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Published on 07/06/2015 by admin

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Macrocytosis

• Alcohol abuse

• Reticulocytosis

• Vitamin B₁₂ deficiency

• Folic acid deficiency

• Liver disease

• Hypothyroidism

• Marrow aplasia

• Myelofibrosis

Macular Degeneration

• Diabetic retinopathy

• Hypertension

• Histoplasmosis

Mallory-Weiss Tear

• Esophageal or gastric varices

• Esophagitis/esophageal ulcers (peptic or pill induced)

• Gastric erosions

• Gastric or duodenal ulcer

• Arteriovenous malformations

• Neoplasms (usually gastric)

Mastocytosis (Urticaria Pigmentosa)

• Insect bites

• Nevi and congenital pigment abnormalities

• Café au lait spots

• Granuloma annulare

• Drug eruption

• Sarcoidosis

Mastitis

• Plugged lactiferous ducts

• Breast abscess

• Inflammatory breast cancer

• Mastitis as a symptom of hyperprolactinemia or galactorrhea

• Other cancers; 3% of women diagnosed with breast cancer are lactating

• Granulomatous mastitis can be a manifestation of systemic disease, including sarcoidosis, Wegener’s granulomatosis, giant cell arteritis, polyarteritis nodosa, tuberculosis, and syphilis

Mastoiditis

CHILDREN

• Rhabdomyosarcoma

• Histiocytosis X

• Kawasaki’s disease

ADULTS

• Fulminant otitis externa

• Histiocytosis X

• Metastatic disease

Measles (Rubeola)

• Other viral infections by enteroviruses, adenoviruses, human parvovirus B19, rubella

• Scarlet fever

• Allergic reaction

• Kawasaki’s disease

Meckel’s Diverticulum

• Appendicitis

• Crohn’s disease

• All causes of lower GI bleeding (polyp, colon cancer, arteriovenous [AV] malformation, diverticulosis, hemorrhoids)

• Mesenteric adenitis

Melanocytic Nevi (Moles)

• Actinic keratosis

• Seborrheic keratosis

• Basal cell carcinoma

Melasma (Chloasma)

• Postinflammatory hyperpigmentation

• Photolichenoid drug reaction

• Poikiloderma of Civatte

Meniere’s Disease

• Acoustic neuroma

• Migrainous vertigo

• Multiple sclerosis (MS)

• Autoimmune inner ear syndrome

• Otitis media

• Vertebrobasilar disease

• Viral labyrinthitis

Meningioma

OTHER WELL-CIRCUMSCRIBED INTRACRANIAL TUMORS

• Acoustic schwannoma (typically at the pontocerebellar junction)

• Ependymoma, lipoma, and metastases within the spinal cord

BRAIN OR SPINAL CORD ABSCESS

• Metastatic disease from lymphoma or adenocarcinoma, inflammatory disease, or infections such as tuberculosis

Mesenteric Adenitis

• Acute appendicitis (5% to 10% of patients admitted to hospitals with a diagnosis of appendicitis are discharged with a diagnosis of mesenteric adenitis)

• Viral syndrome

• Irritable bowel syndrome (IBS)

• Crohn’s disease

Mesenteric Ischemia, Nonocclusive ²⁷

• Cardiovascular disease resulting in low-flow states (congestive heart failure [CHF], cardiogenic shock, post cardiopulmonary bypass, dysrhythmias)

• Septic shock

• Drug induced (cocaine, vasopressors, ergot alkaloid poisoning)

Mesenteric Venous Thrombosis ²⁷

• Hypercoagulable states (protein C or S deficiency, antithrombin III deficiency, factor V Leyden, malignant neoplasm, polycythemia vera, sickle cell disease, homocystinemia, lupus anticoagulant, cardiolipin antibody)

• Trauma (operative venous injury, abdominal trauma, post splenectomy)

• Inflammatory conditions (pancreatitis, diverticulitis, appendicitis, cholangitis)

• Other: CHF, renal failure, portal hypertension, decompression sickness

Metabolic Syndrome

• Other causes of weight gain or obesity (Cushing’s syndrome, hypothyroidism)

• Other causes of hyperlipidemia (familial hyperlipidemia, hypothyroidism)

• Other causes of hypertension (Cushing’s syndrome, hyperaldosteronism)

• Other forms of diabetes (type 1)

Metastatic Neoplasms

TO BONE

• Endometrium

TO BRAIN

TO LIVER

• Choriocarcinoma

TO LUNG

Microcytosis

• Iron deficiency

• Anemia of chronic disease

• Thalassemia trait or syndrome, other hemoglobinopathies

• Sideroblastic anemia

• Chronic renal failure

• Lead poisoning

Miliaria

• Viral exanthem

• Drug eruption

• Candidiasis

• Insect bites

• Folliculitis

Mitral Regurgitation

• Hypertrophic cardiomyopathy

• Pulmonary regurgitation

• Tricuspid regurgitation

• Ventricular septal defect (VSD)

Mitral Stenosis

• Left atrial myxoma

• Other valvular abnormalities (e.g., tricuspid stenosis, mitral regurgitation)

• Atrial septal defect

Mitral Valve Prolapse

• Other valvular abnormalities

• Constrictive pericarditis

• Ventricular aneurysm

Molluscum Contagiosum

• Verruca plana (flat warts): no central umbilication, not dome shaped, irregular surface, can involve palms and soles

• Herpes simplex: lesions become rapidly umbilicated

• Varicella: blisters and vesicles are present

• Folliculitis: no central umbilication, presence of hair piercing the pustule or papule

• Cutaneous cryptococcosis in AIDS patients: budding yeasts will be present on cytologic examination of the lesions

• Basal cell carcinoma: multiple lesions are absent

Mongolian Spot

• Nevus of Ito

• Dermal melanocytic hamartoma (macular blue nevus)

• Late-onset dermal melanosis

• Acquired bilateral nevus of Ota-like macules

Monocytosis

• Viral diseases

• Inflammatory bowel disease (IBD)

• Monocytic leukemia

• Sarcoidosis

Mononeuropathy

• Herpes zoster

• Herpes simplex

• Trauma, compression

• Postinfectious or postinflammatory

Mononucleosis

• Heterophil-negative infectious mononucleosis caused by cytomegalovirus (CMV); although clinical presentation may be similar, CMV more frequently follows transfusion.

• Bacterial and viral causes of pharyngitis

• Toxoplasmosis

• Acute retroviral syndrome of HIV, lymphoma

Motion Sickness

• Acute labyrinthitis

• Gastroenteritis

• Metabolic disorders

• Viral syndrome

Mucormycosis

• Infection of the site by other organisms (bacterial [including TB and leprosy], viral, fungal, or protozoan)

• Noninfectious tissue necrosis (e.g., neoplasia, vasculitis, degenerative) of the site

Multifocal Atrial Tachycardia

• Atrial fibrillation

• Atrial flutter

• Sinus tachycardia

• Paroxysmal atrial tachycardia

• Extrasystoles

Multiple Myeloma

• Metastatic carcinoma

• Bone neoplasms (e.g., sarcoma)

• Monoclonal gammopathy of undetermined significance (MGUS)

Multiple Sclerosis (MS)

• Autoimmune: acute disseminated encephalomyelitis (ADEM), postvaccination encephalomyelitis

• Degenerative: subacute combined degeneration (vitamin B₁₂ deficiency), inherited spastic paraparesis

• Infections: progressive multifocal leukoencephalopathy, Lyme disease, syphilis, HIV infection, human T-cell lymphotropic virus type 1 (HTLV-1), Whipple’s syndrome, expanded differential in immunocompromised patients

• Inflammatory: systemic lupus erythematosus (SLE), Sjögren’s syndrome, Behçet’s syndrome, vasculitis, sarcoidosis, celiac disease

• Inherited metabolic disorders: leukodystrophies

• Mitochondrial: Leber’s hereditary optic neuropathy; mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS)

• MS variants: recurrent optic neuropathy, neuromyelitis optica (Devic’s), acute tumor-like lesion (Marburg’s variant), Baló’s concentric sclerosis, myelinoclastic diffuse sclerosis (Schilder’s disease)

• Neoplasms: metastases, CNS lymphoma

• Vascular: subcortical infarcts, Binswanger’s disease

Mumps

• Other viruses that may cause acute parotitis: parainfluenza types 1 and 3, coxsackieviruses, influenza A, cytomegalovirus (CMV)

• Suppurative parotitis

• Other conditions that may occur with parotid enlargement or swelling: Sjögren’s syndrome, leukemia, diabetes mellitus (DM), uremia, malnutrition, cirrhosis

• Drugs that cause parotid swelling: phenothiazines, phenylbutazone, thiouracil, iodides

• Conditions that cause unilateral swelling: tumors, cysts, stones causing obstruction, strictures causing obstruction

Munchausen’s Syndrome

• Malingering: a clear secondary gain (e.g., financial gain or avoidance of unwanted duties) is present.

• Somatoform disorders or hypochondriasis: similar presentations, but the disorder is not under the patient’s control.

• Self-injurious behavior is common in many other psychiatric conditions (e.g., borderline personality disorder, psychoses, or nonfatal suicide attempt as may occur in depression); in those conditions, the patients confess the intentional self-harm and describe motivating factors.

• Munchausen’s by proxy: a mother (86% of the time) or other caregiver induces illness in a child (52% between the ages of 3 and 13 years) for the purpose of obtaining medical attention without other secondary gain.

Muscle Weakness

• Physical deconditioning

• Impaired cardiac output (e.g., mitral stenosis, mitral regurgitation)

• Uremia, liver failure

• Electrolyte abnormalities (hypokalemia, hyperkalemia, hypophosphatemia, hypercalcemia, hypoglycemia)

• Drug induced (e.g., statin myopathy)

• Muscular dystrophies

• Steroid myopathy

• Alcoholic myopathy

• Myasthenia gravis, Lambert-Eaton syndrome

• Infections (polio, botulism, HIV, hepatitis, diphtheria, tick paralysis, neurosyphilis, brucellosis, TB, trichinosis)

• Pernicious anemia, other anemias, beriberi

• Psychiatric illness (depression, somatization syndrome)

• Organophosphate or arsenic poisoning

• Inflammatory myopathies (e.g., collagen-vascular disease, rheumatoid arthritis [RA], sarcoidosis)

• Endocrinopathies (e.g., adrenal insufficiency, hypothyroidism), diabetic neuropathy

• Other: motor neuron disease, mitochondrial myopathy, L-tryptophan (eosinophilia-myalgia), rhabdomyolysis, glycogen storage disease, lipid storage disease

Muscle Weakness, Lower Motor Neuron Versus Upper Motor Neuron ⁴⁰

Muscular Dystrophy

• Myasthenia gravis

• Inflammatory myopathy

• Metabolic myopathy

• Endocrine myopathy

• Toxic myopathy

• Mitochondrial myopathy

Mushroom Poisoning

• Food poisoning

• Overdose of prescription or illegal drug

• Other intoxications (e.g., alcohol)

• Viral infection

Myocardial Ischemia ³⁷

• Atherosclerotic obstructive coronary artery disease

• Nonatherosclerotic coronary artery disease

• Coronary artery spasm

• Congenital coronary artery anomalies

• Anomalous origin of coronary artery from pulmonary artery

• Aberrant origin of coronary artery from aorta or another coronary artery

• Coronary arteriovenous fistula

• Coronary artery aneurysm

• Acquired disorders of coronary arteries

• Coronary artery embolism

• Dissection: surgical, during percutaneous coronary angioplasty, aortic dissection, spontaneous (e.g., during pregnancy)

• Extrinsic compression: tumors, granulomas, amyloidosis

• Collagen-vascular disease: polyarteritis nodosa, temporal arteritis, rheumatoid arthritis, systemic lupus erythematosus, scleroderma

• Miscellaneous disorders: irradiation, trauma, Kawasaki’s disease

• Hereditary disorders: pseudoxanthoma elasticum, gargoylism, progeria, homocystinuria, primary oxaluria

• “Functional” causes of myocardial ischemia in absence of anatomic coronary artery disease: syndrome X, hypertrophic cardiomyopathy, dilated cardiomyopathy, muscle bridge, hypertensive heart disease, pulmonary hypertension, valvular heart disease; aortic stenosis, aortic regurgitation

Myocarditis

• Cardiomyopathy

• Acute myocardial infarction

• Valvulopathy

• Viral syndrome

• Anxiety disorder

Myoglobinuria

• Severe trauma

• Hyperthermia

• Polymyositis or dermatomyositis

• Carbon monoxide poisoning

• Drugs (narcotic and amphetamine toxicity)

• Hypothyroidism

• Muscle ischemia

Myopathies, Infectious

• HIV infection

• Viral myositis

• Trichinosis

• Toxoplasmosis

• Cysticercosis

Myopathies, Toxic ¹

• Inflammatory: cimetidine, D-penicillamine

• Noninflammatory necrotizing or vacuolar: statins, chloroquine, colchicine

• Acute muscle necrosis and myoglobinuria: statins, alcohol, cocaine

• Malignant hyperthermia: halothane, ethylene, others; succinylcholine

• Mitochondrial: zidovudine

• Myosin loss: nondepolarizing neuromuscular blocking agents; glucocorticoids

Myositis, Inflammatory ¹

INFECTIOUS

• Viral myositis: retroviruses (HIV, HTLV-1), enteroviruses (echovirus, coxsackievirus), other viruses (influenza, hepatitis A and B, Epstein-Barr)

• Bacterial: pyomyositis

• Parasites: trichinosis, cysticercosis

• Fungi: candidiasis

IDIOPATHIC

• Granulomatous myositis (sarcoid, giant cell)

• Eosinophilic myositis

• Eosinophilia-myalgia syndrome

ENDOCRINE/METABOLIC DISORDERS

• Hypothyroidism

• Hyperthyroidism

• Hypercortisolism

• Hyperparathyroidism

• Hypoparathyroidism

• Hypocalcemia

• Hypokalemia

METABOLIC MYOPATHIES

• Myophosphorylase deficiency (McArdle’s disease)

• Phosphofructokinase deficiency

• Myoadenylate deaminase deficiency

• Acid maltase deficiency

• Lipid storage diseases

• Acute rhabdomyolysis

NEUROLOGIC DISORDERS

• Muscular dystrophies

• Congenital myopathies

• Motor neuron disease

• Guillain-Barré syndrome

• Myasthenia gravis

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