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[Doctor Ali]

I'm opening this thread in terms for educational purposes; particular for USMLE Step 1. Everyone is welcome to write, share, comment, and/or give a thought in terms of Medical Education. Again this thread is meant for MEDICAL EDUCATION - NOT meant for thrashing or bashing each. This is for Medical Education Thread and I'm asking to keep it as clean as it suppose to be. When someone wants to start a new topic, it would be a good idea to start with "Did you know?" and from there, start discussing. This is meant to HELP people around for Step 1. All the best!!!!!!

[Doctor Ali]

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DiGeorge Syndrome:

1. T - lymphocyte immunodefiiciency
2. Maldevelopment of 3rd and 4th branchial pouches
3. Deletion of Chromosome 22
4. Absence of Thymic shadow
5. Hypocalcemic tetany from absence of parathyroids
6. Cleft palate
7. Mandibular deformity
8. Low set ears
9. aortic arch abnormalities
10. TOF

[Doctor Ali]

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Studying for STEP 1 could sometimes lead to out of track or in wrong direction. However, here's a video of how to perpare yourself in the right way. Hope this works for everyone.

[Doctor Ali]

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Angina Pectoris

[Doctor Ali]

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Angina Pectoris

[Doctor Ali]

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[Doctor Ali]

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High estrogen levels during pregnancy → stimulate growth of Pituitary → causing Pituitary gland to enlarge and become more vascular.


IF significant HYPOTENSION occurs while the Pituitary is still enlarged → most common cause is postpartum hemorrhage → ischemic necrosis of the Pituitary occurs. Deficiency of multiple Pituitary hormones → Panhypopituitarism → follows this ischemia.


Prolactin deficiency is one of them. Prolactin → responsible for milk secretion from the breast. Prolactin deficiency → leads → failure to lactate.


Ladies and gentlemen, I am talking about Sheehan Syndrome.


Sheehan Syndrome:

1. Postpartum hemorrhage infarction
2. Ischemic necrosis of Pituitary
3. Fatigue
4. Poor lactation
5. Anorexia
6. Loss of pubic and axillary hair
7. Hypothyroidism
8. Hypocortisolism

[Doctor Ali]

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[Doctor Ali]

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[Doctor Ali]

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21 – Hydroxylase → Converts 17 – Hydroxyprogesterone to 11 – Deoxycortisol.

21 – Hydroxylase → Converts Progesterone to 11 – Deoxycorticosterone.

21 – Hydroxylase deficiency:

1. Adrenal gland cannot synthesize cortisol efficiently.

2. Low cortisol levels → stimulate ACTH release from Pituitary.

3. Elevated ACTH levels → increase → production of adrenal androgens → because → accumulating high levels of cortisol precursors → diverted towards → adrenal androgen biosynthetic pathway.

4. Cortisol and aldosterone deficiency → hypotension.

5. Androgen excess → labial fusion and clitoromegaly.





17 – Hydroxylase → Converts Pregnenolone to 17 – Hydroxypregnenolone.

17 – Hydroxylase → Converts Progesterone to 17 – Hydroxyprogesterone.

17 Hydroxylase → Active in adrenal gland and gonads.

17 – Hydroxylase deficiency:

1. ACTH levels → high due to → decreased cortisol production. ACTH stimulating → formation of 11 – Deoxycorticosterone and Corticosterone in adrenals.

2. Result → low renin levels, hypertension, hypokalemia.

3. In females → genitalia → normal at birth. → Have delayed puberty → no production of sex steroid. Hypertensive → excessive production of 11 – Deoxycorticosterone and Corticosterone.

4. Males → undervirilized and hypertensive.






11 – Hydroxylase → Converts 11 – Deoxycorticosterone to Corticosterone.

11 – Hydroxylase → Converts 11 – Deoxycortisol to Cortisol.

11 – Hydroxylase deficiency:

1. Female ambiguous genitalia → increased androgen levels at birth.

2. Production of 11 – Deoxycorticosterone → increased → have mineralocorticoid excess.






20, 22 – Desmolase → Converts Cholesterol to Pregnenolone.

20, 22 – Desmolase deficiency:

1. Formation of all steroids are affected → decreased.

2. Cholesterol/Cholesterol esters accumulates in adrenal glands.






5 – alpha – reductase deficiency → causes ambiguous genitalia in males → due to → defective conversion of Testosterone to Dihydrotestosterone.






Female ambiguous genitalia → virilization

1. 21 – Hydroxylase deficiency

2. 11 – Hydroxylase deficiency






Male ambiguous genitalia → virilization

1. 5 – alpha – reductase deficiency

2. 21 – Hydroxylase deficiency → first few years of life → not in neonatal period.

[Doctor Ali]

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