Chem Path Flashcards
Difference between osmolality and osmolarity
Osmolality –> more accurate and based on mass of solvent
osmolarity –> more practical and based on volume of solvent
Calculated osmolality equation, what is normaly/abnorml?
2(Na+K) + glucose + urea
NOTE: Normal osmolality is between 275-295. If measured osmolality – calculated osmolality >10, it means there is other substances in the blood that aren’t part of the equation.
- HHS (Hyperosmolar Non-ketotic Coma – HONC) (highest glucose osmolality) - glucose in T2DM, Dx criteria = osmolality >320 ++profound dehydration
- DKA - glucose in T1DM + dehydration
- DI - either no ADH production (cranial) or collecting duct cells insensitive to ADH (nephrogenic), so less H2O reabsorption
- Pneumonia - can result in SIADH, but not all cases
- SIADH - ADH causes excess H2O reabsorption, so would expect serum osmolality <270, hyponatraemia
If both blood volume and osmolality low, which needs to be fixed first? When might this situation arise?
Fix blood volume first, may occur if patient has hypovolaemia due to haemorrhage
NOTE: Low volume –> increased ADH release, but low volume typically suppresses ADH release
Pseudohyponatraemia
Low sodium with normal/high plasma osmolality
Caused by myeloma/lab machine errorr and glucose respectively
MOST IMPORTANT THING TO ASSESS IF BOTH SODIUM AND OSMOLALITY ARE LOW
FLUID STATUS
Hypovolaemic hyponatraemia, how to differentiate between causes, how to manage?
How does urinary sodium differentiate between causes of hyponatraemia?
<20 - extra renal loss
>20 renal loss
Why not to correct hyponatraemia quickly?
central pontine myelinolysis (CPM) is a neurological disorder that most frequently occurs after too rapid medical correction of sodium deficiency (hyponatremia)
Hypervolaemic hyponatraemia, how to differentiate between causes, how to manage?
What medication can be used in hypervolaemic hyponatraemia if fluid restriction doesn’t work?
- DEMOCLOCYCLINE –> REDUCES RESPONSIVENESS OF COLLECTING DUCT TO ADH
- TOLVAPTAN –> V2 ANTAGONIST
Euvolaemic hyponatraemia, how to differentiate between causes, how to manage?
Management of SIADH if resistant
Demeclocycline: REDUCES RESPONSIVENESS OF COLLECTING DUCT TO ADH
Vaptans: V2 ANTAGONIST
Causes of SIADH
BRAIN (CRANIOPHARYNGOMA)
LUNG (PNEUMONIA, SMALL CELL LUNG CANCER - PARANEOPLASTIC)
DRUGS (SSRI, TCA, CARBAMEZAPINE, OPIODS, DOPAMINE ANTAGONISTS)
Osmolality levels in hypernatraemia
High
Investigations that need to be sent for euvolaemic hyponatraemia and respective results
Plasma sodium - low
Plasma Osmolality - low
Urinary sodium - high
Urinary osmolality - high
NOTE: Diagnosis of exclusion - need to check TFTs and cortisol first
Causes of hypernatraemia split by fluid status, and management
Causes of Arginine Vasopressin Insufficiency/resistance
CRANIAL DI –> ARGININE VASOPRESSIN INSUFFICIENNCY
NEPHROGENIC DI –> ARGININE VASOPRESSIN RESISTANCE
Diagnostic criteria for diabetes insipidus
NOTE: NEED TO EXCLUDE OTHER CONDITIONS, BEFORE REACHING THIS DIAGNOSIS. Serum glucose, potassium & calcium, plasma & urine osmolality BEFORE WATER DEPRIVATION TEST WHICH IS DIAGNOSTIC.
Blood and urine findings that suggest diabetes
- URINE OSMOLALITY: PLASMA OSMOLALITY RATIO <2
o DIABETES INSIPIDUS EXCLUDED IF URINE:PLASMA OSMOLALITY >2 - URINE VERY DILUTE DESPITE CONCENTRATED PLASMA
Management of diabetes insipidus
- CRANIAL –> DESMOPRESSION (selective agonist of V2 receptors – mimics action of endogenous ADH)
- NEPHROGENIC –> THIAZIDE DIURETICS
Give some causes of hypokalaemia due to renal loss
o XS CORTISOL AND ALDOSTERONE (COULD BE CONN’S OR CUSHING’S)
o LOOP DIURETICS AND THIAZIDES
o T1 AND T2 RENAL TUBULAR ACIDOSIS (ACID AND POTASSIUM LOW)
–> TYPE 1 ASSOCIATED WITH WILSONS
–> TYPE 4 CAUSES ACIDOSIS BUT POTASSIUM HIGH
o BARTER SYNDROME
o GIELTMAN SYNDROME
Difference between Barter and Gieltman syndrome and where they affect
- BOTH CAUSE HYPOKALAEMIA
- BARTER –> LOOP OF HENLE TRIPLE TRANSPORTER
- GIELTMAN –> DCT
NOTE: Both are autosomal recessive conditions with salt wasting, hypokalaemia, and metabolic alkalosis. Bartter has hypercalciuria and normal serum magnesium. Gitelman has low urinary calcium and low serum magnesium.
What does potassium do in comparison to Hydrogen?
Potassium goes hand in hand with Hydrogen, so if low potassium, low Hydrogen too so metabolic alkalosis –> low hydrogen concentration = high pH
What drugs can cause hypokalaemia?
Insulin + salbutamol
Management of hypokalaemia
- 3-3.5:
o ORAL POTASSIUM CHLORIDE TABLES (2 SANDOK TABLETS)
o RECHECK LEVELS - <3:
o IV KCL (MAX 10 MINS) IRRITANT TO VEINS
Drugs that can cause hyperkalaemia
o ACEi
o ARBs
o SPIRONOLACTONE (K+ sparing diuretics)
o NSAIDs
Causes of hyperkalaemia due to low aldosterone
o T4 RENAL TUBULAR ACIDOSIS (low pH but high K+)
o ADDISONS
Management of hyperkalaemia
NOTE: Treat if ECG changes or K+>6.5
- 10ML 10% CALCIUM GLUCONATE FOR 10 MINS
- 50ML 50% DEXTROSE WITH 10 UNITS OF INSULIN
- NEBULISED SALBUTAMOL
- TREAT CAUSE
Actions of PTH
- INCREASING CALCIUM REABSORPTION IN THE KIDNEY
- INCREASING TUBULAR HYDROXYLATION OF VIT D
- MOBILISING CALCIUM FROM BONE
NOTE: PTH affects phosphate by INCREASING EXCRETION OF PHOSPHATE IN THE KIDNEY
Signs + Sx of hypocalcaemia
(THINK CATs go NUMB)
- CHVOSTEK SIGN – tap cheek, twitching on ipsilateral side of the face
- TROUSSEEAU SIGN – carpopedal spasm induced by inflated BP cuff
- Convulsions
- Arrhythmia –> PROLONGED QT SEEN ON ECG
- Tetany
- Paraesthesia
What is Pseudohypoparathyroidism? What is it due to? How does it present? AKA? What is pseudopseudohypoparathyroidism?
Pseudohypoparathyroidism results from an inherited resistance to PTH. They have short 4th and 5th metacarpals, obesity and rounded facies. This syndrome is now known as Albright hereditary osteodystrophy. Pseudopseudohypoparathyroidism presents with the phenotypic appearances of Albright hereditary osteodystrophy but with normal biochemical findings and without resistance to parathyroid hormone (PTH).
Causes of secondary hyperparathyroidisim
CKD and VIt D Deficiency
Cause of tertiary hyperparathyroidism, blood findings?
PROLONGED SECONDARY HYPERPARATHYROIDISM (FROM DIALYSIS) AND RENAL TRANSPLANTS
Blood findings:
- HIGH CALCIUM
- HIGH PTH
- HIGH PHOSPHATE
Fatal complication of hypocalcaemia
Laryngospasm is a fatal complication of hypocalcaemia, hoarse voice & inability to swallow. Often occurs post-thyroidectomy as a complication.
Management of hypocalcaemia
Mild - >1.9mmol/L w/no Sx - oral Calcium, vit D supplement
Severe - <1.9mmol/L w/Sx present - IV calcium gluconate
What should PTH level be in hypercalcaemia?
0
Questions to ask if hypercalcaemia?
- Is it an anomaly? Repeat Test
- CHECK PTH:
o IF SUPPRESSED –> MOST LIKELY CANCER, THEN SARCOID ETC
o IF HIGH –> HYPERPARATHYROIDISM
Causes of hypercalcaemia, most common cause?
- HYPERPARATHYROIDISM –> MOST COMMON IN YOUNG, HEALTHY AND COMMUNITY
- CANCER –> MOST COMMON IN OLD AND ILL, IN SECONDARY CARE
MOST COMMON CAUSE OF HYPERCALCAEMIA IS PRIMARY HYPERPARATHYROIDISM
Causes of primary hyperparathyroidism in order of likelihood
- SINGLE ADENOMA
- HYPERPLASIA
- MULTIPLE ADENOMAS ASSOCIATED WITH MEN1
What fracture can primary hyperparathyroidism lead to? How does this occur?
NB: PRIMARY HYPERPARATHYROIDISM MOST COMMONLY AFFFECTS THE WRIST –> GET COLLES FRACTURE
NBB: COLLES FRACTURE –> FALL WITH HANDS OUT ON EXTENSORS, SMITHS –> FALL ON FLEXORS OF HANDS
Sign of hypercalcaemia on examination
SEE BAND KERATOPATHY (CORNEAL DEGENERATION) ON EXAMINATION
What to suspect if raised PTH with hypercalcaemia?
Suspect Men1 and 2a if primary, differentiate from tertiary by end stage CKD
Types of malignant hypercalcaemia
- PTHrP FROM SMALL CELL LUNG CANCER
- BONE METASTASES
- HAEMATOLOGICAL MALIGNANCY (E.G. MYELOMA)
Management of hypercalcaemia
What is Browns Tumour? What do you get? On histology?
Browns Tumour - Aggregations of osteoclasts caused by hyperparathyroidism. Causes hypercalcaemia. ON HISTOLOGY MULTINUCLEATE GIANT CELLS
What is familial hypocalcuric/benign hypercalcaemia? What’s the mutation?
Mutation in calcium sensing receptor –> don’t excrete PTH as early as should –> mild hypercalcaemia
Vit D synthesis process
- In the skin 7 dehydrocholesterol is converted to cholecalciferol (Vitamin D3)
- Liver converts to 25 hydroxycholecalciferol
- Kidney converts to 1,25-dihydroxycalciferol (calcitriol
Corrected calcium equation
CORRECTED CALCIUM = SERUM CALCIUM+0.02*(40-SERUM ALBUMIN)
What else can cause hypercalcaemia beside cancer?
- Sarcoidosis (non-renal 1α hydroxylation)
- Thyrotoxicosis (thyroxine -> bone resorption)
- Hypoadrenalism (renal Ca2+ transport)
- Thiazide diuretics (renal Ca2+ transport)
- Excess vitamin D (eg sunbeds…)
Blood findings of vit D deficiency
- LOW CALCIUM AND PHOSPHATE
- LOW VIT D
- RAISED PTH AND ALP
o GET HIGH ALP BECAUSE PTH GETS RAISED WHICH CAUSES IN EXCESS BONE RESORPTION
What deformity can be seen in colles fracture?
Dinner fork deformity
Classic fractures seen in osteoporosis
Colles fracture
Neck of femur
Vertebra
Osteoporosis diagnosis
- DEXA SCAN OF WRIST, LUMBAR SPINE AND NOF
- T SCORE LESS THAN -2.5
o Osteopenia between -1 and -2.5
Difference between T score and Z score
T score - healthy person comparison
Z score - age matched control
Medications that can be used for osteoporosis
o VIT D
o ALENDRONIC ACID (BISPHOSPHONATE) –> SE: GASTRIC IRRITATION –> LOW COMPLIANCE
o PTH ANALOGOUE (E.G. TERIPARATIDE)
o OESTROGEN
o SELECTIVE OESTROGEN RECEPTOR MODULATOR (SERM) E.G. RALOXIFENE
MUST LEARN TABLE FOR CALCIUM
- Osteomalacia – Vitamin D very low need for calcium absorption, calcium will fall the most
- 2° PTH – raised PTH 2° to low Ca (short term) (usually in chronic kidney disease, unable to retain Ca)
- Osteoporosis – calcium normal
- 1° PTH - mainly due to parathyroid adenoma/hyperplasia, PTH secretion less than carcinoma
- Parathyroid carcinoma – highest PTH - autonomous release of Ca2+ (lack of -ve feedback)
Commonest cancers that can metastasise to the bone
PB KTL (PROSTATE, BREAST, KIDNEY, THYROID, LUNG) are most common cancer to metastasise to bone
How is H+ buffered in ECF/ICF/RBCs?
Extracellular fluid (e.g. kidney) –> H+ buffered by Bicarb
Intracellular fluid –> H+ buffered by phosphate
In RBCs –> H+ buffered by Hb
Difference between types of RTA (just read)
NOTE: T1/2 are hypokalaemia, T4 is HYPERkalaemia
What is fanconi syndrome? How does it present? Management?
Fanconi syndrome is when there is complete failure of proximal convoluted tubule in kidney to reabsorb molevules –> can be inherited or acquired.
Will present with polyuria, polydipsia and dehydration, failure to thrive, hypokalaemia, T2 RTA, protein and glycosuria, hypokalaemia
supportive treatment.
Causes of metabolic acidosis
- INCREASED H+ PRODUCTION –> DKA, LACTATE, ASPIRIN OD, METFORMIN, UREA
- DECREASED H+ EXCRETION –> RENAL TUBULAR ACIDOSIS (RENAL FAILURE), ADDISON’S (RETENTION OF K+ AND H+)
- LOSS OF BICARB –> INTESTINAL FISTULA (E.G. PANCREATIC), HIGH OUTPUT STOMA, DIARRHOEA
Approach to diagnosis a metabolic acidosis (LEARN)
NOTE: IN METABOLIC ACIDOSIS LUNGS HYPERVENTILE TO SHIFT EQUATION
SEE A DROP IN CO2 WITH A COMPENSATED H+ IN COMPENSATED METABOLIC ACIDOSIS
Equation for anion gap
(Na + K) - (Cl + HCO3) –> normal is 14-18
Table showing metabolic acidosis
Causes of metabolic alkalosis
- INCREASED H+ EXCRETION (E.G. VOMITING – pyloric stenosis)
- POTAASSIUM EXCRETION (HYPOKALAEMIA, LOOP DIURETICS, CONN’S)
o Causes alkalosis as to retain potassium the kidney retains more soidum at expense of H+ - BICARB INGESTION
NOTE: Compensation for by hypoventilation
Table showing metabolic alkalosis
Difference between type 1 and type 2 respiratory failure
T1RF = low O2, normal CO2
T2RF = low O2, high CO2
Cause of respiratory alkalosis
- HYPERVENTILATION –> PANIC ATTACK, SALICYCYLATE OD –> STIMULATE BRAINSTEM EARLY
What blood gas results does aspirin OD present with?
GET MIXED RESPIRATORY ALKALOSIS AND METABOLIC ACIDOSIS –> RESP ALKALOSIS AS STIMULATES RESP CENTRE –> BUT THEN GET INCREASED EXCRETION OF BICARB –> METABOLIC ACID
Best marker of liver function
Prothrombin time
Liver enzyme abbreviations and what they stand for
AST/ALT: HEPATITIS
GGT: ALCOHOLIC HEPATITIS
ALP: OBSTRUCTIVE CAUSE
AST –> ASPARTATE TRANSAMINASE
ALT –> ALANINE AMINOTRANSFERASE
ALP –> ALKALINE PHOSPHATASE
GGT –> GAMMA GUTAMYL TRANSFERASE
Where is ALP found?
Liver
Bone
Placenta
Where else is AST present?
Heart
Specific blood test result for alcoholic liver disease
AST:ALT >2
ALT in the 1000s
viral hepatitis
Difference between prehepatic/hepatic/post hepatic jaundice and how they present
Prehepatic: No urine bilirubin because unconjugated BR (from haem break down by MØ in spleen) is tightly bound to albumin, unable to pass through glomerulus
Post-hepatic: Dark urine seen due to increase urobilinogen/conjugated BR (lots of them absorbed by blood), pale stool = low levels of stercobilinogen + dark urine
What does the type of bilirubin tell you about where the liver issue is?
NB: CONJUGATION OF BILIRUBIN OCCURS IN THE LIVER. SO UNCONJUGATED BILIRUBIN IS A PRE-HEPATIC ISSUE, CONJUGATED IS POST-HEPATIC. A MIXTURE IS INTRA-HEPATIC.
How to differentiate between Rotor syndrome and dubin-johnson? (Both causes of conjugated bilirubinaemia)
Rotor syndrome can be differentiated from other similar disorders, such as Dubin–Johnson syndrome. For instance, the liver has black pigmentation in Dubin–Johnson syndrome, while in Rotor syndrome liver has normal histology and appearance.
How to differentiate between gilbert and crigler-Najjar syndrome? (Both causes of unconjugated bilirubinaemia)
Gilbert’s - deficiency of UDP glucuronyl transferase
Crigler-Najjar syndrome - absolute syndrome
Table showing deranged LFTs and how to interpret
What to check if a patient has raised ALP?
Check GGT to ensure it is a biliary bilirubin
Which cell in thyroid gland prouces calcitonin?
Parafollicular cells
What does thyroperoxidase enzyme do?
responsible for oxygenation and iodination
How do T4/T3 work?
T4 is the primary hormone secreted from the thyroid however T3 is the primary ACTIVE hormone, and end organ tissues convert T4 to T3.
These feedback onto the pituitary and hypothalamus to inhibit further TSH release.
Causes of hypothyroidism
- IODINE DEFICIENCY (MOST COMMON WORLDWIDE)
- HASHIMITOS (ANTI-THYROIDPEROXIDASE ANTIBODIES – TPO)
o MOST COMMON IN UK - DRUGS:
o LITHIUM
o AMIODORANE
How does myxoedema coma present?
Altered consciousness, hypoglycaemia, low GCS, hypothermia
Biochemical pictures to be aware of in thyroid gland
NB: Sick euthyroid mimics subclinical hypothyroidism, body tries to shut down the thyroid gland directly to reduce energy expenditure. Subclinical hypothyroidism detects a failing thyroid gland (due to age, wasting etc), but pituitary is active enough to secrete TSH (high) and this normalises the T3/4 levels. Doesn’t always need treatment (can use levothyroxine), but can develop hyperlipidaemia. Medication non-adherence usually occurs when a patient has not been taking medication properly, and they try and take levothyroxine just before the appointment –> normalises T3/4 but TSH remains high as still acute.
Causes of hyperthyroidism in order of prevalence
- PRIMARY (IN ORDER OF PREVALENCE)
o GRAVES (ANTI-TSH RECEPTOR ANTIBODIES) –> Type 2 hypersensitivity reactions where anti-thyroid stimulating hormone antibodies attack the TSH receptor
o TOXIC MULTINODULAR GOTIRE
o ADENOMA –> Generally not functional, can sometimes cause hyperthyroidism
Why can molar pregnancies cause hyperthyroidism?
HCG has the same subunits as TSH
What is dequervains thyroiditis?
o Acute inflammatory thyroiditis in response to a viral infection –> causes hypersecretion of thyroid hormones initially, then a hypothyroid period, then euthyroid
WHat is post partum thyroiditis?
o Secondary to gland hypertrophy during pregnancy
Image showing iodine uptake in primary hyperthyroidism
NOTE: Focal lesions are consistent with adenomas, multiple patchy lesions are consistent with toxic goitre, and a graves’ would be assoicated with a generalised increased uptake, de Quervain’s generally shows a ‘cold’ thyroid.
How does thyroid storm present? How to treat?
acute shock secondary to very high levels of thyroxine - circulatory collapse, hyper-pyrexia, reduced GCS
Treatment often involves steroids, cooling, organ support in ITU and fast administration of antithyroid medications.
Difference in blood test results between primary and secondary hyperthyroidism
Specific signs and symptoms in graves disease
Pretibial myxoedema (soft tissue growth at the shins and skin changes)
Graves’ orbitopathy is also another specific sign (caused by retrobulbar soft tissue growth)
Lid lag
Exopthalmos
Opthalmoplegia
Management of graves disease
NOTE: carbimazole and propylthiouracil work by inhibiting the action of thyroid peroxidase and also have mechanisms to prevent antibody generation in graves’. Carbimazole is teratogenic. There is a risk of agranulocytosis with both.
Beta blockers are used to treat AF or palpitations
Risks of radioiodine
risk of permanent hypothyroidism.
Causes of thyroid cancer in order of prevalence
- PAPILLARY –> PSAMMOMA BODIES AND ORPHAN EYES ON HISTOLOGY, BEST PROGNOSIS
- FOLLICULAR
- MEDULLARY –> PRODUCES CALCITONIN
- ANAPLASTIC –> WORST PROGNOSIS
- LYMPHOMA –> risk in Hashimoto’s, DLBCL (monitored using CD20)
NOTE: Thyroglobulin levels are monitored for all cancers, apart from medullary –> calcitonin
Table showing MEN syndromes
Hormones produced in anterior pituitary, how are they split?
- ACTH-> affected by CRH
- TSH-> affected by TRH
- LH > affected by LHRH
- FSH-> affected by LHRH
- GH -> affected by GHRH
- Prolactin- affected by TRH and negatively from dopamine
Trophic cells are split into two categories:
- Acidotrophs – Lacto/cortico
- Basilotrophs – thyro/gonado/somato
Types of visual defects caused by pituitary tumorus
Bitemporal hemianopia caused by compression of the optic nerve fibres at optic chiasm
Superior quadrantanopia caused by damage to the inferior optic radiation (temporal meyer loop)
Inferior quadrantanopia caused by craniopharyngioma
Types of pituitary tumours differentiated by size
Macroadenoma – non-functional adenoma >1cm –> not hormone-secreting
Sx of non-functional – bitemporal hemianopia + Headache
Microadenoma – Sx related to hormone secretion <1cm
Summary slide for prolactinoma
1st line investigation for acromegaly, gold standard diagnosis
- PLASMA IGF-1 (1ST LINE)
- DO OGTT IF RAISED, TO CONFIRM DIAGNOSIS OF ACROMEGALY (GOLD STANDARD)
Blood findings of acromegaly
- HYPERGLYCAEMIA
- PROLACTIN
Management of acromegaly
- Transsphenoidal surgery
- OCTREOTIDE –> SOMATOSTATIN ANALOGUE WHICH REDUCES GHRH RELEASED
- CABERGOLINE –> DOPAMINE AGONIST, tumour expresses a lot of D2 receptors
Causes of Cushing’s in order of prevalence
- PITUITARY TUMOURS (CUSHINGS DISEASE) –> 85%
- ADRENAL ADENOMA/HYPERPLASIA 10%
What medication causes Cushing’s?
Iatrogenic steroids
What surveillance should be done in acromegaly?
Colonoscopy surveillance done as there is an increased risk of colonic polyps (colorectal cancer)
Causes of Cushing’s in regards to ACTH
- ACTH DEPDENDENT
o PITUITARY TUMOUR
o ECTOPIC ACTH PRODUCTION
–> SMALL CELL LUNG CACNER
–> CARCINOID TUMOUR - ACTH INDEPDENDENT
o ADRENAL ADENOMA (TUMOUR OF ZONA FASCIUCULATA)
o ADRENAL NODULAR HYPERPLASIA
o IATROGENIC STEROIDS –> MOST COMMON CAUSE OF CUSHING’S SYNDROME
What can non-functioning pituitary adenomas cause?
HYPERPROLACTIN BY PRESSING ON STALK WHICH PREVENTS DOPAMINE TRAVELLING TO APH
What is the only cause of CUshing’s disease?
Pituitary tumour
Investigations of cushing’s in order
- 24 HOUR URINARY CORTISOL
- OVERNIGHT DEXAMETHASONE SUPPRESSION TEST –> LOW DOSE
o IF NOT SUPPRESSED –> CONFIRMS DIAGNOSIS OF CUSHINGS SYNDROME - INFERIOR PETROSAL SINUS SAMPLING
Management of Cushing’s
NOTE: Management of primary cushing’s is through adrenalectomy and then steroid replacement afterwards [if bilateral]. Nelson’s syndrome is a rare complication resulting from adrenalectomy, if the primary pathology is a pituitary tumour or there is a co-existant pituitary tumour, this grows uncontrollably after the removal of the adrenal glands as there is unregulated ACTH secretion. Certain medications - ketoconazole/metyrapone are CYP450 inhibitors and can slow the generation of the steroid hormones but have many side effects
What visual defect does craniopharyngioma cause?
Inferior quadrantanopia
Causes of Hypopituitarism
Sheehan syndrome occurs when the anterior pituitary gland is damaged due to significant blood loss. Classically, this happens after delivery, in which the mother loses a significant amount of blood. This blood loss results in the pituitary gland not being able to produce hormones.
Apoplexy means bleeding into an organ or loss of blood flow to an organ. Pituitary apoplexy is commonly caused by bleeding inside a noncancerous (benign) tumor of the pituitary.
The underlying cause of Kallmann syndrome or other forms of hypogonadotropic hypogonadism is a failure in the correct action of the hypothalamic hormone GnRH – less FSH/LH.
Order of loss of pituitary hormones in hypopituirarism
GH first lost, then sex hormones, then ACTh, then TSH, then prolactin because when TSH is lost, TRH increases which stimulates prolactin, before stores are depleted and then it drops
How to perform a combined pituitary function test
Management of hypopituitarism
NOTE: MOST URGENT HORMONE REPLACEMENT IS HYDROCORTISONE. Then treat underlying cause
Regions of adrenal gland and what they produce
Glomerulosa - Mineralocorticoids (aldosterone)
Fasciculata - Glucocorticoids (Cortisol)
Reticularis - Sex hormones
Medulla - Catecholamines
Steroid synthesis pathway
NOTE: 21 hydroxylase – hypoaldosteronism picture. 11B hydroxylase – hyperaldosteronism picture, as no cortisol formed. 17a hydroxylase – congenital adrenal hyperplasia, disrupted sexual development and maturation.
Causes of addison’s disease (adrenal insufficiency)
- TB (MOST COMMON WORLDWIDE)
- AI (MOST COMMON IN UK)
- ADRENAL HAEMORRHAGE CAUSED BY MENINGOCOCCAL INFECTIONS WATERHOUSE FRIEDRICHSON SYNDROME