating transferrin; globin chains are synthesized on ribosomes. δ‐ALA, δ‐aminolaevulinic acid; CoA, coenzyme A.

       Lead inhibits both haem and globin synthesis at a number of points. In addition it interferes with the breakdown of RNA by inhibiting the enzyme pyrimidine 5′ nucleotidase, causing accumulation of denatured RNA in red cells, the RNA giving an appearance called basophilic stippling on the ordinary (Romanowsky) stain (see Fig. 2.17). 
Differential Diagnosis Of Hypochromic

Differential Diagnosis Of Hypochromic


Differential Diagnosis Of Hypochromic
Table 3.7 Laboratory diagnosis of a hypochromic anaemia.


anaemia
Table 3.7 lists the laboratory investigations that may be neces­ sary. The clinical history is particularly important as the source of the haemorrhage leading to iron deficiency or the presence of a chronic disease may be revealed. The country of origin and the family history may suggest a possible diagnosis of thalassaemia or other genetic defect of haemoglobin. Physical examination may also be helpful in determining a site of haemorrhage, features of a chronic inflammatory or malignant disease, koilonychia or, in some haemoglobinopathies, an enlarged spleen or bony deformities.

Friday, November 15, 2019

Anaemia Of Chronic Disorders

Anaemia Of Chronic Disorders


Anaemia Of Chronic Disorders
One of the most common anaemias occurs in patients with a variety of chronic inflammatory and malignant diseases (Table 3.6). The characteristic features are:

1.    Normochromic, normocytic or mildly hypochromic (MCV rarely <75 fL) indices and red cell morphology.
2.    Mild and non‐progressive anaemia (haemoglobin rarely <90 g/L) – the severity being related to the severity of the disease.
3.    Both the serum iron and TIBC are reduced.
4.    The serum ferritin is normal or raised.
5.  Bone marrow storage (reticuloendothelial) iron is normal but erythroblast iron is reduced (Table 3.7).

Tuesday, September 3, 2019

Iron Deficiency

Iron Deficiency


Iron Deficiency
Clinical features
When iron deficiency is developing, the reticuloendothelial stores (haemosiderin and ferritin) become completely depleted before anaemia occurs (Fig. 3.6). As the condition develops, the patient may show the general symptoms and signs of anaemia (see p. 20) and also a painless glossitis, angular stomatitis, brittle, ridged or spoon nails (koilonychia) (Fig. 3.7) and unusual dietary cravings (pica). The cause of the epithelial cell changes is not clear but may be related to reduction of iron‐containing enzymes. In children, iron deficiency is particularly significant as it can cause irritability, poor cognitive function and a decline in psychomotor development. There is also evidence that oral or parenteral iron may reduce fatigue in iron‐deficient (low serum ferritin) non‐anaemic women.

Thursday, August 22, 2019

Neural Plasticity And Neurotrophic Factors I: The Peripheral Nervous System

Neural Plasticity And Neurotrophic Factors I: The Peripheral Nervous System


Neural Plasticity And Neurotrophic Factors I: The Peripheral Nervous System
The peripheral nervous system (PNS) is capable of significant repair, to some extent independent of the age at which damage occurs. In contrast, the central nervous system (CNS) has always been thought of as being unable to repair itself, although there is now mounting evidence for considerable plasticity within it even in the adult state and that most, if not all areas of the CNS, are capable of some degree of reorganization (see Chapter 49).
Emotion, Motivation And Drug Addiction

Emotion, Motivation And Drug Addiction


Emotion, Motivation And Drug Addiction
Emotion
Initial attempts to understand the brain bases of emotions focused on the limbic system (see Chapter 45), with the amygdala as the key component in the system thought to be central to emotional processing. The evidence to support such an association has already been discussed in part (in Chapter 45), but it is also worth mentioning the Klüver–Bucy syndrome. This condition is seen with bilateral amygdala damage and is characterized by, among other phenomena, an apparent absence of the normal fear response and by marked placidity.

Wednesday, August 7, 2019

Oogenesis

Oogenesis


Oogenesis
Time period: week 12 to menopause
Overview
Female germ cells proliferate by mitosis in the ovaries to form a large number of oogonia. These cells are diploid, contain two X sex chromosomes, and will become haploid mature oocytes via the process of oogenesis. This process is similar to spermatogene- sis but has some significant differences.
The germ cells that will form the female gametes (oocytes) are derived from germ cells that migrate from the yolk sac into the site of early gonad formation (see Chapter 38).
Spermatogenesis

Spermatogenesis


Spermatogenesis
Time period: puberty to death
Meiosis continued
In the last chapter we talked about the importance of meiosis in sexual reproduction and diversity, and saw how haploid cells are formed. In males, meiosis occurs during spermatogenesis, in which spermatogonia in the testes become spermatozoa.
The germ cells that will form the male gametes (spermatozoa) are derived from germ cells that migrate from the yolk sac into the site of early gonad formation (see Chapter 38).
Meiosis

Meiosis


Meiosis
Time period: day 0 to adult
Diversity
Cell division by mitosis gives no opportunity for change or diversity, which is ideal for processes like growth and repair. In humans, sex- ual reproduction allows random mingling of maternal and paternal DNA to produce a new, unique individual. This is able to occur because of a different type of cell division called meiosis.

Sunday, August 4, 2019

Lung Cancer

Lung Cancer


Lung Cancer
More people die in the USA and Europe from lung cancer than from breast, prostate and colon cancer combined. Furthermore, the number of cases is likely to increase in the next 25 years due to continued use of cigarettes, particularly in women. Lung cancer has a worse prognosis than other common cancers, with an overall 5-year survival of 13%.
The Immunocompromised Host

The Immunocompromised Host


The Immunocompromised Host
The immune system is most frequently impaired after chemotherapy and in patients with human immunodeficien y virus (HIV) infection. Immunodeficien y also occurs in patients with malignancies of the lym- phoproliferative system (e.g. leukaemia), immediately following bone marrow transplants (BMT) and in those on immunosuppressive drugs (e.g. steroids and azothioprine) particularly after transplant surgery (e.g. renal). Malnutrition or chronic illness (e.g. diabetes) may also impair immunity. Respiratory disease is particularly common in the immunocompromised host.

Friday, July 26, 2019

Memory

Memory


Memory
The term memory is commonly used to refer to the ability to remember information but it is important to understand that there are several different types of memory that subserve different functions. In the first instance, there is a distinction between motor and non-motor memories – the former is a form of implicit memory and typically involves the cerebellum, motor cortical areas and basal ganglia (see Chapters 38–42) and will not be discussed further in this chapter. The other forms of memory are more involved with the taking in, manipulating and storing of information for problem solving (working memory), events and factual knowledge (explicit memory).
Limbic System And Long-Term Potentiation

Limbic System And Long-Term Potentiation


Limbic System And Long-Term Potentiation
Anatomy of the limbic system
Many different definitions of the limbic system exist, and in this chapter we will be restricting our definition to structures that lie primarily along the medial aspect of the temporal lobe: cingulate gyrus, parahippocampal structures (postsubiculum, parasubiculum, presubiculum and perirhinal cortex), entorhinal cortex, hippocampal complex (dentate gyrus, CA1–CA4 subfields and subiculum), septal nuclei and the amygdala. Additional structures closely associated with the limbic system include the mammillary bodies of the hypothalamus, the olfactory cortex and the nucleus accumbens (see Chapters 11, 30, 42 and 47, respectively).
Consciousness And Theory Of Mind

Consciousness And Theory Of Mind


Consciousness And Theory Of Mind
In this chapter we discuss what is meant by consciousness, and how this can be altered in certain pathological conditions. This ability to be aware of what we are doing, namely consciousness, is then discussed further in terms of how we can understand the thought processes of others, so-called theory of mind, disorders of which may underlie a range of conditions, especially autism.

Tuesday, July 16, 2019

Male Reproduction Pathophysiology

Male Reproduction Pathophysiology


Male Reproduction Pathophysiology
Clinical background
Male infertility has a large number of causes, both endocrine and non-endocrine in origin and few are specifically treatable. In the majority of cases an exact diagnosis is not reached despite investigation and the condition may result from previous testicular damage, varicocoele or non-specific inflammation. All patients should be assessed with their partner in a specialist fertility unit and in the undiagnosed group the use of intracytoplasmic sperm injection may offer the best chance of fertility. The clinical features of male infertility are shown in Table 33.1.
Male Reproduction Actions of Androgens

Male Reproduction Actions of Androgens


Male Reproduction Actions of Androgens
Clinical scenario
Effects of the failure of androgen action may be best seen in patients with hypogonadotrophic hypogonadism (Fig. 32a). This is caused by a failure of hypothalamic GnRH secretion or by pituitary disease resulting in impaired gonadotrophin release and hence low androgen concentrations (Table 32.1). The clinical features of hypogonadotrophic hypogonadism depend on the timing of its onset, such that males developing the condition after puberty present with features of secondary testicular failure (poor libido, loss of secondary sexual characteristics and subfertility). Prior to puberty, boys present with delayed or failed puberty or, less commonly, the condition presents in the neonatal period with cryptorchidism and micropenis Idiopathic hypogonadotrophic hypogonadism describes those patients in whom there are no anatomical abnormalities of the hypothalamus and pituitary and no associated endocrine disorders.
Male Reproduction The Testis

Male Reproduction The Testis


Male Reproduction The Testis
Clinical background
Normal fertility in the male is produced by a complex interac- tion between genetic, autocrine, paracrine and endocrine function. The endocrine control of reproductive function in the male depends upon an intact hypothalamo–pituitary–testicular axis. The testis has a dual role – the production of spermatozoa and the synthesis and secretion of testosterone needed for the development and maintenance of secondary sexual characteristics and essential for maintaining spermatogenesis. These functions in turn depend upon the pituitary gonadotrophin hormones: luteinizing hormone (LH; required to stimulate testicular Leydig cells to produce testosterone); and follicle stimulating hormone (FSH; required for the development of the immature testis and a possible role in adult spermatogenesis). Gonadotrophin production occurs in response to stimulation by hypothalamic GnRH. Testosterone exerts a negative feedback on the secretion of LH and FSH and the hormone inhibin-β, also synthesized by the testis, has a specific regulatory role for FSH. Thus in primary seminiferous tubular failure, low testosterone concentrations are associated with elevated gonadotrophins whereas in the presence of hypothalamic pituitary disease the gonadotrophin concentrations are low (secondary testicular failure).
Female Reproduction Contraception

Female Reproduction Contraception


Female Reproduction Contraception
Clinical background
There are many oral contraceptive preparations on the market and a choice should be made to prescribe the one with the lowest estrogen and progesterone concentrations that give good cycle control. Combined oral contraceptives (COCs) can also be used to treat a number of gynaecological conditions involving irregular cycles, menorrhagia or dysmenorrhoea. In addition to progesterone only pills (POPs), intrauterine devices which release progesterone locally to the endometrium are available (Mirena Intrauterine Systems, Schering Health) and are used both for contraception and for the treatment of endometriosis and other painful disorders of menstruation.

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