Which of the following statements is true regarding X-linked recessive inheritance?
Correct Answer A:
X-linked recessive:
In X-linked recessive inheritance only males are affected. An exception to this seen in examinations are patients with Turner's syndrome, who are affected due to only having one X chromosome. X linked recessive disorders are transmitted by heterozygote females (carriers) and male-to-male transmission is not seen. Affected males can only have unaffected sons and carrier daughters.
Each male child of a heterozygous female carrier has a 50% chance of being affected whilst each female child of a heterozygous female carrier has a 50% chance of being a carrier.
The possibility of an affected father having children with a heterozygous female carrier is generally speaking extremely rare. However, in certain Afro-Caribbean communities G6PD deficiency is relatively common and homozygous females with clinical manifestations of the enzyme defect are seen.
A 61-year-old female who has recently emigrated from the Indian subcontinent presents with muscle weakness. Bloods reveal a low serum calcium. A diagnosis of osteomalacia is suspected.
Which one of the following, per average serving, provides the best source of vitamin D?
Correct Answer D:
Cod liver oil provides around 1,300 IU per 15 ml serving.
Vitamin deficiency:
The table below summarises vitamin deficiency states:
You are asked for advice from a local GP.
He has received the following blood results for one of his patients, a 50-year-old non-smoker:
Which one of his medications is most likely to explain this result?
Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH) - drug causes: carbamazepine, sulfonylureas, SSRIs, tricyclics.
SIADH: causes: Malignancy:
Neurological:
Infections:
Drugs:
Other causes:
Which one of the following cell types secretes the majority of pulmonary surfactant?
Pulmonary surfactant:
Surfactant is a mixture of phospholipids, carbohydrates and proteins released by type 2 pneumocytes. The main functioning component is dipalmitoyl phosphatidylcholine (DPPC) which reduces alveolar surface tension.
Basics:
Which one of the following statements concerning altitude related disorders is true?
Altitude related disorders:
There are three main types of altitude related disorders: acute mountain sickness (AMS), which may progress to high altitude pulmonary edema (HAPE) or high altitude cerebral edema (HACE). All three conditions are due to the chronic hypobaric hypoxia which develops at high altitudes Acute mountain sickness is generally a self-limiting condition.
Features of AMS start to occur above 2,500 - 3,000m, developing gradually over 6-12 hours and potentially last a number of days:
Prevention and treatment of AMS:
minority of people above 4,000m go onto develop high altitude pulmonary oedema (HAPE) or high altitude cerebral oedema (HACE), potentially fatal conditions:
Management of HACE:
Management of HAPE:
*Tthe relative merits of these different treatments has only been studied in small trials. All seem to work by reducing systolic pulmonary artery pressure.
Click to expand