aspergillus fumigatus

My UWorld notes- 5

To those who were waiting yesterday for this post, I’m extremely sorry. For some reason I Thought yesterday was sunday -____- but here it is. 

  • reflex tachycardia caused by nitrate can be prevented by administering beta adrenergic blockers w

  • prazosin- selective alpha 1 adrenergic blocking medication used for HTN and BPH

  • hydrochlorothiazide is a weak diuretic

  • phenylephirine is an alpha agonist which is classified as a vasopressor agent. Its used in cases of shock and severe hypotension

  • hydralazine is a direct acting arteriolar dilator . It causes a reflex tachycardia which can also be prevented with administering beta blocker

  • ataxia telangiectasia an autosomal recessive d/o characterized by DNA hypersensitivity to ionizing radiation. Cerebellar atrophy leads to ataxia that occurs in first years of life. . Patients with ataxia telangiectasia also have sever immunodeficiency with repeated sinopulmonary infections. This risk of cancer in these patients in increased significantly b/c of inefficient DNA repair

  • XP is characterized by DNA hypersensitivity to UV radiation causing premature skin agin and increased risk of skin cancer (malignant melanoma and squamous cell carcinoma)

  • Fanconi anemia is caused by hypersensitivity of DN TO CROSS LINKING AGENTS

  • Bloom syndrome is characterized by generalized chromosome instability. Increased susceptibility to neoplasms is present

  • HNPCC d/t to defect in DNA mismatch repair enzymes leading to increased susceptibility to colon cancer

  • caudate nucleus atrophy- huntington dz

  • Lewy bodies- Parkinsonism

  • loss of neurons in substantia nigra- Parkinson’s dz

  • neurofibrillary tangles in neocortex – Alzheimer’s dz

  • double vision while walking down the stairs or while reading the newspaper- palsy of cranial nerve 4 (trochlear nerve)

  • optic nerve (CN2) transmits visual info to brain damage causes loss of vision

  • CN3 occulomotor nerve innervates superior rectus medial rectus inferior rectus and inferior oblique. Which all collectively perform most ye movement. Palsies of this nerve can cause vertical and horizontal diplopia and an enlarged nonreactive pupil

  • abducens nerve CN6 innervates lateral rectus which is responsible for abdcution of eye. Palsy of this nerve can cause horizontal diplopia and inward deviation ( inward deviation)

  • MLF lesion a/w internuclear ophthalmoplegia, which presents with impaired horizontal eye movement and weak adduction of affected eye with simultaneous abduction nystagmus of contralateral eye

  • at low doses atenolol is a selective beta 1 adrenergic antagonist . Beta 1 receptors are found in cardiac tissue and on renal juxtaglomerular cells but not on vascular smooth muscle. The beta 1 receptor is G protein coupled receptor a/w Gs G protein which increases cAMP levels. Blockage of beta receptor therefore means decreased cAMP levels in cardia and renal tissue without affecting cAMP levels in vascular smooth muscle

  • pure red cell aplasia is a rare form of marrow failure characterized by sever hypoplasia of marrow erythroid elements in setting of normal granulopoiesis and thrombopoiesis. Pure red cell aplasia is a/w thymoma lymphocytic leukemias and parvovirus B19 infections

  • deficiency of 21 hydroxylase is MC type of CAH. . These patients present with cortisol and aldosterone deficiency combined with androgen excess.. genitalia of females infants may be masculinized to some degree; male infants however are normal in appx

  • When asked a question regarding DKA know that ph is decreased H2PO4 is increased (it is titratable acid) and also bicarbonate excretion is decreased. This response is overtime meaning these changes are made because of the acidosis that the patient has . Therefore in order to fix metabolic acidosis d/t DKA bicarbonate excretion is decreased and urinary ph is decreased and titratable acid excretion is increased.

  • Musculocutaneous nerve innervates flexor muscles of upper arm and provides sensory innervation to lateral forearm. Musculocutaneous nerve is derived from upper trunk of brachial plexus and can be injured by forceful injuries that cause separation of neck and shoulder. It is derived from C5-C7 ventral rami

  • posterior arm and forearm are both innervated by the branch of the radial nerve which is posterior cutaneous nerve of the arm and posterior cutaneous nevre of the forearm

  • thenar eminence is innervated by recurrent branch of median nerve

  • g6pd deficiency – cant convert glucose 6 phosphate to 6 phosphogluconate . G6Pd requires NadPH as a cofactor to work

  • urine sample turned black= alkaptonuria which is an autosomal recessive d/o in which lack of homogentisic oxidase blocks the metabolism of phenylalanine and tyrosine at the level of homogentisic acid leading to accumulation of homogentisic acid. Turns black because homogentisic acid excreted in urine undergoes oxidation when exposed to oxygen in air

  • alkaptonuria cause ochronosis a blue black pigment evident in ears nose and cheeks

  • conversion of phenylalanine to tyrosine is defective in PKU and usually occurs d/t defect in phenylalanine hydroxylase

  • small percentage of PKU cases are also d/t dihydrobiopterin reductase deficiency

  • branched chain a.a. Are valine isoleucine and leucine

  • blastomyces dermatidis is a dimorphic fungus that is seen in tissue as round yeasts with doubly refractive walls and broad based budding. Endemic to great lakes and ohio and Mississippi river regions, present in soil and rotten organic matter

  • blastomyces mold form (branching hyphae) predominates in environment with average temperature 25-30 degrees Celsius. In the human body it assumes yeast form (single cells)

    • blastomyces in lungs assumes yeast form and induces granulomatous response

    • aspergillus fumigatus causes lung dz in immunocompromised and only has a mold form . It is seen as septate hyphae that branch at 45 degrees (angle)

    • oppotunistic mold with irregular non septate hyphae that branch at wide angles (>90)= mucor and rhizopus

    • starts with just a sinus infection and then you end up getting a rapid infection to the brain because this organism can penetrate the cribriform plate causing frontal lobe abscess – Mucor and rhizopus

    • cryptococcus neoformans can also cause lung dz but in addition causes meningitis in immunocompromised and in contrast to blastomycosis it forms narrow based buds and has thick polysaccharide capsule which stains with india ink

    • histoplasma capsulatum causes lung dz and is also a dimorphic fungus like blastomyces but the yeast form of histoplasma is found intracellularly within macrophages

    • coccidioides immitis is also a dimorphic fungus but is seen as spherules (round encapsulated structures containing many endospores) in tissue sample, barrel shaped arthroconidia a/w dust storms which causes San Joaquin Valley fever (inhalation of dust particles) 

from the archives: aspergillus fumigatus

When I was studying microbiology in med school, I was struck by the beauty of many of the pathogens responsible for some of the most devastating illnesses. This is a microscopic image of the fungal species Aspergillus fumigatus, which can cause aspergillosis–an overwhelming, invasive infection–in people whose immune systems are suppressed (ie. people living with HIV, organ donor recipients or cancer patients receiving immunotherapy).  

Aspergillus fumigatus 
Watercolor on paper
3.5" x 5"